Detection of antibodies to ovine lentivirus using recombinant capsid and transmembrane proteins

The coding sequences of the capsid protein p25 and transmembrane protein of Maedi-Visna virus were amplified using polymerase chain reaction and cloned into the plasmid expression vector pRSET-B. Both DNA constructs expressed proteins tagged with polyhistidine. The recombinant proteins were purified using Ni-NTA agarose and used in immunoblot to detect antibodies against Maedi-Visna virus. A total of 260 ovine serum specimens was analysed. The total number of p25-positive sera was 111 (42.7%). Higher sensitivity was achieved with rTM antigen, which detected antibodies in 118 (45.4%) sera. The combination of both recombinant proteins as antigens resulted in higher sensitivity of serological detection compared to whole virus antigen.