Patent Application
20230041057
Checkpoint inhibitor and adoptive tumor infiltrating lymphocytes (TIL) transfer therapies have achieved responses in cancer patients demonstrating the importance of neoantigen T cell targeting to destroy tumors. Yet, only a fraction of patients benefit from treatment. Checkpoint inhibitors are prone to off-target toxicity and are most successful against tumors with high mutational burden. TIL therapies are limited to indications where bulk tumors are accessible and have high TIL content. They are also derived from non-specific expansion of T cells from a single tumor which limits neoantigen targeting and makes treatment more prone to metastatic tumor escape. Other cell therapy approaches, in which T cells are engineered to express a chimeric antigen receptor (CAR-T) or antigen-specific T cell receptors (TCR) have also shown limited success but are generally restricted to a single antigen specificity and therefore also prone to tumor escape. There remains a need for additional therapeutic approaches to treat tumors.
One aspect of the disclosure includes a method of treating a subject, comprising obtaining a sample of PBMCs from a subject having a tumor or a cancer, identifying, in the sample of PBMCs, a plurality of T cells responsive to at least one inhibitory antigen, re-educating the plurality of (or at least a portion of the plurality of) T cells by contacting the T cells with an agent or a combination of agents, and administering a cellular therapeutic comprising the re-educated T cells to the subject. Upon administration, the re-educated T cells mediate an immune response that enhances immune control of the tumor or cancer cell.
In some embodiments, the method further comprises isolating the plurality of T cells from the sample of PBMCs prior to the re-educating step. In some embodiments, the method further comprises combining the re-educated T cells with the remaining sample of PBMCs, or a subset of the remaining sample of PBMCs, prior to administration to the subject.
In some embodiments, re-education drives a T cell towards a Th1 phenotype (e.g., increases the number and/or proportion of Th1 cells, e.g., cells expressing one or more Th1-associated cytokines, relative to a control). In some embodiments, re-education drives a T cell towards a Th2 phenotype (e.g., increases the number and/or proportion of Th2 cells, e.g., cells expressing one or more Th2-associated cytokines, relative to a control).
In some embodiments, the method further comprises expanding (e.g., specifically or non-specifically expanding) the recombined cells prior to administration to the subject. In some embodiments, the method further comprises expanding (e.g., specifically or non-specifically expanding) the re-educated T cells prior to administration to the subject. In some embodiments, the re-educating step is concurrent with expansion. In some embodiments, the re-educating step precedes expansion. In some embodiments, the re-educating step follows expansion. In some embodiments, re-education and expansion drive a T cell towards a Th1 phenotype (e.g., increases the number and/or proportion of Th1 cells, e.g., cells expressing one or more Th1-associated cytokine, relative to a control). In some embodiments, re-education and expansion drive a T cell towards a Th2 phenotype (e.g., increases the number and/or proportion of Th2 cells, e.g., cells expressing one or more Th2-associated cytokine, relative to a control).
In some embodiments, the cells are expanded by culturing the cells in culture medium comprising one or more stimulatory cytokines (e.g., IL-2, IL-7, IL-15, IL-21, IL-12p40, IFN-gamma). In some embodiments, the culture medium further comprises blocking antibodies to TGF-beta and/or IL-10. In some embodiments, the culture medium further comprises at least one inhibitory antigen.
In some embodiments, the method further comprises combining the re-educated T cells with unexpanded or expanded (e.g., specifically or non-specifically expanded) T cells responsive to at least one stimulatory antigen prior to administration to the subject. In some embodiments, the plurality of T cells is isolated by contacting the sample of PBMCs with a separation bead (e.g., a magnetic bead). In some embodiments, the bead may be coupled to a tetramer comprising one or more T cell receptors (TCR) that specifically bind the inhibitory antigen.
In some embodiments, the plurality of T cells is isolated by contacting the sample of PBMCs with an antibody directed to a marker of T cell activation, e.g., an anti-4-1BB antibody, anti-CD40L antibody, or IL-2R antibody. In some embodiments, the antibody is conjugated to a fluorophore or a magnetic bead.
In some embodiments, the agent or combination of agents comprises an adjuvant. In some embodiments, the adjuvant is a TLR agonist, an inflammasome activator, a NOD2 agonist, a RIG1 helicase inhibitor, and/or a STING agonist. In some embodiments, the agent or combination of agents comprises a checkpoint inhibitor (e.g., a PD-1 inhibitor, a PD-L1 inhibitor, or a CTLA-4 inhibitor). In some embodiments, the combination of agents comprises a checkpoint inhibitor and an adjuvant. In some embodiments, the agent or combination of agents comprises a viral vector, a bacterial vector, an exosome, a liposome, DNA, mRNA, or saRNA, a chemotherapeutic agent or an IDO inhibitor.
In some embodiments, the agent or combination of agents comprises a cytokine, or a cocktail comprising two or more cytokines. In some embodiments, the agent or combination of agents comprises a Th1-associated cytokine, or a cocktail comprising two or more Th1-associated cytokines (e.g., IL-2, IL-7, IL-15, IL-21, IL-12p40, IFN-gamma). In some embodiments, the agent or combination of agents comprises a Th2-associated cytokine, or a cocktail comprising two or more Th2-associated cytokines (e.g., IL-4, IL-5, IL-13).
In some embodiments, the inhibitory antigen is a tumor antigen (e.g., tumor specific antigen [TSA or neoantigen], tumor associated antigen [TAA], or cancer/testis antigen [CTA]). In some embodiments, the immune response comprises a T cell-mediated immune response. In some embodiments, the immune response comprises an antigen presenting cell (APC)-mediated immune response. In some embodiments, the immune response comprises a B cell-mediated immune response. In some embodiments, the immune response comprises a response mediated by one or more cells of the innate immune system (e.g., an NK cell, an NKT cell, or a monocyte).
In some embodiments, an immune response that enhances immune control of the tumor or cancer comprises one or more beneficial clinical responses. In some embodiments, an immune response that enhances immune control of the tumor or cancer comprises clearance, regression, or stabilization of the tumor or cancer, e.g., a level of one or more clinical measures associated with clearance, regression, or stabilization of a cancer. In some embodiments, an immune response that enhances immune control of the tumor or cancer comprises an absence of relapse, recurrence, and/or metastasis of a cancer, e.g., over a defined period of time (e.g., at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 weeks, or at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 months, or at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 years). In some embodiments, an immune response that enhances immune control of the tumor or cancer comprises a positive cancer prognosis. In some embodiments, an immune response that enhances immune control of the tumor or cancer comprises an absence or reduction of one or more toxic responses and/or side effects (e.g., one or more measurable toxic responses and/or side effects) to a cancer therapy or combination of therapies.
In some embodiments, the method further comprises administering to the subject a cancer therapy or combination of therapies.
Another aspect of the disclosure includes a method of treating a subject, comprising obtaining a sample of PBMCs from a subject having a tumor or a cancer, removing, from the sample of PBMCs, a plurality of T cells responsive to an inhibitory antigen, to produce a depleted cell population comprising remaining PBMCs, and administering a cellular therapeutic comprising the depleted cell population to the subject. Upon administration, the depleted cell population mediates an immune response that enhances immune control of the tumor or cancer cell.
In some embodiments, the method further comprises contacting the depleted cell population with at least one stimulatory antigen prior to administration to the subject. In some embodiments, the method further comprises expanding (e.g., specifically or non-specifically expanding) T cells in the depleted cell population prior to administration to the subject.
In some embodiments, the depleted cell population is expanded by culturing the cells in culture medium comprising one or more stimulatory cytokines (e.g., IL-2, IL-7, IL-15, IL-21, IL-12p40, IFN-gamma). In some embodiments, the culture medium further comprises blocking antibodies to TGF-beta and/or IL-10. In some embodiments, the culture medium further comprises at least one stimulatory antigen.
In some embodiments, the plurality of T cells is isolated by contacting the sample of PBMCs with a separation bead (e.g., a magnetic bead) or a fluorophore. In some embodiments, the bead or fluorophore is coupled to a tetramer comprising one or more T cell receptors (TCR) that specifically bind the inhibitory antigen or a stimulatory antigen. In some embodiments, the plurality of T cells is isolated by contacting the sample of PBMCs with an antibody directed to a marker of T cell activation, e.g., an anti-4-1BB antibody, anti-IL-2R antibody, or anti-CD40L antibody. In some embodiments, the antibody is conjugated to a fluorophore or a magnetic bead.
In some embodiments, the inhibitory antigen is a tumor antigen (e.g., tumor specific antigen [TSA or neoantigen], tumor associated antigen [TAA], or cancer/testis antigen [CTA]).
In some embodiments, the cellular therapeutic induces a T cell-mediated immune response. In some embodiments, the cellular therapeutic induces an antigen presenting cell (APC)-mediated immune response. In some embodiments, the cellular therapeutic induces a B cell-mediated immune response. In some embodiments, the cellular therapeutic induces a response mediated by one or more cells of the innate immune system (e.g., an NK cell, an NKT cell, or a monocyte).
In some embodiments, an immune response that enhances immune control of the tumor or cancer comprises one or more beneficial clinical responses. In some embodiments, an immune response that enhances immune control of the tumor or cancer comprises clearance, regression, or stabilization of the tumor or cancer, e.g., a level of one or more clinical measures associated with clearance, regression, or stabilization of a cancer. In some embodiments, an immune response that enhances immune control of the tumor or cancer comprises an absence of relapse, recurrence, and/or metastasis of a cancer, e.g., over a defined period of time (e.g., at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 weeks, or at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 months, or at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12 years). In some embodiments, an immune response that enhances immune control of the tumor or cancer comprises a positive cancer prognosis. In some embodiments, an immune response that enhances immune control of the tumor or cancer comprises an absence or reduction of one or more toxic responses and/or side effects (e.g., one or more measurable toxic responses and/or side effects) to a cancer therapy or combination of therapies.
In some embodiments, the method further comprises administering to the subject a cancer therapy or combination of therapies.
Another aspect of the disclosure includes a method of re-educating a population of T cells, comprising obtaining a sample of PBMCs from a subject having a tumor or a cancer, identifying, in the sample of PBMCs, a plurality of T cells responsive to an inhibitory antigen, and re-educating the plurality of (or at least a portion of the plurality of) T cells by contacting the T cells with an agent or a combination of agents. Upon administration to the subject, the re-educated T cells mediate an immune response that enhances immune control of the tumor or cancer cell. In some embodiments, the method produces a plurality of re-educated T cells.
In some embodiments, the method for inducing an immune response in a subject further comprises a module for identifying an inhibitory antigen and/or stimulatory antigen. The module may identify an inhibitory and/or stimulatory antigen through measuring secretion of one or more immune mediators associated with one or more deleterious or non-beneficial responses to cancer.
In some embodiments, the method further comprises: identifying one or more inhibitory antigens and/or one or more stimulatory antigens. In some embodiments, the method further comprises a) obtaining, providing, or generating a library comprising bacterial cells or beads comprising a plurality of tumor antigens, wherein each bacterial cell or bead of the library comprises a different tumor antigen; b) contacting the bacterial cells or beads with antigen presenting cells (APCs) from a subject, wherein the APCs internalize the bacterial cells or beads; c) contacting the APCs with lymphocytes from the subject, under conditions suitable for activation of lymphocytes by a tumor antigen presented by one or more APCs; d) determining whether one or more lymphocytes are activated by, or not responsive to, one or more tumor antigens presented by one or more APCs, e.g., by assessing (e.g., detecting or measuring) a level (e.g., an increased or decreased level, relative to a control) of expression and/or secretion of one or more immune mediators; e) identifying one or more tumor antigens that stimulate, inhibit and/or suppress, and/or have a minimal effect on a level of expression and/or secretion of one or more immune mediators; and (f) identifying as one or more inhibitory antigens one or more tumor antigens that increase expression or secretion of immune mediators associated with deleterious or non-beneficial responses to cancer, and/or one or more tumor antigens that inhibit and/or suppress expression or secretion of immune mediators associated with beneficial responses to cancer; and/or (g) identifying as one or more stimulatory antigens (i) one or more tumor antigens that increase level of expression and/or secretion of one or more immune mediators associated with one or more beneficial responses to cancer, and/or (ii) one or more tumor antigens that inhibit and/or suppress level of expression and/or secretion of one or more immune mediators associated with one or more deleterious or non-beneficial responses to cancer.
In some embodiments, the APCs are human APCs isolated from the subject; and/or the bacterial cells further comprise a cytolysin polypeptide; and/or the cytolysin polypeptide is listeriolysin O (LLO); and/or the APCs are provided in an array, and/or the APCs in each location of the array are contacted with a set of bacterial cells, each set comprising a different tumor antigen; and/or the APCs and lymphocytes are isolated from peripheral blood; and/or the APCs comprise immortalized cells; and/or the lymphocytes are derived from a cancer or tumor.
In some embodiments, the tumor antigens comprise full length polypeptides encoding mutations, splice variants, or translocations present in a cancer or tumor; and/or the tumor antigens comprise polypeptides that are fragments of full length polypeptides encoding mutations, splice variants, or translocations present in a cancer or tumor; and/or the tumor antigens comprise full length polypeptides encoded by a virus or other infectious agent present in a cancer or tumor; and/or the tumor antigens comprise polypeptides that are fragments of full length polypeptides encoded by a virus or other infectious agent present in a cancer or tumor; and/or the tumor antigens comprise full length polypeptides encoding autoantigens associated with a cancer or tumor; and/or the tumor antigens comprise polypeptides that are fragments of full length polypeptides encoding autoantigens associated with a cancer or tumor.
The present teachings described herein will be more fully understood from the following description of various illustrative embodiments, when read together with the accompanying drawings. It should be understood that the drawings described below are for illustration purposes only and are not intended to limit the scope of the present teachings in any way.
Activate: As used herein, a peptide presented by an antigen presenting cell (APC) “activates” a lymphocyte if lymphocyte activity is detectably modulated after exposure to the peptide presented by the APC under conditions that permit antigen-specific recognition to occur. Any indicator of lymphocyte activity can be evaluated to determine whether a lymphocyte is activated, e.g., T cell proliferation, phosphorylation or dephosphorylation of a receptor, calcium flux, cytoskeletal rearrangement, increased or decreased expression and/or secretion of immune mediators such as cytokines or soluble mediators, increased or decreased expression of one or more cell surface markers.
Administration: As used herein, the term “administration” typically refers to the administration of a composition to a subject or system. Those of ordinary skill in the art will be aware of a variety of routes that may, in appropriate circumstances, be utilized for administration to a subject, for example a human. For example, in some embodiments, administration may be systemic or local. In some embodiments, administration may be enteral or parenteral. In some embodiments, administration may be by injection (e.g., intramuscular, intravenous, or subcutaneous injection). In some embodiments, injection may involve bolus injection, drip, perfusion, or infusion. In some embodiments administration may be topical. Those skilled in the art will be aware of appropriate administration routes for use with particular therapies described herein, for example from among those listed on www.fda.gov, which include auricular (otic), buccal, conjunctival, cutaneous, dental, endocervical, endosinusial, endotracheal, enteral, epidural, extra-amniotic, extracorporeal, interstitial, intra-abdominal, intra-amniotic, intraarterial, intra-articular, intrabiliary, intrabronchial, intrabursal, intracardiac, intracartilaginous, intracaudal, intracavernous, intracavitary, intracerebral, intracisternal, intracorneal, intracoronal, intracorporus cavernosum, intradermal, intranodal, intradiscal, intraductal, intraduodenal, intradural, intraepidermal, intraesophageal, intragastic, intragingival, intralesional, intraluminal, intralymphatic, intramedullary, intrameningeal, intramuscular, intraocular, intraovarian, intrapericardial, intraperitoneal, intrapleural, intraprostatic, intrapulmonary, intrasinal, intraspinal, intrasynovial, intratendinous, intratesticular, intrathecal, intrathoracic, intratubular, intratumor, intratympanic, intrauterine, intravascular, intravenous, intravenous bolus, intravenous drip, intraventricular, intravitreal, laryngeal, nasal, nasogastric, ophthalmic, oral, oropharyngeal, parenteral, percutaneous, periarticular, peridural, perineural, periodontal, rectal, respiratory (e.g., inhalation), retrobulbar, soft tissue, subarachnoid, subconjunctival, subcutaneous, sublingual, submucosal, topical, transdermal, transmucosal, transplacental, transtracheal, ureteral, urethral, or vaginal. In some embodiments, administration may involve electro-osmosis, hemodialysis, infiltration, iontophoresis, irrigation, and/or occlusive dressing. In some embodiments, administration may involve dosing that is intermittent (e.g., a plurality of doses separated in time) and/or periodic (e.g., individual doses separated by a common period of time) dosing. In some embodiments, administration may involve continuous dosing.
Adoptive cell therapy: As used herein, “adoptive cell therapy” or “ACT” involves the transfer of cells (e.g., immune cells) into a subject (e.g., a subject having cancer). In some embodiments, ACT is a treatment approach that involves the use of lymphocytes with antitumor activity, the in vitro expansion of these cells to suitable numbers, and their infusion into a subject having cancer.
Antigen: The term “antigen”, as used herein, refers to a molecule (e.g., a polypeptide) that elicits a specific immune response. Antigen-specific immunological responses, also known as adaptive immune responses, are mediated by lymphocytes (e.g., T cells, B cells, NK cells) that express antigen receptors (e.g., T cell receptors, B cell receptors). In certain embodiments, an antigen is a T cell antigen, and elicits a cellular immune response. In certain embodiments, an antigen is a B cell antigen, and elicits a humoral (i.e., antibody) response. In certain embodiments, an antigen is both a T cell antigen and a B cell antigen. As used herein, the term “antigen” encompasses both a full-length polypeptide as well as a portion or immunogenic fragment of the polypeptide, and a peptide epitope within the polypeptides (e.g., a peptide epitope bound by a Major Histocompatibility Complex (MHC) molecule (e.g., MHC class I, or MHC class II)).
Antigen presenting cell: An “antigen presenting cell” or “APC” refers to a cell that presents peptides on MHC class I and/or MHC class II molecules for recognition by T cells. APC include both professional APC (e.g., dendritic cells, macrophages, B cells), which have the ability to stimulate naïve lymphocytes, and non-professional APC (e.g., fibroblasts, epithelial cells, endothelial cells, glial cells). In certain embodiments, APC are able to internalize (e.g., endocytose) members of a library (e.g., cells of a library of bacterial cells) that express heterologous polypeptides as candidate antigens.
Autolysin polypeptide: An “autolysin polypeptide” is a polypeptide that facilitates or mediates autolysis of a cell (e.g., a bacterial cell) that has been internalized by a eukaryotic cell. In some embodiments, an autolysin polypeptide is a bacterial autolysin polypeptide. Autolysin polypeptides include, and are not limited to, polypeptides whose sequences are disclosed in GenBank® under Acc. Nos. NP_388823.1, NP_266427.1, and P0AGC3.1.
Cancer: As used herein, the term “cancer” refers to a disease, disorder, or condition in which cells exhibit relatively abnormal, uncontrolled, and/or autonomous growth, so that they display an abnormally elevated proliferation rate and/or aberrant growth phenotype characterized by a significant loss of control of cell proliferation. In some embodiments, a cancer may be characterized by one or more tumors. Those skilled in the art are aware of a variety of types of cancer including, for example, adrenocortical carcinoma, astrocytoma, basal cell carcinoma, carcinoid, cardiac, cholangiocarcinoma, chordoma, chronic myeloproliferative neoplasms, craniopharyngioma, ductal carcinoma in situ, ependymoma, intraocular melanoma, gastrointestinal carcinoid tumor, gastrointestinal stromal tumor (GIST), gestational trophoblastic disease, glioma, histiocytosis, leukemia (e.g., acute lymphoblastic leukemia (ALL), acute myeloid leukemia (AML), chronic lymphocytic leukemia (CLL), chronic myelogenous leukemia (CML), hairy cell leukemia, myelogenous leukemia, myeloid leukemia), lymphoma (e.g., Burkitt lymphoma [non-Hodgkin lymphoma], cutaneous T cell lymphoma, Hodgkin lymphoma, mycosis fungoides, Sezary syndrome, AIDS-related lymphoma, follicular lymphoma, diffuse large B-cell lymphoma), melanoma, merkel cell carcinoma, mesothelioma, myeloma (e.g., multiple myeloma), myelodysplastic syndrome, papillomatosis, paraganglioma, pheochromacytoma, pleuropulmonary blastoma, retinoblastoma, sarcoma (e.g., Ewing sarcoma, Kaposi sarcoma, osteosarcoma, rhabdomyosarcoma, uterine sarcoma, vascular sarcoma), Wilms' tumor, and/or cancer of the adrenal cortex, anus, appendix, bile duct, bladder, bone, brain, breast, bronchus, central nervous system, cervix, colon, endometrium, esophagus, eye, fallopian tube, gall bladder, gastrointestinal tract, germ cell, head and neck, heart, intestine, kidney (e.g., Wilms' tumor), larynx, liver, lung (e.g., non-small cell lung cancer, small cell lung cancer), mouth, nasal cavity, oral cavity, ovary, pancreas, rectum, skin, stomach, testes, throat, thyroid, penis, pharynx, peritoneum, pituitary, prostate, rectum, salivary gland, ureter, urethra, uterus, vagina, or vulva.
