Heat shock protein-based vaccines and immunotherapies

Abstract

The present invention relates to methods and compositions for inducing an immune response in a subject, wherein the subject is administered an effective amount of at least one heat shock protein in combination with one or more defined target antigens. These methods and compositions may be used in the treatment of infectious diseases and cancers.

Description

INTRODUCTION

[0002] The present invention relates to methods and compositions for inducing an immune response in a subject, wherein the subject is administered an effective amount of at least one heat shock protein in combination with one or more defined target antigens. These methods and compositions may be used in the treatment of infectious diseases and cancers.

BACKGROUND OF THE INVENTION

[0003] Heat shock proteins were originally observed to be expressed in increased amounts in mammalian cells which were exposed to sudden elevations of temperature, while the expression of most cellular proteins is significantly reduced. It has since been determined that such proteins are produced in response to various types of stress, including glucose deprivation. As used herein, the term “heat shock protein” will be used to encompass both proteins that are expressly labeled as such as well as other stress proteins, including homologs of such proteins that are expressed constitutively (i.e., in the absence of stressful conditions). Examples of heat shock proteins include BiP (also referred to as grp78), hsp/hsc70, gp96 (grp94), hsp60, hsp40 nd hsp90.

[0004] Heat shock proteins have the ability to bind other proteins in their non-native states, and in particular to bind nascent peptides emerging from ribosomes or extruded into the endoplasmic reticulum. Hendrick and Hartl, Ann. Rev. Biochem. 62:349-384 (1993); Hartl, Nature 381:571-580 (1996). Further, heat shock proteins have been shown to play an important role in the proper folding and assembly of proteins in the cytosol, endoplasmic reticulum and mitochondria; in view of this function, they are referred to as “molecular chaperones.” Frydman et al., Nature 370:111-117 (1994); Hendrick and Hartl, Ann. Rev. Biochem. 62:349-384 (1993); Hartl, Nature 381:571-580 (1996).

[0005] For example, the protein BiP, a member of a class of heat shock proteins referred to as the hsp70 family, has been found to bind to newly synthesized, unfolded &mgr; immunoglobulin heavy chain prior to its assembly with light chain in the endoplasmic reticulum. Hendershot et al., J. Cell Biol. 104:761-767 (1987). Another heat shock protein, gp96, is a member of the hsp90 family of stress proteins which localizes in the endoplasmic reticulum. Li and Srivastava, EMBO J. 12:3143-3151 (1993); Mazzarella and Green, J. Biol. Chem. 262:8875-8883 (1987). It has been proposed that gp96 may assist in the assembly of multi-subunit proteins in the endoplasmic reticulum. Wiech et al., Nature 358:169-170 (1992).

[0006] It has been observed that heat shock proteins prepared from tumors in experimental animals were able to induce immune responses in a tumor-specific manner; that is to say, heat shock protein purified from a particular tumor could induce an immune response in an experimental animal which would inhibit the growth of the same tumor, but not other tumors. Srivastava and Maki, Curr. Topics Microbiol. 167:109-123 (1991). The source of the tumor-specific immunogenicity has not been confirmed. Genes encoding heat shock proteins have not been found to exhibit tumor-specific DNA polymorphism. Srivastava and Udono, Curr. Opin. Immunol. 6:728-732 (1994). High resolution gel electrophoresis has indicated that gp96 may be heterogeneous at the molecular level. Feldweg and Srivastava, Int. J. Cancer 63:310-314 (1995). Evidence suggests that the source of heterogeneity may be populations of small peptides adherent to the heat shock protein, which may number in the hundreds. Id. It has been proposed that a wide diversity of peptides adherent to tumor-synthesized heat shock proteins may render such proteins capable of eliciting an immune response in subjects having diverse HLA phenotypes, in contrast to more traditional immunogens which may be somewhat HLA-restricted in their efficacy. Id.

[0007] Recently, Nieland et al. (Proc. Natl. Acad. Sci. U.S.A. 93:6135-6139 (1996)) identified an antigenic peptide containing a cytotoxic T lymphocyte (CTL) vesicular stomatitis virus (VSV) epitope bound to gp96 produced by VSV-infected cells. Neiland's methods precluded the identification of any additional peptides or other compounds which may also have bound to gp96, and were therefore unable to further characterize higher molecular weight material which was bound to gp96 and detected by high pressure liquid chromatography.

[0008] It has been reported that a synthetic peptide comprising multiple iterations of NANP (Asp Ala Asp Pro) malarial antigen, chemically cross-linked to glutaraldehyde-fixed mycobacterial hsp65 or hsp70, was capable of inducing antibody formation (i.e., a humoral response) in mice in the absence of any added adjuvant; a similar effect was observed using heat shock protein from the bacterium Escherichia coli. Del Guidice, Experientia 50:1061-1066 (1994); Barrios et al., Clin. Exp. Immunol. 98:224-228 (1994); Barrios et al., Eur. J. Immunol. 22:1365-1372 (1992). Cross-linking of synthetic peptide to heat shock protein and possibly glutaraldehyde fixation was required for antibody induction. Barrios et al., Clin. Exp. Immunol. 98:229-233.

[0009] It has now been discovered, according to the present invention, that heat shock protein may be combined with target antigen and used to induce an immune response which includes a cytotoxic cellular component, i.e., a cellular response.

SUMMARY OF THE INVENTION

[0010] The present invention relates to methods and compositions for inducing an immune response in a subject, wherein at least one heat shock protein in combination with one or more defined target antigens is administered to the subject.

[0011] Unlike prior disclosures relating to heat shock protein associated with an undefined population of potential antigens which have been restricted, in their immunogenic effect, to a single tumor, the present invention provides for methods and compositions which combine heat shock protein with a defined target antigen which may be selected on the basis that it is immunogenic in diverse occurrences of a neoplastic or infectious disease, or because it has been identified, in an individual instance, as being particularly immunogenic. Further, because the use of one or more defined target antigen permits more control over the immune response elicited, it may avoid the induction of an undesirable immune response.

[0012] In alternative embodiments of the invention, the target antigen may be either (i) an antigen which itself binds to the heat shock protein; or (ii) a hybrid antigen comprising an immunogenic domain as well as a heat shock protein-binding domain. The immunogenic domain may be an entire protein or peptide antigen, or may be only a portion of the selected antigen, for example a selected epitope of the antigen. In specific, nonlimiting embodiments of the invention, the heat shock protein binding domain may comprise a peptide having the sequence:

[0013] His Trp Asp Phe Ala Trp Pro Trp (SEQ ID NO:1).

[0014] The present invention provides for methods of administering such heat shock protein/target antigen compositions comprising (i) combining one or more heat shock protein with one or more target antigens in vitro, under conditions wherein binding of target antigen to heat shock protein occurs to form a target antigen/heat shock protein complex; and (ii) administering the target antigen, bound to heat shock protein, in an effective amount to a subject in need of such treatment.

[0015] Alternatively, heat shock protein/target antigen combinations of the invention may be administered to a subject by introducing nucleic acid encoding the heat shock protein and the target antigen into the subject such that the heat shock protein and target antigen bind in situ.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] FIG. 1 shows the induction of a cellular immune response using hybrid peptide antigens in accordance with the invention.

[0017] FIG. 2 shows the induction of a cellular immune response using hybrid peptide antigens in accordance with the invention.

[0018] FIG. 3 shows the induction of a cellular immune response using hybrid peptide antigens in accordance with the invention.

[0019] FIG. 4 shows the induction of a cellular immune response using hybrid peptide antigens in accordance with the invention.

[0020] FIGS. 5A and 5B shows the results of control experiments in which hybrid peptide or Ova-peptide and heat shock protein were administered individually to EL4 cells.

[0021] FIG. 6 shows co-elution of hybrid peptides and heat shock proteins from a column, demonstrating binding of the polypeptides to the heat shock protein.

[0022] FIG. 7 shows the co-elution of 125I-OVA-BiP with BiP in the presence and absence of ATP.

[0023] FIG. 8 shows the killing efficacy of T-cells primed with various combinations of antigens and heat shock proteins on EL4 cells pulsed with antigen.

[0024] FIG. 9 shows the killing efficacy of T-cells primed with various concentrations of antigens and heat shock proteins on EG7 lymphoma cells.

DETAILED DESCRIPTION OF THE INVENTION

[0025] For purposes of clarity of description, and not by way of limitation, the detailed description is divided into the following subsections:

[0026] (i) heat shock proteins;

[0027] (ii) target antigens; and

[0028] (iii) methods of administration.

[0029] Heat Shock Proteins

[0030] The term “heat shock protein,” as used herein, refers to any protein which exhibits increased expression in a cell when the cell is subjected to a stress. In preferred nonlimiting embodiments, the heat shock protein is originally derived from a eukaryotic cell; in more preferred embodiments, the heat shock protein is originally derived from a mammalian cell. For example, but not by way of limitation, heat shock proteins which may be used according to the invention include BiP (also referred to as grp78), hsp/hsc70, gp96 (grp94), hsp60, hsp40, and hsp90. Especially preferred heat shock proteins are BiP, gp96, and hsp70, as exemplified below. Naturally occurring or recombinantly derived mutants of heat shock proteins may also be used according to the invention. For example, but not by way of limitation, the present invention provides for the use of heat shock proteins mutated so as to facilitate their secretion from the cell (for example having mutation or deletion of an element which facilitates endoplasmic reticulum recapture, such as KDEL or its homologs; such mutants are described in concurrently filed PCT Application No. PCT/US96/13233 (WO 97/06685), which is incorporated herein by reference).

