Differential ability of tumor-unique and cross-reactive antigen(s) on two murine hepatoma cell lines to induce Lyt-1+2- T cells responsible for in vivo protective immunity

The role of the tumor-unique determinant(s) on two syngeneic murine hepatoma cells in inducing in vivo protective immunity was investigated in comparison with that of the tumor-cross-reactive determinant(s). Induction of vaccinia-reactive helper T cells in C3H/He mice by intraperitoneal (i.p.) inoculation of viable vaccinia virus and then immunization with vaccinia-infected syngeneic MH134 or MH129 tumor cells resulted in the production of potent anti-MH134 or -MH129 antibody as well as the generation of in vivo protective immunity. Neither antibody reacted with other syngeneic plasmacytoma or fibrosarcoma cells, but both cross-reacted appreciably with the other hepatoma cells as well reacted strongly as with the tumor cells used for immunization. The absorptions of anti-MH134 and -MH129 antisera with the respective hepatoma cells abolished their reactivities with both the corresponding hepatoma cells and the other hepatoma cells. In contrast, the absorption of these antisera with the other tumor cells resulted in loss of their cross-reactivities with the other hepatoma cells, but not loss of their specific reactivity to the respective hepatoma cells. Although in these hematoma systems, the above-mentioned immunization protocol resulted in in vivo induction of protective immunity and generation of antibodies, in vivo immunity as observed by Winn assays was mediated by Lyt-1+2- T cells and was specific for each type of hepatoma cells. These results indicate that these two types of hepatoma cells bear two kinds of antigenic determinants, one kind unique to each hepatoma and the other kind cross-reactive with the other hepatoma cells.(ABSTRACT TRUNCATED AT 250 WORDS)