[Immunological activities of rat lymphocytes. III. --Isolation of differing subpopulations of lymphocytes by two techniques of T cell separation].

In previous studies we have isolated by density gradient separation a population of relatively dense T lymphocytes capable of inhibiting the mitogenic response to concanavalin A (ConA) and phytohaemagglutinin. In this study we compared two current methods of cell separation for their relative yield in T lymphocytes able or not to respond to Con A. The present results show that cells passed through nylon wool columns--in contrast to those obtained by removal of lymphocytes which bind erythrocyte-antibody-complement complex-partially lose their ability to respond to ConA. The response lost by passage through nylon wool columns can be restored by centrifugation of the T cell suspension on a gradient of "Ficoll-Hypaque". This suggests that methods of T cells purification using density gradient separation may remove the more dense suppressor cells.