Processing of Glycoprotein gB Related to Neutralization of Marek's Disease Virus and Herpesvirus of Turkeys

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Abstract
The glycoprotein gB related to neutralization of Marek's disease virus (MDV) and herpesvirus of turkeys (HVT) is composed of several glycosylated polypeptides, which were immunoprecipitated with monoclonal antibodies and rabbit antiserum cross‐reactive to MDV‐gB and HVT‐gB, and analyzed by SDS‐polyacrylamide gel electrophoresis. The present pulse‐chase experiments showed that the precursor forms of MDV‐ and HVT‐gB were glycoproteins with molecular weights of 110K to 115K (gp 115/110) and 115K (gp115), respectively. These precursor forms were processed to smaller gB's (gp63 and gp50 for MDV; gp62, gp52, and gp48 for HVT), at least in part by sialylation. The proteins synthesized in the presence of tunicamycin were two polypeptides of 88K and 83K in MDV‐infected cells and a 90K polypeptide in HVT‐infected cells, indicating the presence of unglycosylated precursor forms of MDV‐ and HVT‐gB. Differences between virulent and avirulent MDV's and between HVT's with and without protective activity against Marek's disease were observed in the processed forms of MDV‐ and HVT‐gB, especially at the processing step of sialylation.