DIFFERENTIAL RECOGNITION OF MURINE TUMOR-ASSOCIATED ONCOFETAL TRANSPLANTATION ANTIGEN AND INDIVIDUALLY SPECIFIC TUMOR-TRANSPLANTATION ANTIGENS BY SYNGENEIC CLONED BALB C AND RFM MOUSE T-CELLS/

We have previously demonstrated in several species that sarcomas, lymp homas, and carcinomas express a common Ag that cross-reacts with midge station fetal cells. We also produced a mAb to that protein and charac terized it as a 44-kDa glycoprotein. The cross-reactive immunity induc ed by immunization with tumor or fetal cells expressing the oncofetal Ag (OFA) can be adoptively transferred with cell populations containin g T lymphocytes. The experiments discussed within this paper describe the establishment and characterization of two types of T lymphocytes i nduced by immunization with syngeneic tumor cells in two mouse strains . We find that five of the eight cloned T cells derived from spleens o f BALB/c mice that had been immunized with MCA1315 fibrosarcoma cells are specific for an Ag shared by MCA1315 and MCA1321 cells. The other three clones are specific for an Ag present on MCA1315 but not on MCA1 321. Also, none of the clones were reactive with the BALB/c plasmacyto ma MOPC-315, which does not express OFA. We also find that 75% of the RFM T cell clones from spleens of RFM mice immune to the RFM thymoma 5 T show a 5T-specific proliferative response. One of the four clones, h owever, responds to both 4T and 5T RFM thymoma cells. The BALB/c and R FM cross-reactive clones specifically respond to purified 44-kDa OFA d erived from MCA1315 fibrosarcoma cells in the presence of syngeneic ir radiated spleen cells and IL-2. All of the clones from both strains of mice, be they tumor-specific transplantation Ag specific or OFA speci fic, are CD4+, CD3+, alphabeta TCR+ T cells that secrete IFN-gamma on Ag stimulation.