[0031] For embodiments of the invention wherein heat shock protein and target antigen are directly administered to the subject in the form of a protein/peptide complex, the heat shock protein may be prepared, using standard techniques, from natural sources, for example as described in Flynn et al., Science 245:385-390 (1989), or using recombinant techniques such as expression of a heat shock encoding vector in a suitable host cell such as a bacterial, yeast or mammalian cell. If pre-loading of the heat shock protein with peptides from the host organism is a concern, the heat shock protein can be incubated with ATP and then repurified. Nonlimiting examples of methods for preparing recombinant heat shock proteins are set forth below.

[0032] A nucleic acid encoding a heat shock protein may be operatively linked to elements necessary or desirable for expression and then used to express the desired heat shock protein as either a means to produce heat shock protein for use in a protein vaccine or, alternatively, in a nucleic acid vaccine. Elements necessary or desirable for expression include, but are not limited to, promoter/enhancer elements, transcriptional start and stop sequences, polyadenylation signals, translational start and stop sequences, ribosome binding sites, signal sequences and the like. For example, but not by way of limitation, genes for various heat shock proteins have been cloned and sequenced, including, but not limited to, gp96 (human: Genebank Accession No. X15187; Maki et al., Proc. Natl. Acad. Sci. U.S.A. 87:5658-5562 (1990); mouse: Genebank Accession No. M16370; Srivastava et al., Proc. Natl. Acad. Sci. U.S.A. 84:3807-3811 (1987)), BiP (mouse: Genebank Accession No. U16277; Haas et al., Proc. Natl. Acad. Sci. U.S.A. 85:2250-2254 (1988); human: Genebank Accession No. M19645; Ting et al., DNA 7:275-286 (1988)), hsp70 (mouse: Genebank Accession No. M35021; Hunt et al., Gene 87:199-204 (1990); human: Genebank Accession No. M24743; Hunt et al, Proc. Natl. Acad. Sci. U.S.A. 82:6455-6489 (1995)), and hsp40 (human: Genebank Accession No. D49547; Ohtsuka K., Biochem. Biophys. Res. Commun. 197:235-240 (1993)).

[0033] Target Antigens

[0034] A target antigen, according to the invention, may be either (i) an antigen which itself binds to the heat shock protein; or (ii) a hybrid antigen comprising an immunogenic domain as well as a heat shock protein-binding domain. Thus, the target antigen serves at least two functions, namely (i) it contains an epitope capable of inducing the desired immune response; and (ii) it is capable of physically binding to its partner heat shock protein. Of note, the term “physically binds” indicates that the target antigen and heat shock protein exhibit a physical interaction which permits the adherence of one to the other for at least a transient period of time; of note, the binding need not, and in most embodiments of the invention should not, be irreversible.

[0035] In certain embodiments, an antigen capable of inducing the desired immune response may be found to be inherently capable of binding to a partner heat shock protein. In other embodiments, it may be necessary or desirable to link an immunogenic antigen to one or more other compounds so as to create a hybrid antigen which contains both an immunogenic domain as well as a heat shock protein binding domain. In such circumstances, a compound which is, itself, an immunogenic antigen may be linked to a compound which is, itself, capable of binding to a heat shock protein. Alternatively, the linkage of two or more compounds which individually lack either functionality may give rise to the desired immunogenic and binding characteristics.

[0036] The term “antigen” as used herein, refers to a compound which may be composed of amino acids, carbohydrates, nucleic acids or lipids individually or in any combination.

[0037] The term “target antigen,” as used herein, refers to a compound which binds to one or more heat shock proteins and which is representative of the immunogen toward which an immune response is desirably directed. For example, where the immunogen is an influenza virus, the target antigen may be a peptide fragment of the matrix protein of the influenza virus. As used herein, the term “immunogen” is applied to the neoplastic cell, infected cell, pathogen, or component thereof, towards which an immune response is to be elicited, whereas the target antigen is a portion of that immunogen which can provoke the desired response and which inherently or through engineering binds to one or more heat shock proteins. In particular, the target antigen is selected to elicit an immune response to a particular disease or pathogen, including peptides obtained from MHC molecules, mutated DNA gene products, and direct DNA products such as those obtained from tumor cells.

[0038] While the invention may be applied to any type of immunogen, immunogens of particular interest are those associated with, derived from, or predicted to be associated with a neoplastic disease, including but not limited to a sarcoma, a lymphoma, a leukemia, or a carcinoma, and in particular, with melanoma, carcinoma of the breast, carcinoma of the prostate, ovarian carcinoma, carcinoma of the cervix, colon carcinoma, carcinoma of the lung, glioblastoma, astrocytoma, etc. Further, mutations of tumor suppressor gene products such as p53, or oncogene products such as ras may also provide target antigens to be used according to the invention.

[0039] In further embodiments, the immunogen may be associated with an infectious disease, and, as such, may be a bacterium, virus, protozoan, mycoplasma, fungus, yeast, parasite, or prion. For example, but not by way of limitation, the immunogen may be a human papilloma virus (see below), a herpes virus such as herpes simplex or herpes zoster, a retrovirus such as human immunodeficiency virus 1 or 2, a hepatitis virus, an influenza virus, a rhinovirus, respiratory syncytial virus, cytomegalovirus, adenovirus, Mycoplasma pneumoniae, a bacterium of the genus Salmonella, Staphylococcus, Streptococcus, Enterococcus, Clostridium, Escherichia, Klebsiella, Vibrio, Mycobacterium, amoeba, a malarial parasite, Trypanosoma cruzi, etc.

