Antigenic differences between the major glycoproteins of bovine herpesvirus type 1.1 and bovine encephalitis herpesvirus type 1.3.

Differences in the antigenic structure of the major glycoproteins, gI, gIII and gIV, of bovine herpesvirus type 1.1 (BHV1.1) and the neurovirulent BHV1.3 were demonstrated with a panel of monoclonal antibodies (MAbs) prepared against the BHV1.1 glycoproteins. Glycoprotein gIII of BHV1.3 was the most dissimilar, reacting with only four of 15 gIII-specific MAbs. Glycoproteins gI and gIV of BHV1.3 reacted with eight of 11 and eight of 12 specific MAbs, respectively. Monospecific bovine antisera to the two viruses supported findings from the MAb analysis in that gI and gIV glycoproteins were cross-recognized, but gIII was not. Virus-neutralizing MAbs reactive to each glycoprotein and which reacted with both viruses also neutralized both viruses. Previously undescribed glycoproteins which were antigenically related to the intact gIII glycoproteins, but of reduced sizes and lacking at least one gIII epitope, were found for both viruses. Tunicamycin inhibition experiments and immunoprecipitation data suggested that these proteins were intracellular degradation products. Comparisons of the peptide footprints of the glycoproteins from the two viruses using protease V8 digestion after immunoprecipitation with cross-reactive MAbs revealed distinctive footprint patterns for the respective glycoproteins.