title: Specificity of the generation and expression of enhanced anti-plasmacytoma immunity by spleen cells from melphalan-treated MOPC-315 tumor bearers.
abstract: We have shown previously that low-dose melphalan (L-PAM) therapy of mice bearing a large MOPC-315 plasmacytoma enables their hitherto immunosuppressed spleen cells to exert potent anti-MOPC-315 cytotoxicity following in vitro immunization with MOPC-315 tumor cells. Here we show that, following in vitro immunization with MOPC-315 tumor cells, spleen cells from such L-PAM-treated MOPC-315 tumor bearers exhibited enhanced T-cell-mediated cytotoxicity not only against the MOPC-315 tumor, but also against another plasmacytoma (MOPC-104E) possessing surface immunoglobulin (SIg) of a different idiotype than the MOPC-315 cells, as well as against a variant of the MOPC-315 tumor which does not produce nor possess SIg (SIg- MOPC-315). The enhanced cytotoxicity was directed against target antigens which are not expressed on the surface of the syngeneic WEHI 22.1 thymoma or the natural killer-sensitive YAC-1 cells. Plasmacytoma shared antigens, other than immunoglobulins, were able to stimulate spleen cells from L-PAM-cured MOPC-315 tumor bearers to generate in vitro a secondary type anti-plasmacytoma cytotoxic response. L-PAM-cured MOPC-315 tumor bearers exhibited in vivo immunity against SIg- MOPC-315 tumor cells, which was sufficiently triggered by the SIg- cells to bring about the rejection of a challenge of at least 100-fold the minimal lethal tumor dose of the SIg- MOPC-315 cells. Thus, SIg- MOPC-315 tumor cells present among SIg+ tumor cells in the parental MOPC-315 tumor inoculum can be eradicated in the L-PAM-treated MOPC-315 tumor bearers by the immune response to SIg+ tumor cells as well as by the immune response to SIg- tumor cells themselves.
mesh_terms: D000818:Animals; D000918:Antibody Specificity; D000951:Antigens, Neoplasm / Q000008:administration & dosage / Q000276:immunology*; D002460:Cell Line; D003602:Cytotoxicity, Immunologic; D005260:Female; D007121:Immunocompetence; D008212:Lymphocyte Depletion; D008264:Macrophages / Q000276:immunology; D008558:Melphalan / Q000008:administration & dosage / Q000627:therapeutic use*; D051379:Mice; D008807:Mice, Inbred BALB C; D010954:Plasmacytoma / Q000188:drug therapy* / Q000276:immunology; D013154:Spleen / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D013601:T-Lymphocytes / Q000276:immunology; D013945:Thymoma / Q000276:immunology
chemical_list: D000951:Antigens, Neoplasm; D008558:Melphalan