Patent Application
20160220665
This application relates to immuno therapeutic agents employing a plurality of T-cell epitopes. In particular, it relates to agents that can be used to treat a condition characterized by the presence of unwanted cells, such as cancer or other disease-causing cells.
Cancer and other diseases caused by the presence of unwanted cells create significant loss of life, suffering, and economic impact. Immunotherapeutic strategies for targeting cancer have been an active area of translational clinical research.
WO 2012/123755 discusses the concept of re-directed immunotherapy. In this application, an agent for preventing or treating a condition characterized by the presence of unwanted cells includes a targeting moiety that is capable of targeting to the unwanted cells and a T-cell epitope that can be released from the targeting moiety by selective cleavage of a cleavage site in the agent in the vicinity of the unwanted cells.
WO 2014/043523 teaches an agent based on an ScFV directed to cancer cells including from 1-10 immunogenic CD8 T-cell epitopes in one of the following two arrangements: T-c-En-c-Fcn or T-c-Fcn-c-En, where T is the ScFv, En is from 1-10 CD8 T-cell epitopes, c: is a protease cleavage site, and Fcn is from 1-10 Fc portions of an IgG antibody. In this reference, the 1-10 immunogenic CD8 T-cells are released from the ScFv and Fc portions of the agent in a single polypeptide chain, still conjugated to each other.
While some positive test data has been shown with prior approaches, clinically-effective therapeutic strategies must be able to elicit a strong immune response in an individual suffering from a disease such as cancer. Additionally, effective therapies should work well in a wide cross-section of patients from different racial and ethnic groups. Maximally-effective therapies would also generate an immune response against the unwanted cells without generating an inhibitory immune response against the therapeutic agent itself so that multiple rounds of treatment could be administered over a period of time. Therefore, additional developments in this field of re-directed immunotherapy are required.
In accordance with the description, a variety of targeting moiety peptide epitope complexes (TPECs) are described in different embodiment of this application. In each of the embodiments, however, a targeting moiety may be used to deliver the TPEC to an area of unwanted cells, allowing for a therapeutic effect to be delivered locally. The TPEC also contains a plurality of T-cell epitopes. The TPEC further comprises cleavage sites that release the T-cell epitopes from the targeting agent, and in some embodiments from each other, when they are in the microenvironment of the unwanted cells. Although the arrangement and number of T-cell epitopes varies in different embodiments described herein, once cleaved from the targeting agent (and any neighboring T-cell epitopes), the T-cell epitopes function by stimulating an immune response against the unwanted cells. In some embodiments, maximal benefits may be achieved by releasing all of the T-cell epitopes from both the targeting agent and from each other in the cleavage process, allowing each T-cell epitope the structural freedom to attract an immune response to the unwanted cell.
Having a plurality of T-cell epitopes, as discussed in detail below, enhances the immune response against the unwanted cells, either by stimulating a stronger immune response in a given patient or by allowing the TPEC to stimulate an immune response across a wide variety of patients in different ethnic and racial groups.
In one embodiment, a composition for retargeting an immune response to unwanted cells comprises a TPEC wherein:
In one embodiment, a composition for retargeting an immune response to unwanted cells comprises a TPEC having a plurality of T-cell epitopes separately conjugated to a targeting moiety comprising the formula T-(L-C-E)n or T-(L-Ci-Ej)n, wherein:
In some embodiments, a composition for retargeting an immune response to unwanted cells comprises a TPEC with either a (i) linear and/or bundled polytope or a (ii) branched polytope. Such a TPEC may comprise the formula T-L-(Ci-Ej)n, wherein:
Further, in some embodiments, a composition for retargeting an immune response to unwanted cells comprises a TPEC having:
Additional objects and advantages will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice. The objects and advantages will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the claims.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate one (several) embodiment(s) and together with the description, serve to explain the principles described herein.
Target lymphoma cells labeled with branched peptide TPEC are recognized by T cells specific for the RPHERNGFTVL (SEQ ID NO: 2) and TPRVTGGGAM (SEQ ID NO: 49) peptides. Untreated target cells are not recognized by the peptide-specific T cells (negative control) and free peptide pulsed target cells are strongly recognized by T cells (positive control).
Target lymphoma cells labeled with branched peptide TPEC are recognized by T cells specific for the RPHERNGFTVL (SEQ ID NO: 2) and TPRVTGGGAM (SEQ ID NO: 49) peptides. Untreated target cells are not recognized by the peptide-specific T cells (negative control) and free peptide pulsed target cells are strongly recognized by T cells (positive control).
Target ovarian carcinoma cells labelled with the bundled domain TPEC are recognized by T cells specific for the viral epitope NLVPMVATV (SEQ ID NO: 1) by release of IFN-γ. Four different preparations (two TPECs produced on each of two days using different concentrations of DNA) of the bundled domain were used, all of which produced similar amounts of bundled domain TPEC and produced similar recognition of target cells by the peptide-specific T cells. Untreated target cells are not recognized by the peptide-specific T cells (negative control) and free peptide pulsed target cells are strongly recognized by T cells (positive control).
Table 1 provides a listing of certain sequences referenced herein.
CGVANLVPMVATVAVAVLEETSVM
CVARPHERNGFTVLVANLVPMVAT
CGVANLVPMVATVARPHERNGFTV
PRSFFRLGKTPRVTGGGAMG
FRLGKELRRKMMYM
A variety of targeting moiety peptide epitope complexes (TPECs) are described in different embodiments. In each of the embodiments, however, a targeting moiety may be used to deliver the TPEC to an area of unwanted cells, allowing for a therapeutic effect to be delivered locally. The TPEC also contains a plurality of T-cell epitopes. The TPEC further comprises cleavage sites that release the T-cell epitopes from the targeting agent, and in some embodiments from each other, when they are in the microenvironment of the unwanted cells. Although the arrangement and number of T-cell epitopes varies in different embodiments described herein, once cleaved from the targeting agent (and any neighboring T-cell epitopes), the T-cell epitopes function by stimulating an immune response against the unwanted cells. In some embodiments, maximal benefits may be achieved by releasing all of the T-cell epitopes from both the targeting agent and from each other in the cleavage process, allowing each T-cell epitope to attract an immune response to the unwanted cell.
Having a plurality of T-cell epitopes, as discussed in detail below, enhances the immune response against the unwanted cells, either by stimulating a stronger immune response in a given patient or by allowing the TPEC to stimulate an immune response across a wide variety of patients in different ethnic and racial groups. In one embodiment, and while not being bound by theory, the cleavage at the cleavage site allows the T-cell epitopes to be trimmed at either or both ends to the appropriate length to produce a peptide that can fit in the peptide-binding groove of HLA class I and be recognized by T-cells, so as to initiate an immune response.
Without cleavage of these epitopes, the prior art fails to stimulate a sufficient T-cell response because the T-cell epitopes fused together would not be adequately recognized by the patients T-cells and would, thus, not initiate an immune response against the cancer cells.
A. TPECs with a Plurality of T-Cell Epitopes Separately Conjugated
In one embodiment, the TPEC comprises a plurality of T-cell epitopes that are separately conjugated to the targeting moiety. Because the T-cell epitopes will be separately conjugated to the targeting moiety, with two exemplary embodiments shown in
(a) T is a targeting moiety that is capable of targeting unwanted cells;
(b) L is a linker capable of chemical linkage to T;
(c) C is a cleavage site that is (i) cleaved by an enzyme expressed by the unwanted cells; (ii) cleaved through a pH-sensitive cleavage reaction inside the unwanted cell; (iii) cleaved by a complement-dependent cleavage reaction; or (iv) cleaved by a protease that is colocalized to the unwanted cell by a targeting moiety that is the same or different from the targeting moiety in the TPEC; and
(d) E is a T-cell epitope.
