Immunogenicity of tumor cells modified by trinitrobenzene suflonic acid (TNBS).
The ability of trinitrophenylated tumor cells to stimulate syngeneic antitumor response has been tested in 3 different tumor-host systems: A. Trinitrophenylated and inactivated Moloney induced YAC tumor cells (YAC-TNP) were able to induce the production of cytotoxic antibodies in low responding A/J mice, while inactivated YAC tumor cells (YAC-In) failed to induce such a response. Furthermore, A mice which were injected with YAC-TNP rejected 103 viable YAC tumor cells at a higher frequency than those injected with YAC-In. B. Trinitrophenylated and inactivated Gross virus induced G-35 tumor cells or Monoloney induced LSTRA cells (both syngeneic in BALB/c mice) were as immunogenic as nonmodified inactivated tumor cells. About 50% of the immunized mice survived indefinitely after injection of 103 viable tumors. Fruthermore, spleen cells from mice primed with either modified or nonomodified G-35 cells responded in vitro to G-35 in a mixed leukocyte tumor interaction and generated specific cell-mediated cytotoxic activity to 51Cr-G-35 syngeneic tumors. However, the donors of the primed cells did not produce detectable cytotoxic antibodies to G-35. C. In vitro sensitization of C57B1 spleen cells by trinitrophenylated Mitomycin C treated syngeneic EL-4 generated a stronger cytotoxic response to EL-4 cells than obtained by sensitization with Mitomycin C treated EL-4 cells alone, The superiority of the sensitizing capacity of trinitrophenylated EL-4 was readily demonstrated in conditions which were suboptimal for nonmodified Mitomycin C treated tumor. Both theoretical and practical implications of these results are discussed.