Biochemical studies on early cell surface antigen induced by vaccinia and cowpox viruses.

The early cell surface antigen (ECSA) induced by vaccinia or cowpox virus infection was analysed by immunoprecipitation and SDS-polyacrylamide gel electrophoresis (SDS-PAGE), The components with a mol. wt. of about 40 000 (40 K) in vaccinia virus-infected cells and with a mol. wt. of about 43 000 (43 K) in cowpox virus-infected cells were specifically immunoprecipitated with anti-ECSA serum prepared by immunizing rabbits with rabbit kidney cells infected with a conditional lethal mutant. The 40 K and 43 K polypeptides were synthesized even in the presence of cytosine-I-beta-D-arabinofuranosyl-HCl (Ara C) and were detectable even in the cells pulse-labelled between I and 2 h p.i.