Differences in virus-induced polypeptides in cells infected by cytopathic and noncytopathic biotypes of bovine virus diarrhea-mucosal disease virus.

Two biotypes of bovine viral diarrhea-mucosal disease virus are present in nature: one that induces cytopathology in infected bovine cells and the other that infects cells without overt cytopathology. Infections with both types of virus yield similar amounts of infectious progeny virus. Field and laboratory isolates of both biotypes of bovine viral diarrhea (BVD) virus were analyzed by radioimmunoprecipitation and polyacrylamide gel electrophoresis of infected cell extracts. The noncytopathic biotype BVD (NCB-BVD) virus isolates can be differentiated from cytopathic biotype BVD (CB-BVD) isolates on the basis of peculiar polypeptide profiles they induce in the infected cell. The most abundant polypeptide in CB-BVD infected cells is the 80K polypeptide. NCB-BVD virus-infected cells lack the 80K polypeptide and induce a predominant 118K polypeptide. D-[2-3H]Mannose labeling of cells infected with NCB-BVD indicated that at least three polypeptides are N-glycosylated: 75K, 56K-58K, and 48K. In addition the sizes and ratios of the glycoproteins induced by all virus isolates showed a marked variation. We present evidence indicating that there is remarkable heterogeneity among the field viral isolates of BVD and this methodology is of potential value for molecular epidemiology studies.