Mast cell regulatory effect on lymphoid cell proliferation.

It has been shown rat mast cells (MC) can modulate lymphocyte proliferation in vitro. Depending on concentrations tested both serosal MC and their supernatants enhanced the spontaneous and T-mitogen-induced proliferation of spleen and lymph node cells. In addition T-mitogen-induced thymocyte proliferation was also increased. The enhancing effect of MC on lymphoid cell proliferation appeared after MC and lymphocytes were cocultured for 24, 48 or 72 h. The highest enhancing action of MC was observed when MC and lymphocytes were plated simultaneously. In contrast, when MC were added 24 or 48 h after the start of lymphocyte culture, the enhancing action of MC decreased or was abolished, respectively. No dependence was found between histamine concentration in MC supernatants and the enhancing activity of supernatants. After chromatographic separation of MC supernatants the fractions with molecular weights between 1-6 KDa augmented lymphoid cell proliferation.