Heat shock proteins (HSPs) (such as hsp70, hsp90, calreticulin families) are abundant soluble intracellular proteins. They possess powerful immunological properties, that include potentiation of innate and adaptive components of T cell immune response, as well as its down-regulation. The immunological activities of HSPs are dependent upon the interaction of HSPs with antigen presenting cells (APCs). Based on this dependence, the presence of an HSP receptor was envisaged in 1994. Such a receptor, CD91, was structurally identified and characterized and its functional activity demonstrated, in 2000. In this application, we aim to (i) assess other reported HSP receptors and identify new HSP receptors on human dendritic cells (DCs), (ii) define HSP-CD91 interaction in structural terms, (iii) test functional activity of CD91 in vivo in mediating cross-presentation antigens, and (iv) test the adjuvanticity of other CD91 ligands for immunotherapy. Specifically, we propose to study:
Aim 1 : Assessment and identification of HSP receptors on murine and human DCs. (a) Assessment of LOX-1 and other reported HSP receptors with respect to their relative roles vis-a-vis CD91, in cross-presentation of HSP-chaperoned peptides;(b) Generation of monoclonal antibodies to human HSP receptors, characterized by their ability to inhibit cross-presentation of HSP-chaperoned peptides.
Aim 2 : Structural analysis of HSP-CD91 interaction. (a) Definition of the hsp90/gp96/hsp70 domains involved in interaction with CD91, and if necessary, LOX1 ;(b) Definition of the CD91 domain(s) involved in interaction with hsp90 and gp96.
Aim 3 : Role of CD91 in cross-presentation and cross-priming. (a) Test influence of anti-CD91 antibodies on cross-presentation in vitro and on cross-priming in vivo, using HSP peptide complexes or whole cells as immunogens; (b) Test the influence of CD91 ligands alpha2 macroglobulin (alpha2M) and RAP on the same; (c) Test the influence of excess peptide-free HSPs on the same; (d) Construct mice expressing dominant negative forms of CD91 and test priming and cross-priming of T cell responses in such mice.
Aim 4 : Mechanism of immunogenicity of alpha2M and its application to cancer immunotherapy (a) Examine the mechanism of immunogenicity and anti-tumor reactivity of alpha2M-peptide complexes; (b) Test complexes of antigenic peptides with alpha2M in cross-presentation in vitro and for therapy of pre-existing cancers.
|Srivastava, Pramod K (2015) Neoepitopes of Cancers: Looking Back, Looking Ahead. Cancer Immunol Res 3:969-77|
|Li, Changying; Buckwalter, Matthew R; Basu, Sreyashi et al. (2012) Dendritic cells sequester antigenic epitopes for prolonged periods in the absence of antigen-encoding genetic information. Proc Natl Acad Sci U S A 109:17543-8|
|Vatner, Ralph E; Srivastava, Pramod K (2010) The tailless complex polypeptide-1 ring complex of the heat shock protein 60 family facilitates cross-priming of CD8 responses specific for chaperoned peptides. J Immunol 185:6765-73|
|Testori, Alessandro; Richards, Jon; Whitman, Eric et al. (2008) Phase III comparison of vitespen, an autologous tumor-derived heat shock protein gp96 peptide complex vaccine, with physician's choice of treatment for stage IV melanoma: the C-100-21 Study Group. J Clin Oncol 26:955-62|
|Callahan, Margaret K; Garg, Manish; Srivastava, Pramod K (2008) Heat-shock protein 90 associates with N-terminal extended peptides and is required for direct and indirect antigen presentation. Proc Natl Acad Sci U S A 105:1662-7|
|Binder, Robert J; Kelly 3rd, John B; Vatner, Ralph E et al. (2007) Specific immunogenicity of heat shock protein gp96 derives from chaperoned antigenic peptides and not from contaminating proteins. J Immunol 179:7254-61|
|Binder, Robert J; Srivastava, Pramod K (2005) Peptides chaperoned by heat-shock proteins are a necessary and sufficient source of antigen in the cross-priming of CD8+ T cells. Nat Immunol 6:593-9|
|Li, Zihai; Qiao, Yi; Liu, Bei et al. (2005) Combination of imatinib mesylate with autologous leukocyte-derived heat shock protein and chronic myelogenous leukemia. Clin Cancer Res 11:4460-8|
|Binder, Robert J; Srivastava, Pramod K (2004) Essential role of CD91 in re-presentation of gp96-chaperoned peptides. Proc Natl Acad Sci U S A 101:6128-33|
|Makki, Amira; Weidt, Gunnar; Blachere, Nathalie E et al. (2002) Immunization against a dominant tumor antigen abrogates immunogenicity of the tumor. Cancer Immun 2:4|
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