Expression of the E2 envelope glycoprotein of bovine viral diarrhoea virus(BVDV) elicits virus-type specific neutralising antibodies

A region of genome from the NADL strain of BVDV corresponding to the coding sequence for the E2 glycoprotein has been molecularly cloned using RT-PCR. The viral cDNA sequence was used to construct vaccinia virus recombinants that expressed either the entire E2 coding sequence or fragments of it. The se recombinants were used to immunise mice of three H-2 haplotypes to inves tigate their ability to elicit a neutralising antibody rasponse against BVD V. Sera from mice immunised with the recombinant expressing full length E2 contained high levels of virus neutralising antibodies that in addition to giving neutralisation of the homologous NADL strain were also able to neutr alise the Oregon C24V reference strain. These sera failed to give any neutr alisation of the Osloss reference strain providing evidence for the divisio n of BVDV isolates into at least two distinct E2 serotypes. These results w ere confirmed in gnotobiotic lambs. Expression of E2 fragments revealed the presence of at least two distinct neutralising epitopes, one of which was localised within the carboxy terminal 90 amino acids of the protein. (C) 19 99 Elsevier Science B.V. All rights reserved.