Identification of gag Precursor of Equine Infectious Anaemia Virus with Monoclonal Antibodies to the Major Viral Core Protein, p26

Monoclonal antibodies (MAbs) against the major core protein p26 of equine infectious anaemia virus (EIAV) were produced and characterized. Sensitive enzyme-linked immunosorbent assay and Western blot immunoassay were employed to confirm the specificity of these MAbs. Western blot analysis also indicated that MAbs to p26 reacted with another EIAV protein of 55000 apparent M_r (designated here as Pr55^gag) present in density gradient-purified virus preparations. Rabbit antiserum prepared against p26 as well as MAbs to p26 detected Pr55^gag and several other intermediate cleavage products in detergent-soluble lysates of virus-infected cells in Western blot and immunoprecipitation assays. The results suggest that Pr55^gag is the gag polyprotein of EIAV.