Surface Antigen on Hamster Cells Transformed in vitro by two Strains of Rous Sarcoma Virus

Hamster cells transformed in vitro by the Bryan (RB 12) and the Schmidt-Ruppin (RS 2) strains of Rous sarcoma virus were studied for the presence, at their surface, of the virus-induced surface antigen (VISA). VISA expression, as detected by an in vitro colony-inhibition test, was higher in the RS 2 cells than in the RB 12 cells. Cytotoxic antisera directed against the two kinds of cells cross-reacted. Chicken cells infected by a non-transforming virus (RAV-1) did not elicit the appearance of detectable cytotoxic antibodies in hamsters.