Lymphocvte Transformation Induced by A - kutologous Cells : Stimulation by Cultured Lymphoblast Lines MARc E . WEKSLER and GARY BIRNBAUM

cultured lymphoblasts required physical contact with responding lymphocytes to induce transformiiation. In quantitative terms, lymphocytes incorporate as much thymidine when,mixed with irradiated cultured lymphoblasts as they (lo in response to l)hytolhenma-glutin1in. The stimulation of lymphocyte transformation by allogeneic cultured lymphoblasts did not parallel the stimulation of lymphocyte transformation by leukocytes from the donor of the lymphoblast culture. The stimulatory determinants on the cultured lymphoblast are unaffected by neuramini(lase but destroyed by trypsin. The trvpsin-treated cultured lymphoblasts regain their capacity to stimulate atutologous lymphocyte transformation witlhin 48 hr in culture. Cultured lymphoblasts l)ossess concanavalin A binding sites. Concanavalin A inhibits the capacity of cultured lymphoblasts to stimulate autologous lymphocyte transformation. The relevance of these findings to EB virus infection of culture(d lymplhoblasts and to imilmune surveillance is discusse(l.