Characterization of the T antigen induced by SV40

3 or 4 antigenic SV40 specific components were established in hamster tumors induced by SV40-transformed cells, using linear sucrose gradient centrifugation and Sephadex G-200 column chromatography. The lightest component, approximate molecular weight 21,000, did not inhibit the nuclear staining of SV40-transformed cells in the fluorescent antibody inhibition test.