Abstract
Summary Activation of the Epstein-Barr virus (EBV) genome by 5-bromodeoxyuridine (BUDR) in “virus-free” Raji or NC37 cells resulted in the synthesis of early viral antigens (EA) detectable by immunofluorescence. A high proportion of sera (65-97%) from patients with infectious mononucleosis, Burkitt lymphoma and nasopharyngeal carcinoma reacted with these antigens while only 1/3 of the sera from healthy persons were reactive. Forty to 80% of sera from subhuman primates also contained anti-EA antibodies. The significance of these antibodies in man in relation to EBV infection or associated illnesses remains obscure. EA appeared to be immunologically distinct from EBV-related soluble complement-fixing antigens. BUDR activation of Raji or NC37 cells offers a simple and convenient method of obtaining EA preparations free of viral capsid antigens.