Cytolysin polypeptide: A “cytolysin polypeptide” is a polypeptide that has the ability to form pores in a membrane of a eukaryotic cell. A cytolysin polypeptide, when expressed in host cell (e.g., a bacterial cell) that has been internalized by a eukaryotic cell, facilitates release of host cell components (e.g., host cell macromolecules, such as host cell polypeptides) into the cytosol of the internalizing cell. In some embodiments, a cytolysin polypeptide is bacterial cytolysin polypeptide. In some embodiments, a cytolysin polypeptide is a cytoplasmic cytolysin polypeptide. Cytolysin polypeptides include, and are not limited to, polypeptides whose sequences are disclosed in U.S. Pat. No. 6,004,815, and in GenBank® under Acc. Nos. NP_463733.1, NP_979614, NP_834769, YP_084586, YP_895748, YP_694620, YP_012823, NP_346351, YP_597752, BAB41212.2, NP_561079.1, YP_001198769, and NP_359331.1.
Cytoplasmic cytolysin polypeptide: A “cytoplasmic cytolysin polypeptide” is a cytolysin polypeptide that has the ability to form pores in a membrane of a eukaryotic cell, and that is expressed as a cytoplasmic polypeptide in a bacterial cell. A cytoplasmic cytolysin polypeptide is not significantly secreted by a bacterial cell. Cytoplasmic cytolysin polypeptides can be provided by a variety of means. In some embodiments, a cytoplasmic cytolysin polypeptide is provided as a nucleic acid encoding the cytoplasmic cytolysin polypeptide. In some embodiments, a cytoplasmic cytolysin polypeptide is provided attached to a bead. In some embodiments, a cytoplasmic cytolysin polypeptide has a sequence that is altered relative to the sequence of a secreted cytolysin polypeptide (e.g., altered by deletion or alteration of a signal sequence to render it nonfunctional). In some embodiments, a cytoplasmic cytolysin polypeptide is cytoplasmic because it is expressed in a secretion-incompetent cell. In some embodiments, a cytoplasmic cytolysin polypeptide is cytoplasmic because it is expressed in a cell that does not recognize and mediate secretion of a signal sequence linked to the cytolysin polypeptide. In some embodiments, a cytoplasmic cytolysin polypeptide is a bacterial cytolysin polypeptide.
Heterologous: The term “heterologous”, as used herein to refer to genes or polypeptides, refers to a gene or polypeptide that does not naturally occur in the organism in which it is present and/or being expressed, and/or that has been introduced into the organism by the hand of man. In some embodiments, a heterologous polypeptide is a tumor antigen described herein.
Immune mediator: As used herein, the term “immune mediator” refers to any molecule that affects the cells and processes involved in immune responses. Immune mediators include cytokines, chemokines, soluble proteins, and cell surface markers.
Improve, increase, inhibit, stimulate, suppress, or reduce: As used herein, the terms “improve”, “increase”, “inhibit”, “stimulate”, “suppress”, “reduce”, or grammatical equivalents thereof, indicate values that are relative to a baseline or other reference measurement. In some embodiments, an appropriate reference measurement may be or comprise a measurement in a particular system (e.g., in a single individual) under otherwise comparable conditions absent presence of (e.g., prior to and/or after) a particular agent or treatment, or in presence of an appropriate comparable reference agent. The effect of a particular agent or treatment may be direct or indirect. In some embodiments, an appropriate reference measurement may be or may comprise a measurement in a comparable system known or expected to respond in a particular way, in presence of the relevant agent or treatment. In some embodiments, a peptide presented by an antigen presenting cell (APC) “stimulates” or is “stimulatory” to a lymphocyte if the lymphocyte is activated to a phenotype associated with beneficial responses, after exposure to the peptide presented by the APC under conditions that permit antigen-specific recognition to occur, as observed by, e.g., T cell proliferation, phosphorylation or dephosphorylation of a receptor, calcium flux, cytoskeletal rearrangement, increased or decreased expression and/or secretion of immune mediators such as cytokines or soluble mediators, increased or decreased expression of one or more cell surface markers, relative to a control. In some embodiments, a peptide presented by an antigen presenting cell “suppresses”, “inhibits” or is “inhibitory” to a lymphocyte if the lymphocyte is activated to a phenotype associated with deleterious or non-beneficial responses, after exposure to the peptide presented by the APC under conditions that permit antigen-specific recognition to occur, as observed by, e.g., phosphorylation or dephosphorylation of a receptor, calcium flux, cytoskeletal rearrangement, increased or decreased expression and/or secretion of immune mediators such as cytokines or soluble mediators, increased or decreased expression of one or more cell surface markers, relative to a control.
Inhibitory Antigen: An “inhibitory antigen” is an antigen that inhibits, suppresses, impairs and/or reduces immune control of a tumor or cancer. In some embodiments, an inhibitory antigen promotes tumor growth, enables tumor growth, ameliorates tumor growth, activates tumor growth, accelerates tumor growth, and/or increases and/or enables tumor metastasis. In some embodiments, an inhibitory antigen stimulates one or more lymphocyte responses that are deleterious or non-beneficial to a subject; and/or inhibits and/or suppresses one or more lymphocyte responses that are beneficial to a subject. In some embodiments, an inhibitory antigen is the target of one or more lymphocyte responses that are deleterious or non-beneficial to a subject; and/or inhibits and/or suppresses one or more lymphocyte responses that are beneficial to a subject.
Invasin polypeptide: An “invasin polypeptide” is a polypeptide that facilitates or mediates uptake of a cell (e.g., a bacterial cell) by a eukaryotic cell. Expression of an invasin polypeptide in a noninvasive bacterial cell confers on the cell the ability to enter a eukaryotic cell. In some embodiments, an invasin polypeptide is a bacterial invasin polypeptide. In some embodiments, an invasin polypeptide is a Yersinia invasin polypeptide (e.g., a Yersinia invasin polypeptide comprising a sequence disclosed in GenBank® under Acc. No. YP_070195.1).
Listeriolysin O (LLO): The terms “listeriolysin O” or “LLO” refer to a listeriolysin O polypeptide of Listeria monocytogenes and truncated forms thereof that retain pore-forming ability (e.g., cytoplasmic forms of LLO, including truncated forms lacking a signal sequence). In some embodiments, an LLO is a cytoplasmic LLO. Exemplary LLO sequences are shown in Table 1, below.
Polypeptide: The term “polypeptide”, as used herein, generally has its art-recognized meaning of a polymer of at least three amino acids. Those of ordinary skill in the art will appreciate, however, that the term “polypeptide” is intended to be sufficiently general as to encompass not only polypeptides having the complete sequence recited herein (or in a reference or database specifically mentioned herein), but also to encompass polypeptides that represent functional fragments (i.e., fragments retaining at least one activity) and immunogenic fragments of such complete polypeptides. Moreover, those of ordinary skill in the art understand that protein sequences generally tolerate some substitution without destroying activity. Thus, any polypeptide that retains activity and shares at least about 30-40% overall sequence identity, often greater than about 50%, 60%, 70%, or 80%, and further usually including at least one region of much higher identity, often greater than 90% or even 95%, 96%, 97%, 98%, or 99% in one or more highly conserved regions, usually encompassing at least 3-4 and often up to 20 or more amino acids, with another polypeptide of the same class, is encompassed within the relevant term “polypeptide” as used herein. Other regions of similarity and/or identity can be determined by those of ordinary skill in the art by analysis of the sequences of various polypeptides.
Primary cells: As used herein, “primary cells” refers to cells from an organism that have not been immortalized in vitro. In some embodiments, primary cells are cells taken directly from a subject (e.g., a human). In some embodiments, primary cells are progeny of cells taken from a subject (e.g., cells that have been passaged in vitro). Primary cells include cells that have been stimulated to proliferate in culture.
Re-educate: As used herein, in the context of the response of a lymphocyte, “re-educate” refers to alteration in one or more responses of a lymphocyte to a particular antigen. In certain embodiments, an antigen initially stimulates one or more lymphocyte responses that are deleterious or non-beneficial to a subject, and/or the antigen initially inhibits and/or suppresses one or more lymphocyte responses that are beneficial to a subject, and such lymphocyte is re-educated such that the antigen no longer stimulates one or more lymphocyte responses that are deleterious or non-beneficial to a subject, and/or the antigen no longer inhibits and/or suppresses one or more lymphocyte responses that are beneficial to a subject. In some such embodiments, such lymphocyte is re-educated such that the antigen stimulates one or more lymphocyte responses that are beneficial to a subject and/or the antigen inhibits and/or suppresses one or more lymphocyte responses that are deleterious or non-beneficial to a subject.
Redirect: As used herein, in the context of an immune response, “redirect” refers to an alteration in one or more aspects of an immune response. In certain embodiments, an initial immune response (e.g., an initial immune response to an antigen) impairs or reduces immune control of a tumor or cancer, and such initial immune response is redirected such that the immune response (e.g., to the antigen) no longer impairs or reduces immune control of a tumor or cancer. In some such embodiments, such redirected immune response enhances immune control of a tumor.
Response: As used herein, in the context of a subject (a patient or experimental organism), “response”, “responsive”, or “responsiveness” refers to an alteration in a subject's condition that occurs as a result of, or correlates with, treatment. In certain embodiments, a response is a beneficial response. In certain embodiments, a beneficial response can include stabilization of a subject's condition (e.g., prevention or delay of deterioration expected or typically observed to occur absent the treatment), amelioration (e.g., reduction in frequency and/or intensity) of one or more symptoms of the condition, and/or improvement in the prospects for cure of the condition, etc. In certain embodiments, for a subject who has cancer, a beneficial response can include: the subject has a positive clinical response to cancer therapy or a combination of therapies; the subject has a spontaneous response to a cancer; the subject is in partial or complete remission from cancer; the subject has cleared a cancer; the subject has not had a relapse, recurrence or metastasis of a cancer; the subject has a positive cancer prognosis; the subject has not experienced toxic responses or side effects to a cancer therapy or combination of therapies. In certain embodiments, for a subject who had cancer, the beneficial responses occurred in the past, or are ongoing.
In certain embodiments, a response is a deleterious or non-beneficial response. In certain embodiments, a deleterious or non-beneficial response can include deterioration of a subject's condition, lack of amelioration (e.g., no reduction in frequency and/or intensity) of one or more symptoms of the condition, and/or degradation in the prospects for cure of the condition, etc. In certain embodiments, for a subject who has cancer, a deleterious or non-beneficial response can include: the subject has a negative clinical response to cancer therapy or a combination of therapies; the subject is not in remission from cancer; the subject has not cleared a cancer; the subject has had a relapse, recurrence or metastasis of a cancer; the subject has a negative cancer prognosis; the subject has experienced toxic responses or side effects to a cancer therapy or combination of therapies. In certain embodiments, for a subject who had cancer, the deleterious or non-beneficial responses occurred in the past, or are ongoing.
As used herein, in the context of a cell, organ, tissue, or cell component, e.g., a lymphocyte, “response”, “responsive”, or “responsiveness” refers to an alteration in cellular activity that occurs as a result of, or correlates with, administration of or exposure to an agent, e.g. a tumor antigen. In certain embodiments, a beneficial response can include increased expression and/or secretion of immune mediators associated with positive clinical responses or outcomes in a subject. In certain embodiments, a beneficial response can include decreased expression and/or secretion of immune mediators associated with negative clinical response or outcomes in a subject. In certain embodiments, a deleterious or non-beneficial response can include increased expression and/or secretion of immune mediators associated with negative clinical responses or outcomes in a subject. In certain embodiments, a deleterious or non-beneficial response can include decreased expression and/or secretion of immune mediators associated with positive clinical responses or outcomes in a subject. In certain embodiments, a response is a clinical response. In certain embodiments, a response is a cellular response. In certain embodiments, a response is a direct response. In certain embodiments, a response is an indirect response. In certain embodiments, “non-response”, “non-responsive”, or “non-responsiveness” mean minimal response or no detectable response. In certain embodiments, a “minimal response” includes no detectable response. In certain embodiments, presence, extent, and/or nature of response can be measured and/or characterized according to particular criteria. In certain embodiments, such criteria can include clinical criteria and/or objective criteria. In certain embodiments, techniques for assessing response can include, but are not limited to, clinical examination, positron emission tomography, chest X-ray, CT scan, MM, ultrasound, endoscopy, laparoscopy, presence or level of a particular marker in a sample, cytology, and/or histology. Where a response of interest is a response of a tumor to a therapy, ones skilled in the art will be aware of a variety of established techniques for assessing such response, including, for example, for determining tumor burden, tumor size, tumor stage, etc. Methods and guidelines for assessing response to treatment are discussed in Therasse et al., J. Natl. Cancer Inst., 2000, 92(3):205-216; and Seymour et al., Lancet Oncol., 2017, 18:e143-52. The exact response criteria can be selected in any appropriate manner, provided that when comparing groups of tumors, patients or experimental organism, and/or cells, organs, tissues, or cell components, the groups to be compared are assessed based on the same or comparable criteria for determining response rate. One of ordinary skill in the art will be able to select appropriate criteria.
Stimulatory Antigen: A “stimulatory antigen” is an antigen that enhances. improves, increases and/or stimulates immune control of a tumor or cancer. In some embodiments, a stimulatory antigen is the target of an immune response that reduces, kills, shrinks, resorbs, and/or eradicates tumor growth; does not promote, enable, ameliorate, activate, and/or accelerate tumor growth; decreases tumor metastasis, and/or decelerates tumor growth. In some embodiments, a stimulatory antigen inhibits and/or suppresses one or more lymphocyte responses that are deleterious or non-beneficial to a subject; and/or stimulates one or more lymphocyte responses that are beneficial to a subject.
Tumor: As used herein, the term “tumor” refers to an abnormal growth of cells or tissue. In some embodiments, a tumor may comprise cells that are precancerous (e.g., benign), malignant, pre-metastatic, metastatic, and/or non-metastatic. In some embodiments, a tumor is associated with, or is a manifestation of, a cancer. In some embodiments, a tumor may be a disperse tumor or a liquid tumor. In some embodiments, a tumor may be a solid tumor.
Neoantigens are emerging as attractive targets for personalized cancer immunotherapy. Unlike tumor-associated antigens (TAAs) that are recognized as self, neoantigens can contain non-synonymous mutations that may be identified as foreign to the immune system and are not subject to central tolerance.
Recent advances in immune checkpoint inhibitor therapies such as ipilimumab, nivolumab, and pembrolizumab for cancer immunotherapy have resulted in dramatic efficacy in subjects suffering from NSCLC, among other indications. Nivolumab and pembroluzimab have been approved by the Food and Drug Administration (FDA) and European Medicines Agency (EMA) for use in patients with advanced NSCLC who have previously been treated with chemotherapy. They have solidified the importance of T cell responses in control of tumors. Neoantigens, potential cancer rejection antigens that are entirely absent from the normal human genome, are postulated to be relevant to tumor control; however, attempts to define them and their role in tumor clearance has been hindered by the paucity of available tools to define them in a biologically relevant and unbiased way (Schumacher and Schreiber, 2015 Science 348:69-74, Gilchuk et al., 2015 Curr Opin Immunol 34:43-51)
Taking non-small cell lung carcinoma (NSCLC) as an example, whole exome sequencing of NSCLC tumors from patients treated with pembrolizumab showed that higher non-synonymous mutation burden in tumors was associated with improved objective response, durable clinical benefit, and progression-free survival (Rizvi et al., (2015) Science 348(6230): 124-8). In this study, the median non-synonymous mutational burden of the discovery cohort was 209 and of the validation cohort was 200. However, simply because a mutation was identified by sequencing, does not mean that the epitope it creates can be recognized by a T cell or serves as a protective antigen for T cell responses (Gilchuk et al., 2015 Curr Opin Immunol 34:43-51), making the use of the word neoantigen somewhat of a misnomer. With 200 or more potential targets of T cells in NSCLC, it is not feasible to test every predicted epitope to determine which of the mutations serve as neoantigens, and which neoantigens are associated with clinical evidence of tumor control. Recently, a study by McGranahan et al., showed that clonal neoantigen burden and overall survival in primary lung adenocarcinomas are related. However, even enriching for clonal neoantigens results in potential antigen targets ranging from 50 to approximately 400 (McGranahan et al., 2016 Science 351:1463-69). Similar findings have been described for melanoma patients who have responded to ipilimumab therapy (Snyder et al., 2015 NEJM; Van Allen et al., 2015 Science) and in patients with mismatch-repair deficient colorectal cancer who were treated with pembrolizumab (Le et al., 2015 NEJM).
Adoptive T cell therapies (ACT) enriched for neoantigen-targeting with tumor infiltrating lymphocytes (TILs) have demonstrated clinical responses in metastatic cancer with limited off-target toxicity1, 2. While adoptive TIL therapy has produced durable tumor regression in some patients, the majority do not benefit. Furthermore, tumor infiltrating lymphocyte (TIL) therapy is limited to large, resectable tumors with high TIL content.
ATLAS™ is the only existing platform for rapid, high throughput quantification of pre-existing, antigen-specific CD4+ and CD8+ T cell responses without the use of algorithms or in silico downselection criteria, and has previously yielded antigens with clinical efficacy when administered as a vaccine4. In cancer, ATLAS enables comprehensive screening of a tumor mutanome by using a patient's own autologous immune cells, specifically monocyte-derived dendritic cells (MDDC) as antigen presenting cells (APCs) and sorted CD8+ and CD4+ T cells. By utilizing autologous APCs and T cells, ATLAS is agnostic to MEW type and assesses pre-existing T cell responses to any given mutation3. Patient MDDC are pulsed with an ordered array of Escherichia coli expressing patient-specific mutations as short polypeptides, with or without co-expressed listeriolysin O (cLLO) facilitating MEW class I or class II presentation, respectively. CD8+ or CD4+ T cells are subsequently added, and after an overnight incubation, antigens are differentially characterized as stimulatory or inhibitory by significant up- or downregulation of T cell cytokine secretion relative to control responses; thus, the ATLAS assay allows for identification and characterization of desired as well as potentially unwanted antigen-specific T cell responses.
The system and methods described herein improve upon ACT by identifying neoantigen- or other tumor specific antigen-reactive T cells from peripheral blood using ATLAS™ technology3 and specifically expanding these cells for T cell infusion. This personalized ACT is able to target a broad array of neoantigens, limit metastatic tumor escape, balance neoantigen-specific CD4+ and CD8+ T cell content, and broaden indication selection.
The present disclosure provides, in part, methods and systems for the rapid identification of tumor antigens (e.g., tumor specific antigens (TSAs, or neoantigens), tumor associated antigens (TAAs), or cancer/testis antigens (CTAs)) that elicit T cell responses and particularly that elicit human T cell responses, as well as polypeptides that are potential tumor antigens. For purposes of this disclosure, “tumor antigens” includes both tumor antigens and potential tumor antigens. As described herein, methods of the present disclosure identified stimulatory tumor antigens that were not identified by known algorithms. Further, methods of the present disclosure identified suppressive and/or inhibitory tumor antigens that are not identifiable by known algorithms. Methods of the present disclosure also identified polypeptides that are potential tumor antigens, i.e., polypeptides that activate T cells of non-cancerous subjects, but not T cells of subjects suffering from cancer. The present disclosure also provides methods of selecting tumor antigens and potential tumor antigens, methods of using the selected tumor antigens and potential tumor antigens, immunogenic compositions comprising the selected tumor antigens and potential tumor antigens, and methods of manufacturing immunogenic compositions.
In addition, the present disclosure provides methods of re-educating lymphocytes to alter one or more responses of lymphocytes to a particular antigen (e.g., an inhibitory antigen); methods of redirecting one or more immune responses (e.g., to an antigen, e.g., an inhibitory antigen); and methods of treating subjects (e.g., subjects having a tumor or cancer) by re-educating lymphocytes to alter one or more immune responses of lymphocytes to a particular antigen (e.g., an inhibitory antigen) and/or redirecting one or more immune responses (e.g., to an antigen, e.g., an inhibitory antigen).
A library is a collection of members (e.g., cells or non-cellular particles, such as virus particles, liposomes, or beads (e.g., beads coated with polypeptides, such as in vitro translated polypeptides, e.g., affinity beads, e.g., antibody coated beads, or NTA-Ni beads bound to polypeptides of interest). According to the present disclosure, members of a library include (e.g., internally express or carry) polypeptides of interest described herein. In some embodiments, members of a library are cells that internally express polypeptides of interest described herein. In some embodiments, members of a library which are particles carry, and/or are bound to, polypeptides of interest. Use of a library in an assay system allows simultaneous evaluation in vitro of cellular responses to multiple candidate antigens. According to the present disclosure, a library is designed to be internalized by human antigen presenting cells so that peptides from library members, including peptides from internally expressed polypeptides of interest, are presented on MHC molecules of the antigen presenting cells for recognition by T cells.
Libraries can be used in assays that detect peptides presented by human MHC class I and MHC class II molecules. Polypeptides expressed by the internalized library members are digested in intracellular endocytic compartments (e.g., phagosomes, endosomes, lysosomes) of the human cells and presented on MHC class II molecules, which are recognized by human CD4+ T cells. In some embodiments, library members include a cytolysin polypeptide, in addition to a polypeptide of interest. In some embodiments, library members include an invasin polypeptide, in addition to the polypeptide of interest. In some embodiments, library members include an autolysin polypeptide, in addition to the polypeptide of interest. In some embodiments, library members are provided with cells that express a cytolysin polypeptide (i.e., the cytolysin and polypeptide of interest are not expressed in the same cell, and an antigen presenting cell is exposed to members that include the cytolysin and members that include the polypeptide of interest, such that the antigen presenting cell internalizes both, and such that the cytolysin facilitates delivery of polypeptides of interest to the MHC class I pathway of the antigen presenting cell). A cytolysin polypeptide can be constitutively expressed in a cell, or it can be under the control of an inducible expression system (e.g., an inducible promoter). In some embodiments, a cytolysin is expressed under the control of an inducible promoter to minimize cytotoxicity to the cell that expresses the cytolysin.
Once internalized by a human cell, a cytolysin polypeptide perforates intracellular compartments in the human cell, allowing polypeptides expressed by the library members to gain access to the cytosol of the human cell. Polypeptides released into the cytosol are presented on MHC class I molecules, which are recognized by CD8+ T cells.
