Patent Grant
8961989
This application relates to the field of immunology, more specifically to methods for the production of an immune response to tuberculosis antigens in a subject.
The Sequence Listing is submitted as an ASCII text file in the form of the file named Sequence_Listing.txt, which was created on May 15, 2012, and is 120,062 bytes, which is incorporated by reference herein.
Mycobacterium is a genus of aerobic intracellular bacterial organisms that, upon infection of a host, survive within endosomal compartments of monocytes and macrophages. Human mycobacterial diseases include tuberculosis (caused by M. tuberculosis), leprosy (caused by M. leprae), Bairnsdale ulcers (caused by M. ulcerans), and various infections caused by M. marinum, M. kansasii, M. scrofulaceum, M. szulgai, M. xenopi, M. fortuitum, M. chelonae, M. haemophilum and M. intracellulare (see Wolinsky, Chapter 37 in Microbiology: Including Immunology and Molecular Genetics, 3rd Ed., Harper & Row, Philadelphia, 1980).
One third of the world's population harbors M. tuberculosis and is at risk for developing tuberculosis (TB). In immunocompromised patients, tuberculosis is increasing at a nearly logarithmic rate, and multidrug resistant strains are appearing. In addition, mycobacterial strains which were previously considered to be nonpathogenic strains (e.g., M. avium) have now become major killers of immunosuppressed AIDS patients. Moreover, current mycobacterial vaccines are either inadequate (such as the BCG vaccine for M. tuberculosis) or unavailable (such as for M. leprae) (Kaufmann, Microbiol. Sci. 4:324-328, 1987; U.S. Congress, Office of Technology Assessment, The Continuing Challenge of Tuberculosis, pp. 62-67, OTA-H-574, U.S. Government Printing Office, Washington, D.C., 1993).
Inhibiting the spread of tuberculosis requires effective vaccination and accurate, early diagnosis of the disease. Currently, vaccination with live bacteria is the most efficient method for inducing protective immunity. The most common mycobacterium employed for this purpose is Bacillus Calmette-Guerin (BCG), an avirulent strain of Mycobacterium bovis. However, the safety and efficacy of BCG is a source of controversy and some countries, such as the United States, do not vaccinate the general public.
Mycobacterium tuberculosis (Mtb)-specific CD4+ and CD8+ T cells are critical for the effective control of Mtb infection. In the mouse model, passive transfer of CD4+ T cells to sublethally irradiated animals renders them less susceptible to Mtb infection (Orme, J. Immunol. 140:3589-3593, 1988). Mice in which the gene(s) for CD4 or for MHC Class II molecules are disrupted, as well as wild-type mice depleted of CD4+ T cells, demonstrate increased susceptibility to Mtb infection (Flory et al., J. Leukoc. Biol. 51:225-229, 1992). In humans, human immunodeficiency virus-infected individuals are exquisitely susceptible to developing TB after exposure to Mtb, supporting an essential role for CD4+ T cells (Hirsch et al., J. Infect. Dis. 180:2069-2073, 1999). CD8+ T cells are also important for effective T cell immunity (see Lazarevic and Flynn, Am. J. Respir. Crit. Care Med. 166:1116-1121, 2002). In humans, Mtb-specific CD8+ T cells have been identified in Mtb-infected individuals and include CD8+ T cells that are both classically HLA-Ia restricted (see, for example, Lewinsohn et al., J. Immunol. 165:925-930, 2000) and nonclassically restricted by the HLA-Ib molecule HLA-E (Lewinsohn et al., J. Exp. Med. 187:1633-1640, 1998). However, there are no vaccines or therapeutic strategies that effectively induce an immune response, such as a CD8 response, to Mtb.
Accordingly, there is a need in the art for agents that can produce an immune response to Mtb that can be used for treatment and/or protection from an Mtb infection.
Methods for producing an immune response to Mycobacterium tuberculosis (Mtb) are disclosed herein. Methods for treating an Mtb infection, inhibiting an Mtb infection, or preventing an Mtb infection in a subject, are also disclosed herein. The Mtb infection can be latent or active.
In several embodiments, the methods include administering to the subject a therapeutically effective amount of a polypeptide, or a polynucleotide encoding the polypeptide, wherein the polypeptide comprises at least one of the amino acid sequences set forth as SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 17, or SEQ ID NO: 18. In additional embodiments, the methods include administering to the subject a therapeutically effective amount of a polypeptide comprising at least nine to twenty consecutive amino acids of at least one of the amino acid sequences set forth as SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO: 3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO: 6, SEQ ID NO: 7, SEQ ID NO: 8, SEQ ID NO: 9, SEQ ID NO: 10, SEQ ID NO: 11, SEQ ID NO: 12, SEQ ID NO: 13, SEQ ID NO: 14, SEQ ID NO: 15, SEQ ID NO: 16, SEQ ID NO: 17, or SEQ ID NO: 18, wherein the nine to twenty consecutive amino acids specifically bind major histocompatibility complex (MHC) class I. In some examples, the polypeptide includes a conservative variant of the polypeptide (for example, one or more conservative amino acid substitutions). In several examples, the immune response is a protective immune response. In additional embodiments, methods are disclosed for inhibiting or preventing an infection with Mtb, or treating an infection with Mtb.
Isolated polypeptides are described herein that include nine to twenty consecutive amino acids of at least one of the amino acid sequences set forth as SEQ ID NOs: 1-18, wherein the nine to twenty consecutive amino acids specifically bind major histocompatibility complex (MHC) class I, wherein the isolated polypeptide does not include any of the full length amino acid sequences set forth as SEQ ID NOs: 1-18. Nucleic acids encoding these polypeptides, vectors including these nucleic acids, host cells including these nucleic acids, and immunogenic compositions including these polypeptides, nucleic acids and/or host cells are also disclosed. Pharmaceutical compositions including a therapeutically effective amount of these polypeptides, nucleic acids, and/or host cells are also described.
The foregoing and other features will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures.
The nucleic acid and amino acid sequences listed herein or in the accompanying sequence listing are shown using standard letter abbreviations for nucleotide bases, and one letter code for amino acids. Only one strand of each nucleic acid sequence is shown, but the complementary strand is understood as included by any reference to the displayed strand.
The Sequence Listing is submitted as an ASCII text file in the form of the file named Sequence_Listing.txt, which was created on Oct. 29, 2010, and is 117 kilobytes, which is incorporated by reference herein.
SEQ ID NOs: 1-18 are the amino acid sequences of Mtb polypeptides.
SEQ ID NOs: 19-36 are the nucleic acid sequences of polynucleotides encoding the Mtb polypeptides.
Methods for producing an immune response to Mycobacterium tuberculosis (Mtb) are disclosed herein. In several examples, the immune response is a protective immune response. In additional embodiments, methods are disclosed for inhibiting an infection with Mtb, or treating an infection with Mtb. Pharmaceutical compositions for the inhibition, prevention and/or treatment of tuberculosis are also disclosed.
I. Abbreviations
APC: antigen presenting cell
BCG: Bacillus Calmette-Guerin
DC: dendritic cell
HLA: human leukocyte antigen
IFN-γ: interferon-γ
MHC: major histocompatibility complex
Mtb: Mycobacterium tuberculosis
TB: tuberculosis
II. Terms
Unless otherwise noted, technical terms are used according to conventional usage. Definitions of common terms in molecular biology may be found in Benjamin Lewin, Genes V, published by Oxford University Press, 1994 (ISBN 0-19-854287-9); Kendrew et al. (eds.), The Encyclopedia of Molecular Biology, published by Blackwell Science Ltd., 1994 (ISBN 0-632-02182-9); and Robert A. Meyers (ed.), Molecular Biology and Biotechnology: a Comprehensive Desk Reference, published by VCH Publishers, Inc., 1995 (ISBN 1-56081-569-8).
In order to facilitate review of the various embodiments of this disclosure, the following explanations of specific terms are provided:
Adjuvant: A vehicle used to enhance antigenicity. Adjuvants include a suspension of minerals (alum, aluminum hydroxide, or phosphate) on which antigen is adsorbed; or water-in-oil emulsion in which antigen solution is emulsified in mineral oil (Freund incomplete adjuvant), sometimes with the inclusion of killed mycobacteria (Freund's complete adjuvant) to further enhance antigenicity (inhibits degradation of antigen and/or causes influx of macrophages). Immunostimulatory oligonucleotides (such as those including a CpG motif) can also be used as adjuvants (for example see U.S. Pat. No. 6,194,388; U.S. Pat. No. 6,207,646; U.S. Pat. No. 6,214,806; U.S. Pat. No. 6,218,371; U.S. Pat. No. 6,239,116; U.S. Pat. No. 6,339,068; U.S. Pat. No. 6,406,705; and U.S. Pat. No. 6,429,199). Adjuvants include biological molecules (a “biological adjuvant”), such as costimulatory molecules. Exemplary adjuvants include IL-2, RANTES, GM-CSF, TNF-α, IFN-γ, G-CSF, LFA-3, CD72, B7-1, B7-2, OX-40L and 4-1 BBL
Amplification: Use of a technique that increases the number of copies of a nucleic acid molecule (e.g., a DNA or RNA molecule) in a specimen. An example of amplification is the polymerase chain reaction, in which a biological sample collected from a subject is contacted with a pair of oligonucleotide primers, under conditions that allow for the hybridization of the primers to a nucleic acid template in the sample. The primers are extended under suitable conditions, dissociated from the template, and then re-annealed, extended, and dissociated to amplify the number of copies of the nucleic acid. The product of amplification can be characterized by electrophoresis, restriction endonuclease cleavage patterns, oligonucleotide hybridization or ligation, and/or nucleic acid sequencing using standard techniques. Other examples of amplification include strand displacement amplification, as disclosed in U.S. Pat. No. 5,744,311; transcription-free isothermal amplification, as disclosed in U.S. Pat. No. 6,033,881; repair chain reaction amplification, as disclosed in WO 90/01069; ligase chain reaction amplification, as disclosed in EP-A-320 308; gap filling ligase chain reaction amplification, as disclosed in U.S. Pat. No. 5,427,930; and NASBA™ RNA transcription-free amplification, as disclosed in U.S. Pat. No. 6,025,134.
Animal: Living multi-cellular vertebrate organisms, a category that includes, for example, mammals and birds. The term mammal includes both human and non-human mammals. Similarly, the term “subject” includes both human and veterinary subjects.
Antibody: Immunoglobulin molecules and immunologically active portions of immunoglobulin molecules, i.e., molecules that contain an antigen binding site that specifically binds (immunoreacts with) an antigen, such as an Mtb polypeptide.
A naturally occurring antibody (e.g., IgG, IgM, IgD) includes four polypeptide chains, two heavy (H) chains and two light (L) chains interconnected by disulfide bonds. However, it has been shown that the antigen-binding function of an antibody can be performed by fragments of a naturally occurring antibody. Thus, these antigen-binding fragments are also intended to be designated by the term “antibody.” Specific, non-limiting examples of binding fragments encompassed within the term antibody include (i) a Fab fragment consisting of the VL, VH, CL and CH1 domains; (ii) an Fd fragment consisting of the VH and CH1 domains; (iii) an Fv fragment consisting of the VL and VH domains of a single arm of an antibody, (iv) a dAb fragment (Ward et al., Nature 341:544-546, 1989) which consists of a VH domain; (v) an isolated complementarity determining region (CDR); and (vi) a F(ab′)2 fragment, a bivalent fragment comprising two Fab fragments linked by a disulfide bridge at the hinge region.
Immunoglobulins and certain variants thereof are known and many have been prepared in recombinant cell culture (e.g., see U.S. Pat. Nos. 4,745,055 and 4,444,487; WO 88/03565; EP 256,654; EP 120,694; EP 125,023; Falkner et al., Nature 298:286, 1982; Morrison, J. Immunol. 123:793, 1979; Morrison et al., Ann. Rev. Immunol. 2:239, 1984).
Antigen: A compound, composition, or substance that can stimulate the production of antibodies or a T cell response in an animal, including compositions that are injected or absorbed into an animal. An antigen reacts with the products of specific humoral or cellular immunity, including those induced by heterologous immunogens. The term “antigen” includes all related antigenic epitopes. “Epitope” or “antigenic determinant” refers to a site on an antigen to which B and/or T cells respond. In one embodiment, T cells respond to the epitope, when the epitope is presented in conjunction with an MHC molecule. Epitopes can be formed both from contiguous amino acids or noncontiguous amino acids juxtaposed by tertiary folding of a protein. Epitopes formed from contiguous amino acids are typically retained on exposure to denaturing solvents whereas epitopes formed by tertiary folding are typically lost on treatment with denaturing solvents. An epitope typically includes at least 3, and more usually, at least 5, about 9, or about 8-10 amino acids in a unique spatial conformation. Methods of determining spatial conformation of epitopes include, for example, x-ray crystallography and 2-dimensional nuclear magnetic resonance.
An antigen can be a tissue-specific antigen, or a disease-specific antigen. These terms are not exclusive, as a tissue-specific antigen can also be a disease-specific antigen. A tissue-specific antigen is expressed in a limited number of tissues, such as a single tissue. A tissue-specific antigen may be expressed by more than one tissue, such as, but not limited to, an antigen that is expressed in more than one reproductive tissue, such as in both prostate and uterine tissue. A disease-specific antigen is expressed coincidentally with a disease process. Specific non-limiting examples of a disease-specific antigen are an antigen whose expression correlates with, or is predictive of, tuberculosis. A disease-specific antigen can be an antigen recognized by T cells or B cells.
Antigen presenting cell (APC): A cell that can present an antigen to T cell, such that the T cells are activated. Dendritic cells (DCs) are the principle APCs involved in primary immune responses. Their major function is to obtain antigen in tissues, migrate to lymphoid organs and present the antigen in order to activate T cells.
When an appropriate maturational cue is received, DCs are signaled to undergo rapid morphological and physiological changes that facilitate the initiation and development of immune responses. Among these are the up-regulation of molecules involved in antigen presentation; production of pro-inflammatory cytokines, including IL-12, key to the generation of Th1 responses; and secretion of chemokines that help to drive differentiation, expansion, and migration of surrounding naive Th cells. Collectively, these up-regulated molecules facilitate the ability of DCs to coordinate the activation and effector function of other surrounding lymphocytes that ultimately provide protection for the host.
cDNA (complementary DNA): A piece of DNA lacking internal, non-coding segments (introns) and regulatory sequences that determine transcription. cDNA is synthesized in the laboratory by reverse transcription from messenger RNA extracted from cells.
CD4: Cluster of differentiation factor 4, a T cell surface protein that mediates interaction with the MHC Class II molecule. CD4 also serves as the primary receptor site for HIV on T cells during HIV infection. Cells that express CD4 are often helper T cells.
