Dissociation of stimulatory capacity in mixed lymphocyte reaction and proliferative responses to pokeweed mitogen among peripheral blood non-T cells.

The stimulatory capacity in mixed lymphocyte reaction (MLR) and responsiveness to pokeweed mitogen (PWM) by peripheral blood non-T cells were studied. E rosette- and adherent cell-depleted lymphocytes were divided into low, medium and high density populations using discontinuous Percoll gradient. Low density non-T cells were potent stimulators in both autologous and allogeneic MLR despite low proliferative response to PWM. In contrast, those with medium density showed weaker stimulation in autologous though not in allogeneic reactions and underwent strong blastogenesis in PWM cultures. Non-T cells with high density had low MLR-stimulatory capacity and yet manifested the highest stimulation indices on PWM stimulation. These findings suggest that functional characteristics of non-T cells may be separable on the basis of cell density.