A library can include any type of cell or particle that can be internalized by and deliver a polypeptide of interest (and a cytolysin polypeptide, in applications where a cytolysin polypeptide is desirable) to, antigen presenting cells for use in methods described herein. Although the term “cell” is used throughout the present specification to refer to a library member, it is understood that, in some embodiments, the library member is a non-cellular particle, such as a virus particle, liposome, or bead. In some embodiments, members of the library include polynucleotides that encode the polypeptide of interest (and cytolysin polypeptide), and can be induced to express the polypeptide of interest (and cytolysin polypeptide) prior to, and/or during internalization by antigen presenting cells.
In some embodiments, the cytolysin polypeptide is heterologous to the library cell in which it is expressed, and facilitates delivery of polypeptides expressed by the library cell into the cytosol of a human cell that has internalized the library cell. Cytolysin polypeptides include bacterial cytolysin polypeptides, such as listeriolysin O (LLO), streptolysin O (SLO), and perfringolysin O (PFO). Additional cytolysin polypeptides are described in U.S. Pat. No. 6,004,815. In certain embodiments, library members express LLO. In some embodiments, a cytolysin polypeptide is not significantly secreted by the library cell (e.g., less than 20%, 10%, 5%, or 1% of the cytolysin polypeptide produced by the cell is secreted). For example, the cytolysin polypeptide is a cytoplasmic cytolysin polypeptide, such as a cytoplasmic LLO polypeptide (e.g., a form of LLO which lacks the N-terminal signal sequence, as described in Higgins et al., Mol. Microbiol. 31(6):1631-1641, 1999). Exemplary cytolysin polypeptide sequences are shown in Table 1. The listeriolysin O (43-25) sequence shown in the second row of Table 1 has a deletion of residues 3-25, relative to the LLO sequence in shown in the first row of Table 1, and is a cytoplasmic LLO polypeptide. In some embodiments, a cytolysin is expressed constitutively in a library host cell. In other embodiments, a cytolysin is expressed under the control of an inducible promoter. Cytolysin polypeptides can be expressed from the same vector, or from a different vector, as the polypeptide of interest in a library cell.
monocytogenes)
pyogenes)
perfringens)
pneumoniae)
In some embodiments, a library member (e.g., a library member which is a bacterial cell) includes an invasin that facilitates uptake by the antigen presenting cell. In some embodiments, a library member includes an autolysin that facilitates autolysis of the library member within the antigen presenting cell. In some embodiments, a library member includes both an invasin and an autolysin. In some embodiments, a library member which is an E. coli cell includes an invasin and/or an autolysin. In various embodiments, library cells that express an invasin and/or autolysin are used in methods that also employ non-professional antigen presenting cells or antigen presenting cells that are from cell lines. Isberg et al. (Cell, 1987, 50:769-778), Sizemore et al. (Science, 1995, 270:299-302) and Courvalin et al. (C.R. Acad. Sci. Paris, 1995, 318:1207-12) describe expression of an invasin to effect endocytosis of bacteria by target cells. Autolysins are described by Cao et al., Infect. Immun. 1998, 66(6): 2984-2986; Margot et al., J. Bacteriol. 1998, 180(3):749-752; Buist et al., Appl. Environ. Microbiol., 1997, 63(7):2722-2728; Yamanaka et al., FEMS Microbiol. Lett., 1997, 150(2): 269-275; Romero et al., FEMS Microbiol. Lett., 1993, 108(1):87-92; Betzner and Keck, Mol. Gen. Genet., 1989, 219(3): 489-491; Lubitz et al., J. Bacteriol., 1984, 159(1):385-387; and Tomasz et al., J. Bacteriol., 1988, 170(12): 5931-5934. In some embodiments, an autolysin has a feature that permits delayed lysis, e.g., the autolysin is temperature-sensitive or time-sensitive (see, e.g., Chang et al., 1995, J. Bact. 177, 3283-3294; Raab et al., 1985, J. Mol. Biol. 19, 95-105; Gerds et al., 1995, Mol. Microbiol. 17, 205-210). Useful cytolysins also include addiction (poison/antidote) autolysins, (see, e.g., Magnuson R, et al., 1996, J Biol. Chem. 271(31), 18705-18710; Smith A S, et al., 1997, Mol. Microbiol. 26(5), 961-970).
In some embodiments, members of the library include bacterial cells. In certain embodiments, the library includes non-pathogenic, non-virulent bacterial cells. Examples of bacteria for use as library members include E. coli, mycobacteria, Listeria monocytogenes, Shigella flexneri, Bacillus subtilis, or Salmonella.
In some embodiments, members of the library include eukaryotic cells (e.g., yeast cells). In some embodiments, members of the library include viruses (e.g., bacteriophages). In some embodiments, members of the library include liposomes. Methods for preparing liposomes that include a cytolysin and other agents are described in Kyung-Dall et al., U.S. Pat. No. 5,643,599. In some embodiments, members of the library include beads. Methods for preparing libraries comprised of beads are described, e.g., in Lam et al., Nature 354: 82-84, 1991, U.S. Pat. Nos. 5,510,240 and 7,262,269, and references cited therein.
In certain embodiments, a library is constructed by cloning polynucleotides encoding polypeptides of interest, or portions thereof, into vectors that express the polypeptides of interest in cells of the library. The polynucleotides can be synthetically synthesized. The polynucleotides can be cloned by designing primers that amplify the polynucleotides. Primers can be designed using available software, such as Primer3Plus (available the following URL: bioinformatics.nl/cgi-bin/primer3plus/primer3plus.cgi; see Rozen and Skaletsky, In: Krawetz S, Misener S (eds) Bioinformatics Methods and Protocols: Methods in Molecular Biology. Humana Press, Totowa, N.J., pp. 365-386, 2000). Other methods for designing primers are known to those of skill in the art. In some embodiments, primers are constructed so as to produce polypeptides that are truncated, and/or lack hydrophobic regions (e.g., signal sequences or transmembrane regions) to promote efficient expression. The location of predicted signal sequences and predicted signal sequence cleavage sites in a given open reading frame (ORF) sequence can be determined using available software, see, e.g., Dyrløv et al., J. Mol. Biol., 340:783-795, 2004, and the following URL: cbs.dtu.dk/services/SignalP/). For example, if a signal sequence is predicted to occur at the N-terminal 20 amino acids of a given polypeptide sequence, a primer is designed to anneal to a coding sequence downstream of the nucleotides encoding the N-terminal 20 amino acids, such that the amplified sequence encodes a product lacking this signal sequence.
Primers can also be designed to include sequences that facilitate subsequent cloning steps. ORFs can be amplified directly from genomic DNA (e.g., genomic DNA of a tumor cell), or from polynucleotides produced by reverse transcription (RT-PCR) of mRNAs expressed by the tumor cell. RT-PCR of mRNA is useful, e.g., when the genomic sequence of interest contains intronic regions. PCR-amplified ORFs are cloned into an appropriate vector, and size, sequence, and expression of ORFs can be verified prior to use in immunological assays.
In some embodiments, a polynucleotide encoding a polypeptide of interest is linked to a sequence encoding a tag (e.g., an N-terminal or C-terminal epitope tag) or a reporter protein (e.g., a fluorescent protein). Epitope tags and reporter proteins facilitate purification of expressed polypeptides, and can allow one to verify that a given polypeptide is properly expressed in a library host cell, e.g., prior to using the cell in a screen. Useful epitope tags include, for example, a polyhistidine (His) tag, a V5 epitope tag from the P and V protein of paramyxovirus, a hemagglutinin (HA) tag, a myc tag, and others. In some embodiments, a polynucleotide encoding a polypeptide of interest is fused to a sequence encoding a tag which is a known antigenic epitope (e.g., an MHC class I- and/or MHC class II-restricted T cell epitope of a model antigen such as an ovalbumin), and which can be used to verify that a polypeptide of interest is expressed and that the polypeptide-tag fusion protein is processed and presented in antigen presentation assays. In some embodiments a tag includes a T cell epitope of a murine T cell (e.g., a murine T cell line). In some embodiments, a polynucleotide encoding a polypeptide of interest is linked to a tag that facilitates purification and a tag that is a known antigenic epitope. Useful reporter proteins include naturally occurring fluorescent proteins and their derivatives, for example, Green Fluorescent Protein (Aequorea Victoria) and Neon Green (Branchiostoma lanceolatum). Panels of synthetically derived fluorescent and chromogenic proteins are also available from commercial sources.
Polynucleotides encoding a polypeptide of interest are cloned into an expression vector for introduction into library host cells. Various vector systems are available to facilitate cloning and manipulation of polynucleotides, such as the Gateway® Cloning system (Invitrogen). As is known to those of skill in the art, expression vectors include elements that drive production of polypeptides of interest encoded by a polynucleotide in library host cells (e.g., promoter and other regulatory elements). In some embodiments, polypeptide expression is controlled by an inducible element (e.g., an inducible promoter, e.g., an IPTG- or arabinose-inducible promoter, or an IPTG-inducible phage T7 RNA polymerase system, a lactose (lac) promoter, a tryptophan (trp) promoter, a tac promoter, a trc promoter, a phage lambda promoter, an alkaline phosphatase (phoA) promoter, to give just a few examples; see Cantrell, Meth. in Mol. Biol., 235:257-276, Humana Press, Casali and Preston, Eds.). In some embodiments, polypeptides are expressed as cytoplasmic polypeptides. In some embodiments, the vector used for polypeptide expression is a vector that has a high copy number in a library host cell. In some embodiments, the vector used for expression has a copy number that is more than 25, 50, 75, 100, 150, 200, or 250 copies per cell. In some embodiments, the vector used for expression has a ColE1 origin of replication. Useful vectors for polypeptide expression in bacteria include pET vectors (Novagen), Gateway® pDEST vectors (Invitrogen), pGEX vectors (Amersham Biosciences), pPRO vectors (BD Biosciences), pBAD vectors (Invitrogen), pLEX vectors (Invitrogen), pMAL™ vectors (New England BioLabs), pGEMEX vectors (Promega), and pQE vectors (Qiagen). Vector systems for producing phage libraries are known and include Novagen T7Select® vectors, and New England Biolabs Ph. D.™ Peptide Display Cloning System.
In some embodiments, library host cells express (either constitutively, or when induced, depending on the selected expression system) a polypeptide of interest to at least 10%, 20%, 30%, 40%, 50%, 60%, or 70% of the total cellular protein. In some embodiments, the level a polypeptide available in or on a library member (e.g., cell, virus particle, liposome, bead) is such that antigen presenting cells exposed to a sufficient quantity of the library members are presented on MHC molecules polypeptide epitopes at a density that is comparable to the density presented by antigen presenting cells pulsed with purified peptides.
Methods for efficient, large-scale production of libraries are available. For example, site-specific recombinases or rare-cutting restriction enzymes can be used to transfer polynucleotides between expression vectors in the proper orientation and reading frame (Walhout et al., Meth. Enzymol. 328:575-592, 2000; Marsischky et al., Genome Res. 14:2020-202, 2004; Blommel et al., Protein Expr. Purif. 47:562-570, 2006).
For production of liposome libraries, expressed polypeptides (e.g., purified or partially purified polypeptides) can be entrapped in liposomal membranes, e.g., as described in Wassef et al., U.S. Pat. No. 4,863,874; Wheatley et al., U.S. Pat. No. 4,921,757; Huang et al., U.S. Pat. No. 4,925,661; or Martin et al., U.S. Pat. No. 5,225,212.
A library can be designed to include full length polypeptides and/or portions of polypeptides. Expression of full length polypeptides maximizes epitopes available for presentation by a human antigen presenting cell, thereby increasing the likelihood of identifying an antigen. However, in some embodiments, it is useful to express portions of polypeptides, or polypeptides that are otherwise altered, to achieve efficient expression. For example, in some embodiments, polynucleotides encoding polypeptides that are large (e.g., greater than 1,000 amino acids), that have extended hydrophobic regions, signal peptides, transmembrane domains, or domains that cause cellular toxicity, are modified (e.g., by C-terminal truncation, N-terminal truncation, or internal deletion) to reduce cytotoxicity and permit efficient expression a library cell, which in turn facilitates presentation of the encoded polypeptides on human cells. Other types of modifications, such as point mutations or codon optimization, may also be used to enhance expression.
The number of polypeptides included in a library can be varied. For example, in some embodiments, a library can be designed to express polypeptides from at least 5%, 10%, 15%, 20%, 25%, 35%, 40%, 45%, 50%, 55%, 60%, 70%, 75%, 80%, 85%, 90%, 95%, 97%, 98%, 99%, or more, of ORFs in a target cell (e.g., tumor cell). In some embodiments, a library expresses at least 10, 15, 20, 25, 30, 40, 50, 75, 100, 150, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1000, 2500, 5000, 10,000, or more different polypeptides of interest, each of which may represent a polypeptide encoded by a single full length polynucleotide or portion thereof.
In some embodiments, assays may focus on identifying antigens that are secreted polypeptides, cell surface-expressed polypeptides, or virulence determinants, e.g., to identify antigens that are likely to be targets of both humoral and cell mediated immune responses.
In addition to polypeptides of interest, libraries can include tags or reporter proteins that allow one to easily purify, analyze, or evaluate MHC presentation, of the polypeptide of interest. In some embodiments, polypeptides expressed by a library include C-terminal tags that include both an MHC class I and an MHC class II-restricted T cell epitope from a model antigen, such as chicken ovalbumin (OVA). Library protein expression and MHC presentation is validated using these epitopes. In some embodiments, the epitopes are OVA247-265 and OVA258-265 respectfully, corresponding to positions in the amino acid sequence found in GenBank® under Acc. No. NP_990483. Expression and presentation of linked ORFs can be verified with antigen presentation assays using T cell hybridomas (e.g., B3Z T hybridoma cells, which are H2-Kb restricted, and KZO T hybridoma cells, which are H2-Ak restricted) that specifically recognize these epitopes.
Sets of library members (e.g., bacterial cells) can be provided on an array (e.g., on a solid support, such as a 96-well plate) and separated such that members in each location express a different polypeptide of interest, or a different set of polypeptides of interest.
Methods of using library members for identifying T cell antigens are described in detail below. In addition to these methods, library members also have utility in assays to identify B cell antigens. For example, lysate prepared from library members that include polypeptides of interest can be used to screen a sample comprising antibodies (e.g., a serum sample) from a subject (e.g., a subject who has been exposed to an infectious agent of interest, a subject who has cancer, and/or a control subject), to determine whether antibodies present in the subject react with the polypeptide of interest. Suitable methods for evaluating antibody reactivity are known and include, e.g., ELISA assays.
In some embodiments, methods and compositions described herein can be used to identify and/or detect immune responses to a polypeptide of interest. In some embodiments, a polypeptide of interest is encoded by an ORF from a target tumor cell, and members of a library include (e.g., internally express or carry) ORFs from a target tumor cell. In some such embodiments, a library can be used in methods described herein to assess immune responses to one or more polypeptides of interest encoded by one or more ORFs. In some embodiments, methods of the disclosure identify one or more polypeptides of interest as stimulatory antigens (e.g., that stimulate an immune response, e.g., a T cell response, e.g., expression and/or secretion of one or more immune mediators). In some embodiments, methods of the disclosure identify one or more polypeptides of interest as antigens or potential antigens that have minimal or no effect on an immune response (e.g., expression and/or secretion of one or more immune mediators). In some embodiments, methods of the disclosure identify one or more polypeptides of interest as inhibitory and/or suppressive antigens (e.g., that inhibit, suppress, down-regulate, impair, and/or prevent an immune response, e.g., a T cell response, e.g., expression and/or secretion of one or more immune mediators). In some embodiments, methods of the disclosure identify one or more polypeptides of interest as tumor antigens or potential tumor antigens, e.g., tumor specific antigens (TSAs, or neoantigens), tumor associated antigens (TAAs), or cancer/testis antigens (CTAs).
In some embodiments, a polypeptide of interest is a putative tumor antigen, and methods and compositions described herein can be used to identify and/or detect immune responses to one or more putative tumor antigens. For example, members of a library include (e.g., internally express or carry) putative tumor antigens (e.g., a polypeptide previously identified (e.g., by a third party) as a tumor antigen, e.g., identified as a tumor antigen using a method other than a method of the present disclosure). In some embodiments, a putative tumor antigen is a tumor antigen described herein. In some such embodiments, such libraries can be used to assess whether and/or the extent to which such putative tumor antigen mediates an immune response. In some embodiments, methods of the disclosure identify one or more putative tumor antigens as stimulatory antigens. In some embodiments, methods of the disclosure identify one or more putative tumor antigens as antigens that have minimal or no effect on an immune response. In some embodiments, methods of the disclosure identify one or more putative tumor antigens as inhibitory and/or suppressive antigens.
In some embodiments, a polypeptide of interest is a pre-selected tumor antigen, and methods and compositions described herein can be used to identify and/or detect immune responses to one or more pre-selected tumor antigens. For example, in some embodiments, members of a library include (e.g., internally express or carry) one or more polypeptides identified as tumor antigens using a method of the present disclosure and/or using a method other than a method of the present disclosure. In some such embodiments, such libraries can be used to assess whether and/or the extent to which such tumor antigens mediate an immune response by an immune cell from one or more subjects (e.g., a subject who has cancer and/or a control subject) to obtain one or more response profiles described herein. In some embodiments, methods of the disclosure identify one or more pre-selected tumor antigens as stimulatory antigens for one or more subjects. In some embodiments, methods of the disclosure identify one or more pre-selected tumor antigens as antigens that have minimal or no effect on an immune response for one or more subjects. In some embodiments, methods of the disclosure identify one or more pre-selected tumor antigens as inhibitory and/or suppressive antigens for one or more subjects.
In some embodiments, a polypeptide of interest is a known tumor antigen, and methods and compositions described herein can be used to identify and/or detect immune responses to one or more known tumor antigens. For example, in some embodiments, members of a library include (e.g., internally express or carry) one or more polypeptides identified as a tumor antigen using a method of the present disclosure and/or using a method other than a method of the present disclosure. In some such embodiments, such libraries can be used to assess whether and/or the extent to which such tumor antigens mediate an immune response by an immune cell from one or more subjects (e.g., a subject who has cancer and/or a control subject) to obtain one or more response profiles described herein. In some embodiments, methods of the disclosure identify one or more known tumor antigens as stimulatory antigens for one or more subjects. In some embodiments, methods of the disclosure identify one or more known tumor antigens as antigens that have minimal or no effect on an immune response for one or more subjects. In some embodiments, methods of the disclosure identify one or more known tumor antigens as inhibitory and/or suppressive antigens for one or more subjects.
In some embodiments, a polypeptide of interest is a potential tumor antigen, and methods and compositions described herein can be used to identify and/or detect immune responses to one or more potential tumor antigens. For example, in some embodiments, members of a library include (e.g., internally express or carry) one or more polypeptides identified as being of interest, e.g., encoding mutations associated with a tumor, using a method of the present disclosure and/or using a method other than a method of the present disclosure. In some such embodiments, such libraries can be used to assess whether and/or the extent to which such polypeptides mediate an immune response by an immune cell from one or more subjects (e.g., a subject who has cancer and/or a control subject) to obtain one or more response profiles described herein. In some embodiments, methods of the disclosure identify one or more polypeptides as stimulatory antigens for one or more subjects. In some embodiments, methods of the disclosure identify one or more polypeptides as antigens that have minimal or no effect on an immune response for one or more subjects. In some embodiments, methods of the disclosure identify one or more polypeptides as inhibitory and/or suppressive antigens for one or more subjects.