CD8: Cluster of differentiation factor 8, a T cell surface protein that mediates interaction with the MHC Class 1 molecule. Cells that express CD8 are often cytotoxic T cells. “CD8+ T cell mediated immunity” is an immune response implemented by presentation of antigens to CD8+ T cells.
Conservative variants: A substitution of an amino acid residue for another amino acid residue having similar biochemical properties. “Conservative” amino acid substitutions are those substitutions that do not substantially affect or decrease an activity or antigenicity of the Mycobacterium polypeptide. A peptide can include one or more amino acid substitutions, for example 1-10 conservative substitutions, 2-5 conservative substitutions, 4-9 conservative substitutions, such as 1, 2, 5 or 10 conservative substitutions. Specific, non-limiting examples of a conservative substitution include the following examples (Table 1).
The term conservative variation also includes the use of a substituted amino acid in place of an unsubstituted parent amino acid, provided that antibodies raised to the substituted polypeptide also immunoreact with the unsubstituted polypeptide, or that an immune response can be generated against the substituted polypeptide that is similar to the immune response against the unsubstituted polypeptide, such as a Mycobacterium antigen. Thus, in one embodiment, non-conservative substitutions are those that reduce an activity or antigenicity.
Consists Essentially Of/Consists Of: With regard to a polypeptide, a polypeptide consists essentially of a specified amino acid sequence if it does not include any additional amino acid residues. However, the polypeptide can include additional non-peptide components, such as labels (for example, fluorescent, radioactive, or solid particle labels), sugars or lipids. A polypeptide that consists of a specified amino acid sequence does not include any additional amino acid residues, nor does it include additional non-peptide components, such as lipids, sugars or labels.
Contacting: The process of incubating one agent in the presence of another. Thus, when a cell is contacted with an agent, the cell is incubated with the agent for a sufficient period of time for the agent and the cell to interact.
Costimulatory molecule: Although engagement of the T cell receptor with peptide-MHC delivers one signal to the T cell, this signal alone can be insufficient to activate the T cell. Costimulatory molecules are molecules that, when bound to their ligand, deliver a second signal required for the T cell to become activated. The most well-known costimulatory molecule on the T cell is CD28, which binds to either B7-1 (also called CD80) or B7-2 (also known as CD86). An additional costimulatory molecule is B7-3. Accessory molecules that also provide a second signal for the activation of T cells include intracellular adhesion molecule (ICAM-1 and ICAM-2), leukocyte function associated antigen (LFA-1, LFA-2 and LFA-3). Integrins and tumor necrosis factor (TNF) superfamily members can also serve as costimulatory molecules.
Cytokine: Proteins made by cells that affect the behavior of other cells, such as lymphocytes. In one embodiment, a cytokine is a chemokine, a molecule that affects cellular trafficking. Specific, non-limiting examples of cytokines include the interleukins (IL-2, IL-4, IL-6, IL-10, IL-21, etc.), and interferon (IFN)-γ.
Degenerate variant: A polynucleotide encoding an epitope of an Mtb polypeptide that includes a sequence that is degenerate as a result of the genetic code. There are 20 natural amino acids, most of which are specified by more than one codon. Therefore, all degenerate nucleotide sequences are included in this disclosure as long as the amino acid sequence of the Mtb polypeptide encoded by the nucleotide sequence is unchanged.
Dendritic cell (DC): Dendritic cells are the principle APCs involved in primary immune responses. DCs include plasmacytoid dendritic cells and myeloid dendritic cells. Their major function is to obtain antigen in tissues, migrate to lymphoid organs and present the antigen in order to activate T cells. Immature DCs originate in the bone marrow and reside in the periphery as immature cells.
Displaying: The process of localizing a peptide:antigen complex, or a peptide, on the outer surface of a cell where the peptide:antigen complex or peptide is accessible to a second cell, molecules displayed by a second cell, or soluble factors. A peptide, or a peptide:antigen complex, is “displayed” by a cell when it is present on the outer surface of the cell and is accessible to a second cell, to molecules displayed by the second cell, or to soluble factors.
Epitope: An antigenic determinant. These are particular chemical groups or peptide sequences on a molecule that are antigenic, e.g., that elicit a specific immune response. An antibody specifically binds a particular antigenic epitope on a polypeptide, such a Mycobacterium polypeptide.
Expression Control Sequences: Nucleic acid sequences that regulate the expression of a heterologous nucleic acid sequence to which it is operatively linked. Expression control sequences are operatively linked to a nucleic acid sequence when the expression control sequences control and regulate the transcription and, as appropriate, translation of the nucleic acid sequence. Thus expression control sequences can include appropriate promoters, enhancers, transcription terminators, a start codon (e.g., ATG) in front of a protein-encoding gene, splicing signal for introns, maintenance of the correct reading frame of that gene to permit proper translation of mRNA, and stop codons. The term “control sequences” is intended to include, at a minimum, components whose presence can influence expression, and can also include additional components whose presence is advantageous, for example, leader sequences and fusion partner sequences. Expression control sequences can include a promoter.
A promoter is a minimal sequence sufficient to direct transcription. Also included are those promoter elements which are sufficient to render promoter-dependent gene expression controllable for cell-type specific, tissue-specific, or inducible by external signals or agents; such elements may be located in the 5′ or 3′ regions of the gene. Both constitutive and inducible promoters, are included (see e.g., Bitter et al., Meth. Enzymol. 153:516-544, 1987). For example, when cloning in bacterial systems, inducible promoters such as pL of bacteriophage lambda, plac, ptrp, ptac (ptrp-lac hybrid promoter) and the like may be used. In one embodiment, when cloning in mammalian cell systems, promoters derived from the genome of mammalian cells (e.g., metallothionein promoter) or from mammalian viruses (e.g., the retrovirus long terminal repeat; the adenovirus late promoter; the vaccinia virus 7.5K promoter) can be used. Promoters produced by recombinant DNA or synthetic techniques may also be used to provide for transcription of the nucleic acid sequences. In one embodiment, the promoter is a cytomegalovirus promoter.
Functionally Equivalent Sequence alterations, such as in an epitope of an antigen, which yield the same results as described herein. Such sequence alterations can include, but are not limited to, conservative substitutions, deletions, mutations, frameshifts, and insertions.
Heterologous: Originating from separate genetic sources or species. A polypeptide that is heterologous to an Mtb polypeptide originates from a nucleic acid that does not encode the Mtb polypeptide or another Mtb polypeptide. In one specific, non-limiting example, a polypeptide comprising nine consecutive amino acids from an Mtb polypeptide, or at most 20 consecutive amino acids from the Mtb polypeptide, and a heterologous amino acid sequence includes a β-galactosidase, a maltose binding protein, and albumin, hepatitis B surface antigen, or an immunoglobulin amino acid sequence. Generally, an antibody that specifically binds to a protein of interest will not specifically bind to a heterologous protein.
Host cells: Cells in which a vector can be propagated and its DNA expressed. The cell may be prokaryotic or eukaryotic. The cell can be mammalian, such as a human cell. The term also includes any progeny of the subject host cell. It is understood that all progeny may not be identical to the parental cell since there may be mutations that occur during replication. However, such progeny are included when the term “host cell” is used.
Human Leukocyte Antigen (HLA): A genetic designation of the human major histocompatibility complex (MHC). Individual loci are designated by uppercase letters, as in HLA-E, and alleles are designated by numbers, as in HLA-A*0201. The three main MHC class I genes are called HLA-A, HLA-B, and HLA-C. However, there are many genes that encode β2 microglobulin-associated cell surface molecules that are linked to the MHC class I genes. The expression of these genes is variable, both in the tissue distribution and the amount expressed on cells; these genes have been termed the MHC class IB genes.
Immune response: A response of a cell of the immune system, such as a B cell, natural killer cell, or a T cell, to a stimulus. In one embodiment, the response is specific for a particular antigen (an “antigen-specific response”). In one embodiment, an immune response is a T cell response, such as a Th1, Th2, or Th3 response. In another embodiment, an immune response is a response of a suppressor T cell.
Immunogenic composition: A composition comprising an effective amount of an immunogenic Mtb polypeptide or a nucleic acid encoding the immunogenic Mtb polypeptide that induces a measurable T response against Mtb, such as a CD8+ T cell response, or induces a measurable B cell response (such as production of antibodies that specifically bind an Mtb polypeptide). For in vitro use, the immunogenic composition can consist of the isolated nucleic acid, vector including the nucleic acid/or immunogenic peptide. For in vivo use, the immunogenic composition will typically comprise the nucleic acid, vector including the nucleic acid, and/or immunogenic polypeptide in pharmaceutically acceptable carriers and/or other agents. An immunogenic composition can optionally include an adjuvant, a costimulatory molecule, or a nucleic acid encoding a costimulatory molecule. An Mtb polypeptide, or nucleic acid encoding the polypeptide, can be readily tested for its ability to induce a CD8+ T cell response.
Immunogenic peptide: A peptide which comprises an allele-specific motif or other sequence such that the peptide will bind an MHC molecule and induce a T cell response, such as a CD8+ or CD4+ T cell response, or a B cell response (such as antibody production) against the antigen from which the immunogenic peptide is derived.
In one embodiment, immunogenic peptides are identified using sequence motifs or other methods, such as neural net or polynomial determinations, known in the art. Typically, algorithms are used to determine the “binding threshold” of peptides to select those with scores that give them a high probability of binding at a certain affinity and will be immunogenic. The algorithms are based either on the effects on MHC binding of a particular amino acid at a particular position, the effects on antibody binding of a particular amino acid at a particular position, or the effects on binding of a particular substitution in a motif-containing peptide. Within the context of an immunogenic peptide, a “conserved residue” is one which appears in a significantly higher frequency than would be expected by random distribution at a particular position in a peptide. In one embodiment, a conserved residue is one where the MHC structure may provide a contact point with the immunogenic peptide.
Immunogenic peptides can also be identified by measuring their binding to a specific MHC protein and by their ability to stimulate CD4 and/or CD8 when presented in the context of the MHC protein. In one example, an immunogenic “Mtb peptide” is a series of contiguous amino acid residues from the Mtb protein generally between 9 and 20 amino acids in length, such as about 8 to 11 residues in length.
Generally, immunogenic Mtb polypeptides can be used to induce an immune response in a subject, such as a B cell response or a T cell response. In one example, an immunogenic Mtb polypeptide, when bound to a MHC Class I molecule, activates CD8+ T cells, such as cytotoxic T lymphocytes (CTLs) against Mtb. Induction of CTLs using synthetic peptides and CTL cytotoxicity assays are known in the art (see U.S. Pat. No. 5,662,907, which is incorporated herein by reference). In one example, an immunogenic peptide includes an allele-specific motif or other sequence such that the peptide will bind an MHC molecule and induce a CD8+ response against the antigen from which the immunogenic peptide is derived. A CD8+ T cell that specifically recognizes an Mtb polypeptide is activated, proliferates, and/or secretes cytokines in response to that specific polypeptide, and not to other, non-related polypeptides.
Inhibiting or treating a disease: Inhibiting a disease, such as tuberculosis, refers to inhibiting the full development of a disease. In several examples, inhibiting a disease refers to lessening symptoms of a tuberculosis. “Treatment” refers to a therapeutic intervention that ameliorates a sign or symptom of a disease or pathological condition related to the disease, such as tuberculosis.
Interferon gamma (IFN-γ): IFN-γ is a dimeric protein with subunits of 146 amino acids. The protein is glycosylated at two sites, and the pI is 8.3-8.5. IFN-γ is synthesized as a precursor protein of 166 amino acids including a secretory signal sequence of 23 amino acids. Two molecular forms of the biologically active protein of 20 and 25 kDa have been described. Both of them are glycosylated at position 25. The 25 kDa form is also glycosylated at position 97. The observed differences of natural IFN-γ with respect to molecular mass and charge are due to variable glycosylation patterns. 40-60 kDa forms observed under non-denaturing conditions are dimers and tetramers of IFN-γ. The human gene has a length of approximately 6 kb. It contains four exons and maps to chromosome 12q24.1.
IFN-γ can be detected by sensitive immunoassays, such as an ELSA test that allows detection of individual cells producing IFN-γ. Minute amounts of IFN-γ can be detected indirectly by measuring IFN-induced proteins such as Mx protein. The induction of the synthesis of IP-10 has also been used to measure IFN-γ concentrations. In addition, bioassays can be used to detect IFN-γ, such as an assay that employs induction of indoleamine 2,3-dioxygenase activity in 2D9 cells. The production of IFN-γ can be used to assess T cell activation, such as activation of a T cell by a Mycobacterium antigen.
Isolated: An “isolated” biological component (such as a nucleic acid molecule, protein, or organelle) has been substantially separated or purified away from other biological components in the cell of the organism in which the component naturally occurs, such as other chromosomal and extra-chromosomal DNA and RNA, proteins, and organelles. Nucleic acids and proteins that have been “isolated” include nucleic acids and proteins purified by standard purification methods. The term also embraces nucleic acids and proteins prepared by recombinant expression in a host cell, as well as chemically synthesized nucleic acids or proteins, or fragments thereof.
Linker sequence: A linker sequence is an amino acid sequence that covalently links two polypeptide domains. Linker sequences can be included in the between the Mtb epitopes disclosed herein to provide rotational freedom to the linked polypeptide domains and thereby to promote proper domain folding and presentation to the MHC. By way of example, in a recombinant polypeptide comprising two Mtb domains, linker sequences can be provided between them, such as a polypeptide comprising Mtb polypeptide-linker-Mtb polypeptide. Linker sequences, which are generally between 2 and 25 amino acids in length, are well known in the art and include, but are not limited to, the glycine(4)-serine spacer (GGGGS x3) described by Chaudhary et al., Nature 339:394-397, 1989.
Lymphocytes: A type of white blood cell that is involved in the immune defenses of the body. There are two main types of lymphocytes: B cells and T cells.
Mycobacteria: A genus of aerobic intracellular bacterial organisms. Upon invasion of a host, these organisms survive within endosomal compartments of monocytes and macrophages. Human mycobacterial diseases include tuberculosis (cause by M. tuberculosis), Leprosy (caused by M. leprae), Bairnsdale ulcers (caused by M. ulcerans), and other infections that can be caused by M. marinum, M. kansasii, M. scrofulaceum, M. szulgai, M. xenopi, M. fortuitum, M. haemophilum, M. chelonei, and M. intracelluare. Mycobacterium strains that were previously considered to be nonpathogenic (such as M. avium) are also now known to be major killers of immunosuppressed AIDS patients.
