Development of Enzyme-Linked Immunosorbent Assay for Detection of Antibody against Caprine Arthritis Encephalitis Virus Using Recombinant Protein of the Precursor of the Major Core Protein, p55gag

An indirect enzyme-linked immunosorbent assay (ELISA) by using recombinant Caprine arthritis encephalitis virus (CAEV) p55gag antigen (rELISA), an indirect ELISA by using whole CAEV (wELISA), and Western blot analysis by using the recombinant p55gag antigen (rWB) were developed for detection of CAEV-specific antibodies in goats. Seven hundred and forty-five sera from goats were tested by rELISA, wELISA, rWB, and agar gel immunodiffusion test (AGID), and the results were compared with those of WB analysis by using the whole CAEV antigen (wWB). The AGID test and rWB had similar sensitivities of 93.3% (95% confidence interval [CI]) and 93% (95% CI), respectively, and similar specificities of 96.0% (95% CI) and 96.3% (95% CI), respectively, compared with wWB. The wELISA had substantially lower sensitivity (80.4%) and specificity (78.0%) compared with wWB, and rELISA had the lowest sensitivity (78.2%) and specificity (61.1%) compared with wWB. The lack of adequate sensitivity and specificity for rELISA and wELISA suggests that these assays need considerable modification. However, the results for rWB show that this assay has excellent agreement with wWB and that it can be used as a confirmatory test for the presence of anti-CAEV antibodies.