title: Human melanoma cells transfected with the B7-2 co-stimulatory molecule induce tumor-specific CD8+ cytotoxic T lymphocytes in vitro.
abstract: Neoplastic cells express tumor-associated antigens, but tumor rejection seldom occurs in vivo. The absence of an effective immune response may be explained by the inability of tumor cells to deliver co-stimulatory signals. Indeed, transfection of either B7-1 or B7-2 co-stimulatory molecules into mouse tumor cells enhances antitumor immune responses. In this study, we stably transfected human melanoma cells with the cDNA encoding the B7-2 molecule to evaluate in vitro: (i) the induction of anti-melanoma cytotoxic T lymphocytes (CTL) by stimulation of CD8+ T cells, purified from healthy donors and a melanoma patient, with B7-2 transfected allogeneic HLA-matched melanoma cells; (ii) the tumor specificity and the HLA restriction of the induced CTL; and (iii) the feasibility to propagate long-term antimelanoma CTL lines. We found that B7-2 transfected, but not untransfected or mock-transfected, melanoma cells activated MHC-class I-restricted, melanoma-specific CD8+ CTL from healthy donors. More importantly, CD8+ tumor-associated lymphocytes, purified from a tumor-invaded lymph node of a melanoma patient and stimulated with B7-2-transfected melanoma cells, acquired a strong reactivity toward the autologous tumor. CTL lines with specific cytolytic activity could be propagated in long-term culture. These results indicate that: (i) the expression of the B7-2 molecule into human melanoma cells makes them immunogenic and able to act as antigen-presenting cells and (ii) purified CD8+ cells, stimulated with B7-2+ allogeneic HLA-matched melanoma cells, preferentially recognize melanoma-specific rather than allogeneic antigens. This study may have clinical implications for passive and/or active immunotherapy in melanoma patients.
authors.affiliation: Laboratory of Tumor Immunology, Scientific Institute H San Raffaele, Milan, Italy.
authors.forename: M A
authors.initials: MA
authors.lastname: Imro
authors.forename: P
authors.initials: P
authors.lastname: Dellabona
authors.forename: S
authors.initials: S
authors.lastname: Manici
authors.forename: S
authors.initials: S
authors.lastname: Heltai
authors.forename: G
authors.initials: G
authors.lastname: Consogno
authors.forename: M
authors.initials: M
authors.lastname: Bellone
authors.forename: C
authors.initials: C
authors.lastname: Rugarli
authors.forename: M P
authors.initials: MP
authors.lastname: Protti
mesh_terms: D000951:Antigens, Neoplasm / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D003601:Cytotoxicity Tests, Immunologic; D005434:Flow Cytometry; D015793:HLA-B7 Antigen / Q000235:genetics* / Q000276:immunology*; D006650:Histocompatibility Testing; D006801:Humans; D007963:Leukocytes, Mononuclear; D008285:Major Histocompatibility Complex / Q000276:immunology; D008545:Melanoma / Q000235:genetics* / Q000276:immunology*; D058950:Melanoma-Specific Antigens; D009363:Neoplasm Proteins / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D000951:Antigens, Neoplasm; D015793:HLA-B7 Antigen; C072011:MAGEA1 protein, human; C489518:Mageb1 protein, mouse; D058950:Melanoma-Specific Antigens; D009363:Neoplasm Proteins