Polypeptides of interest used in methods and systems described herein include tumor antigens and potential tumor antigens, e.g., tumor specific antigens (TSAs, or neoantigens), tumor associated antigens (TAAs), and/or cancer/testis antigens (CTAs). Exemplary tumor antigens include, e.g., MART-1/MelanA (MART-I or MLANA), gp100 (Pmel 17 or SILV), tyrosinase, TRP-1, TRP-2, MAGE-1, MAGE-3 (also known as HIPS), BAGE, GAGE-1, GAGE-2, p15, Calcitonin, Calretinin, Carcinoembryonic antigen (CEA), Chromogranin, Cytokeratin, Desmin, Epithelial membrane protein (EMA), Factor VIII, Glial fibrillary acidic protein (GFAP), Gross cystic disease fluid protein (GCDFP-15), HMB-45, Human chorionic gonadotropin (hCG), inhibin, lymphocyte marker, MART-1 (Melan-A), Myo D1, muscle-specific actin (MSA), neurofilament, neuron-specific enolase (NSE), placental alkaline phosphatase (PLAP), prostate-specific antigen, PTPRC (CD45), S100 protein, smooth muscle actin (SMA), synaptophysin, thyroglobulin, thyroid transcription factor-1, Tumor M2-PK, vimentin, p53, Ras, HER-2/neu, BCR-ABL, E2A-PRL, H4-RET, IGH-IGK, MYL-RAR, Epstein Barr virus antigens (e.g., EBNA1), human papillomavirus (HPV) antigen E6 or E7 (HPV_E6 or HPV_E7), TSP-180, MAGE-4, MAGE-5, MAGE-6, RAGE, NY-ESO-1 (also known as CTAG1B), erbB, p185erbB2, p180erbB-3, c-met, nm-23H1, PSA, TAG-72, CA 19-9, CA 72-4, CAM 17.1, NuMa, K-ras, beta-Catenin, CDK4, Mum-1, p 15, p 16, 43-9F, 5T4, 791Tgp72, alpha-fetoprotein (AFP), beta-HCG, BCA225, BTAA, CA 125, CA 15-3\CA 27.29\BCAA, CA 195, CA 242, CA-50, CAM43, CD68\P1, CO-029, FGF-5, G250, Ga733\EpCAM, HTgp-175, M344, MA-50, MG7-Ag, MOV18, NB/70K, NY-CO-1, RCAS1, SDCCAG16, TA-90\Mac-2 binding protein\cyclophilin C-associated protein, TAAL6, TAG72, TLP, MUC16, IL13Ra2, FRa, VEGFR2, Lewis Y, FAP, EphA2, CEACAM5, EGFR, CA6, CA9, GPNMB, EGP1, FOLR1, endothelial receptor, STEAP1, SLC44A4, Nectin-4, AGS-16, guanalyl cyclase C, MUC-1, CFC1B, integrin alpha 3 chain (of a3b1, a laminin receptor chain), TPS, CD19, CD20, CD22, CD30, CD31, CD72, CD180, CD171 (L1CAM), CD123, CD133, CD138, CD37, CD70, CD79a, CD79b, CD56, CD74, CD166, CD71, CD34, CD99, CD117, CD80, CD28, CD13, CD15, CD25, CD10, CLL-1/CLEC12A, ROR1, Glypican 3 (GPC3), Mesothelin, CD33/IL3Ra, c-Met, PSCA, PSMA, Glycolipid F77, EGFRvIII, BCMA, GD-2, PSAP, prostein (also known as P501S), PSMA, Survivin (also known as BIRC5), and MAGE-A3, MAGEA2, MAGEA4, MAGEA6, MAGEA9, MAGEA10, MAGEA12, BIRC5, CDH3, CEACAM3, CGB_isoform2, ELK4, ERBB2, HPSE1, HPSE2, KRAS_isoform1, KRAS_isoform2, MUC1, SMAD4, TERT, 2. TERT.3, TGFBR2, EGAG9_isoform1, TP53, CGB_isoform1, IMPDH2, LCK, angiopoietin-1 (Ang1) (also known as ANGPT1), XIAP (also known as BIRC4), galectin-3 (also known as LGALS3), VEGF-A (also known as VEGF), ATP6S1 (also known as ATP6AP1), MAGE-A1, cIAP-1 (also known as BIRC2), macrophage migration inhibitory factor (MIF), galectin-9 (also known as LGALS9), progranulin PGRN (also known as granulin), OGFR, MLIAP (also known as BIRC7), TBX4 (also known as ICPPS, SPS or T-Box4), secretory leukocyte protein inhibitor (Slpi) (also known as antileukoproteinase), Ang2 (also known as ANGPT2), galectin-1 (also known as LGALS1), TRP-2 (also known as DCT), hTERT (telomerase reverse transcriptase) tyrosinase-related protein 1 (TRP-1, TYRP1), NOR-90/UBF-2 (also known as UBTF), LGMN, SPA17, PRTN3, TRRAP_1, TRRAP_2, TRRAP_3, TRRAP_4, MAGEC2, PRAME, SOX10, RAC1, HRAS, GAGE4, AR, CYP1B1, MMP8, TYR, PDGFRB, KLK3, PAX3, PAX5, ST3GAL5, PLAC1, RhoC, MYCN, REG3A, CSAG2, CTAG2-1a, CTAG2-1b, PAGE4, BRAF, GRM3, ERBB4, KIT, MAPK1, MFI2, SART3, ST8SIA1, WDR46, AKAP-4, RGS5, FOSL1, PRM2, ACRBP, CTCFL, CSPG4, CCNB1, MSLN, WT1, SSX2, KDR, ANKRD30A, MAGED1, MAP3K9, XAGE1B, PREX2, CD276, TEK, AIM1, ALK, FOLH1, GRIN2A MAP3K5 and one or more isoforms of any preceding tumor antigens. Exemplary tumor antigens are provided in the accompanying list of sequences. In some embodiments, a tumor antigen comprises a variant of an amino acid sequence provided in the accompanying list of sequences (e.g., a sequence that is at least about 85%, 90%, 95%, 96%, 97% 98%, 99% identical to an amino acid sequence provided in the accompanying list of sequences and/or a sequence that includes a mutation, deletion, and/or insertion of at least one amino acid (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or more amino acids) relative to an amino acid sequence provided in the accompanying list of sequences).
Tumor specific antigens (TSAs, or neoantigens) are tumor antigens that are not encoded in normal host genome (see, e.g., Yarchoan et al., Nat. Rev. Cancer. 2017 Feb. 24. doi: 10.1038/nrc.2016.154; Gubin et al., J. Clin. Invest. 125:3413-3421 (2015)). In some embodiments, TSAs arise from somatic mutations and/or other genetic alterations. In some embodiments, TSAs arise from missense or in-frame mutations. In some embodiments, TSAs arise from frame-shift mutations or loss-of-stop-codon mutations. In some embodiments, TSAs arise from insertion or deletion mutations. In some embodiments, TSAs arise from duplication or repeat expansion mutations. In some embodiments, TSAs arise from splice variants or improper splicing. In some embodiments, TSAs arise from gene fusions. In some embodiments, TSAs arise from translocations. In some embodiments, TSAs include oncogenic viral proteins. For example, as with Merkel cell carcinoma (MCC) associated with the Merkel cell polyomavirus (MCPyV) and cancers of the cervix, oropharynx and other sites associated with the human papillomavirus (HPV), TSAs include proteins encoded by viral open reading frames. For purposes of this disclosure, the terms “mutation” and “mutations” encompass all mutations and genetic alterations that may give rise to an antigen encoded in the genome of a cancer or tumor cell of a subject, but not in a normal or non-cancerous cell of the same subject. In some embodiments, TSAs are specific (personal) to a subject. In some embodiments, TSAs are shared by more than one subject, e.g., less than 1%, 1-3%, 1-5%, 1-10%, or more of subjects suffering from a cancer. In some embodiments, TSAs shared by more than one subject may be known or pre-selected.
In some embodiments, a TSA is encoded by an open reading frame from a virus. For example, a library can be designed to express polypeptides from one of the following viruses: an immunodeficiency virus (e.g., a human immunodeficiency virus (HIV), e.g., HIV-1, HIV-2), a hepatitis virus (e.g., hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis A virus, non-A and non-B hepatitis virus), a herpes virus (e.g., herpes simplex virus type I (HSV-1), HSV-2, Varicella-zoster virus, Epstein Barr virus, human cytomegalovirus, human herpesvirus 6 (HHV-6), HHV-7, HHV-8), a poxvirus (e.g., variola, vaccinia, monkeypox, Molluscum contagiosum virus), an influenza virus, a human papilloma virus, adenovirus, rhinovirus, coronavirus, respiratory syncytial virus, rabies virus, coxsackie virus, human T cell leukemia virus (types I, II and III), parainfluenza virus, paramyxovirus, poliovirus, rotavirus, rhinovirus, rubella virus, measles virus, mumps virus, adenovirus, yellow fever virus, Norwalk virus, West Nile virus, a Dengue virus, Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV), bunyavirus, Ebola virus, Marburg virus, Eastern equine encephalitis virus, Venezuelan equine encephalitis virus, Japanese encephalitis virus, St. Louis encephalitis virus, Junin virus, Lassa virus, and Lymphocytic choriomeningitis virus. Libraries for other viruses can also be produced and used according to methods described herein.
Tumor specific antigens are known in the art, any of which can be used in methods described herein. In some embodiments, gene sequences encoding polypeptides that are potential or putative neoantigens are determined by sequencing the genome and/or exome of tumor tissue and healthy tissue from a subject having cancer using next generation sequencing technologies. In some embodiments, genes that are selected based on their frequency of mutation and ability to encode a potential or putative neoantigen are sequenced using next-generation sequencing technology. Next-generation sequencing applies to genome sequencing, genome resequencing, transcriptome profiling (RNA-Seq), DNA-protein interactions (ChIP-sequencing), and epigenome characterization (de Magalhaes et al. (2010) Ageing Research Reviews 9 (3): 315-323; Hall N (2007) J. Exp. Biol. 209 (Pt 9): 1518-1525; Church (2006) Sci. Am. 294 (1): 46-54; ten Bosch et al. (2008) Journal of Molecular Diagnostics 10 (6): 484-492; Tucker T et al. (2009) The American Journal of Human Genetics 85 (2): 142-154). Next-generation sequencing can be used to rapidly reveal the presence of discrete mutations such as coding mutations in individual tumors, e.g., single amino acid changes (e.g., missense mutations, in-frame mutations) or novel stretches of amino acids generated by frame-shift insertions, deletions, gene fusions, read-through mutations in stop codons, duplication or repeat expansion mutations, and translation of splice variants or improperly spliced introns, and translocations (e.g., “neoORFs”).
Another method for identifying potential or putative neoantigens is direct protein sequencing. Protein sequencing of enzymatic digests using multidimensional MS techniques (MSn) including tandem mass spectrometry (MS/MS)) can also be used to identify neoantigens. Such proteomic approaches can be used for rapid, highly automated analysis (see, e.g., Gevaert et al., Electrophoresis 21:1145-1154 (2000)). High-throughput methods for de novo sequencing of unknown proteins can also be used to analyze the proteome of a subject's tumor to identify expressed potential or putative neoantigens. For example, meta shotgun protein sequencing may be used to identify expressed potential or putative neoantigens (see e.g., Guthals et al. (2012) Molecular and Cellular Proteomics 11(10):1084-96).
Potential or putative neoantigens may also be identified using MHC multimers to identify neoantigen-specific T cell responses. For example, high-throughput analysis of neoantigen-specific T cell responses in patient samples may be performed using MHC tetramer-based screening techniques (see e.g., Hombrink et al. (2011) PLoS One; 6(8): e22523; Hadrup et al. (2009) Nature Methods, 6(7):520-26; van Rooij et al. (2013) Journal of Clinical Oncology, 31:1-4; and Heemskerk et al. (2013) EMBO Journal, 32(2):194-203).
In some embodiments, one or more known or pre-selected tumor specific antigens, or one or more potential or putative tumor specific antigens identified using one of these methods, can be included in a library described herein.
Tumor associated antigens (TAAs) include proteins encoded in a normal genome (see, e.g., Ward et al., Adv. Immunol. 130:25-74 (2016)). In some embodiments, TAAs are either normal differentiation antigens or aberrantly expressed normal proteins. Overexpressed normal proteins that possess growth/survival-promoting functions, such as Wilms tumor 1 (WT1) (Ohminami et al., Blood 95:286-293 (2000)) or Her2/neu (Kawashima et al., Cancer Res. 59:431-435 (1999)), are TAAs that directly participate in the oncogenic process. Post-translational modifications, such as phosphorylation, of proteins may also lead to formation of TAAs (Doyle, J. Biol. Chem. 281:32676-32683 (2006); Cobbold, Sci. Transl. Med. 5:203ra125 (2013)). TAAs are generally shared by more than one subject, e.g., less than 1%, 1-3%, 1-5%, 1-10%, 1-20%, or more of subjects suffering from a cancer. In some embodiments, TAAs are known or pre-selected tumor antigens. In some embodiments, with respect to an individual subject, TAAs are potential or putative tumor antigens. Cancer/testis antigens (CTAs) are expressed by various tumor types and by reproductive tissues (for example, testes, fetal ovaries and trophoblasts) but have limited or no detectable expression in other normal tissues in the adult and are generally not presented on normal reproductive cells, because these tissues do not express MHC class I molecules (see, e.g., Coulie et al., Nat. Rev. Cancer 14:135-146 (2014); Simpson et al., Nat. Rev. Cancer 5:615-625 (2005); Scanlan et al., Immunol. Rev. 188:22-32 (2002)). Library Screens
The present disclosure provides, inter alia, compositions and methods for identifying tumor antigens recognized by human immune cells. Human antigen presenting cells express ligands for antigen receptors and other immune activation molecules on human lymphocytes. Given differences in MHC peptide binding specificities and antigen processing enzymes between species, antigens processed and presented by human cells are more likely to be physiologically relevant human antigens in vivo than antigens identified in non-human systems. Accordingly, methods of identifying these antigens employ human cells to present candidate tumor antigen polypeptides. Any human cell that internalizes library members and presents polypeptides expressed by the library members on MHC molecules can be used as an antigen presenting cell according to the present disclosure. In some embodiments, human cells used for antigen presentation are primary human cells. The cells can include peripheral blood mononuclear cells (PBMC) of a human. In some embodiments, peripheral blood cells are separated into subsets (e.g., subsets comprising dendritic cells, macrophages, monocytes, B cells, or combinations thereof) prior to use in an antigen presentation assay. In some embodiments, a subset of cells that expresses MHC class II is selected from peripheral blood. In one example, a cell population including dendritic cells is isolated from peripheral blood. In some embodiments, a subset of dendritic cells is isolated (e.g., plasmacytoid, myeloid, or a subset thereof). Human dendritic cell markers include CD1c, CD1a, CD303, CD304, CD141, and CD209. Cells can be selected based on expression of one or more of these markers (e.g., cells that express CD303, CD1c, and CD141).
Dendritic cells can be isolated by positive selection from peripheral blood using commercially available kits (e.g., from Miltenyi Biotec Inc.). In some embodiments, the dendritic cells are expanded ex vivo prior to use in an assay. Dendritic cells can also be produced by culturing peripheral blood cells under conditions that promote differentiation of monocyte precursors into dendritic cells in vitro. These conditions typically include culturing the cells in the presence of cytokines such as GM-CSF and IL-4 (see, e.g., Inaba et al., Isolation of dendritic cells, Curr. Protoc. Immunol. May; Chapter 3: Unit 3.7, 2001). Procedures for in vitro expansion of hematopoietic stem and progenitor cells (e.g., taken from bone marrow or peripheral blood), and differentiation of these cells into dendritic cells in vitro, is described in U.S. Pat. No. 5,199,942, and U.S. Pat. Pub. 20030077263. Briefly, CD34+ hematopoietic stem and progenitor cells are isolated from peripheral blood or bone marrow and expanded in vitro in culture conditions that include one or more of Flt3-L, IL-1, IL-3, and c-kit ligand.
In some embodiments, immortalized cells that express human MHC molecules (e.g., human cells, or non-human cells that are engineered to express human MHC molecules) are used for antigen presentation. For example, assays can employ COS cells transfected with human MHC molecules or HeLa cells.
In some embodiments, both the antigen presenting cells and immune cells used in the method are derived from the same subject (e.g., autologous T cells and APC are used). In these embodiments, it can be advantageous to sequentially isolate subsets of cells from peripheral blood of the subject, to maximize the yield of cells available for assays. For example, one can first isolate CD4+ and CD8+ T cell subsets from the peripheral blood. Next, dendritic cells (DC) are isolated from the T cell-depleted cell population. The remaining T- and DC-depleted cells are used to supplement the DC in assays, or are used alone as antigen presenting cells. In some embodiments, DC are used with T- and DC-depleted cells in an assay, at a ratio of 1:2, 1:3, 1:4, or 1:5. In some embodiments, the antigen presenting cells and immune cells used in the method are derived from different subjects (e.g., heterologous T cells and APC are used).
Antigen presenting cells can be isolated from sources other than peripheral blood. For example, antigen presenting cells can be taken from a mucosal tissue (e.g., nose, mouth, bronchial tissue, tracheal tissue, the gastrointestinal tract, the genital tract (e.g., vaginal tissue), or associated lymphoid tissue), peritoneal cavity, lymph nodes, spleen, bone marrow, thymus, lung, liver, kidney, neuronal tissue, endocrine tissue, or other tissue, for use in screening assays. In some embodiments, cells are taken from a tissue that is the site of an active immune response (e.g., an ulcer, sore, or abscess). Cells may be isolated from tissue removed surgically, via lavage, or other means.
Antigen presenting cells useful in methods described herein are not limited to “professional” antigen presenting cells. In some embodiments, non-professional antigen presenting cells can be utilized effectively in the practice of methods of the present disclosure. Non-professional antigen presenting cells include fibroblasts, epithelial cells, endothelial cells, neuronal/glial cells, lymphoid or myeloid cells that are not professional antigen presenting cells (e.g., T cells, neutrophils), muscle cells, liver cells, and other types of cells.
Antigen presenting cells are cultured with library members that express a polypeptide of interest (and, if desired, a cytolysin polypeptide) under conditions in which the antigen presenting cells internalize, process and present polypeptides expressed by the library members on WIC molecules. In some embodiments, library members are killed or inactivated prior to culture with the antigen presenting cells. Cells or viruses can be inactivated by any appropriate agent (e.g., fixation with organic solvents, irradiation, freezing). In some embodiments, the library members are cells that express ORFs linked to a tag (e.g., a tag which comprises one or more known T cell epitopes) or reporter protein, expression of which has been verified prior to the culturing.
In some embodiments, antigen presenting cells are incubated with library members at 37° C. for between 30 minutes and 5 hours (e.g., for 45 min. to 1.5 hours). After the incubation, the antigen presenting cells can be washed to remove library members that have not been internalized. In certain embodiments, the antigen presenting cells are non-adherent, and washing requires centrifugation of the cells. The washed antigen presenting cells can be incubated at 37° C. for an additional period of time (e.g., 30 min. to 2 hours) prior to exposure to lymphocytes, to allow antigen processing. In some embodiments, it is desirable to fix and kill the antigen presenting cells prior to exposure to lymphocytes (e.g., by treating the cells with 1% paraformaldehyde).
The antigen presenting cell and library member numbers can be varied, so long as the library members provide quantities of polypeptides of interest sufficient for presentation on MHC molecules. In some embodiments, antigen presenting cells are provided in an array, and are contacted with sets of library cells, each set expressing a different polypeptide of interest. In certain embodiments, each location in the array includes 1×103-1×106 antigen presenting cells, and the cells are contacted with 1×103-1×108 library cells which are bacterial cells.
In any of the embodiments described herein, antigen presenting cells can be freshly isolated, maintained in culture, and/or thawed from frozen storage prior to incubation with library cells, or after incubation with library cells.
In methods of the present disclosure, human lymphocytes are tested for antigen-specific reactivity to antigen presenting cells, e.g., antigen presenting cells that have been incubated with libraries expressing polypeptides of interest as described above. The methods of the present disclosure permit rapid identification of human antigens using pools of lymphocytes isolated from an individual, or progeny of the cells. The detection of antigen-specific responses does not rely on laborious procedures to isolate individual T cell clones. In some embodiments, the human lymphocytes are primary lymphocytes. In some embodiments, human lymphocytes are NKT cells, gamma-delta T cells, or NK cells. Just as antigen presenting cells may be separated into subsets prior to use in antigen presentation assays, a population of lymphocytes having a specific marker or other feature can be used. In some embodiments, a population of T lymphocytes is isolated. In some embodiments, a population of CD4+ T cells is isolated. In some embodiments, a population of CD8+ T cells is isolated. CD8+ T cells recognize peptide antigens presented in the context of MHC class I molecules. Thus, in some embodiments, the CD8+ T cells are used with antigen presenting cells that have been exposed to library host cells that co-express a cytolysin polypeptide, in addition to a polypeptide of interest. T cell subsets that express other cell surface markers may also be isolated, e.g., to provide cells having a particular phenotype. These include CLA (for skin-homing T cells), CD25, CD30, CD69, CD154 (for activated T cells), CD45RO (for memory T cells), CD294 (for Th2 cells), γ/δ TCR-expressing cells, CD3 and CD56 (for NK T cells). Other subsets can also be selected.
Lymphocytes can be isolated, and separated, by any means known in the art (e.g., using antibody-based methods such as those that employ magnetic bead separation, panning, or flow cytometry). Reagents to identify and isolate human lymphocytes and subsets thereof are well known and commercially available.
Lymphocytes for use in methods described herein can be isolated from peripheral blood mononuclear cells, or from other tissues in a human. In some embodiments, lymphocytes are taken from tumors, lymph nodes, a mucosal tissue (e.g., nose, mouth, bronchial tissue, tracheal tissue, the gastrointestinal tract, the genital tract (e.g., vaginal tissue), or associated lymphoid tissue), peritoneal cavity, spleen, thymus, lung, liver, kidney, neuronal tissue, endocrine tissue, peritoneal cavity, bone marrow, or other tissues. In some embodiments, cells are taken from a tissue that is the site of an active immune response (e.g., an ulcer, sore, or abscess). Cells may be isolated from tissue removed surgically, via lavage, or other means.
Lymphocytes taken from an individual can be maintained in culture or frozen until use in antigen presentation assays. In some embodiments, freshly isolated lymphocytes can be stimulated in vitro by antigen presenting cells exposed to library cells as described above. In some embodiments, these lymphocytes exhibit detectable stimulation without the need for prior non-antigen specific expansion. However, primary lymphocytes also elicit detectable antigen-specific responses when first stimulated non-specifically in vitro. Thus, in some embodiments, lymphocytes are stimulated to proliferate in vitro in a non-antigen specific manner, prior to use in an antigen presentation assay. Lymphocytes can also be stimulated in an antigen-specific manner prior to use in an antigen presentation assay. In some embodiments, cells are stimulated to proliferate by a library (e.g., prior to use in an antigen presentation assay that employs the library). Expanding cells in vitro provides greater numbers of cells for use in assays. Primary T cells can be stimulated to expand, e.g., by exposure to a polyclonal T cell mitogen, such as phytohemagglutinin or concanavalin, by treatment with antibodies that stimulate proliferation, or by treatment with particles coated with the antibodies. In some embodiments, T cells are expanded by treatment with anti-CD2, anti-CD3, and anti-CD28 antibodies. In some embodiments, T cells are expanded by treatment with interleukin-2. In some embodiments, lymphocytes are thawed from frozen storage and expanded (e.g., stimulated to proliferate, e.g., in a non-antigen specific manner or in an antigen-specific manner) prior to contacting with antigen presenting cells. In some embodiments, lymphocytes are thawed from frozen storage and are not expanded prior to contacting with antigen presenting cells. In some embodiments, lymphocytes are freshly isolated and expanded (e.g., stimulated to proliferate, e.g., in a non-antigen specific manner or in an antigen-specific manner) prior to contacting with antigen presenting cells.
