Identification of virus-specific polypeptides by monoclonal antibodies against serotype 2 Marek's disease virus

A total of 41 antibody-secreting hybridoma cells against the HPRS24 strain of Marek's disease virus (MDV) type 2 (MDV2) have been isolated. Of these monoclonal antibodies (MAbs), 24 were found by immunofluorescence tests to react specifically with MDV2-infected cells, but not MDV type 1 (MDV1)- or herpesvirus of turkeys (HVT)-infected cells, while eight reacted with MDV1- or MDV2-infected cells and nine with MDV1-, MDV2- or HVT-infected cells. By using these MAbs, seven classes of MDV type-specific or cross-reactive polypeptides were characterized by immunoprecipitation followed by SDS-PAGE. Among them, a 28K/32K glycoprotein differed from the previously identified gA and gB. The 28K/32K glycoprotein was found on the surface of MDV2-infected cells and in the cytoplasm by an immunofluorescence test with MAbs. In addition, a cross-reactive polypeptide of 25K/29K was also detected in MDV1-infected cells with MAbs reactive with the 28K/32K glycoprotein of MDV2.