The major response to mycobacteria involves cell mediated hypersensitivity (DTH) reactions with T cells and macrophages playing major roles in the intracellular killing and walling off (or containing) of the organism (granuloma formation). A major T cell response involves CD4+ lymphocytes that recognize mycobacterial heat shock proteins and immunodominant antigens.
Operably linked: A first nucleic acid sequence is operably linked with a second nucleic acid sequence when the first nucleic acid sequence is placed in a functional relationship with the second nucleic acid sequence. For instance, a promoter is operably linked to a coding sequence if the promoter affects the transcription or expression of the coding sequence. Generally, operably linked DNA sequences are contiguous and, where necessary to join two protein coding regions, the open reading frames are aligned.
ORF (open reading frame): A series of nucleotide triplets (codons) coding for amino acids without any termination codons. These sequences are usually translatable into a polypeptide.
Peptide Modifications: Mycobacterium polypeptides include synthetic embodiments of peptides described herein. In addition, analogues (non-peptide organic molecules), derivatives (chemically functionalized peptide molecules obtained starting with the disclosed peptide sequences) and variants (homologs) of these proteins can be utilized in the methods described herein. Each polypeptide of the invention is comprised of a sequence of amino acids, which may be either L- and/or D-amino acids, naturally occurring and otherwise.
Peptides may be modified by a variety of chemical techniques to produce derivatives having essentially the same activity as the unmodified peptides, and optionally having other desirable properties. For example, carboxylic acid groups of the protein, whether carboxyl-terminal or side chain, may be provided in the form of a salt of a pharmaceutically-acceptable cation or esterified to form a C1-C16 ester, or converted to an amide of formula NR1R2 wherein R1 and R2 are each independently H or C1-C16 alkyl, or combined to form a heterocyclic ring, such as a 5- or 6-membered ring. Amino groups of the peptide, whether amino-terminal or side chain, may be in the form of a pharmaceutically-acceptable acid addition salt, such as the HCl, HBr, acetic, benzoic, toluene sulfonic, maleic, tartaric and other organic salts, or may be modified to C1-C16 alkyl or dialkyl amino or further converted to an amide.
Hydroxyl groups of the peptide side chains may be converted to C1-C16 alkoxy or to a C1-C16 ester using well-recognized techniques. Phenyl and phenolic rings of the peptide side chains may be substituted with one or more halogen atoms, such as fluorine, chlorine, bromine or iodine, or with C1-C16 alkyl, C1-C16 alkoxy, carboxylic acids and esters thereof, or amides of such carboxylic acids. Methylene groups of the peptide side chains can be extended to homologous C2-C4 alkylenes. Thiols can be protected with any one of a number of well-recognized protecting groups, such as acetamide groups. Those skilled in the art will also recognize methods for introducing cyclic structures into the peptides of this invention to select and provide conformational constraints to the structure that result in enhanced stability.
Peptidomimetic and organomimetic embodiments are envisioned, whereby the three-dimensional arrangement of the chemical constituents of such peptido- and organomimetics mimic the three-dimensional arrangement of the peptide backbone and component amino acid side chains, resulting in such peptido- and organomimetics of a Mycobacterium polypeptide having measurable or enhanced ability to generate an immune response. For computer modeling applications, a pharmacophore is an idealized, three-dimensional definition of the structural requirements for biological activity. Peptido- and organomimetics can be designed to fit each pharmacophore with current computer modeling software (using computer assisted drug design or CADD). See Walters, “Computer-Assisted Modeling of Drugs,” in Klegerman & Groves, eds., 1993, Pharmaceutical Biotechnology, Interpharm Press, Buffalo Grove, Ill., pp. 165-174 and Principles of Pharmacology Munson (ed.) 1995, Ch. 102, for descriptions of techniques used in CADD. Also included are mimetics prepared using such techniques.
Pharmaceutical agent or drug: A chemical compound or composition capable of inducing a desired therapeutic or prophylactic effect when properly administered to a subject.
Pharmaceutically acceptable carriers: The pharmaceutically acceptable carriers useful with the polypeptides and nucleic acids described herein are conventional. Remington's Pharmaceutical Sciences, by E. W. Martin, Mack Publishing Co., Easton, Pa., 19th Edition (1995), describes compositions and formulations suitable for pharmaceutical delivery of the polypeptides or polynucleotides herein disclosed.
In general, the nature of the carrier will depend on the particular mode of administration being employed. For instance, parenteral formulations usually comprise injectable fluids that include pharmaceutically and physiologically acceptable fluids such as water, physiological saline, balanced salt solutions, aqueous dextrose, glycerol or the like as a vehicle. For solid compositions (e.g., powder, pill, tablet, or capsule forms), conventional non-toxic solid carriers can include, for example, pharmaceutical grades of mannitol, lactose, starch, or magnesium stearate. In addition to biologically-neutral carriers, pharmaceutical compositions to be administered can contain minor amounts of non-toxic auxiliary substances, such as wetting or emulsifying agents, preservatives, and pH buffering agents and the like, for example sodium acetate or sorbitan monolaurate.
Polynucleotide: A linear nucleotide sequence, including sequences of greater than 100 nucleotide bases in length.
Polypeptide: Any chain of amino acids, regardless of length or post-translational modification (e.g., glycosylation or phosphorylation). A “peptide” is a chain of amino acids that is less than 100 amino acids in length. In one embodiment, a “peptide” is a portion of a polypeptide, such as about 8-11, 9-12, or about 10, 20, 30, 40, 50, or 100 contiguous amino acids of a polypeptide that is greater than 100 amino acids in length.
Probes and primers: Nucleic acid probes and primers may readily be prepared based on the nucleic acids provided by this invention. A probe comprises an isolated nucleic acid attached to a detectable label or reporter molecule. Typical labels include radioactive isotopes, ligands, chemiluminescent agents, and enzymes. Methods for labeling and guidance in the choice of labels appropriate for various purposes are discussed, e.g., in Sambrook et al. (1989) and Ausubel et al. (1987).
Primers are short nucleic acids, preferably DNA oligonucleotides 15 nucleotides or more in length. Primers may be annealed to a complementary target DNA strand by nucleic acid hybridization to form a hybrid between the primer and the target DNA strand, and then extended along the target DNA strand by a DNA polymerase enzyme. Primer pairs can be used for amplification of a nucleic acid sequence, e.g., by the polymerase chain reaction (PCR) or other nucleic-acid amplification methods known in the art.
Methods for preparing and using probes and primers are described, for example, in Molecular Cloning: A Laboratory Manual, 2nd ed., vol. 1-3, ed. Sambrook et al., Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y., 1989, and Current Protocols in Molecular Biology, ed. Ausubel et al., Greene Publishing and Wiley-Interscience, New York, 1987 (with periodic updates). PCR primer pairs can be derived from a known sequence, for example, by using computer programs intended for that purpose such as Primer3 (Version 0.4.0, Whitehead Institute for Biomedical Research, Cambridge, Mass.).
Preventing or treating a disease: “Preventing” a disease refers to inhibiting the full development of a disease, for example in a person who is known to be at risk of infection with M. tuberculosis or M. leprae. An example of a person with a known predisposition is someone living with a person diagnosed with tuberculosis, health care professionals, or someone who has been exposed to M. tuberculosis. “Treatment” refers to a therapeutic intervention that ameliorates a sign or symptom of a disease or pathological condition, such as tuberculosis, after it has begun to develop.
Promoter: A promoter is an array of nucleic acid control sequences which direct transcription of a nucleic acid. A promoter includes necessary nucleic acid sequences near the start site of transcription, such as, in the case of a polymerase II type promoter, a TATA element. A promoter also optionally includes distal enhancer or repressor elements which can be located as much as several thousand base pairs from the start site of transcription. The promoter can be a constitutive or an inducible promoter. A specific, non-limiting example of a promoter is the HCMV IE promoter.
Purified: The term purified does not require absolute purity; rather, it is intended as a relative term. Thus, for example, a purified antigen preparation is one in which the antigen is more pure than the protein in its originating environment within a cell. A preparation of an antigen is typically purified such that the antigen represents at least 50% of the total protein content of the preparation. However, more highly purified preparations may be required for certain applications. For example, for such applications, preparations in which the antigen comprises at least 75% or at least 90% of the total protein content may be employed.
Recombinant: A recombinant nucleic acid or polypeptide is one that has a sequence that is not naturally occurring or has a sequence that is made by an artificial combination of two or more otherwise separated segments of sequence. This artificial combination is often accomplished by chemical synthesis or, more commonly, by the artificial manipulation of isolated segments of nucleic acids, e.g., by genetic engineering techniques.
Sequence identity: The similarity between amino acid sequences is expressed in terms of the similarity between the sequences, otherwise referred to as sequence identity. Sequence identity is frequently measured in terms of percentage identity (or similarity or homology); the higher the percentage, the more similar the two sequences are. Variants of antigen polypeptides will possess a relatively high degree of sequence identity when aligned using standard methods.
Methods of alignment of sequences for comparison are well known in the art. Altschul et al. (1994) presents a detailed consideration of sequence alignment methods and homology calculations. The NCBI Basic Local Alignment Search Tool (BLAST) (Altschul et al., 1990) is available from several sources, including the National Center for Biotechnology Information (NCBI, Bethesda, Md.) and on the Internet, for use in connection with the sequence analysis programs blastp, blastn, blastx, tblastn and tblastx. It can be accessed at the NCBI website. A description of how to determine sequence identity using this program is available at the NCBI website, as are the default parameters.
Variants of antigenic polypeptides, such as a Mycobacterium polypeptide, are typically characterized by possession of at least 50% sequence identity counted over the full length alignment with the amino acid sequence of a native antigen sequence using the NCBI Blast 2.0, gapped blastp set to default parameters. Proteins with even greater similarity to the reference sequences will show increasing percentage identities when assessed by this method, such as at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 90% or at least 95% sequence identity. When less than the entire sequence is being compared for sequence identity, variants will typically possess at least 75% sequence identity over short windows of 10-20 amino acids, and may possess sequence identities of at least 85% or at least 90% or 95% depending on their similarity to the reference sequence. Methods for determining sequence identity over such short windows are described at the NCBI website.
Therapeutically active polypeptide: An agent, such as an epitope of Mtb that causes induction of an immune response, as measured by clinical response (for example increase in a population of immune cells, increased cytolytic activity against Mtb, or measurable reduction of a symptom of an infection). Therapeutically active molecules can also be made from nucleic acids. Examples of a nucleic acid based therapeutically active molecule is a nucleic acid sequence that encodes an Mtb epitope, wherein the nucleic acid sequence is operably linked to a control element such as a promoter.
In one embodiment, a therapeutically effective amount of an Mtb polypeptide is an amount used to generate an immune response. In several examples, “treatment” refers to a therapeutic intervention that ameliorates a sign or symptom of tuberculosis.
Therapeutically effective amount: A dose sufficient to inhibit advancement, or to cause regression of the disease, or which is capable of relieving symptoms caused by the disease. In one embodiment, a therapeutically effective dose is a dose sufficient to inhibit or prevent advancement or relieve symptoms of tuberculosis.
Transduced and Transformed: A virus or vector “transduces” a cell when it transfers nucleic acid into the cell. A cell is “transformed” by a nucleic acid transduced into the cell when the DNA becomes stably replicated by the cell, either by incorporation of the nucleic acid into the cellular genome, or by episomal replication. As used herein, the term transformation encompasses all techniques by which a nucleic acid molecule might be introduced into such a cell, including transfection with viral vectors, transformation with plasmid vectors, and introduction of naked DNA by electroporation, lipofection, and particle gun acceleration.
Tuberculosis (TB): A disease that is generally caused by Mycobacterium tuberculosis that usually infects the lungs. However, other “atypical” mycobacteria such as M. kansasii may produce a similar clinical and pathologic appearance of disease.
Transmission of M. tuberculosis occurs by the airborne route in confined areas with poor ventilation. In more than 90% of cases, following infection with M. tuberculosis, the immune system prevents development of disease from M. tuberculosis, often called, active tuberculosis. However, not all of the M. tuberculosis is killed, and thus tiny, hard capsules are formed. “Primary tuberculosis” is seen as disease that develops following an initial infection, usually in children. The initial focus of infection is a small subpleural granuloma accompanied by granulomatous hilar lymph node infection. Together, these make up the Ghon complex. In nearly all cases, these granulomas resolve and there is no further spread of the infection. “Secondary tuberculosis” is seen mostly in adults as a reactivation of previous infection (or reinfection), particularly when health status declines. The granulomatous inflammation is much more florid and widespread. Typically, the upper lung lobes are most affected, and cavitation can occur. Dissemination of tuberculosis outside of the lungs can lead to the appearance of a number of uncommon findings with characteristic patterns that include skeletal tuberculosis, genital tract tuberculosis, urinary tract tuberculosis, central nervous system (CNS) tuberculosis, gastrointestinal tuberculosis, adrenal tuberculosis, scrofula, and cardiac tuberculosis. “Latent” tuberculosis is an Mtb infection in an individual that can be detected by a diagnostic assay, such as, but not limited to a tuberculin skin test (TST) wherein the infection does not produce symptoms in that individual. “Active” tuberculosis is a symptomatic Mtb infection in a subject.
Microscopically, the inflammation produced with TB infection is granulomatous, with epithelioid macrophages and Langhans giant cells along with lymphocytes, plasma cells, maybe a few polymorphonuclear cells, fibroblasts with collagen, and characteristic caseous necrosis in the center. The inflammatory response is mediated by a type IV hypersensitivity reaction, and skin testing is based on this reaction. In some examples, tuberculosis can be diagnosed by a skin test, an acid fast stain, an auramine stain, or a combination thereof. The most common specimen screened is sputum, but the histologic stains can also be performed on tissues or other body fluids.
TB is a frequent complication of HIV infection. TB infection in subjects infected with a human immunodeficiency virus (HIV) can spread readily and progress rapidly to active disease. Specific symptoms of lung disease due to Mtb infection include chronic cough and spitting blood. Other symptoms of TB disease include fatigue, loss of appetite, weight loss, fever and drenching night sweats.
Vector: A nucleic acid molecule as introduced into a host cell, thereby producing a transformed host cell. A vector may include nucleic acid sequences that permit it to replicate in a host cell, such as an origin of replication. A vector may also include one or more selectable marker gene and other genetic elements known in the art. Vectors include plasmid vectors, including plasmids for expression in gram negative and gram positive bacterial cell. Exemplary vectors include those for expression in E. coli and Salmonella. Vectors also include viral vectors, such as, but not limited to, retrovirus, orthopox, avipox, fowlpox, capripox, suipox, adenovirus, herpes virus, alpha virus, baculovirus, Sindbis virus, vaccinia virus, and poliovirus vectors. Vectors also include vectors for expression in yeast cells
Unless otherwise explained, 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 disclosure belongs. The singular terms “a,” “an,” and “the” include plural referents unless context clearly indicates otherwise. Similarly, the word “or” is intended to include “and” unless the context clearly indicates otherwise. It is further to be understood that all base sizes or amino acid sizes, and all molecular weight or molecular mass values, given for nucleic acids or polypeptides are approximate, and are provided for description. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of this disclosure, suitable methods and materials are described below. The term “comprises” means “includes.” All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including explanations of terms, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.
