THE DEVELOPMENT OF AN ENZYME-LINKED-IMMUN OSORBENT-ASSAY FOR THE DETECTION OF ANTIBODIES AGAINST TYPE-5 BOVINE HERPES-VIRUS (BHV-5) IN SHEEP SERA

The indirect enzyme-linked immunosorbent assay (ELISA) was first devel oped for the detection of antibodies against BHV-5 in sheep sera. Inve stigations of various antigen (Ag) preparations revealed that BHV mate rial which had been purified across a sucrose gradient using sonificat ion followed by ultracentrifugation gave satisfactory results during a pplication in ELISA. Optimal coating of the solid phase was achieved w ith Ag adsorption at 4-degrees-C overnight with 5 mug of virus materia l/ml in a carbonate-bicarbonate-buffer, pH 9,7. The background reactio ns were significantly reduced by blocking the free bonding points with 1 % gelafusal after Ag adsorption. As the extinction values of all th e sera investigated which a dilution of 1:50 or more below 0,2, the di fference threshhold between positive and negative sera was set at 0,2. A total of 490 sera from various stocks of sheep were investigated wi th regard to the occurence of antibodies against BHV-5 in ELISA. The g rowing rate of infection with herpesviruses among ruminants and the su bsequent economic loss have resulted in the increased significance in the last few years of bovine herpesvirus (BHV) disease.