[0040] Immunogens may be obtained by isolation directly from a neoplasm, an infected cell, a specimen from an infected subject, a cell culture, or an organism culture, or may be synthesized by chemical or recombinant techniques. Suitable antigenic peptides, particularly for use in a hybrid antigen, for use against viruses, bacteria and the like can be designed by searching through their sequences for MHC class I restricted peptide epitopes containing HLA binding sequences such as but not limited to HLA-A2 peptide binding sequences: Xaa(Leu/Met)XaaXaaXaa(Val/Ile/Leu/Thr)XaaXaa(Val/Leu) (SEQ ID NO:2), for example, from viruses: 1 (SEQ ID NO:31) Ser Gly Pro Ser Asn Thr Pro Pro Glu Ile; (SEQ ID NO:32) Ser Gly Val Glu Asn Pro Gly Gly Tyr Cys Leu; (SEQ ID NO:33) Lys Ala Val Tyr Asn Phe Ala Thr Cys Gly; (SEQ ID NO:34) Arg Pro Gln Ala Ser Gly Val Tyr Met; (SEQ ID NO:35) Phe Gln Pro Gln Asn Gly Gln Phe Ile; (SEQ ID NO:36) Ile Glu Gly Gly Trp Thr Gly Met Ile; (SEQ ID NO:37) Thr Tyr Val Ser Val Ser Thr Ser Thr Leu; (SEQ ID NO:38) Phe Glu Ala Asn Gly Asn Leu Ile; (SEQ ID NO:39) Ile Tyr Ser Thr Val Ala Ser Ser Leu; (SEQ ID NO:40) Thr Tyr Gln Arg Thr Arg Ala Leu Val; (SEQ ID NO:41) Cys Thr Glu Leu Lys Leu Ser Asp Tyr; (SEQ ID NO:42) Ser Asp Tyr Glu Gly Arg Leu Ile; (SEQ ID NO:43) Glu Glu Gly Ala Ile Val Gly Glu Ile; (SEQ ID NO:44) Val Ser Asp Gly Gly Pro Asn Leu Tyr; (SEQ ID NO:45) Ala Ser Asn Glu Asn Met Glu Thr Met; (SEQ ID NO:46) Ala Ser Asn Glu Asn Met Asp Ala Met; (SEQ ID NO:47) Lys Leu Gly Glu Phe Tyr Asn Gln Met Met; (SEQ ID NO:48) Leu Tyr Gln Asn Val Gly Thr Tyr Val; (SEQ ID NO:49) Thr Tyr Val Ser Val Gly Thr Ser Thr Leu; (SEQ ID NO:50) Phe Glu Ser Thr Gly Asn Leu Ile; (SEQ ID NO:51) Val Tyr Gln Ile Leu Ala Ile Tyr Ala; (SEQ ID NO:52) Ile Tyr Ala Thr Val Ala Gly Ser Leu; (SEQ ID NO:53) Gly Ile Leu Gly Phe Val Phe Thr Leu; (SEQ ID NO:54) Ile Leu Gly Phe Val Phe Thr Leu Thr Val; (SEQ ID NO:55) Ile Leu Arg Gly Ser Val Ala His Lys; (SEQ ID NO:56) Glu Asp Leu Ary Val Leu Ser Phe Ile; (SEQ ID NO:57) Glu Leu Arg Ser Arg Tyr Trp Ala Ile; (SEQ ID NO:58) Ser Arg Tyr Trp Ala Ile Arg Thr Arg; (SEQ ID NO:59) Lys Thr Gly Gly Pro Ile Tyr Lys Arg; (SEQ ID NO:60) Phe Ala Pro Gly Asn Tyr Pro Ala Leu; (SEQ ID NO:61) Arg Arg Tyr Pro Asp Ala Val Tyr Leu; (SEQ ID NO:62) Asp Pro Val Ile Asp Arg Leu Tyr Leu; (SEQ ID NO:63) Ser Pro Gly Arg Ser Phe Ser Tyr Phe; (SEQ ID NO:64) Tyr Pro Ala Leu Gly Leu His Glu Phe; (SEQ ID NO:65) Thr Tyr Lys Asp Thr Val Gln Leu; (SEQ ID NO:66) Phe Tyr Asp Gly Phe Ser Lys Val Pro Leu; (SEQ ID NO:67) Phe Ile Ala Gly Asn Ser Ala Tyr Glu Tyr Val; (SEQ ID NO:68) Tyr Pro His Phe Met Pro Thr Asn Leu; (SEQ ID NO:69) Ala Pro Thr Ala Gly Ala Phe Phe Phe; (SEQ ID NO:70) Ser Thr Leu Pro Glu Thr Thr Val Val Arg Arg; (SEQ ID NO:71) Phe Leu Pro Ser Asp Phe Phe Pro Ser Val; (SEQ ID NQ:72) Trp Leu Ser Leu Leu Val Pro Phe Val; (SEQ ID NO:73) Gly Leu Ser Pro Thr Val Trp Leu Ser Val; (SEQ ID NO:74) Asp Leu Met Gly Tyr Ile Pro Leu Val; (SEQ ID NO:75) Leu Met Gly Tyr Ile Pro Leu Val Gly Ala; (SEQ ID NO:76) Ala Ser Arg Cys Trp Val Ala Met; (SEQ ID NO:77) Lys Leu Val Ala Leu Gly Ile Asn Ala Val; (SEQ ID NO:78) Phe Leu Arg Gly Arg Ala Tyr Gly Leu; (SEQ ID NO:79) Arg Arg Ile Tyr Asp Leu Ile Glu Leu; (SEQ ID NO:80) Ile Val Thr Asp Phe Ser Val Ile Lys; (SEQ ID NO:81) Arg Arg Arg Trp Arg Arg Leu Thr Val; (SEQ ID NO:82) Glu Glu Asn Leu Leu Asp Phe Val Arg Phe; (SEQ ID NO:83) Cys Leu Gly Gly Leu Leu Thr Met Val; (SEQ ID NO:84) Ser Ser Ile Glu Phe Ala Arg Leu; (SEQ ID NO:85) Leu Tyr Arg Thr Phe Ala Gly Asn Pro Arg Ala; (SEQ ID NO:86) Asp Tyr Ala Thr Leu Gly Val Gly Val; (SEQ ID NO:87) Leu Leu Leu Gly Thr Leu Asn Ile Val; (SEQ ID NQ:88) Leu Leu Met Gly Thr Leu Gly Ile Val; (SEQ ID NO:89) Thr Leu Gln Asp Ile Val Leu His Leu; (SEQ ID NO:90) Gly Leu His Cys Tyr Glu Gln Leu Val; (SEQ ID NO:91) Pro Leu Lys Gln His Phe Gln Ile Val; (SEQ ID NO:92) Arg Leu Val Thr Leu Lys Asp Ile Val; (SEQ ID NO:93) Arg Ala His Tyr Asn Ile Val Thr Phe; (SEQ ID NO:94) Leu Leu Phe Gly Tyr Pro Val Tyr Val; (SEQ ID NO:95) Ser Ala Ile Asn Asn Tyr Ala Gln Lys Leu; (SEQ ID NQ:96) His Gln Ala Ile Ser Pro Arg Thr Leu; (SEQ ID NQ:97) Gln Met Val His Gln Ala Ile Ser Pro Arg Thr Leu; (SEQ ID NO:98) Cys Lys Gly Val Asn Lys Glu Tyr Leu; (SEQ ID NO:99) Gln Gly Ile Asn Asn Leu Asp Asn Leu; (SEQ ID NO:100) Asn Asn Leu Asp Asn Leu Arg Asp Tyr; (SEQ ID NO:101) Ser Glu Phe Leu Leu Glu Lys Arg Ile; (SEQ ID NO:102) Ser Tyr Ile Gly Ser Ile Asn Asn Ile; (SEQ ID NO:103) Ile Leu Gly Asn Lys Ile Val Arg Met Tyr; (SEQ ID NO:104) Arg Leu Arg Pro Gly Gly Lys Lys Lys; (SEQ ID NO:105) Glu Ile Lys Asp Thr Lys Glu Ala Leu; (SEQ ID NO:106) Gly Glu Ile Tyr Lys Arg Trp Ile Ile; (SEQ ID NO:107) Glu Ile Tyr Lys Arg Trp Ile Ile Leu; (SEQ ID NO:108) Arg Tyr Leu Lys Asp Gln Gln Leu Leu; (SEQ ID NO:109) Arg Gly Pro Gly Arg Ala Phe Val Thr Ile; (SEQ ID NO:110) Ile Val Gly Leu Asn Lys Ile Val Arg; (SEQ ID NO:111) Thr Val Tyr Tyr Gly Val Pro Val Trp Lys; (SEQ ID NO:112) Arg Leu Arg Asp Leu Leu Leu Ile Val Thr Arg; (SEQ ID NO:113) Lys Arg Trp Ile Ile Leu Gly Leu Asn Lys; (SEQ ID NO:114) Ser Phe Asn Cys Gly Gly Glu Phe Phe; (SEQ ID NO:115) Gly Arg Ala Phe Val Thr Ile Gly Lys; (SEQ ID NO:116) Thr Pro Gly Pro Gly Val Arg Tyr Pro Leu; (SEQ ID NO:117) Gln Val Pro Leu Arg Pro Met Thr Tyr Lys; (SEQ ID NO:118) Thr Glu Met Glu Lys Glu Gly Lys Ile; (SEQ ID NO:119) Ile Leu Lys Glu Pro Val His Gly Val; (SEQ ID NO:120) Val Glu Ala Glu Ile Ala His Gln Ile; (SEQ ID NO:121) Arg Gly Tyr Val Tyr Gln Gly Leu; (SEQ ID NO:122) Tyr Ser Gly Tyr Ile Phe Arg Asp Leu; (SEQ ID NO:123) Val Gly Pro Val Phe Pro Pro Gly Met; (SEQ ID NO:124) Ile Ile Tyr Arg Phe Leu Leu Ile;

[0041] from bacteria: 2 (SEQ ID NO:125) Lys Tyr Gly Val Ser Val Gln Asp Ile; (SEQ ID NO:126) Ile Gln Val Gly Asn Thr Arg Thr Ile; (SEQ ID NO:127) Thr Pro His Pro Ala Arg Ile Gly Leu;

[0042] from parasites: 3 (SEQ ID NO:128) Ser Tyr Ile Pro Ser Ala Glu Lys Ile; (SEQ ID NO:129) Lys Pro Lys Asp Glu Leu Asp Tyr; (SEQ ID NO:130) Lys Ser Lys Asp Glu Leu Asp Tyr; (SEQ ID NO:131) Lys Pro Asn Asp Lys Ser Leu Tyr; (SEQ ID NO:132) Lys Tyr Leu Lys Lys Ile Lys Asn Ser Leu; (SEQ ID NQ:133) Tyr Glu Asn Asp Ile Glu Lys Lys Ile; (SEQ ID NO:134) Asn Tyr Asp Asn Ala Gly Thr Asn Leu; (SEQ ID NO:135) Asp Glu Leu Asp Tyr Glu Asn Asp Ile; (SEQ ID NO:136) Ser Tyr Val Pro Ser Ala Glu Gln Ile;

[0043] from cancers: 4 Phe Glu Gln Asn Thr Ala Gln Pro; (SEQ ID NO:137) Phe Glu Gln Asn Thr Ala Gln Ala; (SEQ ID NO:138) Glu Ala Asp Pro Thr Gly His Ser Tyr; (SEQ ID NO:139) Glu Val Asp Pro Ile Gly His Leu Tyr; (SEQ ID NO:140) Ala Ala Gly Ile Gly Ile Leu Thr Val; (SEQ ID NO:141) Tyr Leu Glu Pro Gly Pro Val Thr Ala; (SEQ ID NO:142) Ile Leu Asp Gly Thr Ala Thr Leu Arg Leu; (SEQ ID NO:143) Met Leu Leu Ala Leu Leu Tyr Cys Leu; (SEQ ID NO:144) Tyr Met Asn Gly Thr Met Ser Gln Val; (SEQ ID NO:145) Leu Pro Tyr Leu Gly Trp Leu Val Phe; (SEQ ID NO:146) Phe Gly Pro Tyr Lys Leu Asn Arg Leu; (SEQ ID NO:147) Lys Ser Pro Trp Phe Thr Thr Leu; (SEQ ID NO:148) Gly Pro Pro His Ser Asn Asn Phe Gly Tyr; and (SEQ ID NO:149) Ile Ser Thr Gln Asn His Arg Ala Leu (SEQ ID NO:150) (Rammensee et al., Immunogenetics 41:178-223 (1995)), Xaa (Leu/Met) XaaXaaXaaXaaXaaXaaVal; (SEQ ID NO:3) (Tarpey et al., Immunology 81:222-227 (1994)), Xaa (Val/Gln)XaaXaaXaaXaaXaaXaaLeu, (SEQ ID NO:28)

[0044] for example, from virus: 5 Tyr Gly Ile Leu Gly Lys Val Phe Thr Leu; (SEQ ID NO:151) Ser Leu Tyr Asn Thr Val Ala Thr Leu; (SEQ ID NO:152) (Barouch et al., J. Exp. Med. 182:1847-1856 (1995)).

[0045] It may also be desirable to consider the type of immune response which is desired. For example, under certain circumstances, a humoral immune response may be appropriate. In other cases, and indeed where an immune response directed toward neoplastic cells or infected cells is sought to be elicited, a cellular immune response is particularly desirable. Accordingly, particular epitopes associated with the activation of B cells, T helper cells, or cytotoxic T cells may be identified and selected for incorporation into the target antigen.

[0046] It may also be desirable to utilize target antigen associated with an autoimmune disease or allergy. Such a target antigen may be administered, together with one or more heat shock proteins, in an amount sufficient to be tolerogenic or to inhibit a pre-existing immune response to the target antigen in a subject. The amount of heat shock protein required to inhibit the immune response is expected to be substantially greater than the amount required for stimulation.

[0047] Although the size of target antigen may vary depending upon the heat shock protein used, in nonlimiting embodiments of the invention, the target antigen may be the size of a peptide having between 4 and 500 amino acid residues, and preferably be the size of a peptide having between 4 and 100, most preferably 7 and 20 amino acid residues. As such, it may be desirable to produce a fragment of an immunogen to serve as a target antigen, or, alternatively, to synthesize a target antigen by chemical or recombinant DNA methods. In some instances, however, an immunogen may, in intact form, serve as a target antigen.