III. Mycobacterium Polypeptides
It is disclosed herein that several Mycobacterium polypeptides can be used to induce an immune response to Mtb, such as a T cell response. In several embodiments, the polypeptide comprises or consists of the amino acid sequence set forth as:
In a second embodiment, an Mtb polypeptide of use in the methods disclosed herein has a sequence at least 75%, 85%, 90%, 95%, 96%, 97%, 98% or 99% homologous to the amino acid sequence set forth in one of SEQ ID NOs: 1-18. For example, the polypeptide can have an amino acid sequence at least 85%, 90%, 95%, 96%, 97%, 98% or 99% homologous to one of the amino acid sequences set forth in SEQ ID NOs: 1-18. Exemplary sequences can be obtained using computer programs that are readily available on the internet and the amino acid sequences set forth herein. In one example, the polypeptide retains a function of the Mtb protein, such as binding to an antibody that specifically binds the Mtb epitope.
Minor modifications of an Mtb polypeptide primary amino acid sequences may result in peptides which have substantially equivalent activity as compared to the unmodified counterpart polypeptide described herein. Such modifications may be deliberate, as by site-directed mutagenesis, or may be spontaneous. All of the polypeptides produced by these modifications are included herein. Thus, a specific, non-limiting example of an Mtb polypeptide is a conservative variant of the Mtb polypeptide (such as a single conservative amino acid substitution, for example, one or more conservative amino acid substitutions, for example 1-10 conservative substitutions, 2-5 conservative substitutions, 4-9 conservative substitutions, such as 1, 2, 5 or 10 conservative substitutions). A table of conservative substitutions is provided herein. Substitutions of the amino acids sequence shown in SEQ ID NOs: 1-18 can be made based on this table.
Mtb polypeptides are disclosed herein that can be used to induce an immune response to Mtb. These peptides include or consist of at least nine amino acids, such as nine to twenty amino acids consecutive amino acids of an Mtb polypeptide set forth above. In particular non-limiting examples, the Mtb polypeptide includes or consists of MDFALLPPEVNSARM (amino acids 1-15 of SEQ ID NO: 2) or AEMWAQDAA (amino acids 141-149 of SEQ ID NO: 2). Specific, non-limiting examples are fifteen, fourteen, thirteen, twelve, eleven, ten, or nine consecutive amino acids of one of the Mtb polypeptides set forth above. In these examples, the Mtb polypeptide does not include the full-length amino acid sequences set forth as SEQ ID NOs: 1-18.
In several embodiments, the isolated Mtb polypeptide is included in a fusion protein. Thus, the fusion protein can include the Mtb polypeptide (see above) and a second heterologous moiety, such as a myc protein, an enzyme or a carrier (such as a hepatitis carrier protein or bovine serum albumin) covalently linked to the Mtb polypeptide. In several examples, a polypeptide consisting of nine to twelve amino acids of one of the amino acid sequences set forth as SEQ ID NOs: 1-18 that bind MHC class I is covalently linked to a carrier. In an additional example, a polypeptide consisting of one of the amino acid sequences set forth as one of SEQ ID NOs: 1-18 is covalently linked to a carrier.
In additional examples, the polypeptide can be a fusion protein and can also include heterologous sequences to Mtb. Thus, in several specific non-limiting examples, the immunogenic peptide is a fusion polypeptide, for example the polypeptide includes six sequential histidine residues, a β-galactosidase amino acid sequence, or an immunoglobulin amino acid sequence. The polypeptide can also be covalently linked to a carrier. In additional embodiments, the protein consists of the Mtb polypeptide.
The polypeptide can optionally include repetitions of one or more of the Mtb polypeptides disclosed herein. In one specific, non-limiting example, the polypeptide includes two, three, four, five, or up to ten repetitions of one of the Mtb polypeptides described above. Alternatively, more than one polypeptide can be included in a fusion polypeptide. Thus, in several examples, the polypeptide can include at least two, at least three, at least four, at least five or at least six of the amino acid sequences set forth as SEQ ID NOs: 1-18 or nine to twenty amino acids of one of the amino acid sequences set forth as SEQ ID NOs: 1-18 and repetitions of these sequences. A linker sequence can optionally be included between the Mtb polypeptides.
The Mtb polypeptides disclosed herein can be chemically synthesized by standard methods, or can be produced recombinantly. An exemplary process for polypeptide production is described in Lu et al., FEBS Lett. 429:31-35, 1998. They can also be isolated by methods including preparative chromatography and immunological separations. Polypeptides can also be produced using molecular genetic techniques, such as by inserting a nucleic acid encoding Mtb or an epitope thereof into an expression vector, introducing the expression vector into a host cell, and isolating the polypeptide (see below).
In particular embodiments provided herein, one or more of the disclosed Mtb polypeptides (or fragments thereof) can be conjugated to a substrate or solid support, such as a plate or array. In one example, the plate or array includes, consists essentially of, or consists of one (such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or all) of SEQ ID NOs: 1-18 or fragments thereof. In some examples, the plate or array also includes one or more control polypeptides. Methods for selecting an appropriate substrate and constructing a plate or array are well known to one of skill in the art (see, e.g., U.S. Pat. Nos. 5,143,854; 5,405,783; 5,445,934; and 5,744,305; all incorporated herein by reference).
Polynucleotides encoding the Mtb polypeptides disclosed herein are also provided. Exemplary nucleic acid sequences are set forth as SEQ ID NOs: 19-36. These polynucleotides include DNA, cDNA and RNA sequences which encode the polypeptide of interest. Silent mutations in the coding sequence result from the degeneracy (i.e., redundancy) of the genetic code, whereby more than one codon can encode the same amino acid residue. Tables showing the standard genetic code can be found in various sources (e.g., L. Stryer, 1988, Biochemistry, 3rd Edition, W.H. Freeman and Co., NY).
A nucleic acid encoding an Mtb polypeptide can be cloned or amplified by in vitro methods, such as the polymerase chain reaction (PCR), the ligase chain reaction (LCR), the transcription-based amplification system (TAS), the self-sustained sequence replication system (3SR) and the Qβ replicase amplification system (QB). For example, a polynucleotide encoding the protein can be isolated by polymerase chain reaction of cDNA using primers based on the DNA sequence of the molecule. A wide variety of cloning and in vitro amplification methodologies are well known to persons skilled in the art. PCR methods are described in, for example, U.S. Pat. No. 4,683,195; Mullis et al., Cold Spring Harbor Symp. Quant. Biol. 51:263, 1987; and Erlich, ed., PCR Technology, (Stockton Press, NY, 1989). Polynucleotides also can be isolated by screening genomic or cDNA libraries with probes selected from the sequences of the desired polynucleotide under stringent hybridization conditions.
The polynucleotides encoding an Mtb polypeptide include a recombinant DNA which is incorporated into a vector into an autonomously replicating plasmid or virus or into the genomic DNA of a prokaryote or eukaryote, or which exists as a separate molecule (such as a cDNA) independent of other sequences. The nucleotides of the invention can be ribonucleotides, deoxyribonucleotides, or modified forms of either nucleotide. The term includes single and double forms of DNA.
In one embodiment, vectors are used for expression in yeast such as S. cerevisiae or Kluyveromyces lactis. Several promoters are known to be of use in yeast expression systems such as the constitutive promoters plasma membrane H+-ATPase (PMA1), glyceraldehyde-3-phosphate dehydrogenase (GPD), phosphoglycerate kinase-1 (PGK1), alcohol dehydrogenase-1 (ADH1), and pleiotropic drug-resistant pump (PDR5). In addition, many inducible promoters are of use, such as GAL1-10 (induced by galactose), PHO5 (induced by low extracellular inorganic phosphate), and tandem heat shock HSE elements (induced by temperature elevation to 37° C.). Promoters that direct variable expression in response to a titratable inducer include the methionine-responsive MET3 and MET25 promoters and copper-dependent CUP1 promoters. Any of these promoters may be cloned into multicopy (2μ) or single copy (CEN) plasmids to give an additional level of control in expression level. The plasmids can include nutritional markers (such as URA3, ADE3, HIS1, and others) for selection in yeast and antibiotic resistance (such as AMP) for propagation in bacteria. Plasmids for expression on K. lactis are known, such as pKLAC1. Thus, in one example, after amplification in bacteria, plasmids can be introduced into the corresponding yeast auxotrophs by methods similar to bacterial transformation.
The Mtb polypeptides can be expressed in a variety of yeast strains. For example, seven pleiotropic drug-resistant transporters, YOR1, SNQ2, PDR5, YCF1, PDR10, PDR11, and PDR15, together with their activating transcription factors, PDR1 and PDR3, have been simultaneously deleted in yeast host cells, rendering the resultant strain sensitive to drugs. Yeast strains with altered lipid composition of the plasma membrane, such as the erg6 mutant defective in ergosterol biosynthesis, can also be utilized. Proteins that are highly sensitive to proteolysis can be expressed in a yeast strain lacking the master vacuolar endopeptidase Pep4, which controls the activation of other vacuolar hydrolases. Heterologous expression in strains carrying temperature-sensitive (ts) alleles of genes can be employed if the corresponding null mutant is enviable.
Viral vectors encoding the Mtb polypeptides disclosed herein can also be prepared. A number of viral vectors have been constructed, including polyoma, SV40 (Madzak et al., 1992, J. Gen. Virol. 73:15331536), adenovirus (Berkner, 1992, Curr. Top. Microbiol. Immunol. 158:39-6; Berliner et al., 1988, BioTechniques 6:616-629; Gorziglia et al., 1992, J. Virol. 66:4407-4412; Quantin et al., 1992, Proc. Natl. Acad. Sci. USA 89:2581-2584; Rosenfeld et al., 1992, Cell 68:143-155; Wilkinson et al., 1992, Nucl. Acids Res. 20:2233-2239; Stratford-Perricaudet et al., 1990, Hum. Gene Ther. 1:241-256), vaccinia virus (Mackett et al., 1992, Biotechnology 24:495-499), adeno-associated virus (Muzyczka, 1992, Curr. Top. Microbiol. Immunol. 158:91-123; On et al., 1990, Gene 89:279-282), herpes viruses including HSV and EBV (Margolskee, 1992, Curr. Top. Microbiol. Immunol. 158:67-90; Johnson et al., 1992, J. Virol. 66:2952-2965; Fink et al., 1992, Hum. Gene Ther. 3:11-19; Breakfield et al., 1987, Mol. Neurobiol. 1:337-371; Fresse et al., 1990, Biochem. Pharmacol. 40:2189-2199), Sindbis viruses (Herweijer et al., 1995, Hum. Gene Ther. 6:1161-1167; U.S. Pat. Nos. 5,091,309 and 5,2217,879), alphaviruses (Schlesinger, 1993, Trends Biotechnol. 11:18-22; Frolov et al., 1996, Proc. Natl. Acad. Sci. USA 93:11371-11377) and retroviruses of avian (Brandyopadhyay et al., 1984, Mol. Cell. Biol. 4:749-754; Petropouplos et al., 1992, J. Virol. 66:3391-3397), murine (Miller, 1992, Curr. Top. Microbiol. Immunol. 158:1-24; Miller et al., 1985, Mol. Cell. Biol. 5:431-437; Sorge et al., 1984, Mol. Cell. Biol. 4:1730-1737; Mann et al., 1985, J. Virol. 54:401-407), and human origin (Page et al., 1990, J. Virol. 64:5370-5276; Buchschalcher et al., 1992, J. Virol. 66:2731-2739). Baculovirus (Autographa californica multinuclear polyhedrosis virus; AcMNPV) vectors are also known in the art, and may be obtained from commercial sources (such as PharMingen, San Diego, Calif.; Protein Sciences Corp., Meriden, Conn.; Stratagene, La Jolla, Calif.).
Thus, in one embodiment, the polynucleotide encoding an Mtb polypeptide is included in a viral vector. Suitable vectors include retrovirus vectors, orthopox vectors, avipox vectors, fowlpox vectors, capripox vectors, suipox vectors, adenoviral vectors, herpes virus vectors, alpha virus vectors, baculovirus vectors, Sindbis virus vectors, vaccinia virus vectors and poliovirus vectors. Specific exemplary vectors are poxvirus vectors such as vaccinia virus, fowlpox virus and a highly attenuated vaccinia virus (MVA), adenovirus, baculovirus and the like.
Pox viruses useful in practicing the present methods include orthopox, suipox, avipox, and capripox virus. Orthopox include vaccinia, ectromelia, and raccoon pox. One example of an orthopox of use is vaccinia. Avipox includes fowlpox, canary pox and pigeon pox. Capripox include goatpox and sheep pox. In one example, the suipox is swinepox. Examples of pox viral vectors for expression as described for example, in U.S. Pat. No. 6,165,460, which is incorporated herein by reference. Other viral vectors that can be used include other DNA viruses such as herpes virus and adenoviruses, and RNA viruses such as retroviruses and poliovirus.
In some cases, vaccinia viral vectors may elicit a strong antibody response. Thus, while numerous boosts with vaccinia vectors are possible, its repeated use may not be useful in certain instances. However, this sensitivity problem can be minimized by using pox from different genera for boosts. In one example, when the first or initial pox virus vector is vaccinia, the second and subsequent pox virus vectors are selected from the pox viruses from a different genus such as suipox, avipox, capripox or an orthopox immunogenically distinct from vaccinia.
The vaccinia virus genome is known in the art. It is composed of a HIND F13L region, TK region, and an HA region. Recombinant vaccinia virus has been used to incorporate an exogenous gene for expression of the exogenous gene product (see, for example, Perkus et al. Science 229:981-984, 1985; Kaufman et al. Int. J. Cancer 48:900-907, 1991; Moss, Science 252:1662, 1991). A gene encoding an antigen of interest, such as an immunogenic Mtb polypeptide, can be incorporated into the HIND F13L region or alternatively incorporated into the TK region of recombinant vaccinia virus vector (or other nonessential regions of the vaccinia virus genome). Baxby and Paoletti (Vaccine 10:8-9, 1992) disclose the construction and use as a vector, of the non-replicating poxvirus, including canarypox virus, fowlpox virus and other avian species. Sutter and Moss (Proc. Natl. Acad. Sci. U.S.A. 89:10847-10851, 1992) and Sutter et al. (Vaccine 12:1032-1040, 1994) disclose the construction and use as a vector of the non-replicating recombinant Ankara virus (MVA, modified vaccinia Ankara).
