Cytotoxic T cell recognition of Epstein‐Barr virus‐infected B cells. II. Blocking studies with monoclonal antibodies to HLA determinants

Abstract

Monoclonal antibodies specifically binding common determinants on all HLA‐A, B and C antigen molecules blocked the lysis of EB virus‐transformed target cells by EB virus‐specific cytotoxic T cells reactivated in vitro. Blocking was mediated through binding of the antibodies to the target rather than to the effector cells and was maximal (75 to 85% inhibition of lysis) at saturating antibody concentrations. A similar blocking effect was also shown by a monoclonal antibody binding to β₂‐microglobulin, a molecule physically associated with HLA‐A, B and C antigens on the target cell surface, but not by a monoclonal antibody binding to the non‐HLA‐associated leukocyte‐common antigen. Saturating concentrations of monoclonal antibodies specific for common determinants on all HLA‐DRw antigen molecules either had no effect at all upon EB virus‐specific T cell cytotoxicity or caused a slight, but nonspecific, inhibition. The results demonstrate unequivocally that HLA‐A, B and C antigens on the target cell surface are indeed the polymorphic elements which impose genetic restriction upon EB virus‐specific cytotoxic T cell function.