Application of Western Blot to detect bovine leukaemia virus infections using recombinant p24 antigen

The article describes the Western Blot assay used in detecting antibodies f or bovine leukaemia virus (BLV) p24 antigen (WB/p24). The test employs a ba cterially synthesised p24 antigen which represents a fusion protein consist ing of thioredoxin and the mature viral p24. This assay is compared with tw o other techniques for detecting either total (ELISA/BLV) and anti-p24 and gp51-related antibodies (Western Blot/BLV) in sheep experimentally infected as well as cattle naturally infected with BLV. WB/p24 was a good technique for detecting antibodies in both sheep and cattle infected with BLV. In WB /BLV the well-known immunodominant of gp51 failed as a reliable indicator f or the serological status of 50% of the sera from infected cattle. There wa s also a lack of reaction of gp51 antigen with some sera from experimentall y infected sheep. Antibody titres evaluated by ELISA/BLV and WB/p24 correla ted well to each other in sera from both sheep and cattle infected with BLV . WB/p24 was more sensitive than the three commercially available ELISA kit s. In a selected set of 109 sera from cattle naturally infected with BLV th e WB/p24 and gp51-related ELISA tests detected antibodies in 58 and 55 seru m samples, respectively. These results indicate that Western Blot assay wit h recombinant p24 antigens can be considered to be an efficient confirmator y test for BLV serodiagnosis.