Suitable vectors are disclosed, for example, in U.S. Pat. No. 6,998,252, which is incorporated herein by reference. In one example, a recombinant poxvirus, such as a recombinant vaccinia virus is synthetically modified by insertion of a chimeric gene containing vaccinia regulatory sequences or DNA sequences functionally equivalent thereto flanking DNA sequences which in nature are not contiguous with the flanking vaccinia regulatory DNA sequences that encode a Mtb polypeptide. The recombinant virus containing such a chimeric gene is effective at expressing the Mtb polypeptide. In one example, the vaccine viral vector comprises (A) a segment comprised of (i) a first DNA sequence encoding a Mtb polypeptide and (ii) a poxvirus promoter, wherein the poxvirus promoter is adjacent to and exerts transcriptional control over the DNA sequence encoding an Mtb polypeptide; and, flanking said segment, (B) DNA from a nonessential region of a poxvirus genome. The viral vector can encode a selectable marker. In one example, the poxvirus includes, for example, a thymidine kinase gene (see U.S. Pat. No. 6,998,252, which is incorporated herein by reference).
Viral vectors, such as poxyiral vectors, that encode an Mtb polypeptide include at least one expression control element operationally linked to the nucleic acid sequence encoding the Mtb polypeptide. The expression control elements are inserted in the viral vector to control and regulate the expression of the nucleic acid sequence. Examples of expression control elements of use in these vectors includes, but is not limited to, lac system, operator and promoter regions of phage lambda, yeast promoters and promoters derived from polyoma, adenovirus, retrovirus or SV40. Additional operational elements include, but are not limited to, leader sequence, termination codons, polyadenylation signals and any other sequences necessary for the appropriate transcription and subsequent translation of the nucleic acid sequence encoding the Mtb polypeptide in the host system. The expression vector can contain additional elements necessary for the transfer and subsequent replication of the expression vector containing the nucleic acid sequence in the host system. Examples of such elements include, but are not limited to, origins of replication and selectable markers. It will further be understood by one skilled in the art that such vectors are easily constructed using conventional methods (Ausubel et al., (1987) in “Current Protocols in Molecular Biology,” John Wiley and Sons, New York, N.Y.) and are commercially available.
Basic techniques for preparing recombinant DNA viruses containing a heterologous DNA sequence encoding the one or more Mtb polypeptides are known in the art. Such techniques involve, for example, homologous recombination between the viral DNA sequences flanking the DNA sequence in a donor plasmid and homologous sequences present in the parental virus (Mackett et al., 1982, Proc. Natl. Acad. Sci. USA 79:7415-7419). In particular, recombinant viral vectors such as a poxyiral vector can be used in delivering the gene. The vector can be constructed for example by steps known in the art, such as steps analogous to the methods for creating synthetic recombinants of the fowlpox virus described in U.S. Pat. No. 5,093,258, incorporated herein by reference. Other techniques include using a unique restriction endonuclease site that is naturally present or artificially inserted in the parental viral vector to insert the heterologous DNA.
Generally, a DNA donor vector contains the following elements: (i) a prokaryotic origin of replication, so that the vector may be amplified in a prokaryotic host; (ii) a gene encoding a marker which allows selection of prokaryotic host cells that contain the vector (e.g., a gene encoding antibiotic resistance); (iii) at least one DNA sequence encoding the one or more Mtb polypeptide located adjacent to a transcriptional promoter capable of directing the expression of the sequence; and (iv) DNA sequences homologous to the region of the parent virus genome where the foreign gene(s) will be inserted, flanking the construct of element (iii). Methods for constructing donor plasmids for the introduction of multiple foreign genes into pox virus are described in PCT Publication No. WO 91/19803, incorporated herein by reference.
Generally, DNA fragments for construction of the donor vector, including fragments containing transcriptional promoters and fragments containing sequences homologous to the region of the parent virus genome into which foreign DNA sequences are to be inserted, can be obtained from genomic DNA or cloned DNA fragments. The donor plasmids can be mono-, di-, or multivalent (e.g., can contain one or more inserted foreign DNA sequences). The donor vector can contain an additional gene that encodes a marker that will allow identification of recombinant viruses containing inserted foreign DNA. Several types of marker genes can be used to permit the identification and isolation of recombinant viruses. These include genes that encode antibiotic or chemical resistance (e.g., see Spyropoulos et al., 1988, J. Virol. 62:1046; Falkner and Moss, 1988, J. Virol. 62:1849; Franke et al., 1985, Mol. Cell. Biol. 5:1918), as well as genes such as the E. coli lacZ gene, that permit identification of recombinant viral plaques by colorimetric assay (Panicali et al., 1986, Gene 47:193-199).
The DNA gene sequence to be inserted into the virus can be placed into a donor plasmid, such as an E. coli or a Salmonella plasmid construct, into which DNA homologous to a section of DNA such as that of the insertion site of the poxvirus where the DNA is to be inserted has been inserted. Separately the DNA gene sequence to be inserted is ligated to a promoter. The promoter-gene linkage is positioned in the plasmid construct so that the promoter-gene linkage is flanked on both ends by DNA homologous to a DNA sequence flanking a region of pox DNA that is the desired insertion region. With a parental pox viral vector, a pox promoter is used. The resulting plasmid construct is then amplified by growth within E. coli bacteria and isolated. Next, the isolated plasmid containing the DNA gene sequence to be inserted is transfected into a cell culture, for example chick embryo fibroblasts, along with the parental virus, for example poxvirus. Recombination between homologous pox DNA in the plasmid and the viral genome respectively results in a recombinant poxvirus modified by the presence of the promoter-gene construct in its genome, at a site that does not affect virus viability.
As noted above, the DNA sequence is inserted into a region (insertion region) in the virus that does not affect virus viability of the resultant recombinant virus. One of skill in the art can readily identify such regions in a virus by, for example, randomly testing segments of virus DNA for regions that allow recombinant formation without seriously affecting virus viability of the recombinant. One region that can readily be used and is present in many viruses is the thymidine kinase (TK) gene. The TK gene has been found in all pox virus genomes examined, including leporipoxvirus (Upton et al., 1986, J. Virol. 60:920); shope fibroma virus; capripoxvirus (Gershon et al., 1989, J. Gen. Virol. 70:525); Kenya sheep-1; orthopoxvirus (Weir et al., 1983, J. Virol. 46:530); vaccinia (Esposito et al., 1984, Virology 135:561); monkeypox and variola virus (Hruby et al., 1983, Proc. Natl. Acad. Sci. USA 80:3411); vaccinia (Kilpatrick et al., 1985, Virology 143:399); Yaba monkey tumor virus; avipoxvirus (Binns et al., 1988, J. Gen. Virol. 69:1275); fowlpox; (Boyle et al., 1987, Virology 156:355; Schnitzlein et al., 1988, J. Virol. Meth. 20:341); and entomopox (Lytvyn et al., 1992, J. Gen. Virol. 73:3235-3240). In vaccinia, in addition to the TK region, other insertion regions include, for example, the HindIII M fragment. In fowlpox, in addition to the TK region, other insertion regions include, for example, the BamHI J fragment (Jenkins et al., 1991, AIDS Res. Hum. Retroviruses 7:991-998), the EcoRI-HindIII fragment, EcoRV-HindIII fragment, BamHI fragment and the HindIII fragment set forth in EPO Application No. 0 308220 A1 (see also Calvert et al., 1993, J. Virol. 67:3069-3076; Taylor et al., 1988, Vaccine 6:497-503; Spehner et al., 1990, J. Virol. 64:527-533; Boursnell et al., 1990, J. Gen. Virol. 71:621-628).
In swinepox, insertion sites include the thymidine kinase gene region. In addition to the requirement that the gene be inserted into an insertion region, successful expression of the inserted gene by the modified poxvirus requires the presence of a promoter operably linked to the desired gene. Generally, the promoter is placed so that it is located upstream from the gene to be expressed. Promoters are well known in the art and can readily be selected depending on the host and the cell type to be targeted. In one example, in poxviruses, pox viral promoters are used, such as the vaccinia 7.5K, 40K or fowlpox promoters such as FPV CIA. Enhancer elements can also be used in combination to increase the level of expression. Furthermore, inducible promoters can be utilized.
Homologous recombination between donor plasmid DNA and viral DNA in an infected cell can result in the formation of recombinant viruses that incorporate the desired elements. Appropriate host cells for in vivo recombination are generally eukaryotic cells that can be infected by the virus and transfected by the plasmid vector. Examples of such cells suitable for use with a pox virus are chick embryo fibroblasts, HuTK143 (human) cells, and CV-1 and BSC-40 (both monkey kidney) cells. Infection of cells with pox virus and transfection of these cells with plasmid vectors is accomplished by techniques standard in the art (see U.S. Pat. No. 4,603,112 and PCT Publication No. WO 89/03429).
Following in vivo recombination, recombinant viral progeny can be identified by one of several techniques. For example, if the DNA donor vector is designed to insert foreign genes into the parent virus thymidine kinase (TK) gene, viruses containing integrated DNA will be TK− and can be selected on this basis (Mackett et al., 1982, Proc. Natl. Acad. Sci. USA 79:7415). Alternatively, co-integration of a gene encoding a marker or indicator gene with the foreign gene(s) of interest, as described above, can be used to identify recombinant progeny. One specific non-limiting example of an indicator gene is the E. coli lacZ gene. Recombinant viruses expressing beta-galactosidase can be selected using a chromogenic substrate for the enzyme (Panicali et al., 1986, Gene 47:193). Once a recombinant virus has been identified, a variety of well-known methods can be used to assay the expression of the Mtb sequence encoded by the inserted DNA fragment. These methods include black plaque assay (an in situ enzyme immunoassay performed on viral plaques), Western blot analysis, radioimmunoprecipitation (RIPA), and enzyme immunoassay (EIA).
This disclosure encompasses a recombinant virus comprising more than one antigen of interest for the purpose of having a multivalent vaccine. For example, the recombinant virus may comprise the virus genome or portions thereof, the nucleic acid sequence encoding the Mtb polypeptide and a nucleic acid sequence encoding a hepatitis B surface antigen or any other carrier protein.
In one embodiment, a composition is provided that includes a recombinant virus comprising a vaccinia virus genome or portions thereof, the nucleic acid sequence encoding an Mtb polypeptide and a recombinant virus comprising the nucleic acid sequence encoding the immunostimulatory molecule, B7-1 alone or in combination with the nucleic acid sequence encoding the immunostimulatory molecule, B7-2, or a recombinant virus containing both the genes for an Mtb polypeptide and an immunostimulatory molecule. This disclosure also encompasses a recombinant virus comprising the Mtb polypeptide that is administered with a second recombinant virus comprising the virus genome or portion thereof, and one or more nucleic acid sequences encoding one or more B7 molecules, such as a recombinant vaccinia virus expressing B7-1 and/or B7-2.
Thus, in one example, recombinant virus is disclosed that is a recombinant vaccinia virus containing B7-1 and a recombinant vaccinia virus containing B7-2 (designated rV-B7-1 and rV-B7-2, respectively); the composition can include rV-B7-1 and/or rV-B7-2 in combination with an immunogenic Mtb polypeptide.
The B7 molecule includes but is not limited to B7-1, B7-2 and analogs thereof. The B7 gene may be cloned from mammalian sources, including but not limited to mammalian tissues, genomic libraries or cDNA libraries, such as from murine or human sources. Without being bound by theory, costimulatory molecules of the B7 family (namely B7-1, B7-2, and possibly B7-3) are believed to be members of the immunoglobulin gene superfamily. These molecules are present on macrophages, dendritic cells, monocytes (antigen presenting cells (APCs)). Significant amplification of the immune response against a given antigen generally does not occur without co-stimulation (June et al. Immunology Today 15:321-331, 1994; Chen et al., Immunology Today 14:483-486; Townsend et al., Science 259:368-370). Freeman et al. (J. Immunol. 143:2714-2722, 1989) report cloning and sequencing of a B7-1 gene. Azuma et al. (Nature 366:76-79, 1993) report cloning and sequencing of a B7-2 gene. Thus, in one embodiment the B7-1 gene or the B7-2 genes are administered in conjunction with the Mtb polypeptide. The insertion of nucleic acids encoding B7-1 and B7-2 into vaccinia virus has been disclosed (see for example, U.S. Pat. No. 6,893,869, incorporated herein by reference; this U.S. patent also discloses the use of a nucleic acid encoding IL-2 in a vaccinia virus). Several vectors including IL-2, B7-1 and B7-2 have been deposited with the American Type Culture Collection (ATCC) on Oct. 3, 1994 under the terms of the Budapest Treaty (for example, rV-CEA/nIL-2 (ATCC Designation VR 2480), rV-mB7-2 (ATCC Designation VR 2482); and rV-mB7-1 (ATCC Designation VR 2483)).
DNA sequences encoding an Mtb polypeptide can be expressed in vitro by DNA transfer into a suitable host cell. The cell may be prokaryotic or eukaryotic. The term also includes any progeny of the subject host cell. It is understood that all progeny may not be identical to the parental cell since there may be mutations that occur during replication. Methods of stable transfer, meaning that the foreign DNA is continuously maintained in the host, are known in the art.
As noted above, a polynucleotide sequence encoding an Mtb polypeptide can be operatively linked to expression control sequences. An expression control sequence operatively linked to a coding sequence is ligated such that expression of the coding sequence is achieved under conditions compatible with the expression control sequences. The expression control sequences include, but are not limited to, appropriate promoters, enhancers, transcription terminators, a start codon (i.e., ATG) in front of a protein-encoding gene, splicing signal for introns, maintenance of the correct reading frame of that gene to permit proper translation of mRNA, and stop codons.
Host cells can include microbial, yeast, insect and mammalian host cells. Methods of expressing DNA sequences having eukaryotic or viral sequences in prokaryotes are well known in the art. Non-limiting examples of suitable host cells include bacteria, archea, insect, fungi (for example, yeast), mycobacterium (such as M. smegmatis), plant, and animal cells (for example, mammalian cells, such as human). Exemplary cells of use include E. coli, Bacillus subtilis, Saccharomyces cerevisiae, Salmonella typhimurium, SF9 cells, C129 cells, 293 cells, Neurospora, and immortalized mammalian myeloid and lymphoid cell lines. Techniques for the propagation of mammalian cells in culture are well-known (see, Jakoby and Pastan (eds), 1979, Cell Culture. Meth. Enzymol., volume 58, Academic Press, Inc., Harcourt Brace Jovanovich, N.Y.). Examples of commonly used mammalian host cell lines are VERO and HeLa cells, CHO cells, and WI38, BHK, and COS cell lines, although other cell lines may be used, such as cells designed to provide higher expression, desirable glycosylation patterns, or other features. As discussed above, techniques for the transformation of yeast cells, such as polyethylene glycol transformation, protoplast transformation and gene guns are also known in the art (see Gietz and Woods, Meth. Enzymol. 350: 87-96, 2002).