[0048] Based on the foregoing considerations, a target antigen may be prepared, and then tested for its ability to bind to heat shock protein. In some instances, binding of target antigen to a particular heat shock protein may be facilitated by the presence of at least one other protein, which may be a heat shock protein.

[0049] For example, binding of target antigen to a heat shock protein may be evaluated by labeling the target antigen with a detectable label, such as a radioactive, fluorescent, enzymatic or pigmented label, combining the target antigen with heat shock protein under conditions which would be expected to permit binding to occur, and then isolating the heat shock protein while removing any unbound target antigen, and determining whether any labeled target antigen had adhered to the heat shock protein. As a specific example, and not by way of limitation, the ability of a target antigen to bind to BiP heat shock protein may be evaluated by combining 2 &mgr;g BiP with up to about 1150 pmole of radioactively labeled target antigen in buffer containing 50 mM Tris HCl (pH 7.5), 200 mM NaCl, and 1 mM Na2EDTA, in a final volume of 50 &mgr;l, for 30 minutes at 37 degrees Centigrade. Unbound target antigen may then be removed from bound BiP-target antigen by centrifugation at 100 g by desalting through a 1 ml Sephadex-G column for 2 minutes. Penefsky, J. Biol. Chem. 252:2891 (1977). To prevent binding to the resin, columns may first be treated with 100 &mgr;l of bovine serum albumin in the same buffer and centrifuged as above. Bound target antigen may then be quantitated by liquid scintillation counting. See Flynn et al., Science 245:385-390 (1989).

[0050] Because ATP hydrolysis drives the release of peptides from many known heat shock proteins, the amount of ATPase activity may often be used to quantitate the amount of target antigen binding to heat shock protein. An example of how such an assay may be performed is set forth in Flynn et al., Science 245:385-390 (1989).

[0051] If a particular immunogen or a fragment thereof does not satisfactorily bind to a heat shock protein, then that immunogen or fragment may be linked to another compound so as to create a heat shock protein-binding domain thereby constructing a hybrid antigen. The heat shock protein-binding domain is selected so that the hybrid peptide will bind in vitro to a heat shock protein such as BiP, hsp70, gp96, or hsp90, alone or in combination with accessory heat shock proteins such as hsp40, or hsp60. Peptides which fulfill this criterion may be identified by panning libraries of antigens known to bind well to one or more heat shock proteins as described in Blond-Elguindi et al., Cell 75:717-728 (1993): 6 Leu Phe Trp Pro Phe Glu Trp Ile; (SEQ ID NO:153) Asp Gly Val Gly Ser Phe Ile Gly; (SEQ ID NO:154) Glu Ser Leu Trp Asn Pro Gln Gly; (SEQ ID NO:155) Leu His Phe Asp Val Leu Trp Arg; (SEQ ID NO:156) Cys His Leu Lys Met Val Pro Trp; (SEQ ID NO:157) Asn Ser Val Leu Val Cys Glu Leu; (SEQ ID NO:158) Asp Arg Gly His Ser Thr Tyr Ser; (SEQ ID NO:159) Asp Val Trp Gly Trp Val Thr Trp; (SEQ ID NO:160) Ile Gln Phe Arg Val Glu Leu Phe; (SEQ ID NO:161) Leu Trp Leu Glu Leu Ser Leu Ser; (SEQ ID NO:162) Val Gly Ile Cys Ala Leu Gly Phe; (SEQ ID NO:163) Pro Tyr Pro Ser Gly Leu Asp Ser; (SEQ ID NO:164) Phe Trp Gly Val Leu Pro Tyr Pro; (SEQ ID NO:165) Phe Thr His Gly Ile Ser Leu Tyr; (SEQ ID NO:166) Asn His Ser Phe Gly Gly Ser Thr; (SEQ ID NO:167) Val Asp Tyr Val Tyr Phe His His; (SEQ ID NO:168) Phe Leu Asp Ile Ile Gly Tyr Gly; (SEQ ID NO:169) Trp Asp Asp Leu Leu His Gly Arg; (SEQ ID NO:170) Leu Arg Leu Leu Gly Thr Leu Asn; (SEQ ID NO:171) Phe Glu Gln His Asn Gln Glu Pro; (SEQ ID NO:172) Phe Val Gly Thr Val Thr Trp Ser; (SEQ ID NO:173) Leu Trp Ala Leu Thr Tyr Arg Gly; (SEQ ID NO:174) Ser Trp Gly Ser Asn Gly Gly Phe; (SEQ ID NO:175) Asp Met Trp Arg Arg Ala Val Gln; (SEQ ID NO:176) Cys Arg Val Ile Tyr His Ala Thr; (SEQ ID NO:177) Met Val Val Ala Arg Cys Gly His; (SEQ ID NO:178) His Met Trp Ile Asn Trp Val Gln; (SEQ ID NO:179) Cys Ala Gly Arg Cys Phe Gly Tyr; (SEQ ID NO:180) Cys Thr His Val Leu Ala Tyr Ser; (SEQ ID NO:181) Ser Trp Met Pro Trp Leu Thr Met; (SEQ ID NO:182) Leu Glu Trp Cys Ile Trp Arg Tyr; (SEQ ID NO:183) Cys Leu Ala Cys Ile Ile His Ser; (SEQ ID NO:184) Phe Trp Phe Pro Trp Asp Arg Ser; (SEQ ID NO:185) Trp Arg Thr Gly Val Phe His Gly; (SEQ ID NO:186) Met His Leu Arg Val Ala Asp Arg; (SEQ ID NO:187) Ala Leu Asp Leu Tyr Leu Tyr Val; (SEQ ID NO:188) Phe Phe Trp Phe Thr Leu Lys Glu; (SEQ ID NO:189) Leu Ser Phe Ala Gly Trp Gly Val; (SEQ ID NO:190) Met Met Met Leu Gly Ary Ala Pro; (SEQ ID NO:i9l) Trp Ser Phe Tyr Thr Trp Leu Asn; (SEQ ID NO:192) Phe Val Trp Met Arg Trp Ile Asp; (SEQ ID NO:193) Met Gln Val Asn Thr Pro Asp Asn; (SEQ ID NO:194) Phe Trp Gly Trp Leu Ile Pro Trp; (SEQ ID NQ:195) Trp Gly Trp Val Trp Trp Asp; (SEQ ID NO:196) Trp Ile Phe Pro Trp Ile Gln Leu; (SEQ ID NO:197) Trp Met Phe Asn Trp Pro Trp Tyr; (SEQ ID NO:198) Met Asn Met Ile Val Leu Asp Lys; (SEQ ID NO:199) Phe Trp Gly Trp Pro Gly Trp Ser; (SEQ ID NO:200) Trp Leu Ile Arg Val Gly Thr Ala; (SEQ ID NO:201) Gly Leu Leu Thr His Leu Ile Trp; (SEQ ID NO:202) Leu Trp Trp Leu Asn Val His Gly; (SEQ ID NO:203) Trp Trp Trp Ile Asn Asp Glu Ser; (SEQ ID NO:204) Ala Asn Pro Ser Leu Ala Thr Tyr; (SEQ ID NO:205) Trp Leu Gln Gly Trp Trp Gly Trp; (SEQ ID NO:206) Met Met Pro Val Thr Ser Phe Arg; (SEQ ID NQ:207) Gly Trp Met Asp Trp Trp Tyr Tyr; (SEQ ID NO:208) Leu Ala Ser Met Arg Asn Ser Met; (SEQ ID NO:209) Asp Leu Met Arg Trp Leu Gly Leu; (SEQ ID NO:210) Tyr Phe Tyr Ala Trp Trp Leu Asp; (SEQ ID NO:211) Leu Gly His Leu Trp Thr Gln Val; (SEQ ID NO:212) Leu Trp Trp Arg Asp Val Met Ala; (SEQ ID NO:213) Phe Ile Trp Trp Ala Pro Leu Ala; (SEQ ID NO:214) Gly Ser Val Gly Gly Gly Val Val; (SEQ ID NO:215) Asp Ser His Asp Asp Trp Arg Met; (SEQ ID NO:216) Phe Trp Arg Phe Asp Tyr Tyr Phe; (SEQ ID NO:217) Trp Thr Trp Trp Glu Trp Leu Ala; (SEQ ID NO:218) Trp Leu Trp Asp Trp Ile Val Val; (SEQ ID NO:219) Gly Trp Thr Trp Phe Phe Asp Met; (SEQ ID NO:220) Ala Trp Trp Gln His Phe Ile Val; (SEQ ID NO:221) Leu Trp Trp Asp Ile Ile Thr Gly; (SEQ ID NO:222) Phe Thr Tyr Gly Ser Arg Trp Leu; (SEQ ID NO:223) Phe Ser Leu Trp Pro Leu Ala Trp; (SEQ ID NO:224) Gly Ile Ile Leu Gly Tyr Asn Val; (SEQ ID NO:225) Ser Trp Met Thr Trp Ile Glu His; (SEQ ID NO:226) Gly Trp Trp Val Thr Trp Pro Trp; (SEQ ID NO:227) Val Val Ser Pro Trp Trp Leu Gly; (SEQ ID NQ:228) Asn Val Leu Ser Arg Gly Phe Ser; (SEQ ID NO:229) Ser Phe Glu Ser Leu Gly Gly Leu; (SEQ ID NO:230) Ile Thr Lys Gly Ser Ser Phe Pro; (SEQ ID NO:231) Leu Asp Trp Ala Arg Lys Leu Arg; (SEQ ID NO:232) Thr Ala Trp Asn Leu Leu Gly Tyr; (SEQ ID NO:233) Phe Gly Gln Gly Ile Lys His Val; (SEQ ID NO:234) Asp Val Val Trp Gln Arg Leu Leu; (SEQ ID NO:235) Tyr Val Asp Arg Phe Ile Gly Trp; (SEQ ID NO:236) Lys Met Ala Arg Pro Glu Gly Asn; (SEQ ID NO:237) Leu Gly Arg Trp Gly His Glu Ser; (SEQ ID NO:238) Ser Ile Trp Ser Leu Leu Val Leu; (SEQ ID NO:239) Val Trp Leu Asp Leu Leu Leu Ser; (SEQ ID NO:240) Tyr Leu Asp Thr Ser Leu Phe Gly; (SEQ ID NO:241) Thr Trp Trp Pro Ser Ile Thr Trp; (SEQ ID NO:242) Tyr Gly Leu Trp Trp Phe Pro Trp; (SEQ ID NO:243) Phe Ser Pro Ala Asp Thr Arg Tyr; (SEQ ID NO:244) Cys Asn Arg Leu Gln Ile Asp Cys; (SEQ ID NO:245) Ser Leu Val Ala Ala Arg Asn Leu; (SEQ ID NO:246) Phe Thr Ile His Asn Val Ala Val; (SEQ ID NO:247) Met Gly Pro Leu Gly Pro Leu Leu; (SEQ ID NO:248) Arg Gln Leu Ser Glu Leu Phe Val; (SEQ ID NO:249) Arg Val Val Cys Gln Ala Leu Leu; (SEQ ID NO:250) Trp Pro His Leu Trp Trp Leu Asp; (SEQ ID NO:251) Trp Met Asp Trp Val Trp His Thr; (SEQ ID NO:252) Trp Trp Gly Tyr Leu Ile Cys Gln; (SEQ ID NO:253) Phe Arg Gly Leu Ser Glu Gly Pro; (SEQ ID NO:254) Ser Trp Phe Asp Trp Leu Val Ala; (SEQ ID NO:255) Val Val Met Trp Tyr Ser Val Asp; (SEQ ID NO:256) Trp Gly Trp Ser Leu Ala Thr; (SEQ ID NO:257) Leu Gly Trp Phe Asp Arg Phe Phe; (SEQ ID NO:258) Ala Trp Trp Trp Pro Thr Tyr Val; (SEQ ID NO:259) Gly Phe Leu Ser Ser Trp Phe Leu; (SEQ ID NO:260) Gly Val Ile Asn Cys Ala Gly Thr; (SEQ ID NO:261) Val Cys Ala Arg Ala Ala His Leu; (SEQ ID NO:262) Gly Asn Ser Tyr Gly Asp Gly Gly; (SEQ ID NO:263) Gly Phe Leu Ser Ser Trp Phe Leu; (SEQ ID NO:264) Phe Asp Gln Pro Gly Arg Phe Leu; (SEQ ID NO:265) Arg Ser His Ala Thr Gly Val Val; (SEQ ID NO:266) Gly Tyr Trp Ala Met Met Ser Trp; (SEQ ID NO:267) Cys His Ser Met Trp Asp Gly Leu; (SEQ ID NO:268) Phe Ile Trp Arg Gly Trp Pro His; (SEQ ID NO:269) Leu Ser Phe Leu Gly Gly Arg Leu; (SEQ ID NO:270) Phe Ser Gly Val Arg Gln Pro Asn; (SEQ ID NO:271) Trp Gly Trp Met Pro Phe Tyr Tyr; (SEQ ID NO:272) Phe Thr Arg Pro Ala Val Val Asp; (SEQ ID NO:273) Asp Leu Trp Thr Trp Leu Gly Leu; (SEQ ID NO:274) Cys Asp Thr Ala Ala Val Ala Asp; (SEQ ID NO:275) Trp Trp Val Lys His His Met Leu; (SEQ ID NO:276) Ile Ala Phe Leu Arg Asp Asn Arg; (SEQ ID NO:277) Leu Ala Arg Pro Asp His Tyr Ser; (SEQ ID NO:278) Met Glu Ser Lys Arg Trp Thr Val; (SEQ ID NO:279) Met Ile Leu Lys Gly Tyr Ser Arg; (SEQ ID NO:280) Ala Pro Ser Asp Tyr Asp Glu Ser; (SEQ ID NO:281) His Trp Leu Arg Ser Lys Arg Thr; (SEQ ID NO:282) Gly Ala Arg Val Trp Asn Tyr Gln; (SEQ ID NO:283) Leu Ser Asn Trp Asn Met Arg Leu; (SEQ ID NO:284) Cys Gly Ala Ala Gln Gln Gly Met; (SEQ ID NO:285) Gly Ser Ser Met Val Val Gln Arg. (SEQ ID NO:286)