In antigen presentation assays, T cells are cultured with antigen presenting cells prepared according to the methods described above, under conditions that permit T cell recognition of peptides presented by MHC molecules on the antigen presenting cells. In some embodiments, T cells are incubated with antigen presenting cells at 37° C. for between 12-48 hours (e.g., for 24 hours). In some embodiments, T cells are incubated with antigen presenting cells at 37° C. for 3, 4, 5, 6, 7, or 8 days. Numbers of antigen presenting cells and T cells can be varied. In some embodiments, the ratio of T cells to antigen presenting cells in a given assay is 1:10, 1:5, 1:2, 1:1, 2:1, 5:1, 10:1, 20:1, 25:1, 30:1, 32:1, 35:1 or 40:1. In some embodiments, antigen presenting cells are provided in an array (e.g., in a 96-well plate), wherein cells in each location of the array have been contacted with sets of library cells, each set including a different polypeptide of interest. In certain embodiments, each location in the array includes 1×103-1×106 antigen presenting cells, and the cells are contacted with 1×103-1×106 T cells.
After T cells have been incubated with antigen presenting cells, cultures are assayed for activation. Lymphocyte activation can be detected by any means known in the art, e.g., T cell proliferation, phosphorylation or dephosphorylation of a receptor, calcium flux, cytoskeletal rearrangement, increased or decreased expression and/or secretion of immune mediators such as cytokines or soluble mediators, increased or decreased expression of one or more cell surface markers. In some embodiments, culture supernatants are harvested and assayed for increased and/or decreased expression and/or secretion of one or more polypeptides associated with activation, e.g., a cytokine, soluble mediator, cell surface marker, or other immune mediator. In some embodiments, the one or more cytokines are selected from TRAIL, IFN-gamma, IL-12p70, IL-2, TNF-alpha, MIP1-alpha, MIP1-beta, CXCL9, CXCL10, MCP1, RANTES, IL-1 beta, IL-4, IL-6, IL-8, IL-9, IL-10, IL-13, IL-15, CXCL11, IL-3, IL-5, IL-17, IL-18, IL-21, IL-22, IL-23A, IL-24, IL-27, IL-31, IL-32, TGF-beta, CSF, GM-CSF, TRANCE (also known as RANK L), MIP3-alpha, and fractalkine. In some embodiments, the one or more soluble mediators are selected from granzyme A, granzyme B, sFas, sFasL, perforin, and granulysin. In some embodiments, the one or more cell surface markers are selected from CD107a, CD107b, CD25 (IL-2RA), CD69, CD45RA, CD45RO, CD137 (4-1BB), CD44, CD62L, CD27, CCR7, CD154 (CD40L), KLRG-1, CD71, HLA-DR, CD122 (IL-2RB), CD28, IL7Ra (CD127), CD38, CD26, CD134 (OX-40), CTLA-4 (CD152), LAG-3, TIM-3 (CD366), CD39, PD1 (CD279), FoxP3, TIGIT, CD160, BTLA, 2B4 (CD244), and KLRG1. Cytokine secretion in culture supernatants can be detected, e.g., by ELISA, bead array, e.g., with a Luminex® analyzer. Cytokine production can also be assayed by RT-PCR of mRNA isolated from the T cells, or by ELISPOT analysis of cytokines released by the T cells. In some embodiments, proliferation of T cells in the cultures is determined (e.g., by detecting 3H thymidine incorporation). In some embodiments, target cell lysis is determined (e.g., by detecting T cell dependent lysis of antigen presenting cells labeled with Na251CrO4). Target cell lysis assays are typically performed with CD8+ T cells. Protocols for these detection methods are known. See, e.g., Current Protocols In Immunology, John E. Coligan et al. (eds), Wiley and Sons, New York, N.Y., 2007. One of skill in the art understands that appropriate controls are used in these detection methods, e.g., to adjust for non-antigen specific background activation, to confirm the presenting capacity of antigen presenting cells, and to confirm the viability of lymphocytes.
In some embodiments, antigen presenting cells and lymphocytes used in the method are from the same individual. In some embodiments, antigen presenting cells and lymphocytes used in the method are from different individuals.
In some embodiments, antigen presentation assays are repeated using lymphocytes from the same individual that have undergone one or more previous rounds of exposure to antigen presenting cells, e.g., to enhance detection of responses, or to enhance weak initial responses. In some embodiments, antigen presentation assays are repeated using antigen presenting cells from the same individual that have undergone one or more previous rounds of exposure to a library, e.g., to enhance detection of responses, or to enhance weak initial responses. In some embodiments, antigen presentation assays are repeated using lymphocytes from the same individual that have undergone one or more previous rounds of exposure to antigen presenting cells, and antigen presenting cells from the same individual that have undergone one or more previous rounds of exposure to a library, e.g., to enhance detection of responses, or to enhance weak initial responses. In some embodiments, antigen presentation assays are repeated using antigen presenting cells and lymphocytes from different individuals, e.g., to identify antigens recognized by multiple individuals, or compare reactivities that differ between individuals.
One advantage of methods described herein is their ability to identify clinically relevant human antigens. Humans that have cancer may have lymphocytes that specifically recognize tumor antigens, which are the product of an adaptive immune response arising from prior exposure. In some embodiments, these cells are present at a higher frequency than cells from an individual who does not have cancer, and/or the cells are readily reactivated when re-exposed to the proper antigenic stimulus (e.g., the cells are “memory” cells). Thus, humans that have or have had cancer are particularly useful donors of cells for identifying antigens in vitro. The individual may be one who has recovered from cancer. In some embodiments, the individual has been recently diagnosed with cancer (e.g., the individual was diagnosed less than one year, three months, two months, one month, or two weeks, prior to isolation of lymphocytes and/or antigen presenting cells from the individual). In some embodiments, the individual was first diagnosed with cancer more than three months, six months, or one year prior to isolation of lymphocytes and/or antigen presenting cells.
In some embodiments, lymphocytes are screened against antigen presenting cells that have been contacted with a library of cells whose members express or carry polypeptides of interest, and the lymphocytes are from an individual who has not been diagnosed with cancer. In some embodiments, such lymphocytes are used to determine background (i.e., non-antigen-specific) reactivities. In some embodiments, such lymphocytes are used to identify antigens, reactivity to which exists in non-cancer individuals.
Cells from multiple donors (e.g., multiple subjects who have cancer) can be collected and assayed in methods described herein. In some embodiments, cells from multiple donors are assayed in order to determine if a given tumor antigen is reactive in a broad portion of the population, or to identify multiple tumor antigens that can be later combined to produce an immunogenic composition that will be effective in a broad portion of the population.
Antigen presentation assays are useful in the context of both infectious and non-infectious diseases. The methods described herein are applicable to any context in which a rapid evaluation of human cellular immunity is beneficial. In some embodiments, antigenic reactivity to polypeptides that are differentially expressed by neoplastic cells (e.g., tumor cells) is evaluated. Sets of nucleic acids differentially expressed by neoplastic cells have been identified using established techniques such as subtractive hybridization. Methods described herein can be used to identify antigens that were functional in a subject in which an anti-tumor immune response occurred. In other embodiments, methods are used to evaluate whether a subject has lymphocytes that react to a tumor antigen or set of tumor antigens.
In some embodiments, antigen presentation assays are used to examine reactivity to autoantigens in cells of an individual, e.g., an individual predisposed to, or suffering from, an autoimmune condition. Such methods can be used to provide diagnostic or prognostic indicators of the individual's disease state, or to identify autoantigens. For these assays, in some embodiments, libraries that include an array of human polypeptides are prepared. In some embodiments, libraries that include polypeptides from infectious agents which are suspected of eliciting cross-reactive responses to autoantigens are prepared. For examples of antigens from infectious agents thought to elicit cross-reactive autoimmune responses, see Barzilai et al., Curr Opin Rheumatol., 19(6):636-43, 2007; Ayada et al., Ann N Y Acad Sci., 1108:594-602, 2007; Drouin et al., Mol Immunol., 45(1):180-9, 2008; and Bach, J Autoimmun., 25 Supp1:74-80, 2005.
As discussed, the present disclosure includes methods in which polypeptides of interest are included in a library (e.g., expressed in library cells or carried in or on particles or beads). After members of the library are internalized by antigen presenting cells, the polypeptides of interest are proteolytically processed within the antigen presenting cells, and peptide fragments of the polypeptides are presented on MEW molecules expressed in the antigen presenting cells. The identity of the polypeptide that stimulates a human lymphocyte in an assay described herein can be determined from examination of the set of library cells that were provided to the antigen presenting cells that produced the stimulation. In some embodiments, it is useful to map the epitope within the polypeptide that is bound by MEW molecules to produce the observed stimulation. This epitope, or the longer polypeptide from which it is derived (both of which are referred to as an “antigen” herein) can form the basis for an immunogenic composition, or for an antigenic stimulus in future antigen presentation assays.
Methods for identifying peptides bound by MHC molecules are known. In some embodiments, epitopes are identified by generating deletion mutants of the polypeptide of interest and testing these for the ability to stimulate lymphocytes. Deletions that lose the ability to stimulate lymphocytes, when processed and presented by antigen presenting cells, have lost the peptide epitope. In some embodiments, epitopes are identified by synthesizing peptides corresponding to portions of the polypeptide of interest and testing the peptides for the ability to stimulate lymphocytes (e.g., in antigen presentation assays in which antigen presenting cells are pulsed with the peptides). Other methods for identifying MHC bound peptides involve lysis of the antigen presenting cells that include the antigenic peptide, affinity purification of the MHC molecules from cell lysates, and subsequent elution and analysis of peptides from the MHC (Falk, K. et al. Nature 351:290, 1991, and U.S. Pat. No. 5,989,565).
In other embodiments, it is useful to identify the clonal T cell receptors that have been expanded in response to the antigen. Clonal T cell receptors are identified by DNA sequencing of the T cell receptor repertoire (Howie et al, 2015 Sci Trans Med 7:301). By identifying TCR specificity and function, TCRs can be transfected into other cell types and used in functional studies or for novel immunotherapies.
In other embodiments, it is useful to identify and isolate T cells responsive to a tumor antigen in a subject. The isolated T cells can be expanded ex vivo and administered to a subject for cancer therapy or prophylaxis.
The disclosure provides methods of identifying one or more immune responses of a subject. One exemplary method of identifying tumor antigens is depicted schematically in the left portion of
In some embodiments, lymphocyte stimulation, non-stimulation, inhibition and/or suppression, activation, and/or non-responsiveness is determined by assessing levels of one or more expressed or secreted cytokines or other immune mediators described herein. In some embodiments, levels of one or more expressed or secreted cytokines that is at least 20%, 40%, 60%, 80%, 100%, 120%, 140%, 160%, 180%, 200% or more, higher than a control level indicates lymphocyte stimulation. In some embodiments, a level of one or more expressed or secreted cytokines that is at least 1, 2, 3, 4 or 5 standard deviations greater than the mean of a control level indicates lymphocyte stimulation. In some embodiments, a level of one or more expressed or secreted cytokines that is at least 1, 2, 3, 4 or 5 median absolute deviations (MADs) greater than a median response level to a control indicates lymphocyte stimulation. In some embodiments, a control is a negative control, for example, a clone expressing Neon Green (NG).
In some embodiments, a level of one or more expressed or secreted cytokines that is at least 20%, 40%, 60%, 80%, 100%, 120%, 140%, 160%, 180%, 200% or more, lower than a control level indicates lymphocyte inhibition and/or suppression. In some embodiments, a level of one or more expressed or secreted cytokines that is at least 1, 2, 3, 4 or 5 standard deviations lower than the mean of a control level indicates lymphocyte inhibition and/or suppression. In some embodiments, a level of one or more expressed or secreted cytokines that is at least 1, 2, 3, 4 or 5 median absolute deviations (MADs) lower than a median response level to a control indicates lymphocyte inhibition and/or suppression. In some embodiments, a control is a negative control, for example, a clone expressing Neon Green (NG).
In some embodiments, levels of one or more expressed or secreted cytokines that is at least 20%, 40%, 60%, 80%, 100%, 120%, 140%, 160%, 180%, 200% or more, higher or lower than a control level indicates lymphocyte activation. In some embodiments, a level of one or more expressed or secreted cytokines that is at least 1, 2, 3, 4 or 5 standard deviations greater or lower than the mean of a control level indicates lymphocyte activation. In some embodiments, a level of one or more expressed or secreted cytokines that is at least 1, 2, 3, 4 or 5 median absolute deviations (MADs) greater or lower than a median response level to a control indicates lymphocyte activation. In some embodiments, a control is a negative control, for example, a clone expressing Neon Green (NG).
In some embodiments, a level of one or more expressed or secreted cytokines that is within about 20%, 15%, 10%, 5%, or less, of a control level indicates lymphocyte non-responsiveness or non-stimulation. In some embodiments, a level of one or more expressed or secreted cytokines that is less than 1 or 2 standard deviations higher or lower than the mean of a control level indicates lymphocyte non-responsiveness or non-stimulation. In some embodiments, a level of one or more expressed or secreted cytokines that is less than 1 or 2 median absolute deviations (MADs) higher or lower than a median response level to a control indicates lymphocyte non-responsiveness or non-stimulation.
In some embodiments, a subject response profile can include a quantification, identification, and/or representation of a panel of different cytokines (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, or more cytokines) and of the total number of tumor antigens (e.g., of all or a portion of different tumor antigens from the library) that stimulate, do not stimulate, inhibit and/or suppress, activate, or have no or minimal effect on production, expression or secretion of each member of the panel of cytokines.
In general, immune responses can be usefully defined in terms of their integrated, functional end-effects. Dhabar et al. (2014) have proposed that immune responses can be categorized as being immunoprotective, immunopathological, and immunoregulatory/inhibitory. While these categories provide useful constructs with which to organize ideas, an overall in vivo immune response is likely to consist of several types of responses with varying amounts of dominance from each category. Immunoprotective or beneficial responses are defined as responses that promote efficient wound healing, eliminate infections and cancer, and mediate vaccine-induced immunological memory. These responses are associated with cytokines and mediators such as IFN-gamma, IL-12, IL-2, Granzyme B, CD107, etc. Immunopathological or deleterious responses are defined as those that are directed against self (autoimmune disease like multiple sclerosis, arthritis, lupus) or innocuous antigens (asthma, allergies) and responses involving chronic, non-resolving inflammation. These responses can also be associated with molecules that are implicated in immunoprotective responses, but also include immune mediators such as TNF-alpha, IL-10, IL-13, IL-17, IL-4, IgE, histamine, etc. Immunoregulatory responses are defined as those that involve immune cells and factors that regulate (mostly down-regulate) the function of other immune cells. Recent studies suggest that there is an arm of the immune system that functions to inhibit immune responses. For example, regulatory CD4+CD25+FoxP3+ T cells, IL-10, and TGF-beta, among others have been shown to have immunoregulatory/inhibitory functions. The physiological function of these factors is to keep pro-inflammatory, allergic, and autoimmune responses in check, but they may also suppress anti-tumor immunity and be indicative of negative prognosis for cancer. In the context of tumors, the expression of co-stimulatory molecules often decreases, and the expression of co-inhibitory ligands increases. MEW molecules are often down-regulated on tumor cells, favoring their escape. The tumor micro-environment, including stromal cells, tumor associated immune cells, and other cell types, produce many inhibitory factors, such as, IL-10, TGF-β, and IDO. Inhibitory immune cells, including T regs, Tr1 cells, immature DCs (iDCs), pDCs, and MDSC can be found in the tumor micro-environment. (Y Li UT GSBS Thesis 2016). Examples of mediators and their immune effects are shown in Table 2.
The disclosure provides methods and systems for identifying and selecting (or deselecting) tumor antigens (e.g., stimulatory and/or inhibitory antigens). In some embodiments, a stimulatory antigen is a tumor antigen (e.g., a tumor antigen described herein) that stimulates one or more lymphocyte responses that are beneficial to the subject. In some embodiments, a stimulatory antigen is a tumor antigen (e.g., a tumor antigen described herein) that inhibits and/or suppresses one or more lymphocyte responses that are deleterious or non-beneficial to the subject. Examples of immune responses that may lead to beneficial anti-tumor responses (e.g., that may enhance immune control of a tumor) include but are not limited to 1) cytotoxic CD8+ T cells which can effectively kill cancer cells and release the mediators perforin and/or granzymes to drive tumor cell death; and 2) CD4+ Th1 T cells which play an important role in host defense and can secrete IL-2, IFN-gamma and TNF-alpha. These are induced by IL-12, IL-2, and IFN gamma among other cytokines.
In some embodiments, an inhibitory antigen is a tumor antigen (e.g., a tumor antigen described herein) that stimulates one or more lymphocyte responses that are deleterious or non-beneficial to the subject. In some embodiments, an inhibitory antigen is a tumor antigen (e.g., a tumor antigen described herein) that inhibits and/or suppresses one or more lymphocyte responses that are beneficial to the subject. Examples of immune responses that may lead to deleterious or non-beneficial anti-tumor responses (e.g., that may impair or reduce control of a tumor) include but are not limited to 1) T regulatory cells which are a population of T cells that can suppress an immune response and secrete immunosuppressive cytokines such as TGF-beta and IL-10 and express the molecules CD25 and FoxP3; and 2) Th2 cells which target responses against allergens but are not productive against cancer. These are induced by increased IL-4 and IL-10 and can secrete IL-4, IL-5, IL-6, IL-9 and IL-13.
Additionally or alternatively, tumor antigens may be identified and/or selected (or de-selected) based on association with desirable or beneficial responses, e.g., clinical responses. Additionally or alternatively, tumor antigens may be identified and/or selected (or de-selected) based on association with undesirable, deleterious or non-beneficial responses, e.g., clinical responses. Tumor antigens may be identified and/or selected (or de-selected) based on a combination of the preceding methods, applied in any order.
Responses whereby tumor antigens or immunogenic fragments thereof (i) stimulate lymphocyte responses that are beneficial to the subject, (ii) stimulate expression of cytokines that are beneficial to the subject, (iii) inhibit and/or suppress lymphocyte responses that are deleterious or non-beneficial to the subject, or (iv) inhibit and/or suppress expression of cytokines that are deleterious or non-beneficial to the subject, are termed “beneficial responses”.
In some embodiments, a selected tumor antigen stimulates one or more lymphocyte responses that are beneficial to the subject. In some embodiments, a selected tumor antigen inhibits and/or suppresses one or more lymphocyte responses that are deleterious or non-beneficial to the subject.
In some embodiments, a selected tumor antigen increases expression and/or secretion of cytokines that are beneficial to the subject. In some embodiments, a selected tumor antigen inhibits and/or suppresses expression of cytokines that are deleterious or non-beneficial to the subject.
In some embodiments, administration of one or more selected tumor antigens to the subject elicits an immune response of the subject. In some embodiments, administration of one or more selected tumor antigens to the subject elicits a beneficial immune response of the subject. In some embodiments, administration of one or more selected tumor antigens to the subject elicits a beneficial response of the subject. In some embodiments, administration of one or more selected tumor antigens to the subject improves clinical response of the subject to a cancer therapy.
Responses whereby tumor antigens or immunogenic fragments thereof (i) stimulate lymphocyte responses that are deleterious or not beneficial to the subject, (ii) stimulate expression of cytokines that are deleterious or not beneficial to the subject, (iii) inhibit and/or suppress lymphocyte responses that are beneficial to the subject, or (iv) inhibit and/or suppress expression of cytokines that are beneficial to the subject, are termed “deleterious or non-beneficial responses”.
In some embodiments, one or more tumor antigens are selected (or de-selected) based on association with desirable or beneficial immune responses. In some embodiments, one or more tumor antigens are selected (or de-selected) based on association with undesirable, deleterious, or non-beneficial immune responses.
In some embodiments, a selected tumor antigen stimulates one or more lymphocyte responses that are deleterious or non-beneficial to the subject. In some embodiments, a selected tumor antigen inhibits and/or suppresses one or more lymphocyte responses that are beneficial to the subject.
In some embodiments, a selected tumor antigen increases expression and/or secretion of cytokines that are deleterious or non-beneficial to the subject. In some embodiments, a selected tumor antigen inhibits and/or suppresses expression of cytokines that are beneficial to the subject.
In some embodiments, the one or more tumor antigens are de-selected by the methods herein.
In some embodiments, the one or more selected tumor antigens are excluded from administration to a subject.
In well-established tumors, activation of endogenous anti-tumor T cell responses is often insufficient to result in complete tumor regression. Moreover, T cells that have been educated in the context of the tumor micro-environment sometimes are sub-optimally activated, have low avidity, and ultimately fail to recognize the tumor cells that express antigen. In addition, tumors are complex and comprise numerous cell types with varying degrees of expression of mutated genes, making it difficult to generate polyclonal T cell responses that are adequate to control tumor growth. As a result, researchers in the field have proposed that it is important in cancer subjects to identify the mutations that are “potential tumor antigens” in addition to those that are confirmed in the cancer subject to be recognized by their T cells.
There are currently no reliable methods of identifying potential tumor antigens in a comprehensive way. Computational methods have been developed in an attempt to predict what is an antigen, however there are many limitations to these approaches. First, modeling epitope prediction and presentation needs to take into account the greater than 12,000 HLA alleles encoding MHC molecules, with each subject expressing as many as 14 of them, all with different epitope affinities. Second, the vast majority of predicted epitopes fail to be found presented by tumors when they are evaluated using mass spectrometry. Third, the predictive algorithms do not take into account T cell recognition of the antigen, and the majority of predicted epitopes are incapable of eliciting T cell responses even when they are present. Finally, the second arm of cellular immunity, the CD4+ T cell subset, is often overlooked; the majority of in silico tools focus on MHC class I binders. The tools for predicting MHC class II epitopes are under-developed and more variable.
