Induction of plaque-forming cells in cultured human lymphocytes by combined action of antigen and EB virus

PRIMARY in vitro immune responses of human peripheral blood lymphocytes (PBL), desirable for both basic and clinical studies, have been rather difficult to achieve. Positive results were obtained when other stimulatory factors, besides antigen, were given to the cells1,2, and other reports have suggested a critical role of antigen presentation and antigen concentration3,4. In view of the difficulty encountered in stimulating an antibody response with antigen alone, we have attempted to use Epstein–Barr virus (EBV) together with sheep red blood cells (SRBC) to induce a specific response. Human B lymphocytes possess membrane receptors for EBV5,6and the virus stimulates DNA synthesis in human PBL7, so EBV provides a ‘nonspecific’ stimulus in addition to the specific one given by the antigen. We report here that use of EBV and SRBC in this way consistently induces an anti-SRBC response from human PBL.