Mouse rosette positive B cells stimulate poorly in the autologous and allogeneic mixed lymphocyte reaction

Mouse erythrocytes form spontaneous rosettes with a population of B lymphocytes from normal individuals and in the majority of lymphocytes from patients with B cell chronic lymphocytic leukaemia (CLL). We have compared the ability of mouse rosette positive (MR+) cells with mouse rosette negative (MR-) cells and monocytes to act as stimulators in the autologous mixed lymphocyte reaction (AMLR) and allogeneic mixed lymphocyte reaction (MLR). Mononuclear cells from the peripheral blood of healthy individuals were fractionated into T cells, MR+ cells, MR- cells and monocytes. Lymphocyte cultures were harvested on days 6, 8 and 10 and the incorporation of tritiated thymidine was determined. MR- cells and monocytes were potent stimulators in the AMLR and MLR. In contrast MR+ cells, like B cells from patients with CLL, stimulated less in the AMLR and MLR. We conclude that MR+ cells from normal individuals function similarly to cells from CLL in the AMLR and MLR.