N is an integer of at least 2 (optionally from about 2 to 50). The same cleavage site may optionally be used multiple times in the TPEC and the same epitope may optionally be used multiple times in the TPEC.
The C and E moieties may be the same in the plurality of L-C-E moieties affixed to a single T or a single T may have different C and E moieties in the plurality of L-C-E moieties. Thus, there may be more than one type of cleavage site or only one type of cleavage site. There may also, independently, be more than one type of T-cell epitope or only one type of T-cell epitope.
In certain aspects of the embodiments discussed in this section, the L-C-E complexes may be affixed to the targeting moiety in a random fashion. Thus, in a preparation of TPECs with a plurality of T-cell epitopes separately conjugated to the targeting moiety, some TPECs may have greater numbers of T-cell epitopes and some may have fewer numbers. Additionally, in a preparation of TPECs with a plurality of T-cell epitopes separately conjugated to the targeting moiety, the location of TPECs may differ throughout the preparation. In this vein, when these compounds are administered to a patient suffering from a disease such as cancer, the patient's body will have a much more difficult time mounting an inhibitory immune response against the preparation of TPECs. This may allow the patient to receive multiple doses of the TPEC preparation over a significant period of time, as discussed further below in Section III.B below.
B. TPECs with at Least One Polytope
In another embodiment, the TPEC comprises a plurality of T-cell epitopes that are conjugated to the targeting moiety as a polytope (for poly-epitope), but the conjugation within the polytope and to the targeting moiety occurs through cleavage sites allowing the release of the individual T-cell epitopes in the microenvironment of the unwanted cells. Several embodiments of this arrangement are shown in
In
In
In all of the embodiments of
(a) T is a targeting moiety that is capable of targeting unwanted cells;
(b) L is a linker capable of chemical or peptide linkage to T (including a peptide bond);
(c) C is a cleavage site (i) cleaved by an enzyme expressed by the unwanted cells; (ii) cleaved through a pH-sensitive cleavage reaction inside the unwanted cell; (iii) cleaved by a complement-dependent cleavage reaction; or (iv) cleaved by a protease that is colocalized to the unwanted cell by a targeting moiety that is the same or different from the targeting moiety in the TPEC; and
(d) E is a T-cell epitope;
wherein n is an integer of at least 2 (optionally from about 2 to 50).
The C and E moieties may be the same in the plurality of C-E moieties affixed through L to a single T or a single T may have different C and E moieties in the plurality of C-E moieties. Thus, there may be more than one type of cleavage site or only one type of cleavage site. There may also, independently, be more than one type of T-cell epitope or only one type of T-cell epitope.
In some embodiments, the plurality of the T-cell epitopes being conjugated in a polytope allow for a uniform product to be produced that contains a standard group, number, and arrangement of T-cell epitopes, while still allowing for the release of all of the T-cell epitopes in the microenvironment of the unwanted cells. Microenvironment means the specific set of physical, chemical, and biological conditions in the vicinity of cells within a distance where these conditions can have an effect on or be sensed by the cells.
In some embodiments, more than one polytope are conjugated to the targeting moiety. In some embodiments from about 1 to 30, 1 to 20, or 1 to 10 polytopes are conjugated to the targeting moiety. In some embodiments, about 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 polytopes are conjugated to the targeting moiety, each group by one cleavage site. In these embodiments, the polytopes may be the same or different.
In some embodiments, the TPEC may have both at least one separately conjugated T-cell epitope and at least one polytope, according to sections I.A and I.B, respectively.
C. TPECs with More than 10 T-Cell Epitopes
In another embodiment, the TPEC comprises a plurality of T-cell epitopes that, irrespective of how they are arranged on the targeting moiety, comprise more than 10 T-cell epitopes. In these embodiments, the T-cell epitopes may be separately conjugated or conjugated in a polytope. In other words, a composition for retargeting an immune response to unwanted cells may comprise a TPEC having:
(a) a targeting moiety that is capable of targeting unwanted cells;
(b) a plurality of more than 10 T-cell epitopes conjugated to the targeting moiety with at least one cleavage site, wherein the cleavage site is (i) cleaved by an enzyme expressed by the unwanted cells; (ii) cleaved through a pH-sensitive cleavage reaction inside the unwanted cell; (iii) cleaved by a complement-dependent cleavage reaction; or (iv) cleaved by a protease that is colocalized to the unwanted cell by a targeting moiety that is the same or different from the targeting moiety in the TPEC.
In some embodiments, including TPECs with more than 10 T-cell epitopes, the immune response against the unwanted cells is notably stronger. In some embodiments, including TPECs with more than 10 T-cell epitopes, the TPEC can be used to treat a greater proportion of patients suffering from the condition characterized by unwanted cells.
In some compositions with TPECs having more than 10 T-cell epitopes, the T-cell epitopes may be separately conjugated to the targeting moiety, each T-cell epitope by a cleavage site. In some embodiments, with TPECs having more than 10 T-cell epitopes, the T-cell epitopes may be conjugated to the targeting moiety as at least one polytope, each polytope conjugated to the targeting moiety by a cleavage site. In some embodiments, the T-cell epitopes within a polytope have cleavage sites between them.
D. Compositions Comprising TPECs
A composition may comprise a plurality of TPECs. In some embodiments, all of the TPECs in the composition are the same. In some embodiments, at least some of the TPECs in the composition are not identical.
In some embodiments, each TPEC is conjugated to a plurality of identical T-cell epitopes.
In some embodiments, at least some of the TPECs in the composition are conjugated to a plurality of T-cell epitopes that are not identical.
In some embodiments, a composition may comprise at least about 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, or more different TPECs.
E. T-Cell Epitopes
T-cell epitopes function in the TPECs to attract the patient's own immune response to attack the unwanted cell by labeling it with antigenic T-cell epitopes from infectious agents.
Depending on desired aspects of the therapy, a variety of optional factors may be considered when choosing T-cell epitopes. Every person has six HLA class-I molecules that can bind peptides to present to CD8 T cells with some HLA types more prevalent in the population than others, such as HLA-A201 which is found in ˜45% of the Caucasian population. In situations where the epitopes chosen for conjugation are able to bind to a limited set of HLA molecules that are only found in a proportion of the population, the TPEC may not have any or as much effectiveness in other segments of the population. Using HLA-A201 as an example, if the targeting moiety is conjugated with a T-cell epitope that binds to HLA-A201 then only patients that express HLA-A201 would bind the epitope and present it to T cells and initiate an immune response. However, in patients who are HLA-A201 negative the epitope may not be able to bind to their HLA molecules and there would be no or a lesser immune response. In situations where the therapy may be provided to a wide segment of the population having different HLA molecules, using different epitopes that bind to more HLA molecules could enhance the effectiveness of the TPEC across the population.
As an additional factor to consider, in some embodiments, T-cell epitopes may be chosen from those that a particular person has been exposed to, a wide variety of people have been exposed to, or for which vaccines have or can be administered. T cells generally recognize the epitope in complex with an HLA molecule when the patient has been previously infected with the virus from which the epitope is derived (or in instances where the patient has previously received a vaccine containing those epitopes). Vaccines may have been administered for a prior purpose (such as childhood vaccines) or may be administered preceding TPEC treatment with the same epitope.
In certain instances, T-cell epitopes are chosen from cytomegalovirus (CMV), influenza, Epstein Barr virus (EBV), varicella zoster, mumps, measles, rubella, adenovirus, polio, vaccinia, RSV, rotavirus, tetanus, vaccinia, and yellow fever T-cell epitopes. Epitopes may be chosen from infectious agents that are prevalent across the population in question or for which there are vaccines that are regularly administered or could be administered as part of a combination therapy approach.