[0052] Using this technique, Blond-Elguindi have concluded that the heat shock protein BiP recognizes polypeptides that contain a heptameric region having the sequence

Hy(Trp/X)HyXHyXHy

[0053] where Hy represents a hydrophobic amino acid residue (SEQ ID NO:29), particularly tryptophan, leucine or phenylalanine (SEQ ID NO:30), and X is any amino acid. High affinity heat-shock protein-binding sequences incorporating this motif include: 7 His Trp Asp Phe Ala Trp Pro Trp; and (SEQ ID NO:1) Phe Trp Gly Leu Trp Pro Trp Glu. (SEQ ID NO:4)

[0054] Other heat shock protein binding motifs have also been identified. For example, Auger et al., Nature Medicine 2:306-310 (1996) have identified two pentapeptide binding motifs 8 Gln Lys Arg Ala Ala; and (SEQ ID NO:5) Arg Arg Arg Ala Ala (SEQ ID NO:6)

[0055] in HLA-DR types associated with rheumatoid arthritis which bind to heat shock proteins. Heat shock protein binding motifs have also been identified as consisting of seven to fifteen residue long peptides which are enriched in hydrophobic amino acids. 9 Lys Arg Gln Ile Tyr Thr Asp Leu Glu Met Asn Arg Leu Gly Lys; (SEQ ID NO:287) Leu Ser Ser Leu Phe Arg Pro Lys Arg Arg Pro Ile Tyr Lys Ser; (SEQ ID NO:288) Lys Leu Ile Gly Val Leu Ser Ser Leu Phe Arg Pro Lys; (SEQ ID NO:289) Arg Arg Pro Ile Tyr Lys Ser Asp Val Gly Met Ala His Phe Arg; (SEQ ID NO:290) Cys Lys Ile Gln Ser Thr Pro Val Lys Gln Ser; (SEQ ID NO:291) Glu Gly Met Ile Asp Gly Trp Tyr Gly Phe Arg His Gln Asn Cys; (SEQ ID NO:292) Val Gly Ile Asp Leu Gly Thr Thr Tyr Ser Cys; (SEQ ID NO:293) Ser Asn Gly Ser Leu Gln Cys Arg Ile Cys (SEQ ID NO:294) (Flynn et al., Science 245:385-390 (1989)), Gly Lys Trp Val Tyr Ile; (SEQ ID NO:295) Ala Lys Arg Glu Thr Lys; (SEQ ID NO:296) Lys Trp Val His Leu Phe; (SEQ ID NO:297) Arg Leu Val Leu Val Leu; (SEQ ID NO:298) Trp Lys Trp Gly Ile Tyr; (SEQ ID NO:299) Ser Ser His Ala Ser Ala; (SEQ ID NO:300) Trp Gly Pro Trp Ser Phe; (SEQ ID NO:301) Ala Ile Pro Gly Lys Val; (SEQ ID NO:302) Arg Val His Asp Pro Ala; (SEQ ID NO:303) Arg Ser Val Ser Ser Phe; (SEQ ID NO:304) Leu Gly Thr Arg Lys Gly; (SEQ ID NO:305) Lys Asp Pro Leu Phe Asn; (SEQ ID NO:306) Leu Ser Gln His Thr Asn; (SEQ ID NO:307) Asn Arg Leu Leu Leu Thr; (SEQ ID NO:308) Tyr Pro Leu Trp Val Ile; (SEQ ID NO:309) Leu Leu Ile Ile Asp Arg; (SEQ ID NO:310) Arg Val Ile Ser Leu Gln; (SEQ ID NO:311) Glu Val Ser Arg Glu Asp; (SEQ ID NO:312) Ser Ile Leu Arg Ser Thr; (SEQ ID NO:313) Pro Gly Leu Val Trp Leu; (SEQ ID NO:314) Val Lys Lys Leu Tyr Ile; (SEQ ID NO:315) Asn Asn Arg Leu Leu Asp; (SEQ ID NO:316) Ser Lys Gly Arg Trp Gly; (SEQ ID NO:317) Ile Arg Pro Ser Gly Ile; (SEQ ID NO:318) Ala Ser Leu Cys Pro Thr; (SEQ ID NO:319) Asp Val Pro Gly Leu Arg; (SEQ ID NO:320) Arg His Arg Glu Val Gln; (SEQ ID NO:321) Leu Ala Arg Lys Arg Ser; (SEQ ID NO:322) Ser Val Leu Asp His Val; (SEQ ID NO:323) Asn Leu Leu Arg Arg Ala; (SEQ ID NO:324) Ser Gly Ile Ser Ala Trp; (SEQ ID NO:325) Phe Tyr Pro Trp Val Arg; (SEQ ID NO:326) Lys Leu Phe Leu Pro Leu; (SEQ ID NO:327) Thr Pro Thr Leu Ser Asp; (SEQ ID NO:328) Thr His Ser Leu Ile Leu; (SEQ ID NO:329) Leu Leu Leu Leu Ser Arg; (SEQ ID NO:330) Leu Leu Arg Val Arg Ser; (SEQ ID NO:331) Glu Arg Arg Ser Arg Gly; (SEQ ID NO:332) Arg Met Leu Gln Leu Ala; (SEQ ID NO:333) Arg Gly Trp Ala Asn Ser; (SEQ ID NO:334) Arg Pro Phe Tyr Ser Tyr; (SEQ ID NO:335) Ser Ser Ser Trp Asn Ala; (SEQ ID NO:336) Leu Gly His Leu Glu Glu; (SEQ ID NO:337) Ser Ala Val Thr Asn Thr; (SEQ ID NO:338) Leu Arg Arg Ala Ser Leu; (SEQ ID NO:339) Leu Arg Arg Trp Ser Leu; (SEQ ID NO:340) Lys Trp Val His Leu Phe; (SEQ ID NO:341) Asn Arg Leu Leu Leu Thr; (SEQ ID NO:342) Ala Arg Leu Leu Leu Thr; (SEQ ID NO:343) Asn Ala Leu Leu Leu Thr; (SEQ ID NO:344) Asn Arg Leu Ala Leu Thr; (SEQ ID NO:345) Asn Leu Leu Arg Leu Thr; (SEQ ID NO:346) Asn Arg Leu Trp Leu Thr; (SEQ ID NO:347) Asn Arg Leu Leu Leu Ala; and (SEQ ID NO:348) Met Gln Glu Arg Ile Thr Leu Lys Asp Tyr Ala Met (SEQ ID NO:349) (Gragerov et al., J. Molec. Biol. 235:848-854 (1994)).

