Identification of T‐ and B‐cell epitopes associated with a restricted component of the epstein‐barr virus‐induced early antigen complex

Experiments were designed in an attempt to identify T‐and B‐cell epitopes expressed on the 17‐kDa early‐antigen‐restricted (EA‐R) polypeptide of the EBV‐induced early antigen complex. Using Berzofsky's algorithm, 3 hypothetical T‐cell epitopes on p 17 were synthesized and employed in EBV‐specific lymphoproliferative assays. Lymphocytes from all EBV‐infected donors responded against one of these epitopes (p 17.1) irrespective of their serological status relative to antibodies to EA‐R. Both CD4 + and CD8 + T‐cell subpopulations from seropositive donors proliferated in the presence of p17.1 in short‐term cultures. These experiments therefore identified one T‐cell epitope on the 17‐kDa polypeptide. In contrast, sera from anti‐EA antibody‐positive individuals reacted with all 3 synthetic peptides to varying degrees, with p 17.1 being the most frequently reactive epitope. When the sera were grouped according to diagnosis, it was noted that 82% of the sera from patients with aggressive lymphomas, whether Africans with Burkitt's lymphoma or North Americans with intermediate‐grade large‐cell or high‐grade B‐cell lymphoma, contained antibody reactive with p17.1, while 64% were reactive with p 17.2 and 29% with p 17.3. In contrast, high anti‐EA antibody‐positive sera from nasopharyngeal carcinoma patients were relatively less reactive with these synthetic peptides (23% positive with p17.1; 19% with p17.2; and 13% with p17.3). These results therefore identified 3 8‐cell EA‐R epitopes which might be potentially useful for clinical or epidemiological studies of EBV‐associated lymphoproliferative diseases.