In certain embodiments, the T-cell epitopes are chosen from at least 2, 3, 4, or 5 different infectious agents. In certain embodiments, at least some of the T-cell epitopes are CMV epitopes.
In any of the various TPECs described herein, in some embodiments, the plurality of T-cell epitopes are not all identical. In some embodiments, the plurality of T-cell epitopes are the same. In certain embodiments, the plurality of T-cell epitopes comprise some that are the same and some that are different.
The T-cell epitopes may be all MHC Class I restricted peptides, all MHC class II restricted peptides, or a combination of both Class I and Class II.
In some embodiments, the plurality of T-cell epitopes are from about 7 to 14 amino acids in length, from about 8 to 13, from about 9 to 12, about 9, or about 10 amino acids.
In some embodiments, at least 2, 3, 4, 5, 6, 7, 8, 9, or 10 different T-cell epitopes are used in the TPECs, whether the TPECs are the same or different. In some embodiments, using a plurality of different T-cell epitopes allows the agent to stimulate a T-cell response in at least about 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 60%, 70%, 80%, or 90% of the human population.
In some embodiments, the T-cell epitopes are chosen from HLA-A, HLA-B, HLA-C, HLA-E, HLA-F, HLA-G, CD1d, and MR1. In certain embodiments, the T-cell epitopes are chosen from HLA-A*01, HLA-A*02, HLA-A*03, HLA-A*11, HLA-A*24, HLA-B*44, HLA-B*07, HLA-B*08, HLA-B*15, HLA-B*35, HLA-B*40, HLA-C*07, HLA-C*03, HLA-C*05, HLA-C*04, HLA-C*06, and HLA-E*0101 restricted antigens.
In certain embodiments, the composition comprises at least the following T-cell epitopes HLA-A*02, HLA-A*01, and HLA-A*03.
When desired, more immunodominant T-cell epitopes may be selected. By immunodominant, we mean those epitopes that elicit the strongest immune response in a given patient and/or those that are known to be immunogenic across a wide cross-section of people.
In some embodiments, the T-cell epitopes comprise at least one of the epitopes provided in Table 2. In some embodiments, the T-cell epitopes are chosen from the epitopes provided in Table 2.
F. Targeting Moiety
The targeting moiety functions in the TPEC by delivering the TPEC to the local environment of the unwanted cells, enabling a localized treatment strategy. In certain embodiments, the targeting moiety targets the unwanted cells by specifically binding to the unwanted cells. In some instances, the targeting moiety specifically binds the unwanted cells even while the plurality of T-cell epitopes are conjugated to the targeting moiety.
In certain embodiments, the targeting moiety is an antibody or functional part thereof.
Certain antibody targets (with examples of unwanted cell types in parentheses) may include: Her2/Neu (Epithelial malignancies); CD22 (B cells, autoimmune or malignant); EpCAM (CD326) (Epithelial malignancies); EGFR (epithelial malignancies); PMSA (Prostate Carcinoma); CD30 (B cell malignancies); CD20 (B cells, autoimmune, allergic or malignant); CD33 (Myeloid malignancies); membrane lgE (Allergic B cells); lgE Receptor (CD23) (Mast cells or B cells in allergic disease), CD80 (B cells, autoimmune, allergic or malignant); CD86 (B cells, autoimmune, allergic or malignant); CD2 (T cell or NK cell lymphomas); CA125 (multiple cancers including Ovarian carcinoma); Carbonic Anhydrase IX (multiple cancers including Renal Cell Carcinoma); CD70 (B cells, autoimmune, allergic or malignant); CD74 (B cells, autoimmune, allergic or malignant); CD56 (T cell or NK cell lymphomas); CD40 (B cells, autoimmune, allergic or malignant); CD19 (B cells, autoimmune, allergic or malignant); c-met/HGFR (Gastrointestinal tract and hepatic malignancies; TRAIL-R1 (multiple malignancies including ovarian and colorectal carcinoma); DRS (multiple malignancies including ovarian and colorectal carcinoma); PD-1 (B cells, autoimmune, allergic or malignant); PD1L (Multiple malignancies including epithelial adenocarcinoma); IGF-1R (Most malignancies including epithelial adenocarcinoma); VEGF-R2 (The vasculature associated with the majority of malignancies including epithelial adenocarcinomas; Prostate stem cell antigen (PSCA) (Prostate Adenocarcinoma); MUC1 (Epithelial malignancies); CanAg (tumors such as carcinomas of the colon and pancreas); Mesothelin (many tumors including mesothelioma and ovarian and pancreatic adenocarcinoma); P-cadherin (Epithelial malignancies, including breast adenocarcinoma); Myostatin (GDF8) (many tumors including sarcoma and ovarian and pancreatic adenocarcinoma); Cripto (TDGF1) (Epithelial malignancies including colon, breast, lung, ovarian, and pancreatic cancers); ACVRL 1/ALK1 (multiple malignancies including leukaemias and lymphomas); MUC5AC (Epithelial malignancies, including breast adenocarcinoma); CEACAM (Epithelial malignancies, including breast adenocarcinoma); CD137 (B cells or T cells, autoimmune, allergic or malignant); CXCR4 (B cells or T cells, autoimmune, allergic or malignant); Neuropilin 1 (Epithelial malignancies, including lung cancer); Glypicans (multiple cancers including liver, brain and breast cancers); HERS/EGFR (Epithelial malignancies); PDGFRa (Epithelial malignancies); EphA2 (multiple cancers including neuroblastoma, melanoma, breast cancer, and small cell lung carcinoma); CD38 (Myeloma); CD138 (Myeloma); α4-integrin (AML, myeloma, CLL, and most lymphomas).
In certain modes, antibodies include an anti-epidermal growth factor receptor antibody such as Cetuximab, an anti-Her2 antibody, an anti-CD20 antibody such as Rituximab, an anti-CD22 antibody such as Inotuzumab, G544 or BU59, an anti-CD70 antibody, an antiCD33 antibody such as hp67.6 or Gemtuzumab, an anti-MUC1 antibody such as GP1.4 and SM3, an anti-CD40 antibody, an anti-CD74 antibody, an anti-P-cadherin antibody, an anti-EpCAM antibody, an anti-CD138 antibody, an anti-E-cadherin antibody, an antiCEA antibody, an anti-FGFR3 antibody, and an anti α4-integrin antibody such as natalizumab.
G. Cleavage Sites
The cleavage sites function to release the T-cell epitope from the targeting moiety and, in some embodiments, to release the T-cell epitopes from each other. Releasing the T-cell epitopes into single epitopes allows them to most effectively label the unwanted cell for immune attack.
In some instances, the cleavage site may be a separate sequence and in other instances the cleavage site may be integrated into the T-cell epitope such that one sequence serves the function of both elements. This may apply to any of the embodiments described herein and is determined by the selection of the epitope sequences.
The cleavage sites can function in different ways to release the T-cell epitopes in the microenvironment of the unwanted cells. The cleavage may occur inside the unwanted cell or outside the unwanted cell, depending on the strategy employed. If cleavage occurs outside the unwanted cell, the T-cell epitope peptides can be presented without first being internalized into a cell and being engaged in the classical antigen-processing pathways. If cleavage occurs outside the unwanted cell, it may occur in the microenvironment surrounding the cell, including at the cell surface. For example, when the unwanted cell is a cancer cell, the cleavage may occur in the tumor microenvironment (outside of an in the vicinity of the cancer cell), including at the surface of the cancer cell.