[0056] The hybrid antigen of the invention incorporates one immunogenic domain and one heat shock protein-binding domain, optionally separated by a short peptide linker. The hybrid peptide of the invention may be synthesized using chemical peptide synthesis methods or it can be synthesized by expression of a nucleic acid construct containing linked sequences encoding the antigenic and heat shock protein binding domains. One suitable technique utilizes initial separate PCR amplification reactions to produce separate DNA segments encoding the two domains, each with a linker segment attached to one end, followed by fusion of the two amplified products in a further PCR step. This technique is referred to as linker tailing. Suitable restriction sites may also be engineered into regions of interest, after which restriction digestion and ligation is used to produce the desired hybrid peptide-encoding sequence.

[0057] Methods of Administration

[0058] The heat shock protein/target antigen combinations of the invention may be administered to a subject using either a protein-based or nucleic acid vaccine, so as to produce, in the subject, an amount of heat shock protein/target antigen complex which is effective in inducing a therapeutic immune response in the subject.

[0059] The subject may be a human or nonhuman subject.

[0060] The term “therapeutic immune response,” as used herein, refers to an increase in humoral and/or cellular immunity, as measured by standard techniques, which is directed toward the target antigen. Preferably, but not by way of limitation, the induced level of humoral immunity directed toward target antigen is at least four-fold, and preferably at least 16-fold greater than the levels of the humoral immunity directed toward target antigen prior to the administration of the compositions of this invention to the subject. The immune response may also be measured qualitatively, by means of a suitable in vitro or in vivo assay, wherein an arrest in progression or a remission of neoplastic or infectious disease in the subject is considered to indicate the induction of a therapeutic immune response.

[0061] Specific amounts of heat shock protein/target antigen administered may depend on numerous factors including the immunogenicity of the particular vaccine composition, the immunocompetence of the subject, the size of the subject and the route of administration. Determining a suitable amount of any given composition for administration is a matter of routine screening.

[0062] In specific nonlimiting embodiments of the invention, it may be desirable to include more than one species of heat shock protein, and/or more than one target antigen, in order to optimize the immune response. Such an approach may be particularly advantageous in the treatment of cancer or in the treatment of infections characterized by the rapid development of mutations that result in evasion of the immune response.

[0063] In other specific nonlimiting embodiments of the invention, in order to promote binding among members of each heat shock protein/target antigen pair, the ratio of heat shock protein to target antigen may preferably be 1:2 to 1:200. Higher relative levels of antigen are suitable to enhance binding to the heat shock protein.

[0064] According to still further specific but nonlimiting embodiments of the invention, the target antigen is not chemically cross-linked to the heat shock protein.

[0065] Compositions comprising target antigen/heat shock protein as set forth above are referred to herein as “vaccines.” The term vaccine is used to indicate that the compositions of the invention may be used to induce a therapeutic immune response.

[0066] A vaccine composition comprising one or more heat shock proteins and one or more target antigens in accordance with the invention may be administered cutaneously, subcutaneously, intravenously, intramuscularly, parenterally, intrapulmonarily, intravaginally, intrarectally, nasally or topically. The vaccine composition may be delivered by injection, particle bombardment, orally or by aerosol.

[0067] Incubation of heat shock proteins in solution with the target antigen is sufficient to achieve loading of the antigen onto the heat shock protein in most cases. It may be desirable in some cases, however, to add agents which can assist in the loading of the antigen.

[0068] Incubation with heating of the heat shock protein with the target antigen will in general lead to loading of the antigen onto the heat shock protein. In some cases, however, it may be desirable to add additional agents to assist in the loading. For example, hsp40 can facilitate loading of peptides onto hsp70. Minami et al., J. Biol. Chem. 271:19617-19624 (1996). Denaturants such as guanidinium HCl or urea can be employed to partially and reversibly destabilize the heat shock protein to make the peptide binding pocket more accessible to the antigen.

[0069] Vaccine compositions in accordance with the invention may further include various additional materials, such as a pharmaceutically acceptable carrier. Suitable carriers include any of the standard pharmaceutically accepted carriers, such as phosphate buffered saline solution, water, emulsions such as an oil/water emulsion or a triglyceride emulsion, various types of wetting agents, tablets, coated tablets and capsules. An example of an acceptable triglyceride emulsion useful in intravenous and intraperitoneal administration of the compounds is the triglyceride emulsion commercially known as Intralipid®. Typically such carriers contain excipients such as starch, milk, sugar, certain types of clay, gelatin, stearic acid, talc, vegetable fats or oils, gums, glycols, or other known excipients. Such carriers may also include flavor and color additives or other ingredients.

[0070] The vaccine composition of the invention may also include suitable diluents, preservatives, solubilizers, emulsifiers, adjuvants and/or carriers. Such compositions may be in the form of liquid or lyophilized or otherwise dried formulations and may include diluents of various buffer content (e.g., Tris-HCl, acetate, phosphate), pH and ionic strength, additives such as albumin or gelatin to prevent absorption to surfaces, detergents (e,g., Tween 20, Tween 80, Pluronic F68, bile acid salts), solubilizing agents (e.g. glycerol, polyethylene glycerol), anti-oxidants (e.g., ascorbic acid, sodium metabisulfite), preservatives (e.g., Thimerosal, benzyl alcohol, parabens), bulking substances or tonicity modifiers (e.g., lactose, mannitol), covalent attachment of polymers such as polyethylene glycol to the protein, complexing with metal ions, or incorporation of the material into or onto particulate preparations of polymeric compounds such as polylactic acid, polyglycolic acid, hydrogels, etc. or onto liposomes, microemulsions, micelles, unilamellar or multilamellar vesicles, erythrocyte ghosts, or spheroplasts. Such compositions will influence the physical state, solubility, stability, rate of in vivo release, and rate of in vivo clearance. The choice of compositions will depend on the physical and chemical properties of the vaccine. For example, a product derived from a membrane-bound form of a protein may require a formulation containing detergent. Controlled or sustained release compositions include formulation in lipophilic depots (e.g. fatty acids, waxes, oils). Also comprehended by the invention are particulate compositions coated with polymers (e.g. poloxamers or poloxamines) and coupled to antibodies directed against tissue-specific receptors, ligands or antigens or coupled to ligands of tissue-specific receptors. Other embodiments of the compositions of the invention incorporate particulate forms protective coatings, protease inhibitors or permeation enhancers for various routes of administration, including intramuscular, parenteral, pulmonary, nasal and oral.

[0071] As an alternative to direct administration of the heat shock protein and target antigen, one or more polynucleotide constructs may be administered which encode heat shock protein and target antigen in expressible form. The expressible polynucleotide constructs are introduced into cells in the subject using ex vivo or in vivo methods. Suitable methods include injection directly into tissue and tumors, transfecting using liposomes (Fraley et al., Nature 370:111-117 (1980)), receptor-mediated endocytosis (Zatloukal et al., Ann. NY Acad. Sci. 660:136-153 (1992)), particle bombardment-mediated gene transfer (Eisenbraun et al., DNA & Cell Biol. 12:792-797 (1993)) and transfection using peptide presenting bacteriophage (Barry et al, Nature Medicine 2:299-305 (1996)). The polynucleotide vaccine may also be introduced into suitable cells in vitro which are then introduced into the subject.

[0072] To construct an expressible polynucleotide, a region encoding the heat shock protein and/or target antigen is prepared as discussed above and inserted into a mammalian expression vector operatively linked to a suitable promoter such as the SV40 promoter, the cytomegalovirus (CMV) promoter or the Rous sarcoma virus (RSV) promoter. The resulting construct may then be used as a vaccine for genetic immunization. The nucleic acid polymer(s) could also be cloned into a viral vector. Suitable vectors include but are not limited to retroviral vectors, adenovirus vectors, vaccinia virus vectors, pox virus vectors and adenovirus-associated vectors. Specific vectors which are suitable for use in the present invention are pcDNA3 (InVitrogen), plasmid AH5 (which contains the SV40 origin and the adenovirus major late promoter), pRC/CMV (InVitrogen), pCMU II (Paabo et al., EMBO J. 5:1921-1927 (1986)), pZip-Neo SV (Cepko et al., Cell 37:1053-1062 (1984)) and pSR&agr; (DNAX, Palo Alto, Calif.).

