Abstract
Methods for obtaining antigens for the diagnosis of equine rhinopneumonitis, also known as viral abortion of horses, using enzyme-linked immunosorbent assay were studied. The methods were based on stepwise centrifugation and precipitation with polyethylene glycol. The vaccine strain CB/69 of equine herpesvirus type 1, cultivated in SPEV cell culture, was used as the source material. The infectious titer of the virus was 6.5 lg TCD₅₀/ml. It was found that the most purified antigen was obtained from free virions by stepwise centrifugation followed by purification in a sucrose density gradient. However, this method requires considerable time, material resources, and specialized equipment, and is characterized by a low yield: 400 µl of antigen was obtained from 105 ml of the initial virus-containing suspension. The antigen isolated from the cell-associated viral fraction had a higher yield of 650 µl but contained more cellular impurities. Polyethylene glycol precipitation was technologically simpler and provided a higher antigen yield of 1.5 ml from 125 ml of suspension; however, the resulting preparation was unsuitable for ELISA, despite being effective in the hemagglutination inhibition test. The results indicate that the method for obtaining EHV-1 antigen should be selected depending on the intended diagnostic application. These findings may be used in the development of methodological recommendations for obtaining EHV-1 antigens for the diagnosis of equine rhinopneumonitis.