In certain embodiments, at least one cleavage site may be cleaved by an enzyme expressed by the unwanted cells. Cancer cells, for instance, are known to express certain enzymes, such as proteases, and these may be employed in the TPEC strategy to cleave the TPEC's cleavage site. By way of nonlimiting example, cathepsin B cleaves FR, FK, VA and VR amongst others; cathepsin D cleaves PRSFFRLGK (SEQ ID NO: 181), ADAM28 cleaves KPAKFFRL (SEQ ID NO: 182), DPAKFFRL (SEQ ID NO: 183), KPMKFFRL (SEQ ID NO: 184) and LPAKFFRL (SEQ ID NO: 185); and MMP2 cleaves AIPVSLR (SEQ ID NO: 186).
In some embodiments, at least one cleavage site may be cleaved through a pH-sensitive cleavage reaction inside the unwanted cell. If the TPEC is internalized into the cell, the cleavage reaction may occur inside the cell and may be triggered by a change in pH between the microenvironment outside the unwanted cell and the interior of the cell. Specifically, some cancer types are known to have acidic environments in the interior of the cancer cells. Such an approach may be employed when the interior unwanted cell type has a characteristically different pH from the extracellular microenvironment, such as particularly the glycocalyx. Because pH cleavage can occur in all cells in the lysozymes, selection of a targeting agent when using a pH-sensitive cleavage site may require, when desired, more specificity. For example, when a pH-sensitive cleavage site is used, a targeting agent that binds only or highly preferably to cancer cells may be desired (such as, for example, an antibody binding to mesothelin for treatment of lung cancer).
In certain embodiments, at least one cleavage site may be cleaved by a complement-dependent cleavage reaction. Once TPECs bind to the unwanted cell, the patient's complement cascade may be triggered. In such a case, the complement cascade may also be used to cleave the T-cell epitope from the targeting agent by using a cleavage site sensitive to a complement protease. For example, C1r and C1s and the C3 convertases (C4B,2a and C3b,Bb) are serine proteases. C3/C5 and C5 are also complement proteases Mannose-associated binding proteins (RASP), serine proteases also involved in the complement cascade and responsible for cleaving C4 and C2 into C4b2b (a C3 convertase) may also be used. For example, and without limitation, C1s cleaves YLGRSYKV (SEQ ID NO: 177) and MQLGRX (SEQ ID NO: 178). MASP2 is believed to cleave SLGRKIQI (SEQ ID NO: 179). Complement component C2a and complement factor Bb are believed to cleave GLARSNLDE (SEQ ID NO: 180).
In some embodiments, at least one cleavage site may be cleaved by a protease that is colocalized to the unwanted cell by a targeting moiety that is the same or different from the targeting moiety in the TPEC. For example, any protease may be simultaneously directed to the microenvironment of the unwanted cells by conjugating the protease to a targeting agent that delivers the protease to that location. The targeting agent may be any targeting agent described herein. The protease may be affixed to the targeting agent through a peptide or chemical linker and may maintain sufficient enzymatic activity when bound to the targeting agent.
In some embodiments, the TPEC has a plurality of cleavage sites that are the same. In other embodiments, the TPEC has a plurality of cleavage sites that are not all identical, either in sequence and/or in type, as described above.
H. Preparation of the T-Cell Epitopes and Cleavage Sites
1. Preparation of Individual T-Cell Epitopes and Cleavage Sites to be Separately Conjugated to Targeting Agent
Individual T-cell epitopes conjugated to cleavage sites may be prepared through standard peptide synthesis chemistry, such as by coupling the carboxyl group of the incoming amino acid to the N-terminus of the growing peptide chain using a N-terminal protecting group addition strategy, such as tert-butoxycaronyl (Boc) and 9-fluorenylmethoxycarbonyl (Fmoc), with their respective deprotection agents TFA and piperidine. Peptide synthesis may occur by hand or in an automated machine. Alternatively, services may be employed that prepare peptides upon order.
2. Preparation of Linear Polytopes
Polytopes up to ˜50 amino acids could be made by standard peptide synthesis. This would allow up to about 5 epitopes to be incorporated into the polytope. In instances where more epitopes in the polytope are desired, or when human protein domains flank the epitopes in the polytope, then recombinant production of the polytope may occur. The DNA sequence for the polytope would be incorporated into a vector that would allow a cell line such as Chinese hamster ovary (CHO) cells to express the protein. The protein would be secreted by the cell line and could be purified from the cell culture supernatant. The purified polytope could then be conjugated to a targeting moiety through a chemical linker, as described herein. In another embodiment, nucleic acids encoding the polytope could be added on to an end of the DNA sequence encoding the targeting moiety to make one continuous polypeptide chain incorporating the targeting moiety and polytope. This could then be expressed in a cell line in the same way as the previous embodiment.
3. Preparation of Branched Polytope
Branched polytopes, such as shown in
The peptide stem may comprise amino acids that have a reactive property that can be targeted by crosslinking reagents. In some embodiments, cysteine and lysine may be used as there are a large number of crosslinking reagents that may be used at these amino acids. In one embodiment, a connecting stem may be a peptide comprising a large number of lysine or cysteine residues to facilitate linking reactions by sulfo-SMCC, for example. In another embodiment, the connecting stem may comprise serine or threonine, so as to partner with a crosslinking agent that would link to hydroxyl groups on these amino acids.
In another embodiment, spacer amino acids may be used in between those that have a reactive property to the crosslinking reagents in order to allow for protease attack without being blocked by other peptides bound to the stem. In certain aspects, a basic spacer may include glycine and serine. In some embodiments, the incorporation of proline between reactive amino acids may be useful as proline induces a slight rotation of the peptide which may help to keep the protease cleavable peptides bound to the stem further apart.
In certain embodiments, the peptide stem may comprise from about 10 to 80, 20 to 80, or 40 to 80 amino acids. In one embodiment the peptide stem comprises from about 2 to 20 amino acids that are bound to a T-cell epitope and cleavage site.
The individual T-cell epitopes may be conjugated to the peptide stem using the chemical linker technology discussed in Section I.I below. The connecting stem comprising the individual T-cell epitopes may also be conjugated to the targeting moiety using the chemical linker technology discussed in Section I.I below. In some embodiments, a different chemical linker may be chosen for these two conjugations so as to have additional control over the conjugation process. In one embodiment, T-cell epitopes may be affixed to the connecting stem by sulfo-SMCC and the connecting stem comprising the T-cell epitopes to the targeting moiety by 3-MPA, for example.
I. Method of Conjugation to the Targeting Moiety
Different approaches may be employed to conjugate the cleavage site(s) and plurality of T-cell epitopes (whether as separate T-cell epitope and cleavage site pairs or whether as a polytope) to the targeting agent. In some aspects, a polytope comprising a plurality of cleavage sites and a plurality of T-cell epitopes are conjugated to the targeting agent using at least one peptide bond. In certain aspects, the conjugation occurs through at least one bond other than a peptide bond. Such a conjugation may be through a chemical linker A nonpeptide bond, such as using a chemical linker, may be employed for separately conjugated pairs of T-cell epitopes and cleavage sites or for polytopes.
In some instances, a chemical linker may be a heterobifunctional crosslinking reagent. Heterobifunctional crosslinking reagents covalently bind two proteins together by targeting different functional groups on separate proteins. The amine-to-sulphydryl crosslinking reagents contain an NHS-ester at one end of the reagent, which binds to free amine groups on a first protein/pep tide, predominantly on the amino acid lysine. At the other end of the reagent, a maleimide group binds to sulphydryl group of a second protein/peptide, which can be found on the amino acid cysteine. Examples of amine-to-sulphydryl crosslinking reagents may include (a) sulfosuccinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxylate (Sulfo-SMCC, which is soluble in water) or succinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxylate (SMCC, which has poor water solubility), (b) succinimidyl 4-(p-maleimidophenyl)butyrate (SMPB), (c) succinimidyl 6-[(beta-maleimidopropionamido)hexanoate] (SMPH); and (d) Sulfosuccinimidyl 6-(3′-[2-pyridyldithio]-propionamido) hexanoate (Sulfo-LC-SPDP); or (e) maleimide such as 3-maleimidopropionic acid.
