Identification of conserved epitopes on a hog cholera virus protein

Eight monoclonal antibodies directed against the hog cholera virus (HCV) strain Alfort/187 and displaying broad cross-reactivity with other HCV strains were characterized. An enzyme immunoassay on fixed monolayers of porcine or bovine cells infected with 14 different strains and isolates of HCV and 12 bovine viral diarrhea viruses (BVDV), respectively, showed that all antibodies reacted with HCV only. Seven antibodies recognized all HCV tested, thus indicating that they were directed against conserved epitopes. All antibodies neutralized the homologous strain and different patterns of the other HCV tested. Radioimmunoprecipitation analysis showed that the monoclonal antibodies were directed against a doublet of 56-60 kDa, presumably representing the major envelope glycoprotein of HCV. The results of reciprocal antibody blocking assays allowed the mapping of two distinct conserved antigenic domains on this protein.