Marek's disease virus serotype-1 antigens A and B and their unglycosylated precursors detected by Western blot analysis of infected cells.

The antigenic profile of cell cultures infected with Marek's disease virus (MDV) was determined by the immunoblotting method using convalescent immune serum obtained from chickens that survived infection with MDV strain GA5. The MDV antigen profile in infected cell lysates could be accurately determined since this method has advantages over the immunoprecipitation method used in other studies. We studied six very virulent MDV isolates and the prototype of serotype 1 MDV, the GA5 strain. Immunoblots of NaDodSO4-polyacrylamide gel electrophoresis (PAGE) performed under reducing conditions revealed a main viral antigen (B) of 120-130 kD, which was present in all cell lysates infected with MDV isolates. Analysis of infected cell proteins by NaDodSO4-PAGE performed under nonreducing conditions, revealed a 205 kD major MDV antigen, which, under reducing conditions, was identical to the 130 kD major antigen. The unglycosylated precursors of the major MDV antigens were elucidated. Two polypeptides of 43 and 45 kD were found to be the unglycosylated precursors of MDV antigen A (the glycosylated form of which appears in 4 distinct bands). The unglycosylated precursors of the MDV major antigen B were found to be three polypeptides of 80, 110, and 125 kD.