Alternatively, another class of cross-linking reagents are the sulphydryl-to-carbohydrate reagents, which contain a maleimide group at one end and a hydrazide group at the other end. The maleimide group binds to a free sulphydryl on a first protein/peptide, such as that found on the amino acid cysteine, and the hydrazide group binds to an aldehyde group formed from an oxidized carbohydrate on a second protein/peptide. This family of reagents includes (a) 3,3′-N-[ε-Maleimidocaproic acid] hydrazide, trifluoroacetic acid salt (EMCH) and (b)N-beta-Maleimidopropionic acid hydrazide-trifluoroacetic acid (BMPH).
A third group of heterobifunctional cross-linking reagents are the photocleavable reagents including sulfosuccinimidyl 2-([4,4′-azipentanamido]ethyl)-1,3′-dithiopropionate (SDAD). These reagents have an NHS-ester at one end linking to free amines (lysine) and a diazrine group at the other end which can react with any amino acid side chain or peptide backbone upon activation with long-wave ultra violet light (330-370 nm) There are many other reagents from these groups and from other cross-linking groups that can be used in this technology.
J. Inclusion of Human Protein Domains
In certain embodiments, the T-cell epitopes are flanked on one or both ends by at least one human protein domain. In some embodiments, the cleavage sites reside between the T-cell epitopes and the human protein domains.
Various human protein domains may be used in this manner. For example, at least one human protein domain may be a beta barrel or a coiled coil. In some embodiments, the human protein may be a FN3 (Fibronectin type III) domain. In some embodiments, the human protein may be beta-sandwich, Lipocalin, EETI-II/AGRP, Kunitz domain (BPTI), Thioredoxin, Protein A, Ankyrin, gamma-B-crystallin/ubiquitin, CTLD3/Tetranexin, or and LDLR-A In some embodiments, the human protein may be human serum albumin, immunoglobulin CH2 domain, or camelid VHH domain.
In certain instances, a human protein domain may be a CL, CH2, and/or CH3 domain. For example, a T-cell epitope or plurality of T-cell epitopes may be flanked by CH2 sequences. Such CH2 sequences may be within the CH2 domain of an antibody or functional part serving as the targeting moiety. Such CH2 sequences may also be an additional CH2 domain distinct from the targeting moiety. In some embodiments, such as shown in
In some aspects, the human protein domain is not a human immunoglobulin protein domain.
In some aspects, the human protein domain displays the T-cell epitopes on its three-dimensional surface.
The TPECs may be employed as pharmaceutical compositions. As such, they may be prepared along with a pharmaceutically acceptable carrier. If parenteral administration is desired, for instance, the TPECs may be provided in sterile, pyrogen-free water for injection or sterile, pyrogen-free saline. Alternatively, the TPECs may be provided in lyophilized form for resuspension with the addition of a sterile liquid carrier.
A. Reduction of Unwanted Cells, Retargeting of Immune Response, and Treatment of Cancer
The TPECs described herein may be used in a method of treating a disease in a patient characterized by the presence of unwanted cells comprising administering a TPEC composition to the patient. This may include both treating and preventing a disorder. Additionally, the TPECs described herein may also be used in a method of retargeting (i.e., redirecting) a patient's own immune response to unwanted cells comprising administering a TPEC composition to the patient.
The amount of the agent administered to the patient may be chosen by the patient's physician so as to provide an effective amount to treat the condition in question.
The patient receiving treatment may be a human. The patient may be a primate or any mammal. Alternatively, the patient may be an animal, such as a domesticated animal (for example, a dog or cat), a laboratory animal (for example, a laboratory rodent, such as a mouse, rat, or rabbit), or an animal important in agriculture (such as horses, cattle, sheep, or goats).
The condition characterized by unwanted cells may include cancer. The cancer may be a solid or non-solid malignancy. The cancer may be any cancer such as breast cancer, ovarian cancer, endometrial cancer, cervical cancer, bladder cancer, renal cancer, melanoma, lung cancer, prostate cancer, testicular cancer, thyroid cancer, brain cancer, oesophageal cancer, gastric cancer, pancreatic cancer, colorectal cancer, liver cancer, leukaemia, myeloma, nonHodgkin's lymphoma, Hodgkin's lymphoma, acute myeloid leukaemia, acute lymphoblastic leukaemia, chronic lymphoblastic leukaemia, lymphoproliferative disorder, myelodysplastic disorder, myeloproliferative disease and premalignant disease.
The condition characterized by unwanted cells may also include an allergic or autoimmune disease. For instance, autoimmune diseases may include Addison's disease, celiac disease, dermatomyositis, Graves' disease, Hashimoto's thyroiditis, multiple sclerosis, myasthenia gravis, pernicious anemia, reactive arthritis, rheumatoid arthritis, Sjogren syndrome, and systemic lupus erythematosus.
The TPECs may be administered alone or in conjunction with other forms of therapy, including surgery, radiation, or traditional chemotherapy. In some embodiments, the activity of the TPECs may also be enhanced by boosting the patient's immune response against one or more of the T-cell epitopes used, such as by vaccinating the subject with the T-cell epitope or by administering immunostimulatory agents.
In some embodiments, the patient receives multiple doses of the composition over at least 30, 45, 60, 75, 90, 120, 150, or more days, or on an ongoing basis. In certain modes the patient receives multiple doses of the composition over at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 months, or on an ongoing basis. If approaches are employed to reduce the patient's immune response against the TPEC itself, additional benefits may be achieved by administering the composition to a patient in relapse who received the composition for an earlier round of therapy.
B. Reduction of Immune Response Against TPEC Itself
In certain aspects described herein, having multiple copies of the same T-cell epitope increases an immune response against the unwanted cell when the agent is administered to a patient and having a diversity of T-cell epitopes assures effectiveness across a wide variety of patients from different racial and ethnic groups. Nevertheless, if a physician desires to use a TPEC therapy over a continued period of time, optional steps may be taken to reduce the patient's own immune response against the TPEC itself.
In certain embodiments, the arrangement or composition of T-cell epitopes on the TPEC are random in nature. For example, if a mixture of T-cell epitopes are conjugated using a chemical linker to the targeting moiety, different combinations of T-cell epitopes may affix to the targeting moieties. This makes it significantly more difficult for the patient to mount an immune response against the TPECs themselves. Even in instances where the plurality of T-cell epitopes are the same, affixing them separately to the targeting moiety through a chemical linker may also result in a random placement of the T-cell epitopes along the targeting moiety, likewise damping the patient's own immune response against the TPEC.
Such approaches may ensure that the patient does not develop an immune response against the TPEC composition sufficient to inactivate the TPEC composition upon subsequent administrations, meaning that no more than about 0%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% of the composition is inactivated by the patient's own antibodies to the TPEC.
Immunogenicity of a composition may be measured in an ELISA assay using human serum. For example, test compositions may be immobilized on a 96-well plate, blocked and diluted serum samples incubated for 1 hour. Antibodies against the test composition present in the human sera may bind to the test compositions on the plate. Biotinylated test agent or a biotinylated secondary antibody such as an anti-human IgG/IgA/IgM in combination with streptavidin-HRP and TMB could be used to generate a signal.
The present compositions are expected to be at least about 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% less immunogenic than prior compositions.
Peptides comprising T-cell epitopes and cleavage sites were ordered from external companies who synthesized them in standard solid phase peptide synthesis. The peptides were dissolved in DMSO to a final concentration of 10 mg/ml to be used for conjugation.
The following procedure was used as a standard-operating protocol for conjugation of polytope peptide (comprising a plurality of T-cell epitopes and cleavage sites) to an antibody serving as a targeting moiety by using sulfo-SMCC.
