title: Differential capacity of chaperone-rich lysates in cross-presenting human endogenous and exogenous melanoma differentiation antigens.
abstract: The goal of immune-based tumor therapies is the activation of immune cells reactive against a broad spectrum of tumor-expressed antigens. Vaccines based on chaperone proteins appear promising as these proteins naturally exist as complexes with various protein fragments including those derived from tumor-associated antigens. Multi-chaperone systems are expected to have highest polyvalency as different chaperones can carry distinct sets of antigenic fragments. A free-solution isoelectric focusing (FS-IEF) technique was established to generate chaperone-rich cell lysates (CRCL). Results from murine systems support the contention that CRCL induce superior anti-tumor responses than single chaperone vaccines. We established an in vitro model for human melanoma to evaluate the capacity of CRCL to transfer endogenously expressed tumor antigens to the cross-presentation pathway of dendritic cells (DC) for antigen-specific T cell stimulation. CRCL prepared from human melanoma lines contained the four major chaperone proteins Hsp/Hsc70, Hsp90, Grp94/gp96 and calreticulin. The chaperones within the melanoma cell-derived CRCL were functionally active in that they enhanced cross-presentation of exogenous peptides mixed into the CRCL preparation. Superior activity was observed for Hsp70-rich CRCL obtained from heat-stressed melanoma cells. Despite the presence of active chaperones, melanoma cell-derived CRCL failed to transfer endogenously expressed melanoma-associated antigens to DC for cross-presentation and cytotoxic T cell (CTL) recognition, even after increasing intracellular protein levels of tumor antigen or chaperones. These findings reveal limitations of the CRCL approach regarding cross-presentation of endogenously expressed melanoma-associated antigens. Yet, CRCL may be utilized as vehicles to enhance the delivery of exogenous antigens for DC-mediated cross-presentation and T cell stimulation.
authors.affiliation: Clinical Cooperation Group Hyperthermia, Helmholtz Zentrum München-German Research Center for Environmental Health, 81377 Munich, Germany. elke.bleifuss@gmx.de
authors.forename: Elke
authors.initials: E
authors.lastname: Bleifuss
authors.forename: Henriette
authors.initials: H
authors.lastname: Bendz
authors.forename: Birgit
authors.initials: B
authors.lastname: Sirch
authors.forename: Sylvia
authors.initials: S
authors.lastname: Thompson
authors.forename: Anna
authors.initials: A
authors.lastname: Brandl
authors.forename: Valeria
authors.initials: V
authors.lastname: Milani
authors.forename: Michael W
authors.initials: MW
authors.lastname: Graner
authors.forename: Ingo
authors.initials: I
authors.lastname: Drexler
authors.forename: Maria
authors.initials: M
authors.lastname: Kuppner
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Katsanis
authors.forename: Elfriede
authors.initials: E
authors.lastname: Noessner
authors.forename: Rolf-Dieter
authors.initials: RD
authors.lastname: Issels
mesh_terms: D000818:Animals; D017951:Antigen Presentation / Q000276:immunology; D000943:Antigens, Differentiation / Q000276:immunology*; D000951:Antigens, Neoplasm / Q000276:immunology*; D015415:Biomarkers / Q000378:metabolism; D019496:Cancer Vaccines / Q000276:immunology; D045744:Cell Line, Tumor; D045142:Cross-Priming / Q000276:immunology*; D003713:Dendritic Cells / Q000276:immunology; D006358:Hot Temperature; D006801:Humans; D018664:Interleukin-12 / Q000276:immunology; D008545:Melanoma / Q000276:immunology* / Q000473:pathology; D018832:Molecular Chaperones / Q000276:immunology*; D014442:Monophenol Monooxygenase / Q000378:metabolism; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology
chemical_list: D000943:Antigens, Differentiation; D000951:Antigens, Neoplasm; D015415:Biomarkers; D019496:Cancer Vaccines; D018832:Molecular Chaperones; D018664:Interleukin-12; D014442:Monophenol Monooxygenase