Stimulation of lectin-dependent cell-mediated cytotoxicity against adherent HEp-2 cells by carrageenan

The effect of carrageenan (CGN) was studied on lectin-dependent cell-mediated cytotoxicity (LDCC) against adherent HEp-2 human epipharynx carcinoma target cells. Cytotoxicity was measured by detachment from the monolayer of 3H-TdR pre-labelled HEp-2 cells. LDCC was evaluated in a 24 h assay at 50:1 effector-target cell ratio in the presence of 25 micrograms/ml concanavalin A (Con A). Under these conditions but without Con A considerable cytotoxicity was not elicited by peripheral blood mononuclear cells (PBMC). Addition of CGN to the system significantly increased LDCC to HEp-2 targets. Monocyte depletion of effector cells had no major influence to the effect of CGN on LDCC activity. In parallel studies CGN also enhanced the Con A-induced proliferation of PBMC.