Transformation of a host cell with recombinant DNA can be carried out by conventional techniques as are well known to those skilled in the art. Where the host is prokaryotic, such as, but not limited to, E. coli, competent cells which are capable of DNA uptake can be prepared from cells harvested after exponential growth phase and subsequently treated by the CaCl2 method using procedures well known in the art. Alternatively, MgCl2 or RbCl can be used. Transformation can also be performed after forming a protoplast of the host cell if desired, or by electroporation.
When the host is a eukaryote, such methods of transfection of DNA as calcium phosphate coprecipitates, conventional mechanical procedures such as microinjection, electroporation, insertion of a plasmid encased in liposomes, or virus vectors can be used. Eukaryotic cells can also be co-transformed with polynucleotide sequences encoding an Mtb polypeptide, and a second foreign DNA molecule encoding a selectable phenotype, such as the herpes simplex thymidine kinase gene. Another method is to use a eukaryotic viral vector, such as simian virus 40 (SV40) or bovine papilloma virus, to transiently infect or transform eukaryotic cells and express the protein (see for example, Eukaryotic Viral Vectors, Cold Spring Harbor Laboratory, Gluzman ed., 1982).
In particular embodiments provided herein, one or more of the disclosed Mtb polynucleotides (or fragments thereof) can be conjugated to a substrate or solid support, such as a plate or array. In one example, the plate or array includes, consists essentially of, or consists of one (such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, or all) of SEQ ID NOs: 19-36 or fragments thereof. In some examples, the plate or array also includes one or more control polynucleotides. Methods for selecting an appropriate substrate and constructing a plate or array are well known to one of skill in the art (see, e.g., U.S. Pat. Nos. 5,554,501; 5,985,567; 5,981,185; and 6,013,789; and PCT Publications WO 85/01051 and WO 89/10977; all incorporated herein by reference).
IV. Therapeutic Methods and Pharmaceutical Compositions
The Mtb polypeptides disclosed herein, or nucleic acids encoding the Mtb polypeptides, can be used to generate an immune response in a subject. In several examples, the subject is infected with Mtb or is at risk of being infected with Mtb. Thus, in several embodiments, the methods include administering to a subject a therapeutically effective amount of one or more of the Mtb polypeptides disclosed herein (or polynucleotides encoding these polypeptides) in order to generate an immune response, such as, but not limited to, a protective immune response.
In exemplary applications, compositions are administered to a subject in an amount sufficient to produce an immune response to Mtb. These Mtb polypeptides, or polynucleotides encoding these polypeptides, are of use to inhibit or prevent an infection with Mtb, inhibit or prevent progression to disease in a subject having a latent Mtb infection, or to treat tuberculosis in a subject infected with Mtb. In several examples, administration of a therapeutically effective amount of a composition including one or more of the Mtb polypeptides disclosed herein (or polynucleotides encoding these polypeptides) induces a sufficient immune response to decrease a symptom of a disease due to Mtb infection, to inhibit the development of one or more symptoms of tuberculosis, or to inhibit infection with Mtb.
In some examples, the compositions are of use in inhibiting or preventing a future infection with Mtb. Thus, a therapeutically effective amount of the composition is administered to a subject at risk of becoming infected with Mtb. The composition inhibits or prevents the development of tuberculosis, such as latent or active tuberculosis, in the subject upon subsequent exposure to Mtb.
In additional examples, the compositions are administered to a subject with a latent Mtb infection, and inhibit or prevent the development of symptoms of tuberculosis. In some examples, the compositions are of use in treating a subject with latent tuberculosis, such that the subject does not develop active tuberculosis.
Amounts effective for these uses will depend upon the severity of the disease, the general state of the patient's health, and the robustness of the patient's immune system. In one example, a therapeutically effective amount of the compound is that which provides either subjective relief of a symptom(s) or an objectively identifiable improvement as noted by the clinician or other qualified observer. In other examples, a therapeutically effective amount is an amount sufficient to inhibit an infection with Mtb in a subject upon subsequent exposure of the subject to Mtb. In additional examples, a therapeutically effective amount is an amount sufficient to inhibit development of one or more symptoms in a subject infected with Mtb.
In some examples, one or more Mtb polypeptide described herein may be covalently linked to at least one other immunogenic protein, wherein the conjugate elicits an immune response to the Mtb polypeptide in a subject. The other immunogenic protein (sometimes referred to as a “carrier” protein) ideally has the properties of being immunogenic by itself, usable in a subject, and of a size that can be easily purified and conjugated to at least one other protein or peptide. Suitable carrier proteins are known to one of skill in the art. In particular examples, the other immunogenic protein (carrier protein) is bovine serum albumin (BSA), ovalbumin, tetanus toxoid, diphtheria toxoid, cholera toxin, Clostridium difficile toxin A, C. difficile toxin B, Shiga toxin, or Pseudomonas aeruginosa recombinant exoprotein A.
An Mtb polypeptide can be administered by any means known to one of skill in the art (see Banga, A., “Parenteral Controlled Delivery of Therapeutic Peptides and Proteins,” in Therapeutic Peptides and Proteins, Technomic Publishing Co., Inc., Lancaster, Pa., 1995) either locally or systemically, such as by intramuscular injection, subcutaneous injection, intraperitoneal injection, intravenous injection, oral administration, nasal administration, transdermal administration, or even anal administration. In one embodiment, administration is by oral administration, subcutaneous injection, or intramuscular injection. To extend the time during which the peptide or protein is available to stimulate a response, the peptide or protein can be provided as an implant, an oily injection, or as a particulate system. The particulate system can be a microparticle, a microcapsule, a microsphere, a nanocapsule, or similar particle. (see, e.g., Banga, supra). A particulate carrier based on a synthetic polymer has been shown to act as an adjuvant to enhance the immune response, in addition to providing a controlled release. Aluminum salts can also be used as adjuvants to produce an immune response.
In one specific, non-limiting example, the Mtb polypeptide is administered in a manner to direct the immune response to a cellular response (that is, a cytotoxic T lymphocyte (CTL) response), rather than a humoral (antibody) response.
Optionally, one or more cytokines, such as IL-2, IL-6, IL-12, RANTES, GM-CSF, TNF-α, or IFN-γ, one or more growth factors, such as GM-CSF or G-CSF; one or more molecules such as OX-40L or 4-1 BBL, or combinations of these molecules, can be used as biological adjuvants (see, for example, Salgaller et al., 1998, J. Surg. Oncol. 68(2):122-38; Lotze et al., 2000, Cancer J. Sci. Am. 6(Suppl 1):S61-6; Cao et al., 1998, Stem Cells 16(Suppl 1):251-60; Kuiper et al., 2000, Adv. Exp. Med. Biol. 465:381-90). These molecules can be administered systemically (or locally) to the host. In several examples, IL-2, RANTES, GM-CSF, TNF-α, IFN-γ, G-CSF, LFA-3, CD72, B7-1, B7-2, B7-1 B7-2, OX-40L, 4-1 BBL, and/or ICAM-1 are administered.
A number of means for inducing cellular responses, both in vitro and in vivo, are known. Lipids have been identified as agents capable of assisting in priming CTL in vivo against various antigens. For example, as described in U.S. Pat. No. 5,662,907, palmitic acid residues can be attached to the alpha and epsilon amino groups of a lysine residue and then linked (for example, via one or more linking residues, such as glycine, glycine-glycine, serine, serine-serine, or the like) to an immunogenic peptide. The lipidated peptide can then be injected directly in a micellar form, incorporated in a liposome, or emulsified in an adjuvant. As another example, E. coli lipoproteins, such as tripalmitoyl-S-glycerylcysteinlyseryl-serine can be used to prime tumor specific CTL when covalently attached to an appropriate peptide (see, Deres et al., Nature 342:561, 1989). Further, as the induction of neutralizing antibodies can also be primed with the same molecule conjugated to a peptide which displays an appropriate epitope, two compositions can be combined to elicit both humoral and cell-mediated responses where that is deemed desirable.
A pharmaceutical composition including an Mtb polypeptide is thus provided. These compositions are of use to promote an immune response to Mtb. In one embodiment, the Mtb polypeptide is mixed with an adjuvant containing two or more of a stabilizing detergent, a micelle-forming agent, and an oil. Suitable stabilizing detergents, micelle-forming agents, and oils are detailed in U.S. Pat. No. 5,585,103; U.S. Pat. No. 5,709,860; U.S. Pat. No. 5,270,202; and U.S. Pat. No. 5,695,770, all of which are incorporated by reference. A stabilizing detergent is any detergent that allows the components of the emulsion to remain as a stable emulsion. Such detergents include polysorbate, 80 (TWEEN) (Sorbitan-mono-9-octadecenoate-poly(oxy-1,2-ethanediyl; manufactured by ICI Americas, Wilmington, Del.), TWEEN 40™ (polysorbate 40), TWEEN 20™ (polysorbate 20), TWEEN 60® (polysorbate 60), ZWITTERGENT™ 3-12 (3-(Dodecyldimethylammonio)propanesulfonate solution, 3-(Lauryldimethylammonio)propanesulfonate, 3-(N,N-Dimethyldodecylammonio)propanesulfonate, 3-(N,N-Dimethyllaurylammonio)propanesulfonate, Detergent Screening Solution 46/Fluka kit no 66317, N-Dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate solution), TEEPOL HB7™ (Sodium Alkyl Sulphate), and SPAN 85™ (C60H108O8). These detergents are usually provided in an amount of approximately 0.05 to 0.5%, such as at about 0.2%. A micelle forming agent is an agent which is able to stabilize the emulsion formed with the other components such that a micelle-like structure is formed. Such agents generally cause some irritation at the site of injection in order to recruit macrophages to enhance the cellular response. Examples of such agents include polymer surfactants described by BASF Wyandotte publications, e.g., Schmolka, J. Am. Oil. Chem. Soc. 54:110, 1977; and Hunter et al., J. Immunol. 127:1244-1250, 1981; for example, PLURONIC™ (difunctional block copolymer surfactant) L62LF, L101, and L64, PEG1000, and TETRONIC™ 1501, 150R1, 701, 901, 1301, and 130R1. The chemical structures of such agents are well known in the art. In one embodiment, the agent is chosen to have a hydrophile-lipophile balance (HLB) of between 0 and 2, as defined by Hunter and Bennett, J. Immun. 133:3167, 1984. The agent can be provided in an effective amount, for example between 0.5 and 10%, or in an amount between 1.25 and 5%.
The oil included in the composition is chosen to promote the retention of the antigen in oil-in-water emulsion, such as to provide a vehicle for the desired antigen, and preferably has a melting temperature of less than 65° C. such that emulsion is formed either at room temperature (about 20° C. to 25° C.), or once the temperature of the emulsion is brought down to room temperature. Examples of such oils include squalene, squalane, EICOSANE™ (CH3(CH2)18CH3) tetratetracontane, glycerol, and peanut oil or other vegetable oils. In one specific, non-limiting example, the oil is provided in an amount between 1 and 10%, or between 2.5 and 5%. The oil should be both biodegradable and biocompatible so that the body can break down the oil over time, and so that no adverse affects, such as granulomas, are evident upon use of the oil.
In one embodiment, the adjuvant is a mixture of stabilizing detergents, micelle-forming agent, and oil available under the name PROVAX® (poxvirus vaccine, IDEC Pharmaceuticals, San Diego, Calif.). An adjuvant can also be an immunostimulatory nucleic acid, such as a nucleic acid including a CpG motif, or a biological adjuvant (see above).
Controlled release parenteral formulations can be made as implants, oily injections, or as particulate systems. For a broad overview of protein delivery systems, see Banga, Therapeutic Peptides and Proteins: Formulation, Processing, and Delivery Systems, Technomic Publishing Company, Inc., Lancaster, Pa., 1995. Particulate systems include microspheres, microparticles, microcapsules, nanocapsules, nanospheres, and nanoparticles. Microcapsules contain the therapeutic protein as a central core. In microspheres, the therapeutic agent is dispersed throughout the particle. Particles, microspheres, and microcapsules smaller than about 1 μm are generally referred to as nanoparticles, nanospheres, and nanocapsules, respectively. Capillaries have a diameter of approximately 5 μm so that only nanoparticles are administered intravenously. Microparticles are typically around 100 μm in diameter and are administered subcutaneously or intramuscularly (see Kreuter, Colloidal Drug Delivery Systems, J. Kreuter, ed., Marcel Dekker, Inc., New York, N.Y., pp. 219-342, 1994; Tice & Tabibi, Treatise on Controlled Drug Delivery, A. Kydonieus, ed., Marcel Dekker, Inc. New York, N.Y., pp. 315-339, 1992).
Polymers can be used for controlled release. Various degradable and nondegradable polymeric matrices for use in controlled drug delivery are known in the art (Langer, Accounts Chem. Res. 26:537, 1993). For example, the block copolymer, polaxamer 407 exists as a viscous yet mobile liquid at low temperatures but forms a semisolid gel at body temperature. It has shown to be an effective vehicle for formulation and sustained delivery of recombinant interleukin-2 and urease (Johnston et al., Pharm. Res. 9:425, 1992; and Pec, J. Parent. Sci. Tech. 44(2):58, 1990). Alternatively, hydroxyapatite has been used as a microcarrier for controlled release of proteins (Ijntema et al., Int. J. Pharm. 112:215, 1994). In yet another aspect, liposomes are used for controlled release as well as drug targeting of the lipid-capsulated drug (Betageri et al., Liposome Drug Delivery Systems, Technomic Publishing Co., Inc., Lancaster, Pa., 1993). Numerous additional systems for controlled delivery of therapeutic proteins are known (e.g., U.S. Pat. Nos. 5,055,303; 5,188,837; 4,235,871; 4,501,728; 4,837,028; 4,957,735; 5,019,369; 5,055,303; 5,514,670; 5,413,797; 5,268,164; 5,004,697; 4,902,505; 5,506,206; 5,271,961; 5,254,342; and 5,534,496).
In another embodiment, a pharmaceutical composition includes a nucleic acid encoding an Mtb polypeptide. A therapeutically effective amount of the Mtb polynucleotide can be administered to a subject in order to generate an immune response.