1. Cysteinylated peptides dissolved in DMSO to final concentration of 10 mg/ml.
2. Weigh 1 mg Sulfosuccinimidyl 4-[N-maleimidomethyl]cyclohexane-1-carboxylate (Sulfo-SMCC) and dissolve in 200 μl phosphate buffered saline (PBS) (final concentration 5 mg/ml).
3. Add 100 μl antibody (10 mg/ml, 1 mg antibody) to 10 μl dissolved Sulfo-SMCC (5 mg/ml) and incubate at room temperature for 30 minutes.
4. Wash a ZebaSpin desalting column (Pierce) by firstly spinning the column at 1500 g for 60 seconds to remove the ethanol (storage buffer).
5. Add 300 μl PBS and spin at 1500 g for 60 seconds. Remove eluate and repeat a further three times.
6. Add up to 125 μl antibody-SMCC to each column, and centrifuge at 1500 g for 120 seconds, collecting the eluate.
7. To 100 μl antibody-SMCC conjugate, add 3 μl cysteinylated peptide (10 mg/ml) and incubate at room temperature for 30 minutes.
8. Wash a Protein A column (GE Healthcare) by firstly spinning the column at 100 g for 30 seconds to remove the ethanol (storage buffer).
9. Add 500 μl PBS and spin at 100 g for 30 seconds. Remove eluate and repeat a further two times.
10. Dilute antibody-peptide conjugate to 500 μl in PBS and add it to the protein A column, mixing the antibody with the beads. Leave at room temperature for 20 minutes, shaking.
11. Spin the column at 100 g and remove the eluate, the antibody-peptide complex should still be coupled to the beads.
12. Wash the column by adding 500 μl PBS and mixing the beads well before spinning at 100 g for 30 seconds and removing eluate. Repeat this step a further three times.
13. To elute the bound antibody, add 200 μl 0.1M citric acid to the beads and incubate for 5 minutes at room temperature. Place column in a 2 ml eppendorf containing 25 μl 1M Tris pH9 and spin at 100 g for 30 seconds; collect eluate.
14. Optionally repeat step 13.
15. Store antibody-peptide complex at 4° C.
The following procedure was used as a standard-operating protocol for separately conjugating a plurality of T-cell epitopes and their corresponding cleavage sites to an antibody serving as a targeting moiety by using sulfo-SMCC.
1. Cysteinylated peptides dissolved in DMSO to final concentration of 10 mg/ml.
2. Weigh 1 mg Sulfosuccinimidyl 4-[N-maleimidomethyl]cyclohexane-1-carboxylate (Sulfo-SMCC) and dissolve in 200 μl phosphate buffered saline (PBS) (final concentration 5 mg/ml).
3. Add 100 μl antibody (10 mg/ml, 1 mg antibody) to 10 μl dissolved Sulfo-SMCC (5 mg/ml) and incubate at room temperature for 30 minutes.
4. Wash a ZebaSpin desalting column (Pierce) by firstly spinning the column at 1500 g for 60 seconds to remove the ethanol (storage buffer).
5. Add 300 μl PBS and spin at 1500 g for 60 seconds. Remove eluate and repeat a further three times.
6. Add up to 125 μl antibody-SMCC to each column, and centrifuge at 1500 g for 120 seconds, collecting the eluate.
7. Generate a mixture or required peptides in a tube so that there is a total of 30 μg of total peptide. Add the peptide mixture to 100 μl of antibody-SMCC complex and leave at room temperature for 30 minutes.
8. Wash a Protein A column (GE Healthcare) by firstly spinning the column at 100 g for 30 seconds to remove the ethanol (storage buffer).
9. Add 500 μl PBS and spin at 100 g for 30 seconds. Remove eluate and repeat a further two times.
10. Dilute antibody-peptide conjugate to 500 μl in PBS and add it to the protein A column, mixing the antibody with the beads. Leave at room temperature for 20 minutes, shaking.
11. Spin the column at 100 g and remove the eluate, the antibody-peptide complex should still be coupled to the beads.
12. Wash the column by adding 500 μl PBS and mixing the beads well before spinning at 100 g for 30 seconds and removing eluate. Repeat this step a further three times.
13. To elute the bound antibody, add 200 μl 0.1M citric acid to the beads and incubate for 5 minutes at room temperature. Place column in a 2 ml eppendorf containing 25 μl 1M Tris pH9 and spin at 100 g for 30 seconds; collect eluate.
14. Optionally repeat step 13.
15. Store antibody-peptide complex at 4° C.
The following procedure was used as a standard-operating protocol for separately conjugating a polytope to an antibody serving as a targeting moiety by using 3-MPA.
1. 3-maleimidopropioinc acid linked peptides dissolved in DMSO to final concentration of 10 mg/ml.
2. To 100 μl antibody (diluted in PBS if required), add 3 μl polytope peptide (10 mg/ml) and incubate at room temperature for 30 minutes.
3. Wash a Protein A column (GE Healthcare) by firstly spinning the column at 100 g for 30 seconds to remove the ethanol (storage buffer).
4. Add 500 μl PBS and spin at 100 g for 30 seconds. Remove eluate and repeat a further two times.
5. Dilute antibody-peptide conjugate to 500 μl in PBS and add it to the protein A column, mixing the antibody with the beads. Leave at room temperature for 20 minutes, shaking.
6. Spin the column at 100 g and remove the eluate, the antibody-peptide complex should still be coupled to the beads.
7. Wash the column by adding 500 μl PBS and mixing the beads well before spinning at 100 g for 30 seconds and removing eluate. Repeat this step a further three times.
8. To elute the bound antibody, add 200 μl 0.1M citric acid to the beads and incubate for 5 minutes at room temperature. Place column in a 2 ml eppendorf containing 25 μl 1M Tris pH9 and spin at 100 g for 30 seconds; collect eluate.
9. Optionally repeat step 8.
10. Store antibody-peptide complex at 4° C.
The following procedure was used as a standard-operating protocol for separately conjugating a plurality of T-cell epitopes and their corresponding cleavage sites to an antibody serving as a targeting moiety by using 3-MPA.
1. 3-maleimidopropioinc acid linked peptides dissolved in DMSO to final concentration of 10 mg/ml.
2. Generate a mixture or required peptides in a tube so that there is a total of 30 μg of total peptide, add to 100 μl of antibody (diluted in PBS if required) and incubate at room temperature for 30 minutes.
3. Wash a Protein A column (GE Healthcare) by firstly spinning the column at 100 g for 30 seconds to remove the ethanol (storage buffer).
4. Add 500 μl PBS and spin at 100 g for 30 seconds. Remove eluate and repeat a further two times.
5. Dilute antibody-peptide conjugate to 500 μl in PBS and add it to the protein A column, mixing the antibody with the beads. Leave at room temperature for 20 minutes, shaking.
6. Spin the column at 100 g and remove the eluate, the antibody-peptide complex should still be coupled to the beads.
7. Wash the column by adding 500 μl PBS and mixing the beads well before spinning at 100 g for 30 seconds and removing eluate. Repeat this step a further three times.
8. To elute the bound antibody, add 200 μl 0.1M citric acid to the beads and incubate for 5 minutes at room temperature. Place column in a 2 ml eppendorf containing 25 μl 1M Tris pH9 and spin at 100 g for 30 seconds; collect eluate.
Optionally repeat step 8.
Store antibody-peptide complex at 4° C.
We contacted B-lymphoblastoid cells (B-LCL) with an agent comprising Rituximab conjugated to two different cytomegalovirus peptides NLVPMVATV (SEQ ID NO: 1) and RPHERNGFTVL (SEQ ID NO: 2) each with a cleavage site for cathepsin B. Subsequent exposure to peptide-specific T cells resulted in the generation of a T cell response to the B-LCL.
