Isolation of polyoma virus-induced surface antigens in hamster cells: potassium chloride solubilization and differential precipitation.

Surface antigens were extracted in soluble and active form with 3 M KCL from polyoma virus-transformed and embryonic hamster cells. These were tumor-specific transplantation antigens (TSTA), shown by tumor rejection, and a surface (S) antigen, demonstrated by the inhibition of surface fluorescence on living polyoma virus-transformed cells. The extracts were fractionated by salting out with ammonium sulfate. In tumor cell extracts, all TSTA activity and a part of S antigen activity were found in the fraction precipitated with 60% saturation in (NH/)2SO4. Another part of S antigen activity was found in the fraction precipitating at 80% saturation in tumor cell extracts. The precipitate at 60% saturation of embryonic cell extracts also had a part of S antigen activity. Receptor site activity for concanavalin A was also retained after solubilization and was confined to the 40% saturation (NH4)2SO4 precipitate in the case of tumor and embryonic cell extracts.