title: Anti-tumor activity of class II MHC antigen-restricted cloned autoreactive T cells. I. Destruction of B16 melanoma cells mediated by bystander cytolysis in vitro.
abstract: Two Lyt-1+, L3T4a+ autoreactive T cell clones specific for self-class II major histocompatibility complex (MHC) gene products were established from lymph node cells and spleen cells of C57BL/6J mice, respectively, by different methods. They were stimulated to proliferate in culture in response to I-Ab antigen-bearing syngeneic spleen cells in a class II MHC-restricted manner. This stimulation was inhibited completely by the addition of anti-L3T4a (GK1.5) or anti-I-Ab (3JP) monoclonal antibodies. The autoreactive T cell clones lysed syngeneic I-Ab+ target cells such as lipopolysaccharide (LPS) blasts. They also lysed I-A- bystander cells such as Cloudman and B16 melanoma and lymphoid tumor cells in the presence of I-Ab+ stimulator cells but not I-Ad+ cells. This bystander killing was most likely mediated by soluble factors released from the autoreactive T cells in response to I-Ab antigens, because culture supernatants from activated autoreactive T cells inhibited the proliferation of B16 melanoma cells in vitro and also had significant cytolytic activity. Both lymphotoxin and interferon-gamma were released from activated autoreactive T cells, suggesting that these cytotoxic lymphokines were responsible for autoreactive T cell-mediated cytolysis. The finding that the two clones, established independently and by different methods, show self-class II MHC antigen-restricted cytolysis, and bystander cytolysis suggests that these properties are not restricted to a unique population of autoreactive T cells. These results favor the concept that in vivo, autoreactive T cells may express not only regulatory activity in regard to antibody responses, but also anti-tumor activity via bystander cytolysis.
mesh_terms: D000818:Animals; D002455:Cell Division; D002999:Clone Cells; D003602:Cytotoxicity, Immunologic; D000949:Histocompatibility Antigens Class II / Q000276:immunology; D007111:Immunity, Cellular; D007371:Interferon-gamma / Q000276:immunology; D008213:Lymphocyte Activation; D008222:Lymphokines / Q000276:immunology*; D008233:Lymphotoxin-alpha / Q000276:immunology; D008546:Melanoma, Experimental / Q000276:immunology*; D051379:Mice; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
chemical_list: D000949:Histocompatibility Antigens Class II; D008222:Lymphokines; D008233:Lymphotoxin-alpha; D007371:Interferon-gamma