Optionally, one or more cytokines, such as IL-2, IL-6, IL-12, RANTES, GM-CSF, TNF-α, or IFN-γ, one or more growth factors, such as GM-CSF or G-CSF, one or more costimulatory molecules, such as ICAM-1, LFA-3, CD72, B7-1, B7-2, or other B7 related molecules; one or more molecules such as OX-40L or 4-1 BBL, or combinations of these molecules, can be used as biological adjuvants (see, for example, Salgaller et al., 1998, J. Surg. Oncol. 68(2):122-38; Lotze et al., 2000, Cancer J. Sci. Am. 6(Suppl 1):S61-6; Cao et al., 1998, Stem Cells 16(Suppl 1):251-60; Kuiper et al., 2000, Adv. Exp. Med. Biol. 465:381-90). These molecules can be administered systemically to the host. It should be noted that these molecules can be co-administered via insertion of a nucleic acid encoding the molecules into a vector, for example, a recombinant pox vector (see, for example, U.S. Pat. No. 6,045,802). In various embodiments, the nucleic acid encoding the biological adjuvant can be cloned into same vector as the Mtb polypeptide coding sequence, or the nucleic acid can be cloned into one or more separate vectors for co-administration. In addition, nonspecific immunomodulating factors such as BCG and levamisole can be co-administered.
One approach to administration of nucleic acids is direct immunization with plasmid DNA, such as with a mammalian expression plasmid. As described above, the nucleotide sequence encoding an Mtb polypeptide can be placed under the control of a promoter to increase expression of the molecule.
Immunization by nucleic acid constructs is well known in the art and taught, for example, in U.S. Pat. No. 5,643,578 (which describes methods of immunizing vertebrates by introducing DNA encoding a desired antigen to elicit a cell-mediated or a humoral response), and U.S. Pat. Nos. 5,593,972 and 5,817,637 (which describe operably linking a nucleic acid sequence encoding an antigen to regulatory sequences enabling expression). U.S. Pat. No. 5,880,103 describes several methods of delivery of nucleic acids encoding immunogenic peptides or other antigens to an organism. The methods include liposomal delivery of the nucleic acids (or of the synthetic peptides themselves), and immune-stimulating constructs, or ISCOMS™ (immune stimulating complexes, negatively charged cage-like structures of 30-40 nm in size formed spontaneously on mixing cholesterol and saponin). Protective immunity has been generated in a variety of experimental models of infection, including toxoplasmosis and Epstein-Barr virus-induced tumors, using ISCOMS™ (immune stimulating complexes) as the delivery vehicle for antigens (Mowat and Donachie, Immunol. Today 12:383, 1991). Doses of antigen as low as 1 μg encapsulated in ISCOMS™ (immune stimulating complexes) have been found to produce Class I mediated CTL responses (Takahashi et al., Nature 344:873, 1990).
In another approach to using nucleic acids for immunization, an Mtb polypeptide can also be expressed by attenuated viral hosts or vectors or bacterial vectors. Recombinant vaccinia virus, adeno-associated virus (AAV), herpes virus, retrovirus, or other viral vectors can be used to express the peptide or protein, thereby eliciting a CTL response. For example, vaccinia vectors and methods useful in immunization protocols are described in U.S. Pat. No. 4,722,848. BCG provides another vector for expression of the peptides (see Stover, Nature 351:456-460, 1991).
When a viral vector is utilized, it is desirable to provide the recipient with a dosage of each recombinant virus in the composition in the range of from about 105 to about 1010 plaque forming units, although a lower or higher dose can be administered. The composition of recombinant viral vectors can be introduced into a mammal (1) prior to any evidence of an infection with Mtb; (2) to inhibit development of tuberculosis in an individual infected with Mtb; or (3) to decrease a symptom of tuberculosis in a mammal infected with Mtb. Examples of methods for administering the composition into mammals include, but are not limited to, exposure of cells to the recombinant virus ex vivo, or injection of the composition into the affected tissue or intravenous, subcutaneous, intradermal or intramuscular administration of the virus. Alternatively the recombinant viral vector or combination of recombinant viral vectors may be administered locally in a pharmaceutically acceptable carrier. Generally, the quantity of recombinant viral vector, carrying the nucleic acid sequence of one or more Mtb polypeptides to be administered is based on the titer of virus particles. An exemplary range of the immunogen to be administered is 105 to 1010 virus particles per mammal, such as a human.
In the embodiment where a combination of a first recombinant viral vector carrying a nucleic acid sequence of one or more Mtb polypeptide and a second recombinant viral vector carrying the nucleic acid sequence of one or more immunostimulatory molecules is used, the mammal can be immunized with different ratios of the first and second recombinant viral vector. In one embodiment the ratio of the first vector to the second vector is about 1:1, or about 1:3, or about 1:5. Optimal ratios of the first vector to the second vector may easily be titered using the methods known in the art (see, for example, U.S. Pat. No. 6,893,869, incorporated herein by reference).
In one embodiment the recombinant viruses have been constructed to express cytokines (such as TNF-α, IL-6, GM-CSF, and IL-2), and costimulatory and accessory molecules (B7-1, B7-2) alone and in a variety of combinations. Simultaneous production of an immunostimulatory molecule and the Mtb polypeptide enhances the generation of specific effectors. Without being bound by theory, dependent upon the specific immunostimulatory molecules, different mechanisms might be responsible for the enhanced immunogenicity: augmentation of help signal (IL-2), recruitment of professional APC (GM-CSF), increase in CTL frequency (IL-2), effect on antigen processing pathway and MHC expression (IFNγ and TNFα) and the like. For example, IL-2, IL-6, interferon, tumor necrosis factor, or a nucleic acid encoding these molecules, can be administered in conjunction with an Mtb immunogenic polypeptide, or a nucleic acid encoding an Mtb polypeptide. The co-expression of an Mtb polypeptide together with at least one immunostimulatory molecule can be effective in an animal model to show therapeutic effects.
In one embodiment, a nucleic acid encoding an Mtb polypeptide is introduced directly into cells. For example, the nucleic acid can be loaded onto gold microspheres by standard methods and introduced into the skin by a device such as the Helios™ Gene Gun (Bio-Rad, Hercules, Calif.). The nucleic acids can be “naked,” consisting of plasmids under control of a strong promoter. Typically, the DNA is injected into muscle, although it can also be injected directly into other sites. Dosages for injection are usually around 0.5 μg/kg to about 50 mg/kg, and typically are about 0.005 mg/kg to about 5 mg/kg (see, for example, U.S. Pat. No. 5,589,466).
In one specific, non-limiting example, a pharmaceutical composition for intravenous administration would include about 0.1 μg to 10 mg of immunogenic Mtb polypeptide per patient per day. Dosages from 0.1 to about 100 mg per patient per day can be used, particularly if the agent is administered to a secluded site and not into the circulatory or lymph system, such as into a body cavity or into a lumen of an organ. Actual methods for preparing administrable compositions will be known or apparent to those skilled in the art and are described in more detail in such publications as Remington's Pharmaceutical Sciences, 19th Ed., Mack Publishing Company, Easton, Pa., 1995.
Single or multiple administrations of the compositions are administered, depending on the dosage and frequency as required and tolerated by the subject. In one embodiment, the dosage is administered once as a bolus, but in another embodiment can be applied periodically until a therapeutic result is achieved. In one embodiment, the dose is sufficient to treat or ameliorate symptoms or signs of tuberculosis without producing unacceptable toxicity to the subject. In another embodiment, the dose is sufficient to inhibit infection with Mtb upon subsequent exposure to Mtb. In a further embodiment, the dose is sufficient to inhibit a symptom of tuberculosis in a subject with a latent Mtb infection. Systemic or local administration can be utilized.
In another method, antigen presenting cells (APCs), such as dendritic cells (DCs), are isolated from a subject of interest and pulsed or co-incubated with peptides comprising an Mtb polypeptide in vitro. In one specific, non-limiting example, the APCs are autologous cells isolated from the subject of interest. A therapeutically effective amount of the antigen presenting cells is administered (re-introduced) to the subject of interest.
The Mtb polypeptide can be delivered to the DCs or to DC precursors via any method known in the art, including, but not limited to, pulsing DCs directly with antigen, or utilizing a broad variety of antigen delivery vehicles, such as, for example, liposomes, or other vectors known to deliver antigen to cells. In one specific, non-limiting example an antigenic formulation includes about 0.1 μg to about 1,000 μg, or about 1 to about 100 μg of a selected Mtb polypeptide. The Mtb polypeptide can also be administered with agents that promote DC maturation. Specific, non-limiting examples of agents of use are interleukin-4 (IL-4) and granulocyte/macrophage colony stimulating factor (GM-CSF), or flt-3 ligand (flt-3L). The preparation can also contain buffers, excipients, and preservatives, amongst other ingredients.
In one embodiment, mature APCs are generated to present the immunogenic Mtb polypeptide. These DCs are then administered alone to a subject infected with Mtb, or at risk for infection with Mtb. In another embodiment, the mature DCs are administered in conjunction with an antibacterial or antiviral agent.
Alternatively, the APCs are used to sensitize CD8 cells, such as peripheral blood lymphocytes (PBLs). The PBLs can be from the same subject (autologous) that is to be treated. Alternatively, the PBLs can be heterologous. However, they should at least be MHC Class-I restricted to the HLA types the subject possesses. An effective amount of the sensitized cells is then administered to the subject.
Peripheral blood mononuclear cells (PBMCs) can be used as the responder cell source of cytotoxic T lymphocyte (CTL) precursors. The appropriate antigen-presenting cells are incubated with peptide, after which the peptide-loaded antigen-presenting cells are then incubated with the responder cell population under optimized culture conditions. Positive CTL activation can be determined by assaying the culture for the presence of CTLs that kill radio-labeled target cells, both specific peptide-pulsed targets as well as target cells expressing endogenously processed forms of the antigen from which the peptide sequence was derived.
Alternatively, a CD8+ T cell clone that recognizes the Mtb polypeptide can be isolated from a subject of interest. This CD8+ T cell clone can be expanded in vitro, using methods known in the art. A therapeutically effective amount of the CD8+ T cells is then administered to the subject of interest.
Thus, cells can be administered to a subject to treat, inhibit, or even prevent an Mtb infection, such as to decrease a symptom of an Mtb infection. In these applications, a therapeutically effective amount of activated APCs, or activated lymphocytes, are administered to a subject in an amount sufficient to raise an immune response to Mtb.
In supplemental methods, any therapeutic regimen is augmented by administering a cytokine, such as interleukin (IL)-2, IL-3, IL-6, IL-10, IL-12, IL-15, GM-CSF, interferons. In further methods, an additional antibacterial or antiviral agent is administered to the subject.
The disclosure is illustrated by the following non-limiting Examples.
A peptide library encompassing 39,499 Mtb peptides was screened for antigens and/or epitopes that were both strongly and commonly recognized in individuals with Mtb infection in Portland, Oreg. This peptide library represents 389 genes, representing roughly 10% of the Mtb genome. The peptides are 15 mers overlapping by 11 amino acids for each gene product. 50 nmol of each peptide was synthesized individually and then pooled into 777 pools of 50 peptides in a 96 well format (nine plates). Five blank wells and one well of an irrelevant peptide pool, SIV gag, were included on each of the nine plates.
CD8+ T cells from donors were screened against the peptide library by IFN-γ ELISPOT. The IFN-γ ELISPOT assay was performed as described previously (Beckman et al., J. Immunol. 157:2795-2803, 1996). For determination of ex vivo frequencies of CD8+ T cells responding to Mtb infection or Mtb antigens, CD8+ T-cells were positively selected from peripheral blood mononuclear cells using magnetic beads (Miltenyi Biotec, Auburn Calif.) as a source of responder T cells and tested for their response to autologous DC. Each plate of the genomic peptide library was screened in duplicate, for a total of 18 ELISPOT plates per screen. CD8+ T cells were prepared from cryopreserved PBMC by CD8 selection using magnetic bead separations. Resulting cell populations contained >99% CD8+ T cells. CD8+ T cells (250,000 cells/well), autologous DCs (20,000 cells/well), and IL-2 (0.5 ng/ml) were added to peptide (final 5 ug/ml, individual peptides) in the ELISPOT plates. Five media control wells were included on each plate. Spots are enumerated using with the AID EliSpot Reader System. For each plate, the mean of these five wells was subtracted from each well of that plate to normalize between plates. Each technical replicate on each plate was then scored. A well was scored positive if the spot forming units (SFU), less the mean of the media wells, was greater than or equal to ten and the SFU was greater than or equal to twice the mean of the media. Twenty donors were tested, including fifteen LTBI (6 Caucasian, 4 African American, 5 SE Asian) and five donors with active TB.
Two criteria were used to select the peptide pools. First, peptide pools had to be in the top 5% of a donor's response. Second, the peptide pool had to be recognized by three or more donors. The peptide pools selected by this method were identical independent of the order these criteria were applied. A well was considered positive in the donor screen if only one technical replicate was statistically positive. However, since there is more confidence in a well where both technical replicates are positive, the selected wells were compared if the average spot forming units (SFU) for wells with two positive technical replicates was weighted by 200% to the selected wells if the average SFU was not weighted. 32 wells were selected if there was no weighting given to the technical replicates and 35 wells were selected if the weighting was applied. However, 19 wells were selected by both weighting and not weighting the average SFU and these were chosen for further analysis (Table 2).
1Number of peptides from each gene shown in parentheses
The antigens identified in Example 1 were screened in a CD8 ELISPOT assay against latent and active TB donors from Uganda. ELISPOT plates were read using the AID ELISPOT reader and output was exported into excel files. Data were imported into SAS® (statistical analysis system software) version 9.1 (SAS Institute, Inc., Cary, N.C.) and analyzed. A categorical variable for a positive ELISPOT was created in SAS® (statistical analysis system software). For a positive response to the antigen, the mean of the antigen containing wells must be greater than the background wells by two standard deviations. If this was true, the background was subtracted and this difference must then be greater than 10 spots. Similarly, a continuous ELISPOT variable was created for each antigen detailing the spot forming units remaining if the antigen met the categorical criteria above. The results were graphed by proportion of positive responses stratified by active or latent TB along with the corresponding spot forming unit (
Five antigens were selected for the validation stage. Several factors were considered in the selection, including those antigens that had a suggestion of disease specificity, as well as antigens with a broad and strong response. These antigens included PPE50:51, PE3, CtpF, PPE15, and EsxJ. Fifty-six latent and 52 active TB individuals were studied in the validation phase. Twenty-one individuals (19.2%) responded to all five antigens at the predefined cut-off, whereas 10 individuals (9%) responded to four of the antigens. Forty individuals (36%) responded to up to three antigens and 35% did not respond to any of the five antigens selected. Although some disease specificity was noted in the screening stage, especially as it applied to PPE50:51, this was not apparent in the validation stage.