EXAMPLE 1

Preparation of Hybrid Peptides

[0073] Hybrid peptides containing a BiP-binding domain (His-Trp-Asp-Phe-Ala-Trp-Pro-Trp; SEQ ID NO:1) and an OVA antigenic domain (Ser-Ile-Ile-Asn-Phe-Glu-Lys-Leu; SEQ ID NO:7) separated by a tripeptide linker (gly-ser-gly) were synthesized. Peptides were produced in both orientations, OVA-BiP-binding domain and BiP-binding domain-OVA as follows: Ser-Ile-Ile-Asn-Phe-Glu-Lys-Leu-Gly-Ser-Gly-His-Trp-Asp-Phe-Ala-Trp-Pro-Trp (SEQ ID NO:8) and His-Trp-Asp-Phe-Ala-Trp-Pro-Trp-Gly-Ser-Gly-Ser-Ile-Ile-Asn-Phe-Glu-Lys-Leu (SEQ ID NO:9).

EXAMPLE 2

[0074] Purified mouse cytosolic hsp70 was prepared from E. coli DH5&agr; cells transformed with pMS236 encoding mouse cytosolic hsp70. The cells were grown to an optical density (600 nm) of 0.6 at 37° C., and expression was induced by the addition of IPTG to a final concentration of 1 mM. Cells were harvested by centrifugation 2 to 5 hours post induction and the pellets were resuspended to 20 ml with Buffer A (20 mM Hepes pH 7.0, 25 mM KCl, 1 mM DTT, 10 mM (NH4)2SO4, 1 mM PMSF). The cells were lysed by passing three times through a French press. The lysate was cleared by a low speed spin, followed by centrifugation at 100,000 X G for 30 minutes. The cleared lysate was applied to a Pharmacia XK26 column packed with 100 ml DEAE Sephacel and equilibrated with Buffer A at a flow rate of 0.6 cm/min. The column was washed to stable baseline with Buffer A and eluted with Buffer A adjusted to 175 mM KCl. The eluate was applied to a 25 ml ATP-agarose column (Sigma A2767), washed to baseline with Buffer A, and eluted with Buffer A containing 1 mM MgATP preadjusted to pH 7.0. EDTA was added to the eluate to a final concentration of 2 mM. The eluate which contained essentially pure hsp70 was precipitated by addition of (NH4)2SO4 to 80% saturation. The precipitate was resuspended in Buffer A containing 1 mM MgCl2 and dialyzed against the same buffer with multiple changes. The purified hsp70 was frozen in small aliquots at −70° C.

EXAMPLE 3

[0075] The purified hsp70 was combined with the synthesized peptides and used for immunization. To form the hsp70/peptide mixtures, approximately 15 &mgr;g (21.5 &mgr;M) hsp70 was combined with 5 &mgr;g of Ova-peptide (0.5 mM; SEQ ID NO:7) or 10 &mgr;g (0.5 mM) hybrid peptide (SEQ ID NOS:8 and 9) were mixed on ice to a final volume of 10 &mgr;l in Buffer B (final concentration: 20 mM Hepes pH 7.0, 150 mM KCl, 10 mM (NH4)2SO4, 2 mM MgCl2 and 2 mM MGADP, pH 7.0). The mixtures were incubated for 30 minutes at 37° C. and then used for in vivo immunizations.

[0076] C57BL/6 mice were immunized intradermally once a week for a total of two weeks with 10 &mgr;l of one of the mixtures described above or with a mixture of TITERMAX® (Vaxcell, Norcross, Ga.) and Ova-peptide (5 &mgr;g). One week after the second immunization, spleen cells were removed and mononuclear cells (6-8×107) were cultured with 3×106 &ggr;-irradiated (3000 rad) stimulator cells. The stimulator cells were obtained from naive mice that had been sensitized in vitro with Ova-peptide (10 mg/ml) for 30 minutes at room temperature, washed and irradiated at 3000 rads.

[0077] Cytotoxicity of spleen cells from vaccinated mice were assayed on Ova-peptide pulsed EL4 cells in an 18-hour chromium release assay. CTL were generated by culturing in vivo immunized spleen cells for 5 days at a concentration of 106 cells/ml in RPMI medium, 10% FCS, penicillin, streptomycin and 2 mM L-glutamine, together with 3×106 &ggr;-irradiated (3,000 rad) stimulator cells/ml. Target cells were prepared by culturing cells for 1 hour in the presence of 250 &mgr;Ci of 51Cr sodium chromate (DuPont, Boston, Mass.) in Tris-phosphate buffer, pH 7.4 at 37° C. for 60 minutes. After washing, 104 51Cr-labeled target cells were mixed with effector lymphocytes to yield several different effector/target (E/T) ratios and were incubated for 18 hours. Supernatants were harvested and the radioactivity was measured in a gamma counter. Percent specific lysis was calculated as: 100×[(cpm release by CTL−cpm spontaneous release)/(cpm maximal release−cpm spontaneous release)]. Maximal response was determined by addition of 1% Triton X-100. Spontaneous release of all target in the absence of effector cells was less than 25% of the maximal release.

[0078] As shown in FIG. 1, the combination of Hsp70 and the hybrid peptide of either orientation (hsp70+BiP-OVA or hsp70+OVA-BiP) evoked a higher immune response as measured by specific lysis of cells than the hsp70 or TITERMAX® adjuvant plus Ova-peptide alone.

EXAMPLE 4

[0079] The assay of Example 3 was repeated using CTL cell lines which had been maintained by stimulation with irradiated stimulators, syngeneic splenic feeder cells plus T cell growth factors for a period of two weeks. As shown in FIG. 2, the combination of hsp70 and the hybrid peptide of either orientation (hsp70+BiP-OVA or hsp70+OVA-BiP) evoked a higher immune response as measured by specific lysis of cells than the hsp70 or TITERMAX® adjuvant plus Ova-peptide alone. Thus, the immune response elicited by the hybrid peptides persisted through additional passages and can be maintained over a period of time.

EXAMPLE 5

[0080] The experiment of Example 2 was repeated for the combinations of hsp70 plus BiP-OVA and TITERMAX® plus OVA peptide using only a single immunization one week before removal of the spleen cells. As shown in FIG. 3, the single immunization with either composition was effective in eliciting a cellular immune response.

EXAMPLE 6

[0081] The assay of Example 3 was repeated using mixtures of TITERMAX® with Ova-peptide or the hybrid peptides of Example 1. As shown in FIG. 4, no significant difference was observed between the Ova-peptide and hybrid peptides demonstrating the specificity of the effect when hybrid peptides are used in association with the heat shock protein.

EXAMPLE 7

[0082] FIGS. 5A and 5B show the results when the procedure of Example 3 was repeated immunizing the mice with hsp70 alone, Ova-peptide alone, OVA-BiP alone or BiP-OVA alone. As shown, the results in all cases were the same when the cells were pulsed with Ova-peptide (FIG. 5A) and when they had not been pulsed. (FIG. 5B). This demonstrates that the response is the result of the combination of the mixture of the antigen (Ova-peptide or hybrid peptide) and the heat shock protein and not to any of the components individually.

EXAMPLE 8

[0083] 14C-labeled OVA-BiP was prepared by alkylation of OVA-BiP with 14C-formaldehyde. 0.9 mg of OVA-BIP in 300 &mgr;l 10% DMSO/water was added to 175 &mgr;l of 14C-formaldehyde (62 &mgr;Ci) and immediately 50 &mgr;l of freshly made up 200 mM NaCNBH3 was added. The reaction was mixed and left at 25° C. for 3 hours. The labeled peptide was repurified by reverse phase HPLC on a C-4 column in a 15 minute 0-100% acetonitrile (0.1% TFA) gradient.

[0084] The ability of the OVA-BiP peptide to bind to heat shock proteins was measured by incubating 100 &mgr;M (5 &mgr;g) 14C-labeled OVA-BiP with 50 &mgr;g of BiP (prepared as in Example 11), hsp70 (as prepared in Example 2) or gp96 (prepared as in Example 10) in a final volume of 20 &mgr;l of buffer (50 mM Mops, pH 7.2, 200 mM NaCl, 5 mM MgAcetate) at 37° C. for 30 minutes. The samples were then spun down (5 minutes in a microfuge) and loaded onto a 17 cm long Sephacryl S-300 column equilibrated in binding buffer (50 mM Mops, pH 7.2, 200 mM NaCl, 5 mM MgAcetate) and fractions were collected dropwise. 50 &mgr;l of each ˜225 &mgr;l fraction was counted in scintillation liquid. 10 &mgr;l of each fraction was also run on a 12% SDS-PAGE reducing gel. FIG. 6 shows the radioactivity detected in each fraction eluted from the column, together with the center of the peak of heat shock protein as determined by SDS-PAGE. As shown, a significant amount of radioactivity elutes with BiP and hsp70, thus providing evidence that the hybrid peptide binds to these two heat shock proteins. The result for gp96 is unclear because the peak at fraction 11 (which may represent an aggregation phenomenon) and the gp96 peak (fraction 14) elute close together on the column used.

EXAMPLE 9

[0085] To prepare 125I-OVA-BiP, 250 &mgr;Ci of monoiodinated Bolton-Hunter reagent was transferred into a stoppered vial and the solvent in which it was dissolved was evaporated with a gentle stream of argon gas. To the dried reagent 222 &mgr;l of 4.5 mg/ml OVA-BiP in 100 mM NaBO3, pH 8.9, 10% DMSO was added. The reaction was mixed and incubated at 25° C. for 45 minutes and continued at 4° C. for a further hour. The labeled peptide was repurified by reverse phase HPLC on a C-4 column in a 20 minute, 0-100% acetonitrile (0.1% TFA) gradient.

[0086] The iodinated OVA-BIP was combined with BiP in substantially the same manner as the heat shock proteins in Example 7, except that since the iodinated peptide was at a very low concentration, 1 &mgr;l (approx. 32 ng) of labeled peptide was mixed with 5 &mgr;g of unlabeled peptide and this was incubated with 50 &mgr;g of BiP in 20 &mgr;l of binding buffer. To observe ATP-mediated peptide release, ATP was added to a final concentration of 2 mM after the 30 minute incubation and incubated for a further 5 minutes prior to spinning. These samples were run on the same column as above, but equilibrated in binding buffer supplemented with 2 mM ATP.

