Abstract:

[Objective] The aims of this study were to prepare the polyclonal antibody against capsid （CA） protein of a maedi-visna virus （MVV） strain isolated from naturally infected sheep and to assess its specificity. [Method] A set of specific primers was designed according to the CA gene sequence of MVV Inner Mongolia strain, and the CA gene was subsequently amplified by PCR assay for constructing a recombinant plasmid. The MVV CA recombinant protein was prokaryotically expressed and purified. The rabbit-derived polyclonal antibody against MVV CA recombinant protein was prepared, and its titer and specificity were determined and identified by using indirect ELISA assay as well as Western blot and immunohistochemical analyses. [Result] The prokaryotic expression system of MVV CA recombinant protein was successfully constructed, and the target protein was about 27 kDa after purification. The titer of the prepared polyclonal antibody was determined as 1∶8 192 by indirect ELISA assay. Western blot analysis showed that there was a specific band with a size of 25 kDa in lung tissues of sheep infected with MVV. Immunohistochemical analysis demonstrated that there were obvious brownish yellow positive signals in cytoplasm of macrophages in lung tissues of sheep infected with MVV. [Conclusion] Polyclonal antibody prepared with soluble recombinant MVV CA protein had good specificity, which might serve as a candidate antibody in MVV serological diagnosis technology.

Key words: sheep, maedi-visna virus, capsid protein, prokaryotic expression, polyclonal antibody