Selection of antigenic variants in maedi-visna virus infection.

In order to analyse the pattern of sequence variation in maedi-visna virus (MVV) in persistently infected sheep and to answer the question of whether antigenic variants are selected in a long-term MVV infection, an 87 bp variable region in the env gene of ten antigenic variants and 24 non-variants was sequenced. Nine of the ten antigenic variants had mutations in this region, comprising 24 point mutations and a deletion of 3 bp. Twenty-three of the point mutations (96%) were non-synonymous.