Antigenic variation in the bovine ephemeral fever virus glycoprotein

Antigenic variation in the bovine ephemeral fever virus glycoprotein was demonstrated using monoclonal antibodies and comparing a particular passage level of the BB7721 strain with (1) other Australian isolates of BEF virus, (2) the Beijing 1 strain of BEF virus, isolated in China and (3) batches of the BB7721 strain with different passage histories. Escape mutants of BEF virus were selected from cell culture and suckling mice, by growing virus in the presence of neutralising monoclonal antibodies. Escape frequencies were calculated for 14 monoclonal antibodies and an epitope map constructed of antigenic sites on the BEF viral glycoprotein which induce the production of neutralising antibodies