Molecular association between transplantation antigens and cell surface antigen in adenovirus-transformed cell line.

Abstract

A rat cell line (A2T2C4), transformed with adenovirus type 2, elicited cytotoxic T [thymus derived] lymphocytes in syngeneic rats. Cytotoxicity was abolished by a rabbit antiserum directed against the major histocompatibility (AgB) antigens and by a syngeneic rat antiserum raised against the virus-transformed cell line. The syngeneic antiserum immunoprecipitated surface proteins with apparent MW of 45,000, 19,000, 17,000 and 12,000 from the A2T2C4 cells but it displayed no reactivity against primary rat fibroblasts and spleen cells. The rabbit antiserum against AgB antigens precipitated a 19,000-dalton component from the A2T2C4 cells, which was not observed in primary rat fibroblasts. Sequential immunoprecipitation revealed identity between the major polypeptides recognized by the 2 antisera. Because the rabbit anti-AgB antigen serum was specific for the transplantation antigen subunits and because the syngeneic rat antiserum against the A2T2C4 cells failed to react with the AgB antigens in normal cells, the 19,000-dalton component is apparently coprecipitated with the AgB antigens. Antisera directed specifically against .beta.2-microglobulin and the alloantigenic AgB antigen subunit also coprecipitated the 19,000-dalton component. The AgB antigen subunits apparently form a ternary complex with a virus-coded protein on the surface of the virus-transformed A2T2C4 cells. This molecular complex may be recognized by the cytolytic T lymphocytes.