IMMUNODOMINANT E2 (GP53) SEQUENCES OF HIGHLY VIRULENT BOVINE VIRAL DIARRHEA GROUP-II VIRUSES INDICATE A CLOSE RESEMBLANCE TO A SUBGROUP OF BORDER DISEASE VIRUSES

The genes for the E2 envelope protein, which elicits virus-neutralizin g antibodies, from members of the newly described group II of bovine v iral diarrhea viruses (BVDVs) were cloned and sequenced. These BVDVs i ncluded a thrombocytopenic strain from the United States, a fetal bovi ne serum contaminant, a strain from Western Canada, and two highly vir ulent strains, causing high mortality rates, from Quebec. The nucleoti de and amino acid sequences of these E2s had only a 60-65% homology wi th group I BVDV E2s but >90% homology with the E2 of a subgroup of she ep border disease viruses. The E2 gene of the NADL strain was expresse d and monospecific antibodies were raised in calves and rabbits. The v irus-neutralizing titers of these antisera were 15- to 80-fold lower f or the heterologous group of BVDVs as compared to those for the homolo gous BVDVs. (C) 1996 Academic Press, Inc.