Rituximab was conjugated with the peptides NLVPMVATVASGV{CIT}GC (SEQ ID NO: 3) and RPHERNGFTVLASGFKGC (SEQ ID NO: 4) at the following ratios from Table 3, wherein CIT represents citrulline, a type of amino acid that is similar to arginine
After staining the cells with Rituximab conjugated to the mixture of peptides, labeled cells were washed and cultured overnight at 37° C. in the presence of peptide-specific T cells. Supernatant was harvested and assayed for the presence of IFN-γ.
Using NLV-specific T cells, TPEC #11 was recognized strongly as seen by a large production of IFN-γ whereas TPEC #1 is not recognized at all as there was no production of IFN-γ. See
We contacted B-lymphoblastoid cells (B-LCL) with an agent comprising Rituximab conjugated to three different cytomegalovirus peptides VLEETSVML (SEQ ID NO: 5), BRVLBBYVL (SEQ ID NO: 6) and YILEETSVM (SEQ ID NO: 7) each with a cleavage site for cathepsin B. Subsequent exposure to peptide-specific T cells resulted in the generation of a T cell response to the B-LCL.
Rituximab was conjugated with VLEETSVMLASGFKGC (SEQ ID NO: 8), BRVLBBYVLASGFKGC (SEQ ID NO: 9) where B is amino butyric acid, a homolog for cysteine, and YILEETSVMASGFKGC (SEQ ID NO: 10) at equal amounts of peptide. B-LCL cells were labeled with Rituximab TPEC and after incubation, washed to remove excess TPEC. Labeled target cells were incubated overnight at 37° C. in the presence of VLE-specific, CRV-specific or YIL-specific T cells. Supernatant from the cultures was used to assess the presence of IFN-γ.
Results are shown in
We contacted B-lymphoblastoid cells (B-LCL) with an agent comprising Rituximab conjugated to a single peptide which comprised two different cytomegalovirus peptides: (i) NLVPMVATV (SEQ ID NO: 1) and RPHERNGFTVL (SEQ ID NO: 2) or (ii) NLVPMVATV (SEQ ID NO: 1) and VLEETSVML (SEQ ID NO: 5) each separated from the other by a cleavage site for cathepsin B. Subsequent exposure to NLV peptide-specific T cells resulted in the generation of a T cell response to the B-LCL.
Rituximab was conjugated with the peptides (i) CGVANLVPMVATVAVAVLEETSVML (SEQ ID NO: 11), (ii) CVARPHERNGFTVLVANLVPMVATV (SEQ ID NO: 12) and (iii) CGVANLVPMVATVARPHERNGFTVL (SEQ ID NO: 13). Target cells were labeled with TPEC and washed after incubation to remove excess TPEC. Target cells were cultured overnight at 37° C. in the presence of NLV-specific T cells and the supernatant assayed for the presence of IFN-γ the following day.
NLV-specific T cells were able to recognize target cells labeled with each of the three TPECs tested as determined by IFN-γ release. This demonstrates the ability of a peptide containing more than one cytomegalovirus derived peptide, separated by a protease cleavage site, to stimulate peptide-specific T cells. Furthermore, the position of the NLVPMVATV (SEQ ID NO: 1) peptide in the polytope appears to affect the magnitude of the response with the NLV peptide being furthest from the antibody CVARPHERNGFTVLVANLVPMVATV (SEQ ID NO: 12) producing the largest response. However, both polytope peptides containing the NLV peptide closest to the antibody CGVANLVPMVATVAVAVLEETSVML (SEQ ID NO: 11) and CGVANLVPMVATVARPHERNGFTVL (SEQ ID NO: 13) also demonstrate a T cell response above background.
Results are shown in
A stem peptide that contains four azidonorleucine residues was provided along with peptides (branches) that contain propargyl glycine at the amino terminus (
And for Branched TPEC 3, the sequences of the branched peptides were BAIPVSLRTPRVTGGGAM-nh2, wherein B is propargyl glycine (SEQ ID NO: 173), BAIPVSLRRPHERNGFTVL-nh2, wherein B is propargyl glycine (SEQ ID NO: 174), BAIPVSLRELRRKMMYM-nh2, wherein B is propargyl glycine (SEQ ID NO: 175), and BAIPVSLVTEHDTLLY-nh2, wherein B is propargyl glycine (SEQ ID NO: 176).
Incubation of equimolar concentrations of the branches with the stem peptide in DMSO in the presence of 10 mg in 4 ml of the CuSO4.5H2O catalyst mixed with 10 mg in 4 ml ascorbic acid overnight resulted in the formation of the branched peptide used for conjugation. The final concentration of DMSO for the reaction was 50%. The branched peptides were purified using HPLC and verified using mass spectrometry (
The branched peptide was conjugated to either Rituximab or Cetuximab by firstly reducing the antibody in the presence of approximately 0.1 mM (tris(2-carboxyethyl)phosphine (TCEP) for 90 minutes. The branched peptide is then added at 3× the concentration as TCEP for 60 minutes and N-acetyl cysteine is added to quench the free peptide using the same concentration as the branched peptide for 30 minutes. The free peptide is removed using protein A sepahrose beads to bind the TPEC whilst the free peptide is washed off. The TPEC is then collected from the protein A beads by eluting using 0.1M glycine and buffered using 1 m Tris pH8.
Two agents comprised of Rituximab conjugated with a branched peptide consisting of four different viral epitopes, each linked to a single stem peptide. In Branched TPEC 1, each of the four peptides was separated from the stem peptide by an ADAM28 protease cleavage sequence. In Branched TPEC 3, each of the four peptides was separated from the stem peptide by an MMP2 cleavage sequence. The target cells were labelled with the Rituximab-TPEC before being incubated with CD8 T cells specific for one of two different viral epitopes. Specifically, TPR T cells were specific for the viral epitope TPRVTGGGAM (SEQ ID NO: 49) and this epitope was present in branches 1-1 and 3-1. RPH T cells were specific for the viral epitope RPHERNGFTVL (SEQ ID NO: 2) and this epitope was present in branches 1-2 and 3-2.
Upon binding malignant cells (transformed B cell line), viral epitopes were released from the stem peptide by proteolytic cleavage releasing the viral epitopes TPRVTGGGAM (SEQ ID NO: 49), RPHERNGFTVL (SEQ ID NO: 2), ELRRKMMYM (SEQ ID NO: 24) and VTEHDTLLY (SEQ ID NO: 53). Upon release, the peptides were presented on MHC class I molecules on the malignant cells where they could be recognized by the CD8 T cells. Recognition of malignant cells by the CD8 T cells was measured by release of IFN-γ by the T cells which can be used as a proxy for T cell killing.
Results are shown in
These results demonstrate that branched TPECs can obtain positive results in a widely-recognized model for retargeting a T cell response.
Two agents comprised of Cetuximab conjugated with a branched peptide consisting of four different viral epitopes, all linked to a single stem peptide was provided. In Branched TPEC 1, each of the four peptides was separated from the stem peptide by an ADAM28 protease cleavage sequence. In Branched TPEC 3, each of the four peptides was separated from the stem peptide by an MMP2 cleavage sequence. The target cells were labelled with the Cetuximab-TPEC before being incubated with CD8 T cells specific for one of two different viral epitopes. Specifically, TPR T cells were specific for the viral epitope TPRVTGGGAM (SEQ ID NO: 49) and this epitope was present in branches 1-1 and 3-1. RPH T cells were specific for the viral epitope RPHERNGFTVL (SEQ ID NO: 2) and this epitope was present in branches 1-2 and 3-2.
