Serological definition of individually distinct surface antigens in mouse mammary carcinomas

Abstract

For serological analysis of surface antigens in mouse mammary carcinoma, 13 cultured lines were established from spontaneous and MTV-induced tumors of 6 different mouse strains. Six of the cultured lines, SHK of C 3H, Ta 3Ha and TA 3St of A, S 2Y of ABY, SBfnHB and SBfnHD of C 3H foster-nursed CBA origin were highly sensitive to polyvalent anti-MTV and anti-MTV gp 52 sera, and this was invariably correlated with the presence of MTVgp 52 and p27 antigens in the cell extracts. All cultured lines were sensitive to anti-MuLVgp 70 serum, and several lines also contained considerable amounts of MuLVp 30 antigen in the cell extracts. By immunization with cultured or in vivo passaged tumor cells, 5 of 10 lines tested, SHF of C 3H, S 3W of ASW, S 2Y of ABY; and SBfnHA and SBfnHB of C 3H foster-nursed CBA origin could raise antisera containing complement-dependent cytotoxic antibodies to them in syngeneic or semisyngeneic mice. All the antisera contained antibodies against multiple specificities, although they were not cross-reactive to normal cells of C 3H and BALB/c fetal origin, and normal spleen cells of C 3H, DBA/ 2 and C 57BL origin. One specificity of anti-S 3W, anti-S 2Y, anti-SBfnHA and anti-SBfnHB sera is cross-reactive for several leukemias and sarcomas, and the second specificity of anti-S 3W, anti-SBfnHA and anti-SBfnHB sera is cross-reactive for polyoma virus-induced tumors. These antisera, after intensive absorption with leukemias and polyoma virus-induced tumor cells, and anti-SHF serum, demonstrated the third specificity which is cross-reactive for other mammary carcinomas and a C 3H sarcoma. Further absorption with mammary carcinomas showed that anti-S 3W and anti-SBfnHA sera have a fourth specificity, which had an absolute restriction to the immunizing tumor cells. These results suggest that individually distinct surface antigens were detectable in mouse mammary carcinomas by serological assays after absorption with cross-reactive cell lines.