[0087] FIG. 7 shows the elution profile for a mixture of the 125I-OVA-BiP and BiP in the presence and absence of 2 mM ATP. As shown, addition of ATP causes the release of the hybrid peptide from the BiP. This is consistent with the observation that ATP mediates release of bound proteins or polypeptides from heat shock proteins.

EXAMPLE 10

[0088] Hybrid peptides for use in a vaccine in accordance with the invention against human papilloma virus are prepared using a peptide synthesizer as follows: 10 E7 (Type 11)-BiP (SEQ ID NO:10) Leu-Leu-Leu-Gly-Thr-Leu-Asn-Ile-Val-gly-ser-gly- His-Trp-Asp-Phe-Ala-Trp-Pro-Trp DiP-E7 (Type 11) (SEQ ID NO:11) His-Trp-Asp-Phe-Ala-Trp-Pro-Trp-gly-ser-gly-Leu- Leu-Leu-Gly-Thr-Leu-Asn-Ile-Val E7 (Type 16)-BiP (SEQ ID NO:12) Leu-Leu-Met-Gly-Thr-Leu-Gly-Ile-Val-gly-Ser-gly- His-Trp-Asp-Phe-Ala-Trp-Pro-Trp BiP-E7 (Type 16) (SEQ ID NO:13) His-Trp-Asp-Phe-Ala-Trp-Pro-Trp-gly-Ser-gly-Leu- Leu-Met-Gly-Thr-Leu-Gly-Ile--Val E7 (Type 18)-BiP (SEQ ID NO:14) Thr-Leu-Gln-Asp-Ile-Val-Leu-His-Leu-gly-Ser-gly- His-Trp-Asp-Phe-Ala-Trp-Pro-Trp BiP-E7 (Type 18) (SEQ ID NO:15) His-Trp-Asp-Phe-Ala-Trp-Pro-Trp-gly-ser-gly-Thr- Leu-Gln-Asp-Ile-Val-Leu-His-Leu E7.1 (Type 6b)-BiP (SEQ ID NO:16) Gly-Leu-His-Cys-Tyr-Glu-Gln-Leu-Val-gly-ser-gly- His-Trp-Asp-Phe-Ala-Trp-Pro-Trp BiP-E7.1 (Type 6b) (SEQ ID NO:17) His-Trp-Asp-Phe-Ala-Trp-Prc-Trp-gly-ser-gly-Gly- Leu-His-Cys-Tyr-Glu-Gln-Leu-Val E7.2 (Type 6b)-BiP (SEQ ID NO:18) Pro-Leu-Lys-Gln-His-Phe-Gln-Ile-Val-gly-ser-gly- His-Trp-Asp-Phe-Ala-Trp-Pro-Trp Bip-E7.2 (Type 6b) (SEQ ID NO:19) His-Trp-Asp-Phe-Ala-Trp-Pro-Trp-gly-ser-gly-Pro- Leu-Lys-Gln-His-Phe-Gln-Ile-Val

[0089] Hybrid polypeptides for use in vaccines against human papilloma virus or other types of proteins from other viruses, bacteria etc. can be developed by searching their sequences for MHC class I restricted peptide epitopes containing the HLA-A2 peptide binding motif.

EXAMPLE 11

[0090] Preparation of Recombinant gp96

[0091] The DNA sequence encoding a wild-type or KDEL deleted gp96 polypeptide was subcloned from pRc/CMV into the vector pET11a (Novagen). Thus upon expression, mature gp96 could be purified from cell lysates.

[0092] Vector Construction

[0093] PCR amplification of the sequence encoding gp96 (from pRc/CMV) was performed with the following primers. The 5′ primer for both wild-type and KDEL-deleted gp96 was complementary to the DNA sequence encoding the amino terminal end of the mature form of gp96 and an Nde I restriction site (CATATC) the ATC of which forms the initiator codon: 5′ AGA TAT ACA TAT GGA TGA TGA AGT CGA CGT GG 3′ (SEQ ID NO:20)

[0094] The 3′ primers were complementary to the DNA sequence of gp96 encoding the carboxyl terminal end of the protein, with the nucleotides encoding the KDEL sequence removed in the primer for the KDEL-deleted variant. Both primers contain a BamH I restriction site (GGATCC) followed by a STOP codon as shown:

Claims

1. A composition for inducing a therapeutic immune response in a subject, comprising:

(a) a target antigen; and

(b) a heat shock protein;

wherein the target antigen and the heat shock protein are combined in vitro under conditions wherein binding of target antigen to heat shock protein occurs to form a target antigen/heat shock protein complex;

wherein the administration of the target antigen/heat shock protein complex to the subject induces an immune response comprising a cytotoxic cellular component.

2. The composition of claim 1, wherein the heat shock protein is hsp70.

3. The composition of claim 1, wherein the heat shock protein is gp96.

4. The composition of claim 1, wherein the heat shock protein is hsp40.

5. The composition of claim 1, wherein the heat shock protein is BiP.

6. The composition of any of claims 1 to 5, wherein the target antigen is a hybrid antigen.

7. The composition according to claim 6 wherein the hybrid antigen comprises an antigenic domain derived from a first source and a binding domain which binds to a heat shock protein from a second source different from the first source.

8. The composition of claim 7, wherein the binding domain comprises at least a heptameric region having the sequence

HyXHyXHyXHy

where Hy represents a hydrophobic amino acid residue and X is any amino acid.

9. The composition of claim 7, wherein the binding domain comprises a region having the sequence His Trp Asp Phe Ala Trp Pro Trp [Seq. ID No. 1].

10. A composition for inducing a therapeutic immune response in a subject, comprising:

(a) a nucleic acid molecule comprising a region encoding a target antigen operably linked to a promoter element; and

(b) a nucleic acid molecule comprising a region encoding a heat shock protein operably linked to a promoter element;

wherein the introduction of the nucleic acids of (a) and (b) into a cell result in the binding of target antigen to heat shock protein.

11. The composition of claim 10, wherein the nucleic acid molecules of (a) and (b) are comprised in the same vector.

12. The composition of claim 10 or 11, wherein the heat shock protein is hsp70.

13. The composition of claim 10 or 11, wherein the heat shock protein is gp96.

14. The composition of claim 10 or 11, wherein the heat shock protein is hsp40.

15. The composition of claim 10 or 11, wherein the heat shock protein is BiP.

16. The composition of any of claims 10 to 15, wherein the target antigen is a hybrid antigen.

17. The composition according to claim 16, wherein the hybrid antigen comprises an antigenic domain derived from a first source and a binding domain which binds to a heat shock protein from a second source different from the first source.

18. The composition of claim 17, wherein the binding domain comprises at least a heptameric region having the sequence

HyXHyXHyXHy

where Hy represents a hydrophobic amino acid residue and X is any amino acid.

19. The composition of claim 17, wherein the binding domain comprises a region having the sequence His Trp Asp Phe Ala Trp Pro Trp [Seq. ID No. 1].

20. A method of inducing an immune response in a subject in need of such treatment, comprising administering to the subject a therapeutically effective amount of the composition of any of claims 1 to 19.

21. A hybrid peptide comprising:

(a) an antigenic domain derived from a first source; and

(b) a binding domain which binds to a heat shock protein, said binding domain being derived from a second source different from the first source.

22. The hybrid peptide of claim 21, wherein the antigenic domain is derived from a virus, a parasite, a mycoplasma, a fungus or a bacterium.

23. The hybrid peptide of any of claims 21-22, wherein the antigenic domain elicits an immune response to a neoplastic disease.

24. The hybrid peptide of claim 23, wherein the neoplastic disease is selected from among a sarcoma, a lymphoma, a carcinoma, a leukemia and a melanoma.

25. The hybrid peptide of any of claims 21 to 24, wherein the binding domain comprises at least a heptameric region having the sequence

HyXHyXHyXHy

where Hy represents a hydrophobic amino acid residue and X is any amino acid.

26. The hybrid peptide of any of claim 21 to 24, wherein the binding domain comprises a region having the sequence

His Trp Asp Phe Ala Trp Pro Trp [Seq. ID No. 1].

27. The hybrid peptide of any of claims 21 to 24, wherein the binding domain comprises at least a pentapeptide region selected from among

14 Gln Lys Arg Ala Ala, and [Seq. ID No.5] Arg Arg Arg Ala Ala. [Seq. ID No.6]

28. A polynucleotide construct comprising:

(a) a region encoding a hybrid peptide comprising an antigenic domain derived from a first source; and a binding domain which binds to a heat shock protein said binding domain being derived from a second source different from the first source;

(b) a promoter effective to promote expression on the hybrid peptide in mammalian cells.

29. The polynucleotide construct of claim 28, wherein the antigenic domain is derived from a virus, a parasite, a mycoplasma, a fungus or a bacterium.

30. The polynucleotide construct of claim 28, wherein the antigenic domain elicits an immune response to a neoplastic disease.

31. The polynucleotide construct of claim 30, wherein the neoplastic disease is selected from among a sarcoma, a lymphoma, a carcinoma, a leukemia and a melanoma.

32. The polynucleotide construct of any of claims 28 to 31, wherein the binding domain comprises at least a heptameric region having the sequence

HyXHyXHyXHy

where Hy represents a hydrophobic amino acid residue and X is any amino acid.

33. The polynucleotide construct of any of claims 28 to 31, wherein the binding domain comprises a region having the sequence

His Trp Asp Phe Ala Trp Pro Trp [Seq. ID No. 1].

34. The polynucleotide construct of any of claims 28 to 31, wherein the binding domain comprises at least a pentapeptide region selected from among

15 Gln Lys Arg Ala Ala, and [Seq. ID No.5] Arg Arg Arg Ala Ala. [Seq. ID No.6]