The magnitude of the response was studied as well. Using Poisson modeling, individuals with latent disease had a significantly greater spot count than those with active disease for 4 antigens (PPE50:51, cTPF, PPE15, EsXJ) however the difference was not clinically meaningful (
Additional antigens were selected using the methods described in Example 1. The additional antigens are provided in Table 3.
The additional identified antigens were screened in a CD8 ELISPOT assay (as described in Examples 1 and 2) against latent and active TB donors from Uganda. The results were graphed by the corresponding spot forming unit (
Peptide-specific T cell clones were isolated from individuals with LTBI or active TB, using peptide pulsed DCs as APCs and limiting dilution cloning methodology. Briefly, CD8+ T cells were isolated from PBMCs using positive selection using CD8 antibody-coated magnetic beads per the manufacturer's instructions (Miltenyi Biotec, Bergisch Gladbach, Germany). T cells were seeded at various concentrations in the presence of a 2×104-irradiated autologous peptide pulsed DC, 1×105 irradiated autologous PBMC, and rIL-2 (5 ng/ml) in cell culture media consisting of 200 μl of RPMI 1640 supplemented with 10% human sera. Wells exhibiting growth between 10-14 days were assessed for peptide specificity using ELISPOT and peptide pulsed DCs as a source of APCs. T cells retaining peptide specificity were further phenotyped for αβ T cell receptor expression and CD8 expression by FACS.
Using the 15 mer Rv3136137-151, T cell clones were generated to the peptide using the methods described. Having derived an antigen-specific CD8+ T cell clone, the minimal epitope was determined. The minimal epitope was defined as the epitope which allowed for T cell recognition at the lowest concentration of peptide. Each 9-mer, 10-mer, and 11-mer peptide within the 15-mer was tested over a broad range of peptide concentrations, and by definition, the peptide eliciting a response at the lowest peptide concentration is the minimal epitope. Peptides including amino acids 139-149 of Rv3136 (SEQ ID NO: 2) allowed for T cell recognition at the lowest concentrations (
In tuberculosis research, mouse and guinea pig models have been used extensively to model various aspects of the disease.
A. Mouse Model:
Mice can be infected by a variety of routes, including intravenous, intraperitoneal and tracheal. One route is aerosolization of the infectious organism for respiratory infection. The mice are exposed to the aerosol in a chamber (wither whole body or nose only infection). The dose of invention can be varied by manipulating the concentration of Mtb in the nebulizer or time of exposure. A low dose infection, such as about 50 colony forming units (CFU) via aerosol, results in a slow and steady increase in bacterial numbers in the lungs, generally reaching a peak in four weeks, which coincides with the peak number of T cells in the lungs. The initial period is considered the acute stage of infection. Following infection, there is a dissemination of bacteria to the mediastinal lymph nodes. T cell priming is generally detectable between two and three weeks. After about four weeks the bacterial numbers stabilize, and there is a slow progressive pathologic response. This system is of use for modeling active infection. Thus, the above-described polypeptides, or polynucleotides encoding these polypeptides, can be administered prior to infection. The ability of the Mtb polypeptides (or polynucleotides encoding these polypeptides) to inhibit or prevent infection is then assessed. Alternatively, the mice are administered Mtb, and the ability of the Mtb polypeptide (or polynucleotide encoding these polypeptides) to treat the Mtb infection is monitored. The effectiveness of the Mtb polypeptides (or polynucleotides) can be monitored by measuring the T cell response, such as the number of CD8+ or CD4+ T cells, and/or measuring the bacterial numbers, and/or evaluating the pathology.
Exemplary protocols are provided below (see also Repique et al., Infec. Immun. 70: 3318-3323, 2002, incorporated herein by reference for an additional protocol).
1. Short Term Mouse Model:
C57BL/6 mice are vaccinated with a composition including one or more Mtb polypeptide, or a polynucleotide encoding these one or more polypeptides according to the appropriate protocol and then rested for 4 to 6 weeks. Immunized mice are infected with a low dose aerosol (50-100 CFU) of virulent M. tuberculosis and protection is evaluated by assessing the number of viable bacilli 30 days post challenge.
Viable counts are performed on the lung and spleen of mice by homogenizing the organs and plating serial 10-fold dilutions on 7H11 agar plates. Plates are incubated for up to 21 days and the number of colony forming units per organ determined.
BCG vaccinated mice have approximately 1 Log10 protection in their lung and spleen when compared to PBS-treated mice.
B. Guinea Pig Models:
1. Short Term Guinea Pig Model
Out-bred Hartley guinea pigs are vaccinated with a composition including one or more Mtb polypeptide, or a polynucleotide encoding these one or more polypeptides, and then rested for 8 to 10 weeks. Immunized guinea pigs are infected with a low dose aerosol (10-30 CFU) of virulent M. tuberculosis and protection is evaluated by assessing the number of viable bacilli 30 days post challenge.
Viable counts are performed on the lung and spleen of guinea pigs by homogenizing the organs and plating serial 10-fold dilutions on 7H11 agar plates. Plates are incubated for up to 21 days and the number of colony forming units per organ determined. Lung and spleen segments are also taken for histological analyses.
BCG vaccinated guinea pigs have approximately 2-3 Log10 protection in their lung and spleen when compared to PBS-treated guinea pigs. In addition, BCG vaccinated guinea pigs have well defined granulomas when compared to unvaccinated animals.
2. Long Term Guinea Pig Model
The guinea pig model is similar to the mouse model, but the experiments are open-ended survival type and can last for as long as 2 years. Guinea pigs develop “classical” granulomas similar to humans with active TB, and as lung tissue necrosis progresses, they begin to lose weight and die of TB similar to humans. The number of colony forming units in the lungs and spleen can be assessed. Histological examination can also be performed to determine the degree of lung involvement and tissue destruction. After low-dose aerosol exposure in the guinea pig the number of organisms increases progressively during the first three weeks and then plateaus into a chronic state. During the later stages of infection there is increased bacterial load in the lung and this is associated with a worsening pathological condition. Without treatment, there is a concomitant rise in both CD4 and CD8 T cells in the lungs of infected guinea pigs.
Out-bred Hartley guinea pigs are vaccinated with the experimental vaccine (such as a composition including one or more Mtb polypeptide, or a polynucleotide encoding these one or more polypeptides) according to the appropriate protocol and then rested for 8 to 10 weeks. Immunized guinea pigs are then infected with a low dose aerosol (10-30 CFU) of virulent M. tuberculosis. Guinea pigs are weighed weekly and monitored daily for signs of disease (such as increased respiration and failure to thrive). Unvaccinated guinea pigs succumb to infection from 20 to 25 weeks post challenge, while BCG vaccinated guinea pigs survive for 50 to 55 weeks post challenge.
At necropsy, the lung and spleen are assessed for the number of CFU and the extent of pathology. The relative protection of the experimental composition is compared to BCG vaccinated animals.
This example describes methods that can be used to induce an immune response in a subject that has or is at risk of having tuberculosis. In particular examples, the method includes selecting a subject having, thought to have, or at risk of having tuberculosis. Subjects having or thought to have tuberculosis include those with symptoms such as persistent cough, blood-tinged sputum, fever, weight loss, Ghon complex, or a positive diagnostic test (such as a tuberculin skin test). Subjects at risk of tuberculosis include those with exposure to an infected individual, those in an area where tuberculosis is endemic, and immunocompromised individuals.
Subjects selected for treatment can be administered a therapeutic amount of a disclosed immunogenic Mtb polypeptide or immunogenic fragment thereof or a polynucleotide encoding the polypeptide or fragment thereof. In some examples, a Mtb polypeptide or immunogenic fragment thereof or a polynucleotide encoding the polypeptide or fragment thereof is administered to the subject at doses of about 0.1 μg to 10 mg of immunogenic Mtb polypeptide or polynucleotide encoding the polypeptide. Dosages from 0.1 mg to about 100 mg per subject can be used, particularly if the agent is administered to a secluded site and not into the circulatory or lymph system, such as into a body cavity or into a lumen of an organ. However, the particular dose can be determined by a skilled clinician. The disclosed Mtb polypeptide (or immunogenic fragment thereof) or polynucleotide encoding the polypeptide or fragment thereof can be administered in one or several doses, for example continuously, daily, weekly, or monthly. When administered sequentially, the time separating the administration of the disclosed Mtb polypeptide (or immunogenic fragment thereof) or a polynucleotide encoding the polypeptide or fragment thereof can be seconds, minutes, hours, days, or even weeks.
The mode of administration can be any used in the art. The amount of agent administered to the subject can be determined by a clinician, and may depend on the particular subject treated. Specific exemplary amounts are provided herein (but the disclosure is not limited to such doses).
It will be apparent that the precise details of the methods or compositions described may be varied or modified without departing from the spirit of the described invention. We claim all such modifications and variations that fall within the scope and spirit of the claims below.
This is the §371 U.S. National Stage of International Application No. PCT/US2010/057479, filed Nov. 19, 2010, which was published in English under PCT Article 21(2), which in turn claims the benefit of U.S. Provisional Application No. 61/263,206, filed Nov. 20, 2009, which is incorporated herein by reference in its entirety.
This invention was made with government support under Grant No. HSSN266200400081C awarded by the National Institutes of Health. The government has certain rights in the invention.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US2010/057479 | 11/19/2010 | WO | 00 | 5/18/2012 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2011/063263 | 5/26/2011 | WO | A |
| Number | Name | Date | Kind |
|---|---|---|---|
| 6982085 | Anderson et al. | Jan 2006 | B2 |
| 6991797 | Anderson et al. | Jan 2006 | B2 |
| 7288261 | Orme et al. | Oct 2007 | B2 |
| 7364740 | Behr et al. | Apr 2008 | B2 |
| 7393540 | James et al. | Jul 2008 | B2 |
| 7538206 | Cole | May 2009 | B2 |
| 20020131975 | Horwitz et al. | Sep 2002 | A1 |
| 20030199012 | Ho | Oct 2003 | A1 |
| 20030236393 | Trucksis | Dec 2003 | A1 |
| 20040057963 | Anderson et al. | Mar 2004 | A1 |
| 20040110269 | Vipond et al. | Jun 2004 | A1 |
| 20040197896 | Cole | Oct 2004 | A1 |
| 20040241826 | James et al. | Dec 2004 | A1 |
| 20050250120 | Cole et al. | Nov 2005 | A1 |
| 20070224217 | Trucksis | Sep 2007 | A1 |
| 20080138356 | Friedman et al. | Jun 2008 | A1 |
| 20080267990 | Anderson et al. | Oct 2008 | A1 |
| 20090123492 | Flores-Valdez et al. | May 2009 | A1 |
| 20090124549 | Lewinsohn et al. | May 2009 | A1 |
| Number | Date | Country |
|---|---|---|
| WO 0104151 | Jan 2001 | WO |
| WO 0179274 | Oct 2001 | WO |
| WO 0204018 | Jan 2002 | WO |
| WO 03033530 | Apr 2003 | WO |
| WO 2005076010 | Aug 2005 | WO |
| WO 2007106560 | Sep 2007 | WO |
| WO 2008124647 | Oct 2008 | WO |
| WO 2011063283 | May 2011 | WO |
| Entry |
|---|
| Greenspan et al. (Nature Biotechnology 7: 936-937, 1999). |
| Cockle et al., “Identification of Novel Mycobacterium tuberculosis Antigens with Potential as Diagnostic Reagents or Subunit Vaccine Candidates by Comparative Genomics,” Infection and Immunity, vol. 70, No. 12, pp. 6996-7003. 2002. |
| Larsen, “Prediction of T-cell Epitopes for Therapeutic and Prophylactic Vaccines,” Center for Biological Sequence Analysis BioCentrum. Technical University of Denmark, 2007 (154 pages). |
| Lewinsohn et al., “Immunodominant Tuberculosis CD8 Antigens Preferentially Restricted by HLA-B,” PLoS Pathogens, vol. 3, No. 9, pp. 1240-1249, 2007. |
| Lewinsohn et al., “Mycobacterium tuberculosis-Specific CD8+ T Cells Preferentially Recognize Heavily Infected Cells,” Am. J. Respir. Crit. Care Med., vol. 168, pp. 1346-1352, 2003. |
| NCBI Accession No. YP—177935, Apr. 24, 2009, 2 pages. |
| NCBI GenBank Accession No. NP—335505, Apr. 24, 2009, 2 pages. |
| NCBI GenBank Accession No. NP—337747, Apr. 24, 2009, 2 pages. |
| Zvi et al., “Whole Genome Identification of Mycobacterium tuberculosis Vaccine Candidates by Comprehensive Data Mining and Bioinformatic Analyses,” BMC Med. Genomics, I:18 2008 (25 pages). |
| Tuberculist Database Rv0394c, printed from http://genome.tbdb.org/annotation/genome/tbdb/GeneDetails.html?sp=S7000000635256770 (published on Jul. 27, 2009). |
| Tuberculist Database Rv1039c, printed from http://genome.tbdb.org/annotation/genome/tbdb/GeneDetails.html?sp=S7000000635246273 (published on Jun. 8, 2006). |
| Tuberculist Database Rv1076c, printed from http://genome.tbdb.org/annotation/genome/tbdb/GeneDetails.html?sp=S7000000635252927 (published on Jul. 27, 2009). |
| Tuberculist Database Rv3539, printed from http://genome.tbdb.org/annotation/genome/tbdb/GeneDetails.html?sp=S7000000635255504 (published on Jul. 27, 2009). |
| Tuberculist Database Rv3136, printed from http://genome.tbdb.org/annotation/genome/tbdb/GeneDetails.html?sp=S7000000635251322 (published on Jun. 10, 2009). |
| Tuberculist Database Rv3641c, printed from http://genome.tbdb.org/annotation/genome/tbdb/GeneDetails.html?sp=S7000000635256770 (published on Jul. 27, 2009). |
| Brosch et al., “Genome plasticity of BCG and impact on vaccine efficacy,” PNAS 104(13):5596-5601 (Mar. 27, 2007). |
| Database UniProt Accession No. A5U183 (online Jul. 10, 2007). |
| Database UniProt Accession No. A5U7F1 (online Jul. 10, 2007). |
| Garnier et al., “The complete genome sequence of Mycobacterium bovis,” PNAS 100(13):7877-7882 (Jun. 24, 2003). |
| Seki et al., “Whole genome sequence analysis of Mycobacterium bovis bacillus Calmette-Guérin (BCG) Tokyo 172: A comparative study of BCG vaccine substrains,” Vaccine 27(11):1710-1716 (2009). |
| Number | Date | Country | |
|---|---|---|---|
| 20120237537 A1 | Sep 2012 | US |
| Number | Date | Country | |
|---|---|---|---|
| 61263206 | Nov 2009 | US |