Upon binding malignant cells (ovarian carcinoma cell line), viral epitopes were released from the stem peptide by proteolytic cleavage releasing the viral epitopes TPRVTGGGAM (SEQ ID NO: 49), RPHERNGFTVL (SEQ ID NO: 2), ELRRKMMYM (SEQ ID NO: 24) and VTEHDTLLY (SEQ ID NO: 53). Upon release, the peptides were presented on MHC class I molecules on the malignant cells where they could be recognized by the CD8 T cells. Recognition of malignant cells by the CD8 T cells was measured by release of IFN-γ by the T cells.
Results are shown in
These results demonstrate that branched TPECs can obtain positive results in a widely-recognized model for retargeting a T cell response.
DNA for an agent comprising Cetuximab containing an additional fibronectin type 3 domain (from fibronectin 1 protein) attached to each heavy chain (depicted in
This would allow release of the viral epitopes from the bundled domain and targeting agent (Cetuximab) after proteolytic cleavage by MMP2. The DNA for the bundled domain TPEC was transfected into Expi293 cells and the supernatant harvested 10 days post transfection. The bundled domain TPEC was purified from the supernatant using protein A sepharose beads. The target cells, ovarian carcinoma cell line, were labelled with the purified Cetuximab-TPEC with excess, unbound TPEC washed off. The labelled target cells were then incubated overnight in the presence of NLV-specific T cells.
Upon binding malignant cells (ovarian carcinoma cell line), viral epitopes were released from the additional protein domain by proteolytic cleavage. The released peptides were presented on MHC class I molecules on the malignant cells where they could be recognized by the CD8+ T cells. Recognition of malignant cells by the CD8+ T cells was measured by release of IFN-γ by the T cells.
Results are shown in
These results demonstrate that bundled domain TPECs can obtain positive results in a widely-recognized model for retargeting a T cell response.
An agent comprising Rituximab or an anti-CD22 antibody is conjugated with a peptide mixture containing equal parts of five different cytomegalovirus-derived peptides each containing a protease cleavage site specific for cathepsin B (i) NLVPMVATVASGV{CIT}GC (SEQ ID NO: 3), (ii) VLEETSVMLASGFKGC (SEQ ID NO: 8), (iii) RPHERNGFTVLASGFKGC (SEQ ID NO: 4), (iv) YILEETSVMASGFKGC (SEQ ID NO: 10) and (v) BRVLBBYVLASGFKGC (SEQ ID NO: 9). The patient is infused with the agent, which targets all B cells, healthy and malignant. Upon binding malignant cells, the agent comes into contact with proteases whereby cleavage of the protease recognition domain releases the T-cell epitopes (i) NLVPMVATV (SEQ ID NO: 1), (ii) VLEETSVML (SEQ ID NO: 5), (iii) RPHERNGFTVL (SEQ ID NO: 2), (iv) YILEETSVM (SEQ ID NO: 7) and (v) BRVLBBYVL (SEQ ID NO: 6), which subsequently bind to HLA molecules on the surface of the malignant B cell. The malignant B cells expressing the T-cell epitopes are targeted by the host immune system for cytolysis by T cells.
An agent comprising Rituximab or an anti-CD22 antibody is conjugated with a peptide containing four different cytomegalovirus-derived epitopes (i) CGSFRVTEHDTLLYGSFRRPHERNGFTVLGSFRELKRKMIYMGSFRN LVPMVATV (SEQ ID NO: 14). Each of the four epitopes is separated from the next one by a protease cleavage site specific for cathepsin B in the conformation targeting agent-C-E1-C-E2-C-E3-C-E4 where C is protease cleavage and E is epitope. The patient is infused with the agent, which targets all B cells, healthy and malignant. Upon binding malignant cells, the agent comes into contact with proteases whereby cleavage of the protease recognition domain releases the T-cell epitopes (i) NLVPMVATV (SEQ ID NO: 1), (ii) VTEHDTLLY (SEQ ID NO: 53), RPHERNGFTVL (SEQ ID NO: 2), and (iv) ELKRKMIYM (SEQ ID NO: 23), which subsequently bind to HLA molecules on the surface of the malignant B cell. The cells expressing the T-cell epitopes are then targeted by the host immune system for cytolysis by T cells.
An agent comprising Rituximab or an anti-CD22 antibody is conjugated with a peptide mixture containing equal parts of five different cytomegalovirus-derived peptides each containing a protease cleavage site specific for either ADAM28 or cathepsin D (i) CKPAKFFRLNLVPMVATV (SEQ ID NO: 58), (ii) CKPAKFFRLRPHERNGFTVL (SEQ ID NO: 59), (iii) CPRSFFRLGKVLEETSVML (SEQ ID NO: 60), (iv) CKPAKFFRLELKRKMIYM (SEQ ID NO: 61) and (v) CPRSFFRLGKQIKVRVDMV (SEQ ID NO: 62). The patient is infused with the agent, which targets all B cells, healthy and malignant. Upon binding malignant cells, the agent comes into contact with proteases whereby cleavage of the protease recognition domain releases the T-cell epitopes (i) NLVPMVATV (SEQ ID NO: 1), (ii) RPHERNGFTVL (SEQ ID NO: 2), (iii) VLEETSVML (SEQ ID NO: 5), (iv) ELKRKMIYM (SEQ ID NO: 23) and (v) QIKVRVDMV (SEQ ID NO: 38), which subsequently bind to HLA molecules on the surface of the malignant B cell. The malignant B cells expressing the T-cell epitopes on their HLA molecules at the cell surface are targeted by the host immune system for cytolysis by T cells.
An agent comprising Rituximab or an anti-CD22 antibody is conjugated with a peptide containing four different cytomegalovirus-derived epitopes (i) CGSKPAKFFRLYSEHPTFTSQYGSPRSFFRLGKTPRVTGGGAMG SKPAKFFRLQIKVRVDMVGSPRSFFRLGKELRRKMMYM (SEQ ID NO: 63). Each of the four epitopes is separated from the next one by a protease cleavage site specific for either ADAM28 or cathepsin D in a potential conformation, but not limited to the conformation, Targeting agent-Ci-E1-Cii-E2-Ci-E3-Cii-E4 where C is protease cleavage and E is epitope. The patient is infused with the agent, which targets all B cells, healthy and malignant. Upon binding malignant cells, the agent comes into contact with proteases whereby cleavage of the protease recognition domain releases the T-cell epitopes (i) YSEHPTFTSQY (SEQ ID NO: 55), (ii) TPRVTGGGAM (SEQ ID NO: 49), (iii) QIKVRVDMV (SEQ ID NO: 38), and (iv) ELRRKMMYM (SEQ ID NO: 24), which subsequently bind to HLA molecules on the surface of the malignant B cell. The cells expressing the T-cell epitopes are then targeted by the host immune system for cytolysis by T cells.
Various embodiments are described in the following nonlimiting items.
Item 1. A composition for retargeting an immune response to unwanted cells comprising a TPEC wherein:
The foregoing written specification is considered to be sufficient to enable one skilled in the art to practice the embodiments. The foregoing description and Examples detail certain embodiments and describes the best mode contemplated by the inventors. It will be appreciated, however, that no matter how detailed the foregoing may appear in text, the embodiment may be practiced in many ways and should be construed in accordance with the appended claims and any equivalents thereof.
As used herein, the term about refers to a numeric value, including, for example, whole numbers, fractions, and percentages, whether or not explicitly indicated. The term about generally refers to a range of numerical values (e.g., +/−5-10% of the recited range) that one of ordinary skill in the art would consider equivalent to the recited value (e.g., having the same function or result). When terms such as at least and about precede a list of numerical values or ranges, the terms modify all of the values or ranges provided in the list. In some instances, the term about may include numerical values that are rounded to the nearest significant figure.
| Number | Date | Country | |
|---|---|---|---|
| 62111069 | Feb 2015 | US |
