Specific Immune of a Syngeneic Response Against Tumor-Associated Simian Virus 40-lnduced Sarcoma in Antigens Mice 1

ABSTRACT-Immune response against syngeneic simian virus 40 (SV40)-lnduced tumor-associated antigens In (BALB/c x C57BL/6)F, female mice was detected by In vivo tumor challenge and an In vivo tumor cell neutralization test (Wlnn) and by the In vitro S1Cr-release cytotoxicity assay. All mice Immunized with as low as 1X10 ' SV4G-transformed cells were protected against the growth of SV40-lnduced tumor, beginning at 3 days and up to 90 days after a single Immunization. In the tumor cell neutralization test, spleen cells (T-cells) from mice Immunized with 1X10 ' SV40-transformed cells prevented tumor growth at 10 days and up to 90 days after Immunization. The specificity of the Immune response was shown by the use of unrelated syngeneic tumor cells In crisscross experiments. In contrast to these In vivo assays, spleen cells from mice Immunized with a minimum of 20X10 ' SV40-transformed cells were cytotoxic In vitro against th