The present disclosure provides methods to a) identify polypeptides that are potential tumor antigens in antigen presentation assays of the disclosure, and b) select polypeptides on the basis of their antigenic potential. The methods are performed without making predictions about what could be a target of T cell responses or presented by MHC, and without the need for deconvolution. The methods can be expanded to explore antigenic potential in healthy subjects who share the same MHC alleles as a subject, to identify those potential tumor antigens that would be most suitable to include in an immunogenic composition or vaccine formulation. The methods ensure that the potential tumor antigen is processed and presented in the context of subject MHC molecules, and that T cells can respond to the potential tumor antigen if they are exposed to the potential tumor antigen under the right conditions (e.g., in the context of a vaccine with a strong danger signal from an adjuvant or delivery system).
The preceding methods for selection of tumor antigens may be applied to selection of potential tumor antigens, that is, polypeptides encoding one or more mutations present or expressed in a cancer or tumor cell of a subject.
Methods of Redirecting Immune Responses and/or Re-Educating Lymphocytes Using Adoptive Cell Therapy
As discussed herein, the disclosure provides methods of redirecting one or more immune responses (e.g., one or more immune responses described herein), e.g., by re-educating one or more lymphocytes.
As discussed herein, in some embodiments, the present disclosure provides methods and systems related to redirecting one or more immune responses in a subject. In some embodiments, an initial immune response in a subject impairs or reduces immune control of a tumor or cancer cell in the subject (e.g., the subject has a clinically negative response or is clinically non-responsive). In some embodiments, an initial immune response in a subject that impairs or reduces immune control of a tumor or cancer cell in the subject is redirected (e.g., using methods of the disclosure) such that the immune response in a subject enhances immune control of a tumor or cancer cell in the subject (e.g., the subject has a clinically positive response).
Whether an immune response impairs or enhances immune control of a tumor or cancer cell can be measured and/or characterized according to particular criteria. In certain embodiments, such criteria can include clinical criteria and/or objective criteria. In certain embodiments, techniques for assessing response can include, but are not limited to, clinical examination, positron emission tomography, chest X-ray, CT scan, MM, ultrasound, endoscopy, laparoscopy, presence or level of a particular marker in a sample, cytology, and/or histology. A positive response, a negative response, and/or no response, of a tumor can be assessed by ones skilled in the art using a variety of established techniques for assessing such response, including, for example, for determining one or more of tumor burden, tumor size, tumor stage, etc. Methods and guidelines for assessing response to treatment are discussed in Therasse et al., J. Natl. Cancer Inst., 2000, 92(3):205-216; and Seymour et al., Lancet Oncol., 2017, 18:e143-52.
In some embodiments, enhanced immune control of a tumor or cancer results in a measured decrease in tumor burden, tumor size, and/or tumor stage. In some embodiments, impaired immune control of a tumor or cancer does not result in a measured decrease in tumor burden, tumor size, or tumor stage. In some embodiments, impaired immune control of a tumor or cancer results in a measured increase in tumor burden, tumor size, or tumor stage.
Exemplary agents that can be used to re-educate a T cell and/or to redirect an immune response include adjuvants, cytokines, immune checkpoint blockade therapies (e.g., described herein), viral vectors, bacterial vectors, exosomes, liposomes, DNAs, mRNAs, saRNAs, chemotherapeutic agents, and IDO inhibitors.
In some embodiments, methods include obtaining lymphocytes from a subject, re-educating such lymphocytes ex vivo and administering such re-educated lymphocytes to a subject as a cancer therapy. In some embodiments, one or more T cells from a patient are obtained and re-educated ex vivo using an effective amount of an agent or a combination of agents. In some embodiments, T cells with one or more specificities are obtained from a patient and re-educated ex vivo using an effective amount of an agent or a combination of agents.
In some embodiments, methods include culturing T cells with an effective amount of an agent or a combination of agents for a certain period of time. In some embodiments the T cells may be cultured with an effective amount of an agent or combination of agents for e.g., at least 6, 12, 18, 24, 30, 36, 42, 48, or more hours. In some embodiments, the T cells may be cultured with an effective amount of an agent or combination of agents for e.g., at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 14, 21 or more days. In some embodiments, the expansion step is performed for no more than 5, 4, 3, 2, or 1 day.
Once the T cells are re-educated, they can then be re-administered to the subject. For example, a cellular therapeutic comprising the re-educated T cells can be administered to the subject. To determine that the T cell populations are re-educated, T cells may be assayed using antigen presentation assays and/or assaying for certain cell markers expressed on the T cells as previously described.
In another embodiment, T cells that are responsive to an inhibitory antigen may be isolated from PBMCs from a subject. T cells responsive to an inhibitory antigen may be isolated from the PBMCs using a particular combination of reagents and culture media in the presence of the inhibitory antigen. For example, tetramers, bi-specific cytokine capture reagents, and antibodies could be used. The T cells may be re-educated using an effective amount of an agent or a combination of agents. In another embodiment, isolated and re-educated T cells may be pooled with PBMCs from which they were isolated from and/or may be pooled with unexpanded or expanded stimulatory T cells prior to administration to the subject. In some embodiments, the T cells may be expanded ex vivo and then administered to the subject. In some embodiments, the T cells may be concurrently re-educated and expanded ex vivo, then administered to the subject.
In other embodiments, PBMCs are obtained from a cancer patient and the T cells present in the PBMCs that are responsive to an inhibitory antigen are identified. The T cells identified may then be depleted ex vivo. T cells in the remaining fraction of PBMCs may be stimulated with one or more stimulatory antigens and may optionally be expanded non-specifically. PBMCs including the stimulated T cells may then be administered back to the cancer patient.
In some embodiments, autologous or HLA matched allogeneic PBMCs are stimulated with one or more inhibitory antigens to induce one or more beneficial immune responses, and such PBMCs are administered to the subject. In some embodiments, a T cell receptor from T cells specific for inhibitory antigens are isolated and transduced into new T cells from the same subject or an HLA-matched allogeneic individual to elicit a beneficial response.
In the exemplary method of
In some embodiments, the agent used for re-educating a lymphocyte may be an adjuvant. Adjuvants can be broadly separated into two classes, based on their principal mechanisms of action: vaccine delivery systems and immunostimulatory adjuvants (see, e.g., Singh et al., Curr. HIV Res. 1:309-20, 2003). Vaccine delivery systems are often particulate formulations, e.g., emulsions, microparticles, immune-stimulating complexes (ISCOMs), which may be, for example, particles and/or matrices, and liposomes. In contrast, immunostimulatory adjuvants are sometimes derived from pathogens and can represent pathogen associated molecular patterns (PAMP), e.g., lipopolysaccharides (LPS), monophosphoryl lipid (MPL), or CpG-containing DNA, which activate cells of the innate immune system.
Alternatively, adjuvants may be classified as organic and inorganic. Inorganic adjuvants include alum salts such as aluminum phosphate, amorphous aluminum hydroxyphosphate sulfate, and aluminum hydroxide, which are commonly used in human vaccines. Organic adjuvants comprise organic molecules including macromolecules. An example of an organic adjuvant is cholera toxin.
Adjuvants may also be classified by the response they induce, and adjuvants can activate more than one type of response. In some embodiments, the adjuvant induces the activation of CD4+ T cells. The adjuvant may induce activation of TH1 cells and/or activation of TH17 cells and/or activation of TH2 cells. Alternately, the adjuvant may induce activation of TH1 cells and/or TH17 cells but not activation of TH2 cells, or vice versa. In some embodiments, the adjuvant induces activation of CD8+ T cells. In further embodiments, the adjuvant may induce activation of Natural Killer T (NKT) cells. In some embodiments, the adjuvant induces the activation of TH1 cells or TH17 cells or TH2 cells. In other embodiments, the adjuvant induces the activation of B cells. In yet other embodiments, the adjuvant induces the activation of antigen-presenting cells. These categories are not mutually exclusive; in some cases, an adjuvant activates more than one type of cell.
In certain embodiments, an adjuvant is a substance that increases the numbers or activity of antigen presenting cells such as dendritic cells. In certain embodiments, an adjuvant promotes the maturation of antigen presenting cells such as dendritic cells. In some embodiments, an adjuvant is an inflammasome activator. In some embodiments, the inflammasome activator is aluminum potassium sulfate, a RIG-1 agonist such as poly(dA:dT), a TLR5 agonist such as flagellin, or a dectin-1 antagonist such as Curdlan. In some embodiments, the adjuvant is or comprises a saponin. Typically, the saponin is a triterpene glycoside, such as those isolated from the bark of the Quillaja saponaria tree. A saponin extract from a biological source can be further fractionated (e.g., by chromatography) to isolate the portions of the extract with the best adjuvant activity and with acceptable toxicity. Typical fractions of extract from Quillaja saponaria tree used as adjuvants are known as fractions A and C. An exemplary saponin adjuvant is QS-21, which is available from Antigenics. QS-21 is an oligosaccharide-conjugated small molecule. Optionally, QS-21 may be admixed with a lipid such as 3D-MPL or cholesterol.
A particular form of saponins that may be used in vaccine formulations described herein is immunostimulating complexes (ISCOMs). ISCOMs are an art-recognized class of adjuvants, that generally comprise Quillaja saponin fractions and lipids (e.g., cholesterol and phospholipids such as phosphatidyl choline). In certain embodiments, an ISCOM is assembled together with a polypeptide or nucleic acid of interest. However, different saponin fractions may be used in different ratios. In addition, the different saponin fractions may either exist together in the same particles or have substantially only one fraction per particle (such that the indicated ratio of fractions A and C are generated by mixing together particles with the different fractions). In this context, “substantially” refers to less than 20%, 15%, 10%, 5%, 4%, 3%, 2% or even 1%. Such adjuvants may comprise fraction A and fraction C mixed into a ratio of 70-95 A: 30-5 C, such as 70 A:30 C to 75 A:25 C, 75 A:25 C to 80 A:20 C, 80 A:20 C to 85 A:15 C, 85 A:15 C to 90 A:10 C, 90 A:10 C to 95 A:5 C, or 95 A:5 C to 99 A:1 C. ISCOMatrix, produced by CSL, and AbISCO 100 and 300, produced by Isconova, are ISCOM matrices comprising saponin, cholesterol and phospholipid (lipids from cell membranes), which form cage-like structures typically 40-50 nm in diameter. Posintro, produced by Nordic Vaccines, is an ISCOM matrix where the immunogen is bound to the particle by a multitude of different mechanisms, e.g. electrostatic interaction by charge modification, incorporation of chelating groups or direct binding.
In some embodiments, the adjuvant is a TLR agonist, a STING agonist, or a molecule that triggers the inflammasome. In some embodiments, the TLR agonist is a TLR2 agonist such as Pam3CSK4. In some embodiments, the TLR agonist is a TLR3 agonist such as Poly-IC or Poly-ICLC (Hiltonol). In some embodiments, the TLR agonist is a TLR4 agonist such as 3D-PHAD. In some embodiments the TLR agonist is a TLR7 agonist such as imiquimod or R848. In some embodiments, the TLR agonist is a TLR5 agonist such as flagellin. In some embodiments, the TLR agonist is a TLR9 agonist such as CpG.
In some embodiments, the adjuvant is a nanoemulsion that is a high-energy, oil-in-water emulsion with a size of 150-400 nanometers, and includes surfactants to provide stability.
Adjuvants may be covalently bound to antigens (e.g., the polypeptides described above). In some embodiments, the adjuvant may be a protein which induces inflammatory responses through activation of antigen-presenting cells (APCs). In some embodiments, one or more of these proteins can be recombinantly fused with an antigen of choice, such that the resultant fusion molecule promotes dendritic cell maturation, activates dendritic cells to produce cytokines and chemokines, and ultimately, enhances presentation of the antigen to T cells and initiation of T cell responses (see Wu et al., Cancer Res 2005; 65(11), pp 4947-4954). Other exemplary adjuvants that may be covalently bound to antigens comprise polysaccharides, small molecules, synthetic peptides, lipopeptides, and nucleic acids.
The adjuvant can be used alone or in combination of two or more kinds. Adjuvants may be directly conjugated to antigens. Adjuvants may also be combined to increase the magnitude of the immune response to the antigen. Typically, the same adjuvant or mixture of adjuvants is administered or present in each stimulation event (e.g., vaccination, prime injection, boost injection, ex vivo or in vitro cell culture). Optionally, however, an adjuvant may be administered or provided with the first stimulation but not in subsequent stimulations. Alternatively, a strong adjuvant may be administered or provided at initial stimulation, and a weaker adjuvant or lower dose of the strong adjuvant may be administered or provided with subsequent re-stimulations. The adjuvant can be administered or provided before the antigen, concurrent with the antigen, or after administration of the antigen to a subject (sometimes within 1, 2, 6, or 12 hours; sometimes within 1, 2, or 5 days; sometimes within 1, 2, or 3 months; sometimes within 6, 12, or 18 months; sometimes within 2, 3, 4, 5, 10, or 15 years), or after provision of the antigen to PBMC or T cell culture (sometimes within 1, 2, 6, or 12 hours, and sometimes within 1, 2, or 5 days). In some embodiments, and adjuvant may be directly combined or formulated with an antigen for in vitro culture or to make a vaccine composition suitable for administration to a subject. In certain embodiments, an adjuvant may be administered or provided separately from an antigen. An adjuvant may be administered or provided separately but concurrently with an antigen, or may be administered or provided in between doses of an antigen.
An adjuvant used may include any of the adjuvants described previously herein for example, TLR agonists and/or STING agonists. The type of adjuvant used to re-educate a T cell can be a combination of one or more adjuvants. In some embodiments, an agent may include an immune checkpoint inhibitor.
In some embodiments, the agent used for re-educating a lymphocyte may be one or more adjuvants alone or in combination with another agent including, e.g., cytokines, immune checkpoint blockade therapies (e.g., described herein), viral vectors, bacterial vectors, exosomes, liposomes, DNAs, mRNAs, saRNAs, chemotherapeutic agents, and IDO inhibitors. In some embodiments, one or more adjuvants and another agent e.g., cytokines, immune checkpoint blockade therapies (e.g., described herein), viral vectors, bacterial vectors, exosomes, liposomes, DNAs, mRNAs, saRNAs, chemotherapeutic agents, and IDO inhibitors, used for re-educating a lymphocyte, are used concurrently or sequentially.
In some embodiments, an agent used for re-educating a lymphocyte may be a cytokine, or a cocktail comprising two or more cytokines. In some embodiments, re-education drives a lymphocyte towards a Th1 phenotype (e.g., increases the number and/or proportion of Th1 cells, e.g., cells expressing one or more Th1-associated cytokine, relative to a control). In some embodiments, the agent used for re-educating a lymphocyte may be a Th1-associated cytokine, or a cocktail comprising two or more Th1-associated cytokines (e.g., IL-2, IL-7, IL-15, IL-21, IL-12p40, IFN-gamma). In some embodiments, re-education drives a lymphocyte towards a Th2 phenotype (e.g., increases the number and/or proportion of Th2 cells, e.g., cells expressing one or more Th2-associated cytokine, relative to a control). In some embodiments, the agent used for re-educating a lymphocyte may be a Th2-associated cytokine, or a cocktail comprising two or more Th2-associated cytokines (e.g., IL-4, IL-5, IL-13).
In some embodiments, an agent used for concurrently re-educating and expanding a lymphocyte may be a cytokine, or a cocktail comprising two or more cytokines. In some embodiments, concurrent re-education and expansion drives a lymphocyte towards a Th1 phenotype (e.g., increases the number and/or proportion of Th1 cells, e.g., cells expressing one or more Th1-associated cytokine, relative to a control). In some embodiments, the agent used for concurrently re-educating and expanding a lymphocyte may be a Th1-associated cytokine, or a cocktail comprising two or more Th-1 cytokines (e.g., IL-2, IL-7, IL-15, IL-21, IL-12p40, IFN-gamma). In some embodiments, concurrent re-education and expansion drives a lymphocyte towards a Th2 phenotype (e.g., increases the number and/or proportion of Th2 cells, e.g., cells expressing one or more Th2-associated cytokine, relative to a control). In some embodiments, the agent used for concurrently re-educating and expanding a lymphocyte may be a Th2-associated cytokine, or a cocktail comprising two or more Th2-associated cytokines (e.g., IL-4, IL-5, IL-13).
In some embodiments, an agent used for re-educating a lymphocyte may include a chemotherapeutic agent. A “chemotherapeutic agent” is a chemical compound useful in the treatment of cancer, regardless of mechanism of action. Classes of chemotherapeutic agents include, but are not limited to: alkylating agents, antimetabolites, spindle poison plant alkaloids, cytotoxic/antitumor antibiotics, topoisomerase inhibitors, antibodies, photosensitizers, and kinase inhibitors. Nonlimiting examples of chemotherapeutic agents include erlotinib (TARCEVA®, Genentech/OSI Pharm.), docetaxel (TAXOTER®, Sanofi-Aventis), 5-FU (fluorouracil, 5-fluorouracil, CAS No. 51-21-8), gemcitabine (GEMZAR®, Lilly), PD-0325901 (CAS No. 391210-10-9, Pfizer), cisplatin (cis-diamine, dichloroplatinum(II), CAS No. 15663-27-1), carboplatin (CAS No. 41575-94-4), paclitaxel (TAXOL®, Bristol-Myers Squibb Oncology, Princeton, N.J.), temozolomide (4-methyl-5-oxo-2,3,4,6,8-pentazabicyclo [4.3.0] nona-2,7,9-triene-9-carboxamide, CAS No. 85622-93-1, TEMODAR®, TEMODAL®, Schering Plough), tamoxifen ((Z)-2-[4-(1,2-diphenylbut-1-enyl)phenoxy]-N,N-dimethyl-ethanamine, NOLVADEX®, ISTUBAL®, VALODEX®), and doxorubicin (ADRIAMYCIN®), Akti-1/2, HPPD, and rapamycin.
Additional examples of chemotherapeutic agents include: oxaliplatin (ELOXATIN®, Sanofi), bortezomib (VELCADE®, Millennium Pharm.), sutent (SUNITINIB®, SU11248, Pfizer), letrozole (FEMARA®, Novartis), imatinib mesylate (GLEEVEC®, Novartis), XL-518 (MEK inhibitor, Exelixis, WO 2007/044515), ARRY-886 (Mek inhibitor, AZD6244, Array BioPharma, Astra Zeneca), SF-1126 (PI3K inhibitor, Semafore Pharmaceuticals), BEZ-235 (PI3K inhibitor, Novartis), XL-147 (PI3K inhibitor, Exelixis), PTK787/ZK 222584 (Novartis), fulvestrant (FASLODEX®, AstraZeneca), leucovorin (folinic acid), rapamycin (sirolimus, RAPAMUNE®, Wyeth), lapatinib (TYKERB®, GSK572016, Glaxo Smith Kline), lonafarnib (SARASAR™, SCH 66336, Schering Plough), sorafenib (NEXAVAR®, BAY43-9006, Bayer Labs), gefitinib (IRESSA®, AstraZeneca), irinotecan (CAMPTOSAR®, CPT-11, Pfizer), tipifarnib (ZARNESTRA™, Johnson & Johnson), ABRAXANE™ (Cremophor-free), albumin-engineered nanoparticle formulations of paclitaxel (American Pharmaceutical Partners, Schaumberg, Ill.), vandetanib (rINN, ZD6474, ZACTIMA®, AstraZeneca), chloranmbucil, AG1478, AG1571 (SU 5271; Sugen), temsirolimus (TORISEL®, Wyeth), pazopanib (GlaxoSmithKline), canfosfamide (TELCYTA®, Telik), thiotepa and cyclosphosphamide (CYTOXAN®, NEOSAR®); alkyl sulfonates such as busulfan, improsulfan and piposulfan; aziridines such as benzodopa, carboquone, meturedopa, and uredopa; ethylenimines and methylamelamines including altretamine, triethylenemelamine, triethylenephosphoramide, triethylenethiophosphoramide and trimethylomelamine; acetogenins (especially bullatacin and bullatacinone); a camptothecin (including the synthetic analog topotecan); bryostatin; callystatin; CC-1065 (including its adozelesin, carzelesin and bizelesin synthetic analogs); cryptophycins (particularly cryptophycin 1 and cryptophycin 8); dolastatin; duocarmycin (including the synthetic analogs, KW-2189 and CB1-TM1); eleutherobin; pancratistatin; a sarcodictyin; spongistatin; nitrogen mustards such as chlorambucil, chlornaphazine, chlorophosphamide, estramustine, ifosfamide, mechlorethamine, mechlorethamine oxide hydrochloride, melphalan, novembichin, phenesterine, prednimustine, trofosfamide, uracil mustard; nitrosoureas such as carmustine, chlorozotocin, fotemustine, lomustine, nimustine, and ranimnustine; antibiotics such as the enediyne antibiotics (e.g., calicheamicin, calicheamicin gamma1I, calicheamicin omegaI1 (Angew Chem. Intl. Ed. Engl. (1994) 33:183-186); dynemicin, dynemicin A; bisphosphonates, such as clodronate; an esperamicin; as well as neocarzinostatin chromophore and related chromoprotein enediyne antibiotic chromophores), aclacinomysins, actinomycin, authramycin, azaserine, bleomycins, cactinomycin, carabicin, carminomycin, carzinophilin, chromomycinis, dactinomycin, daunorubicin, detorubicin, 6-diazo-5-oxo-L-norleucine, morpholino-doxorubicin, cyanomorpholino-doxorubicin, 2-pyrrolino-doxorubicin and deoxydoxorubicin), epirubicin, esorubicin, idarubicin, marcellomycin, mitomycins such as mitomycin C, mycophenolic acid, nogalamycin, olivomycins, peplomycin, porfiromycin, puromycin, quelamycin, rodorubicin, streptonigrin, streptozocin, tubercidin, ubenimex, zinostatin, zorubicin; anti-metabolites such as methotrexate and 5-fluorouracil (5-FU); folic acid analogs such as denopterin, methotrexate, pteropterin, trimetrexate; purine analogs such as fludarabine, 6-mercaptopurine, thiamiprine, thioguanine; pyrimidine analogs such as ancitabine, azacitidine, 6-azauridine, carmofur, cytarabine, dideoxyuridine, doxifluridine, enocitabine, floxuridine; androgens such as calusterone, dromostanolone propionate, epitiostanol, mepitiostane, testolactone; anti-adrenals such as aminoglutethimide, mitotane, trilostane; folic acid replenisher such as frolinic acid; aceglatone; aldophosphamide glycoside; aminolevulinic acid; eniluracil; amsacrine; bestrabucil; bisantrene; edatraxate; defofamine; demecolcine; diaziquone; elfornithine; elliptinium acetate; an epothilone; etoglucid; gallium nitrate; hydroxyurea; lentinan; lonidainine; maytansinoids such as maytansine and ansamitocins; mitoguazone; mitoxantrone; mopidanmol; nitraerine; pentostatin; phenamet; pirarubicin; losoxantrone; podophyllinic acid; 2-ethylhydrazide; procarbazine; PSK® polysaccharide complex (JHS Natural Products, Eugene, Oreg.); razoxane; rhizoxin; sizofiran; spirogermanium; tenuazonic acid; triaziquone; 2,2′,2″-trichlorotriethylamine; trichothecenes (T-2 toxin, verracurin A, roridin A and anguidine); urethan; vindesine; dacarbazine; mannomustine; mitobronitol; mitolactol; pipobroman; gacytosine; arabinoside (Ara-C); cyclophosphamide; thiotepa; 6-thioguanine; mercaptopurine; methotrexate; platinum analogs such as cisplatin and carboplatin; vinblastine; etoposide (VP-16); ifosfamide; mitoxantrone; vincristine; vinorelbine (NAVELBINE®); novantrone; teniposide; edatrexate; daunomycin; aminopterin; capecitabine (XELODA®, Roche); ibandronate; CPT-11; topoisomerase inhibitor RFS 2000; difluoromethylornithine (DMFO); retinoids such as retinoic acid; and pharmaceutically acceptable salts, acids and derivatives of any of the above.
