Human antibodies recognizing the envelope glycoprotein of the baboon endogenous virus BaEV are of heterophil origin.

Human sera were previously shown to possess antibodies capable of recognizing purified retrovirus envelope glycoproteins. In an extension of earlier studies we investigated sera from various groups of patients for an immune reaction against purified glycoprotein of the baboon endogenous virus BaEV. Reproducible demonstrations of oncovirus-like particles in human teratocarcinomas focused our main interest on sera from patients with testicular tumors. The specificity of the positive immune reaction of sera from these patients against BaEV gp 70 was analyzed in a competition RIAs with haptens and different cell lysates and experiments employing deglycosylated BaEV envelope antigen. From these experiments we conclude that the sera from teratocarcinoma patients contain naturally occurring, heterophil antibodies that react with the carbohydrate moieties of retrovirus envelope antigens.