Induction of the EBV cycle in B-lymphocyte-derived lines is accompanied by increased natural killer (NK) sensitivity and the expression of EBV-related antigen(s) detected by the ADCC reaction.

Human B-lymphocyte-derived lines were forced to enter the EBV-cycle by superinfection with the P3HR-1 substrain of EBV or sodium butyrate treatment. The induced cells were used as targets for natural killing (NK) and EBV-specific, antibody-dependent cellular cytotoxicity (ADCC). Two Burkitt lymphoma lines, Raji and Daudi, and one normal adult derived lymphoblastoid cell line, NAD-7, were comparable in their ADCC-sensitivity after induction, but only the Burkitt lymphoma-derived lines showed a major increase in NK-sensitivity. The superinfection-induced membrane change, responsible for both NK and ADCC sensitivity, is an early function of the viral cycle, correlated with the appearance of early antigens (EA). Indirect evidence indicates that the NK and ADCC target sites are different but this problem requires further investigation. Sodium butyrate induced an increased NK sensitivity and EBV-related ADCC sensitivity in the Burkitt lymphoma-derived P3HR-1 line. Lymphocyte effectors from different donors showed great differences in their NK and ADCC activity. Optimal ADCC could be demonstrated with effectors that were intermediate in their NK-activity.