title: Secondary in vitro generation of CTL specific for MM antigen by stimulation with somatic tumor hybrid, but not with parental tumor cells.
abstract: Somatic tumor hybrid cells (L-FM3A#2), obtained by hybridization of MM tumor cells (FM3A/R) with HGPRT-less L cells, could induce CTL directed against MM antigen, a tumor-associated transplantation antigen that is expressed on some ascitic mammary tumor cell lines of C3H/He mice; parental tumor cells (FM3A/R) could not produce such CTL in syngeneic mice. In this study, the mechanisms of the generation of CTL by stimulation with L-FM3A#2 hybrid cells were investigated. In the secondary in vitro stimulation system, L cell component(s) that were introduced into hybrid cells by cell fusion play a role in the induction of CTL, as shown by the fact that stimulation with a mixture of L and FM3A/R cells could induce MM antigen-specific CTL, and that the killer helper effect of L cells could be replaced by cell free culture supernatants obtained from co-cultures of unprimed C3H spleen and L cells. IFN activity, but no IL 2 activity, was detected in the culture supernatants. Both IFN and killer helper activity were lost with pH 2 treatment; furthermore, CTL were generated by stimulation of primed spleen cells with FM3A/R cells in the presence of mouse beta-IFN, but not in its absence. These results suggest that IFN liberated by the helper cells that recognize L cell component(s) on the surfaces of tumor hybrid cells plays an essential role in the generation of CTL specific for MM antigen.
mesh_terms: D000818:Animals; D000951:Antigens, Neoplasm / Q000235:genetics / Q000276:immunology*; D000939:Epitopes; D005260:Female; D006825:Hybridomas / Q000276:immunology*; D007117:Immunization, Secondary; D007370:Interferon Type I / Q000502:physiology; D007376:Interleukin-2 / Q000096:biosynthesis; D007519:Isoantigens / Q000235:genetics / Q000276:immunology*; D007694:Killer Cells, Natural / Q000276:immunology; D007739:L Cells / Q000276:immunology; D008213:Lymphocyte Activation; D008211:Lymphocyte Cooperation; D051379:Mice; D008809:Mice, Inbred C3H; D009368:Neoplasm Transplantation; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*
chemical_list: D000951:Antigens, Neoplasm; D000939:Epitopes; D007370:Interferon Type I; D007376:Interleukin-2; D007519:Isoantigens