Methods of Obtaining T cells
In certain embodiments of the disclosure, a source of T cells can first be obtained, e.g., from a subject. Non-limiting examples of subjects include humans, dogs, cats, mice, rats, and transgenic species thereof. As described herein, T cells or PBMCs depleted of a certain population of T cells can be administered to a subject. Thus, the T cells will have an immunocompatibility relationship to a recipient subject, and any such relationship is contemplated for use according to the present disclosure.
For example, the T cells can be syngeneic to a recipient subject. The term “syngeneic” refers to the state of deriving from, originating in, or being members of the same species that are genetically identical, particularly with respect to antigens or immunological reactions. These include identical twins having matching MHC types.
T cells can be “autologous” if the transferred cells are obtained from and transplanted to the same subject.
T cells can be “matched allogeneic” if the transferred cells are obtained from and transplanted to different members of the same species, yet have sufficiently matched major histocompatibility complex (MHC) antigens to avoid an adverse immunogenic response. Determining the degree of MHC mismatch may be accomplished according to standard tests known and used in the art (see, e.g., Mickelson and Petersdorf (1999) Hematopoietic Cell Transplantation, Thomas, E. D. et al. eds., pg 28-37, Blackwell Scientific, Malden, Mass.; Vaughn, Method. Mol. Biol. MHC Protocol. 210:45-60 (2002); Morishima et al., Blood 99:4200-4206 (2002)).
T cells can be “mismatched allogeneic”, which refers to deriving from, originating in, or being members of the same species having non-identical major histocompatibility complex (MHC) antigens (i.e., proteins) as typically determined by standard assays used in the art, such as serological or molecular analysis of a defined number of MHC antigens, sufficient to elicit adverse immunogenic responses. A “partial mismatch” refers to partial match of the MHC antigens tested between members, typically between a donor and recipient. For instance, a “half mismatch” (haplo-mismatch) refers to 50% of the MHC antigens tested as showing different MHC antigen type between two members. A “full” or “complete” mismatch refers to all MHC antigens tested as being different between two members.
T cells can be “xenogeneic”, which refers to deriving from, originating in, or being members of different species, e.g., human and rodent, human and swine, human and chimpanzee, etc.
T cells can be obtained from a number of sources, including peripheral blood mononuclear cells (PBMCs), bone marrow, lymph node tissue, spleen tissue, thymic tissue and umbilical cord. In certain embodiments, any number of T cell lines available in the art, may be used. In certain embodiments, T cells are obtained from a unit of blood collected from a subject using any number of techniques known to the skilled artisan, such as Ficoll separation. For example, cells from the circulating blood of a subject can be obtained by apheresis or leukapheresis. The apheresis product typically contains lymphocytes, including T cells, monocytes, granulocytes, B cells, other nucleated white blood cells, red blood cells, and platelets. In some embodiments, the cells collected by apheresis can be washed to remove the plasma fraction and to place the cells in an appropriate buffer or media for subsequent processing steps.
In another method, T cells are isolated from peripheral blood by lysing red blood cells and depleting monocytes, for example, by centrifugation through a PERCOLL™ gradient. Alternatively, T cells can be isolated from blood harvested from umbilical cord.
A plurality of T cells of interest (e.g., T cells that mediate an immune response to an inhibitory antigen that impairs or reduces immune control of a tumor or cancer) can then be obtained or isolated (e.g., sorted) from an initial source, e.g., a sample of PBMCs. In one embodiment, fluorescence activated cell sorting (FACS) or magnetic activated cell sorting (MACS), is used to sort, analyze, and/or isolate T cells of interest. For example, cells having a cellular marker or other specific marker of interest can be tagged with an antibody, or a mixture of antibodies, that bind one or more of the cellular markers. Each antibody directed to a different marker can be conjugated to a detectable molecule, e.g., a fluorescent dye, that may be distinguished from other fluorescent dyes coupled to other antibodies. A stream of tagged or “stained” cells can be passed through a light source that excites the fluorochrome and the emission spectrum from the cells detected to determine the presence of a particular labeled antibody. By concurrent detection of different fluorochromes (multicolor fluorescence cell sorting), cells displaying different sets of cell markers can be identified and isolated from other cells in the population. Other FACS parameters, including, e.g., side scatter (SSC), forward scatter (FSC), and vital dye staining (e.g., with propidium iodide) allow selection of cells based on size and viability. FACS and MACS sorting and analysis are well-known in the art and described in, for example, U.S. Pat. Nos. 5,137,809; 5,750,397; 5,840,580; 6,465,249; Miltenyi, et al., Cytometry 11:231-238 (1990). General guidance on fluorescence activated cell sorting is described in, for example, Shapiro (2003) Practical Flow Cytometry, 4th Ed., Wiley-Liss (2003) and Ormerod (2000) Flow Cytometry: A Practical Approach, 3rd Ed., Oxford University Press.
Another method of isolating T cells of interest involves a solid or insoluble substrate to which is bound antibodies or ligands that interact with specific cell surface markers. In immunoadsorption techniques, cells can be contacted with the substrate (e.g., column of beads, flasks, magnetic particles, etc.) containing the antibodies and any unbound cells removed. Immunoadsorption techniques can be scaled up to deal directly with the large numbers of cells in a clinical harvest. Suitable substrates include, e.g., plastic, cellulose, dextran, polyacrylamide, agarose, and others known in the art (e.g., Pharmacia Sepharose 6 MB macrobeads). When a solid substrate comprising magnetic or paramagnetic beads is used, cells bound to the beads can be readily isolated by a magnetic separator (see, e.g., Kato et al., Cytometry 14:384-92 (1993)). Affinity chromatographic cell separations can involve passing a suspension of cells over a support bearing a selective ligand immobilized to its surface. The ligand interacts with its specific target molecule on the cell and is captured on the matrix. The bound cell is released by the addition of an elution agent to the running buffer of the column and the free cell is washed through the column and harvested as a homogeneous population. As apparent to the skilled artisan, adsorption techniques may use nonspecific adsorption.
FACS, MACS, and most batch wise immunoadsorption techniques can be adapted to both positive and negative selection procedures (see, e.g., U.S. Pat. No. 5,877,299). In positive selection, the desired cells are labeled with antibodies and removed away from the remaining unlabeled/unwanted cells. In negative selection, the unwanted cells are labeled and removed. Another type of negative selection that may be employed is use of antibody/complement treatment or immunotoxins to remove unwanted cells.
In some embodiments, a population of cells can be obtained (e.g., using a sorting method described herein) and used in methods of the disclosure that comprises more than about 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99%, or more (e.g., about 65% to about 90%, about 65% to about 95%, about 80% to about 90%, about 80% to about 95%, about 85% to about 90%, about 85% to about 95%, or about 90% to about 95%), cells of interest (e.g., T cells that mediate an immune response to at least one inhibitory antigen). In some embodiments, a population of cells (e.g., a depleted cell population described herein) can be obtained (e.g., using a sorting method described herein) and used in methods of the disclosure that comprises less than about 40%, 35%, 30%, 25%, 20%, 15%, 10%, 5%, 4%, 3%, 2%, 1%, or less (e.g., about 5% to about 10%, about 4% to about 10%, about 3% to about 10%, about 2% to about 10%, about 1% to about 10%, about 1% to about 5%, or about 2% to about 5%), or lack any detectable, cells of interest (e.g., T cells that mediate an immune response to at least one inhibitory antigen).
The obtained populations of cells can be used directly in a method of the disclosure, or can be frozen for use at a later date using a known method. For example, cells can be frozen using a freezing medium comprising 5-10% DMSO, 10-90% serum albumin, and 50-90% culture medium. Other additives useful for preserving cells include, e.g., disaccharides such as trehalose (Scheinkonig et al., Bone Marrow Transplant. 34:531-536 (2004)), a plasma volume expander (such as hetastarch), and/or isotonic buffer solutions (such as phosphate-buffered saline). Compositions and methods for cryopreservation are well-known in the art (see, e.g., Broxmeyer et al., Proc. Natl. Acad. Sci. U.S.A. 100:645-650 (2003)).
Methods of Activating T cells
Methods of the disclosure can include a step of activating a population of cells (e.g., an obtained population of T cells described herein). For example, a population of T cells can be activated by contacting with an activation agent. Agents that activate T cells are known in the art, and any of such agents can be used in an activation step. Exemplary, nonlimiting activating agents include an anti-CD3 antibody, anti-Tac antibody, anti-CD28 antibody, and/or phytohemagglutinin (PHA). In some embodiments, a population of T cells is activated by contacting with an anti-CD3 antibody and with an anti-CD28 antibody. For example, a population of T cells can be contacted with beads that include anti-CD3 antibody and anti-CD28 antibody. Such beads are known in the art and commercially available from, e.g., ThermoFisher Scientific.
The activation step can be performed for, e.g., at least 2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 28, 32, 36, 40, 48, or more hours, or 1, 2, 3, 4, or more weeks.
Methods of the disclosure can include a step of expanding a population of T cells (e.g., an obtained population of T cells described herein). For example, before or after an activation or re-education step described herein, a population of T cells can be expanded by culturing in a suitable cell culture medium that lacks an activation or re-education agent. Alternatively, a population of T cells can be activated or re-educated and expanded concurrently (i.e., in the presence of one or more activation or re-education agents described herein). Additionally or alternatively, the expansion step can include culturing a population of T cells in a culture medium comprising, but not limited to, IL-2, IL-7, IL-15, IL-21, IL-12p40, and/or IFN-gamma. In some embodiments, the expansion step can include culturing a population of T cells comprising combinations of two or more of such cytokines.
In some embodiments, T cells are expanded in an antigen-specific manner (e.g., by contacting T cells with one or more specific antigen and with one or more other mediators (not including anti-CD3). In some cases, multiple antigens are combined. In some embodiments, T cells are expanded in a non-specific manner (e.g., not in the presence of an antigen).
The expansion step can be performed, e.g., for at least 6, 12, 18, 24, 30, 36, 42, 48, or more hours, or 1, 2, 3, 4, or more weeks. In some embodiments, the expansion step is performed for at least 1, 2, 3, 4, 5, 6, or more days. In some embodiments, the expansion step is performed for no more than 5, 4, 3, 2, or 1 day.
The expansion step can be performed until the number of cells in the population reaches at least about 104, 105, 106, 107, 108, or more cells.
Sorted T cells can be cultured under conditions generally appropriate for T cell culture. Conditions can include an appropriate culture medium that can contain factors for proliferation and viability, including serum (e.g., fetal bovine or human serum), interleukin-2 (IL-2), insulin, IFN-γ, IL-4, IL-7, GM-CSF, IL-10, IL-15, TGFβ, TNF-α or any other additives for the growth of cells as known to the skilled artisan. Other additives for the growth of cells include, but are not limited to, surfactant, plasmanate, and reducing agents such as N-acetyl-cysteine and 2-mercaptoethanol. Exemplary media that can be used to culture T cells include RPMI 1640, DMEM, MEM, α-MEM, F-12, X-Vivo 1, X-Vivo 5, X-Vivo 15, X-Vivo 20, and Optimizer. Media can contain or be supplemented with amino acids, sodium pyruvate, and vitamins, either serum-free or supplemented with an appropriate amount of serum (or plasma) or a defined set of hormones, and/or an amount of cytokine(s) sufficient for the growth and expansion of T cells. T cells can be maintained under conditions to support growth, e.g., at an appropriate temperature (e.g., 37° C.) and atmosphere (e.g., air plus 5% CO2), as known to those in the art.
Methods of Administering T cells
Once a population of T cells is isolated, re-educated and/or expanded, various methods of administering T cells to a subject may be used and are described herein. In some embodiments, the method effectively treats cancer in the subject.
A population of re-educated T cells and/or a depleted cell population described herein can be formulated into a cellular therapeutic. In some embodiments, a cellular therapeutic further includes a pharmaceutically acceptable carrier, diluent, and/or excipient. Pharmaceutically acceptable carriers described herein, for example, vehicles, adjuvants, excipients, and diluents, are well-known and readily available to those skilled in the art. Preferably, the pharmaceutically acceptable carrier is chemically inert to the active agent(s), e.g., a cellular therapeutic, and does not elicit any detrimental side effects or toxicity under the conditions of use.
A cellular therapeutic can be formulated for administration by any suitable route, such as, for example, intravenous, intratumoral, intraarterial, intramuscular, intraperitoneal, intrathecal, epidural, and/or subcutaneous administration routes. Preferably, the cellular therapeutic is formulated for a parenteral route of administration. In some embodiments, a cellular therapeutic is administered to a subject via an infusion.
A cellular therapeutic suitable for parenteral administration can be an aqueous or nonaqueous, isotonic sterile injection solution, which can contain anti-oxidants, buffers, bacteriostats, and solutes, for example, that render the composition isotonic with the blood of the intended recipient. An aqueous or nonaqueous sterile suspension can contain one or more suspending agents, solubilizers, thickening agents, stabilizers, and preservatives.
Dosage administered to a subject, particularly a human, will vary with the particular embodiment, the cellular therapeutic employed, the method of administration, and the particular site and subject being treated. However, a dose should be sufficient to provide a therapeutic response, e.g, immune response. A clinician skilled in the art can determine the therapeutically effective amount of a cellular therapeutic to be administered to a human or other subject in order to treat or prevent a particular medical condition. The precise amount of the cellular therapeutic required to be therapeutically effective will depend upon numerous factors, e.g., such as the specific activity of the cellular therapeutic, and the route of administration, in addition to many subject-specific considerations, which are within those of skill in the art.
Any suitable number of cells described herein can be administered to a subject. While a single therapeutic cell described herein is capable of expanding and providing a therapeutic benefit, in some embodiments, 102 or more, e.g., 103 or more, 104 or more, 105 or more, or 108 or more, therapeutic cells are administered as a cellular therapeutic. Alternatively, or additionally 1012 or less, e.g., 1011 or less, 109 or less, 107 or less, or 105 or less, therapeutic cells described herein are administered to a subject as a cellular therapeutic. In some embodiments, 102-105, 104-107, 103-109, or 105-1010 therapeutic cells described herein are administered as a cellular therapeutic.
A dose of a cellular therapeutic described herein can be administered to a mammal at one time or in a series of subdoses administered over a suitable period of time, e.g., on a daily, semi-weekly, weekly, bi-weekly, semi-monthly, bi-monthly, semi-annual, or annual basis, as needed. A dosage unit comprising an effective amount of a cellular therapeutic may be administered in a single daily dose, or the total daily dosage may be administered in two, three, four, or more divided doses administered daily, as needed. In some embodiments, a cellular therapeutic is administered in combination with checkpoint blockade, one or more cytokines such as IL-2 OR IL-7 (coincident, prior or after), or after in vivo ablation therapies such as fludarabine and cyclophosphamide.
The re-direction of an immune response or re-education of a lymphocyte may be determined by measuring the change in lymphocyte response to one or more antigens.
In some embodiments, lymphocyte response may be measured at a cellular level. In some embodiments, lymphocyte response may be measured by performing assays to measure the level of certain immune mediators. Assays may include, but are not limited to the antigen presentation assays described previously. Immune mediators measured may be known immune mediators and immune mediators described herein, for example, cytokines. An exemplary assay to measure lymphocyte response may be an assay that uses an enzyme-linked immunosorbent assay (ELISA) technique, such as an ELISPOT assay. Assays may also include analysis of upregulation of cell surface molecules such as co-stimulatory molecules (i.e. CD28, LFA-1, CD137 [4-1BB], CD154 [CD40L]), effector memory markers (i.e. CD45RO, CD62L), or HLA molecules by flow cytometry. Assays may also include evaluation of beneficial genes via gene chip analyses.
At a cellular level, redirection of immune responses or re-education of a lymphocyte may be determined by the percent change in cytokine secretion in response to an identified antigen compared to a control level where the antigen is not presented for example, by more than 5%, 6%, 7%, 8%, 9%, 10%, 20%. A control level may be without presentation of an antigen or without the addition of a composition to induce redirection of an immune response or re-education, such as an adjuvant. Redirection of an immune response or re-education may be determined by a change in levels of immune mediators in response to an antigen presented alone compared to an antigen presented in combination with an adjuvant. Redirection of an immune response or re-education may be determined by a change in levels of one or more immune mediators over time, for example, by more than 5%, 6%, 7%, 8%, 9%, 10%, 20%. In some embodiments, redirection of an immune response or re-education of a lymphocyte may be determined by a change in the levels of different immune mediators produced by a lymphocyte, or the change in the predominant type of immune mediator produced by a lymphocyte, in response to the presentation of an antigen. For example, the change in expression and/or secretion of IL-10 to IFN-gamma may indicate redirection or re-education from an immunosuppressive response to an immunostimulatory response.
At the tissue level, an immune response may be measured by the pathology of a tissue in a subject. In some embodiments, RECIST criteria (http://recist.eortc.org/publications/) can be used to determine if the tumors shrink, grow, or stay the same. In some embodiments, pathologies characterizing tumors as may be used to characterize an immune response over time and can include tumor size, altered expression of genetic markers, invasion of adjacent organs and/or lymph nodes by tumor cells. In some embodiments, immune response may be evidenced by the size of a tumor, using a metric such as tumor area and/or volume. Tumor area and/or volume may be measured over time and immune response may be indicated by the change in size and/or growth kinetics of the tumor. In some embodiments, a change in tumor size or rate of growth in a subject immunized with an immunogenic composition may be compared to the change in tumor size or rate of growth in an un-immunized control subject. In some embodiments, infiltration of the tumors with immune cells can be monitored with multi-parameter immunohistochemistry, T cell receptor sequencing, or evaluation of enriched tumor infiltrating lymphocytes using conventional immunoassays. Redirection of immune responses or re-education of lymphocytes can be determined by an increase in tumor infiltration by T cells.
Redirection of immune responses or re-education of lymphocytes at a tissue level may be determined by a change in the growth of a tumor over time in a subject immunized with antigen compared to a control, for example, by more than 5%, 6%, 7%, 8%, 9%, 10%, or 20%. Re-education of lymphocytes at a tissue level may be demonstrated by a difference in tumor area or volume in a subject treated with antigen compared to a control for example that is more than %, 6%, 7%, 8%, 9%, 10%, or 20%. A control level may be without presentation of an antigen or without the addition of a composition to induce redirection of an immune response or re-education, such as an adjuvant.
A tumor antigen (e.g., a tumor antigen described herein) suitable for use in any method or composition of the disclosure may be produced by any available means, such as recombinantly or synthetically (see, e.g., Jaradat Amino Acids 50:39-68 (2018); Behrendt et al., J. Pept. Sci. 22:4-27 (2016)). For example, a tumor antigen may be recombinantly produced by utilizing a host cell system engineered to express a tumor antigen-encoding nucleic acid. Alternatively or additionally, a tumor antigen may be produced by activating endogenous genes. Alternatively or additionally, a tumor antigen may be partially or fully prepared by chemical synthesis.
Where proteins are recombinantly produced, any expression system can be used. To give but a few examples, known expression systems include, for example, E. coli, egg, baculovirus, plant, yeast, or mammalian cells.
In some embodiments, recombinant tumor antigen suitable for the present invention are produced in mammalian cells. Non-limiting examples of mammalian cells that may be used in accordance with the present invention include BALB/c mouse myeloma line (NSO/1, ECACC No: 85110503); human retinoblasts (PER.C6, CruCell, Leiden, The Netherlands); monkey kidney CV1 line transformed by SV40 (COS-7, ATCC CRL 1651); human embryonic kidney line (HEK293 or 293 cells subcloned for growth in suspension culture, Graham et al., J. Gen Virol., 36:59, 1977); human fibrosarcoma cell line (e.g., HT1080); baby hamster kidney cells (BHK21, ATCC CCL 10); Chinese hamster ovary cells +/−DHFR (CHO, Urlaub and Chasin, Proc. Natl. Acad. Sci. USA, 77:4216, 1980); mouse sertoli cells (TM4, Mather, Biol. Reprod., 23:243-251, 1980); monkey kidney cells (CV1 ATCC CCL 70); African green monkey kidney cells (VERO-76, ATCC CRL-1 587); human cervical carcinoma cells (HeLa, ATCC CCL 2); canine kidney cells (MDCK, ATCC CCL 34); buffalo rat liver cells (BRL 3A, ATCC CRL 1442); human lung cells (W138, ATCC CCL 75); human liver cells (Hep G2, HB 8065); mouse mammary tumor (MMT 060562, ATCC CCL51); TRI cells (Mather et al., Annals N.Y. Acad. Sci., 383:44-68, 1982); MRC 5 cells; FS4 cells; and a human hepatoma line (Hep G2).
In some embodiments, the present invention provides recombinant tumor antigen produced from human cells. In some embodiments, the present invention provides recombinant tumor antigen produced from CHO cells or HT1080 cells.
Typically, cells that are engineered to express a recombinant tumor antigen may comprise a transgene that encodes a recombinant tumor antigen described herein. It should be appreciated that the nucleic acids encoding recombinant tumor antigen may contain regulatory sequences, gene control sequences, promoters, non-coding sequences and/or other appropriate sequences for expressing the recombinant tumor antigen. Typically, the coding region is operably linked with one or more of these nucleic acid components.
The coding region of a transgene may include one or more silent mutations to optimize codon usage for a particular cell type. For example, the codons of a tumor antigen transgene may be optimized for expression in a vertebrate cell. In some embodiments, the codons of a tumor antigen transgene may be optimized for expression in a mammalian cell. In some embodiments, the codons of a tumor antigen transgene may be optimized for expression in a human cell.
The present disclosure provides methods and systems related to subjects having or diagnosed with cancer, such as a tumor. In some embodiments, the subject has (or had) a positive clinical response to a cancer therapy or combination of therapies. In some embodiments, the subject had a spontaneous response to a cancer. In some embodiments, the subject is in partial or complete remission from cancer. In some embodiments, the subject has cleared a cancer. In some embodiments, the subject has not had a relapse, recurrence or metastasis of a cancer. In some embodiments, the subject has a positive cancer prognosis. In some embodiments, the subject has not experienced toxic responses or side effects to a cancer therapy or combination of therapies. In some embodiments, the subject has (or had) a negative clinical response to a cancer therapy or combination of therapies. In some embodiments, the subject has not cleared a cancer. In some embodiments, the subject has had a relapse, recurrence or metastasis of a cancer. In some embodiments, the subject has a negative cancer prognosis. In some embodiments, the subject has experienced toxic responses or side effects to a cancer therapy or combination of therapies.
In some embodiments, after treatment with a cellular therapeutic described herein, one or more immune responses of the subject adapts. For example, successful cancer therapy leads to a reduced level of one or more tumor antigens to which an immune response is raised.
In some embodiments, a tumor is or comprises a hematologic malignancy, including but not limited to, acute lymphoblastic leukemia, acute myeloid leukemia, chronic lymphocytic leukemia, chronic myelogenous leukemia, hairy cell leukemia, AIDS-related lymphoma, Hodgkin lymphoma, non-Hodgkin lymphoma, Langerhans cell histiocytosis, multiple myeloma, or myeloproliferative neoplasms.
In some embodiments, a tumor is or comprises a solid tumor, including but not limited to breast carcinoma, a squamous cell carcinoma, a colon cancer, a head and neck cancer, ovarian cancer, a lung cancer, mesothelioma, a genitourinary cancer, a bladder cancer, a rectal cancer, a gastric cancer, or an esophageal cancer.
In some particular embodiments, a tumor is or comprises an advanced tumor, and/or a refractory tumor. In some embodiments, a tumor is characterized as advanced when certain pathologies are observed in a tumor (e.g., in a tissue sample, such as a biopsy sample, obtained from a tumor) and/or when cancer patients with such tumors are typically considered not to be candidates for conventional chemotherapy. In some embodiments, pathologies characterizing tumors as advanced can include tumor size, altered expression of genetic markers, invasion of adjacent organs and/or lymph nodes by tumor cells. In some embodiments, a tumor is characterized as refractory when patients having such a tumor are resistant to one or more known therapeutic modalities (e.g., one or more conventional chemotherapy regimens) and/or when a particular patient has demonstrated resistance (e.g., lack of responsiveness) to one or more such known therapeutic modalities.
In some embodiments, a cellular therapeutic described herein can be administered in combination with a cancer therapy. The present disclosure is not limited to any specific cancer therapy, and any known or developed cancer therapy is encompassed by the present disclosure. Known cancer therapies include, e.g., administration of chemotherapeutic agents, radiation therapy, surgical excision, chemotherapy following surgical excision of tumor, adjuvant therapy, localized hypothermia or hyperthermia, anti-tumor antibodies, and anti-angiogenic agents. In some embodiments, cancer and/or adjuvant therapy includes a TLR agonist (e.g., CpG, Poly I:C, etc., see, e.g., Wittig et al., Crit. Rev. Oncol. Hematol. 94:31-44 (2015); Huen et al., Curr. Opin. Oncol. 26:237-44 (2014); Kaczanowska et al., J. Leukoc. Biol. 93:847-863 (2013)), a STING agonist (see, e.g., US20160362441; US20140329889; Fu et al., Sci. Transl. Med. 7:283ra52 (2015); and WO2014189805), a non-specific stimulus of innate immunity, and/or dendritic cells, or administration of GM-CSF, Interleukin-12, Interleukin-7, Flt-3, or other cytokines. In some embodiments, the cancer therapy is or comprises oncolytic virus therapy, e.g., talimogene leherparepvec. (see, e.g., Fukuhara et al., Cancer Sci. 107:1373-1379 (2016)). In some embodiments, the cancer therapy is or comprises bi-specific antibody therapy (e.g., Choi et al., 2011 Expert Opin Biol Ther; Huehls et al., 2015, Immunol and Cell Biol). In some embodiments, the cancer therapy is or comprises cellular therapy such as chimeric antigen receptor T (CAR-T) cells, TCR-transduced T cells, dendritic cells, tumor infiltrating lymphocytes (TIL), or natural killer (NK) cells (e.g., as reviewed in Sharpe and Mount, 2015, Dis Model Mech 8:337-50).
Anti-tumor antibody therapies (i.e., therapeutic regimens that involve administration of one or more anti-tumor antibody agents) are rapidly becoming the standard of care for treatment of many tumors. Antibody agents have been designed or selected to bind to tumor antigens, particularly those expressed on tumor cell surfaces. Various review articles have been published that describe useful anti-tumor antibody agents (see, for example, Adler et al., Hematol. Oncol. Clin. North Am. 26:447-81 (2012); Li et al., Drug Discov. Ther. 7:178-84 (2013); Scott et al., Cancer Immun. 12:14 (2012); and Sliwkowski et al., Science 341:1192-1198 (2013)). The below Table 8 presents a non-comprehensive list of certain human antigens targeted by known, available antibody agents, and notes c
Certain cancer indications for which the antibody agents have been proposed to be useful:
In some embodiments, a cancer therapy is or comprises immune checkpoint blockade therapy (see, e.g., Martin-Liberal et al., Cancer Treat. Rev. 54:74-86 (2017); Menon et al., Cancers (Basel) 8:106 (2016)), or immune suppression blockade therapy. Certain cancer cells thrive by taking advantage of immune checkpoint pathways as a major mechanism of immune resistance, particularly with respect to T cells that are specific for tumor antigens. For example, certain cancer cells may overexpress one or more immune checkpoint proteins responsible for inhibiting a cytotoxic T cell response. Thus, immune checkpoint blockade therapy may be administered to overcome the inhibitory signals and permit and/or augment an immune attack against cancer cells. Immune checkpoint blockade therapy may facilitate immune cell responses against cancer cells by decreasing, inhibiting, or abrogating signaling by negative immune response regulators (e.g., CTLA-4). In some embodiments, a cancer therapy or may stimulate or enhance signaling of positive regulators of immune response (e.g., CD28).
Examples of immune checkpoint blockade and immune suppression blockade therapy include e.g., agents targeting one or more of A2AR, B7-H4, BTLA, CTLA-4, CD28, CD40, CD137, GITR, IDO, KIR, LAG-3, PD-1, PD-L1, OX40, TIM-3, and VISTA. Specific examples of immune checkpoint blockade agents include the following monoclonal antibodies: ipilimumab (targets CTLA-4); tremelimumab (targets CTLA-4); atezolizumab (targets PD-L1); pembrolizumab (targets PD-1); nivolumab (targets PD-1); avelumab; durvalumab; and cemiplimab.
Specific examples of immune suppression blockade agents include: Vista (B7-H5, v-domain Ig suppressor of T cell activation) inhibitors; Lag-3 (lymphocyte-activation gene 3, CD223) inhibitors; IDO (indolemamine-pyrrole-2,3-dioxygenase-1,2) inhibitors; KIR receptor family (killer cell immunoglobulin-like receptor) inhibitors; CD47 inhibitors; and Tigit (T cell immunoreceptor with Ig and ITIM domain) inhibitors.
In some embodiments, a cancer therapy is or comprises immune activation therapy. Specific, non-limiting examples of immune activators include: CD40 agonists; GITR (glucocorticoid-induced TNF-R-related protein, CD357) agonists; OX40 (CD134) agonists; 4-1BB (CD137) agonists; ICOS (inducible T cell stimulator); CD278 agonists; IL-2 (interleukin 2) agonists; and interferon agonists.
In some embodiments, cancer therapy is or comprises a combination of one or more immune checkpoint blockade agents, immune suppression blockade agents, and/or immune activators, or a combination of one or more immune checkpoint blockade agents, immune suppression blockade agents, and/or immune activators, and other cancer therapies.
Methods described herein can include preparing and/or providing a report, such as in electronic, web-based, or paper form. The report can include one or more outputs from a method described herein, e.g., a subject response described herein. In some embodiments, a report is generated, such as in paper or electronic form, which identifies the presence or absence of one or more tumor antigens (e.g., one or more stimulatory and/or inhibitory and/or suppressive tumor antigens, or tumor antigens to which lymphocytes are not responsive, described herein) for a cancer patient, and optionally, a recommended course of cancer therapy. In some embodiments, the report includes an identifier for the cancer patient. In one embodiment, the report is in web-based form.
In some embodiments, additionally or alternatively, a report includes information on prognosis, resistance, or potential or suggested therapeutic options. The report can include information on the likely effectiveness of a therapeutic option, the acceptability of a therapeutic option, or the advisability of applying the therapeutic option to a cancer patient, e.g., identified in the report. For example, the report can include information, or a recommendation, on the administration of a cancer therapy, e.g., the administration of a pre-selected dosage or in a pre-selected treatment regimen, e.g., in combination with one or more alternative cancer therapies, to the patient. The report can be delivered, e.g., to an entity described herein, within 7, 14, 21, 30, or 45 days from performing a method described herein. In some embodiments, the report is a personalized cancer treatment report.
In some embodiments, a report is generated to memorialize each time a cancer subject is tested using a method described herein. The cancer subject can be reevaluated at intervals, such as every month, every two months, every six months or every year, or more or less frequently, to monitor the subject for responsiveness to a cancer therapy and/or for an improvement in one or more cancer symptoms, e.g., described herein. In some embodiments, the report can record at least the treatment history of the cancer subject.
In one embodiment, the method further includes providing a report to another party. The other party can be, for example, the cancer subject, a caregiver, a physician, an oncologist, a hospital, clinic, third-party payor, insurance company or a government office.
All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described herein.
The disclosure is further illustrated by the following examples. The examples are provided for illustrative purposes only. They are not to be construed as limiting the scope or content of the disclosure in any way.
Methods for identifying antigens that stimulate and inhibit the immune response in a tumor environment are detailed below. In addition to identification of stimulatory or inhibitory antigens, methods of redirecting immune responses and/or re-educating T cells by administration of one or more adjuvants or other immune modulating agents are also demonstrated.
Methods
A cohort of C57BL/6J mice bearing B16F10 tumors were euthanized and their tumors and spleens harvested. DNA obtained from pooled tumors was sequenced and analyzed for non-synonymous mutations. Over 1600 such mutations were identified, and these were synthesized as 399 bp DNA fragments centered upon the base pair change and transformed individually into E. coli bacteria expressing cLLO to build a candidate neoantigen library. Splenocytes frozen from pooled spleens of the tumor-bearing mice were thawed, and CD8+ T cells were sorted using a negative selection bead kit. These were subsequently expanded with CD3/CD28 beads and IL-2 for 7 days followed by 1 day of rest after removal of beads and cytokine. Mouse APCs (RAW309 Cr.1 macrophage cell line) were cultured overnight, washed with PBS, then co-cultured with the bacterial library for 2 hours, washed with PBS, and then cultured with the non-specifically expanded and rested CD8+ T cells overnight. Harvested supernatant from the co-culture was tested for IFNγ and TNFα by a custom mouse 384-well Meso Scale Discovery (MSD) electrochemiluminescence assay.
Results
Sixty-eight antigens were identified as stimulatory (exceeding a statistical threshold above the negative control, a 399 bp fragment of the mouse actin gene) and 57 antigens were identified as inhibitory (reduced beyond a statistical threshold below the negative control), for either IFNγ, TNFα, or both (
The top 50 stimulatory and 50 inhibitory antigens, and approximately 50 antigens closest to the negative control (non-responses), were used in two additional repeat mATLAS screens with increased replicates. Each antigen was ranked by its IFNγ signal across all 3 screens, as well as a separate rank for its TNFα signal across all 3 screens. The top 10 ranked antigens (stimulatory) and 8 of the bottom 10 ranked antigens (inhibitory) were each synthesized as 27mer synthetic long peptides (SLPs) for use in mouse vaccination, as well as four 15mer overlapping peptides (OLPs) for use in ex vivo assays (
ATLAS-identified stimulatory and inhibitory antigens are used to expand tumor-specific CD4+ and CD8+ T cells from peripheral blood of cancer patients for personal Adoptive Cell Therapy (ACT). T cells responsive to inhibitory antigens are re-educated to a desirable phenotype, i.e., one that enhances immune control of tumors. These studies offer pre-clinical proof of concept for ATLAS-enabled ACT and pave the way for early phase human trials.
Aim 1: Methods to expand ATLAS-identified antigen-specific T cells from mice splenocytes:
Milestones:
Methods: The goal of this aim is to define optimal conditions for antigen-specific T cell expansion in mice. These methods are subsequently used to demonstrate preclinical proof of concept for an ATLAS-based ACT therapy in a B16F10 mouse tumor efficacy model (Aim 2). Published studies have previously shown the feasibility of in vitro antigen-specific T cell expansion by peptide stimulation in mice with corresponding anti-tumor efficacy when delivered by ACT [Starobinets H et al (2018). Ex vivo ATLAS-identification of neoantigens for personalized cancer immunotherapy in mouse melanoma. American Association for Cancer Research Annual Meeting; Li et al, 2016].
Goal: Maximize beneficial antigen-specific T cell expansion for ACT therapy in mice (˜105-106 total antigen-specific T cells to up to 16 ATLAS-defined stimulatory and/or inhibitory antigens).
Goal: Develop mouse T cell expansion conditions for T cell activation and memory while selecting against a T cell exhaustion phenotype.
Milestones:
Preliminary data: Using a vaccine modality, ATLAS-identified stimulatory antigen candidates demonstrated significant T cell responses as well as anti-tumor efficacy against B16F10 tumor challenge in initial studies [U.S. provisional application No. 62/737,832, filed Sep. 27, 2018]. Strikingly, therapeutic immunization with inhibitory antigen peptides led to a marked and significant increase in tumor growth kinetics. These preliminary data demonstrate the ability of the ATLAS platform to identify and characterize desired as well as potentially unwanted antigen-specific T cell responses in an aggressive in vivo mouse tumor model. The advantages of ATLAS antigen selection are applied in the proposed ACT therapy by selectively expanding T cells that are likely to enhance immune control of tumors and filtering out T cells that are likely to impair immune control of tumors.
Research Methods: In vivo studies are carried out to demonstrate preclinical proof of concept for ATLAS-derived T cell therapy in C57BL/6 mice using the B16F10 cell line, a highly aggressive melanoma model. Previous studies have demonstrated the feasibility of effective ACT in tumor-bearing mice as a monotherapy or in combination with checkpoint inhibitors [Mahvi et al, 2015]. This study improves on existing methods through enrichment of antigen-specific T cells that target tumors for destruction.
Milestones:
Preliminary data: Using ATLAS, stimulatory virus-specific antigens have been identified from human leukapheresis samples. These will be used to develop methods as apheresis products from healthy human donors are readily available.
Research Methods: The goal of this aim is to develop methods for antigen-specific expansion of human T cells obtained from leukapheresis using peptides, cytokine cocktails (IL-2, IL-7, IL-15 and/or IL-21), and other agents.
As frequency of antigen-specific T cells in the blood is low, the expansion takes place in several phases. The first phase specifically expands T cells using overlapping peptides (15mers overlapping by 11 amino acids) of antigens combined with cytokines to induce proliferation. Antigen-specific cells are then sorted by T cell activation markers, and exposed to appropriate media and agents to maintain a desirable phenotype, or re-educated to a desirable phenotype. In the final phase, the enriched antigen-specific T cells of desirable phenotype undergo a rapid, non-specific expansion protocol to generate >109 antigen-specific T cells suitable for administration to a patient [Gerdemann et al, 2012; Huarte et al, 2009; Wolf et al, 2014; Yee et al, 2002].
As described in preliminary data, immunodominant ATLAS-identified antigens from a range of viruses are used to expand T cells from healthy-donor PBMCs. Each milestone below is defined to optimize each phase of the T cell expansion processes in healthy donors and is subsequently verified using whole blood from cancer patients and antigen-specific T cells. Nearly 20 years ago, several groups observed that tumor-reactive T cells can be detected in the peripheral blood and these cells can be isolated and expanded while maintaining anti-tumor activity. With recent advances such as engineered CAR-T cell and TIL-based therapies for cancer, a method to identify antigens using the ATLAS platform and develop antigen-specific T cell therapy with peptides is feasible. However, unlike CAR-T cells which need an actionable target on all tumor cells and TIL therapies which often generate T cells of a single specificity and subset, Applicant's approach generates CD4+ and CD8+ T cells of broad specificities, increasing the likelihood of tumor eradication and the potential to limit metastatic tumor escape.
Methods
Whole exome sequencing of tumor and normal tissue from a patient with bladder cancer (Patient Ig) was performed to identify all mutations (putative neoantigens) present in their tumor. T cells enriched from the peripheral blood of Patient Ig were screened against their monocyte-derived dendritic cells pulsed with E. coli clones expressing each of the eight mutations found in their tumor, using the ATLAS™ technology (as described in U.S. Pat. No. 9,873,870). Three neoantigens that elicited inhibitory responses were identified, defined by IFNγ cytokine secretion that was reduced to levels statistically below the baseline controls (E. coli expressing a non-antigenic polypeptide). The inhibitory neoantigens were denoted I1, I2, and I3. No stimulatory neoantigens were identified.
Overlapping peptides were synthesized (OLPs; 15mers overlapping by 11 aa) and pooled to span each of the three inhibitory neoantigens. Viably frozen peripheral blood mononuclear cells (PBMCs) from the same Patient Ig were thawed and evaluated immediately ex vivo by dual-color fluorospot assay for responsiveness to OLP pools spanning each inhibitory neoantigen (I1, I2, or I3) or a complete pool of all OLPs spanning the three inhibitory neoantigens (I1+I2+I3). In addition, monocytes were sorted and derived into dendritic cells (MDDC) using the ImmunoCult reagent. Eight days later, new vials of PBMCs from Patient Ig were thawed and sorted for T cells using Miltenyi positive selection beads. Sorted T cells were aliquoted into individual wells of a 6-well plate and stimulated with MDDC pulsed with 4 μg/mL of each OLP pool, negative control infectious disease antigens, or no stimulant, in the presence of IL-7, IL-2, IL-15 and IL-21 cytokines for ten days. The cultured, stimulated T cells were washed and again evaluated by overnight dual-color fluorospot assay for responsiveness to each OLP pool.
For the fluorospot assay, cells were counted and normalized to 4×106/mL and seeded into a TNFα/IFNγ ELISPOT plate with OLPs for overnight culture. Each individual sample was split into replicate wells. Each OLP was used at 1 μg/ml in the overnight ELISPOT culture plate. Negative controls included no antigen wells; positive controls included anti-CD3 antibody and mitogen stimulation.
Results
As shown in
It is to be understood that while the disclosure has been described in conjunction with the detailed description thereof, the foregoing description is intended to illustrate and not limit the scope of the invention, which is defined by the scope of the appended claims. Other aspects, advantages, and modifications are within the scope of the following claims:
This application claims the benefit of U.S. Provisional Application No. 62/737,862, filed Sep. 27, 2018, the contents of which are hereby incorporated by reference herein in their entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US19/53669 | 9/27/2019 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 62737862 | Sep 2018 | US |
