Seed extract of Aeginetia indica L induces cytokine production and lymphocyte proliferation in vitro.

We previously reported that the extract of seeds from Aeginetia Indica L (AIL), a parasitic plant, induces potent antitumor immunity in tumor-bearing mice and that CD4+ T cells appear to be the main contributors in the induction of antitumor resistance. The present study was set up to investigate the in vitro effects of AIL on various lymphoid cells. Spleen cells from mice pretreated with AIL every 2 days for 1 week produced interleukin 2 (IL-2), interferon gamma (IFN gamma), tumor necrosis factor (TNF) and interleukin 6 (IL-6) when these cells were stimulated in vitro by AIL. Further, we found that CD4+ T cells were main producers of IL-2 and TNF upon the stimulation with ALL in vitro, while both CD4+ and CD8+ T cells secreted IFN. On the other hand, ALL was mitogenic in vitro to T enriched splenic lymphocytes as well as B enriched splenic lymphocytes. Moreover, AIL also proliferated thymocytes and this activity was potently synergistic with a suboptimal dose of concanavalin A (Con A). Lipopolysaccharide (LPS) contamination in AIL preparation was negligible since proliferative activity of AIL to B enriched splenic lymphocytes was not influenced in the presence of an endotoxin antagonist, polymyxin B sulfate (PMB). Further, B cell mitogenic activity of AIL seems to be mediated by different mechanism(s) from that of LPS since ALL could proliferate B enriched lymphocytes of C3H/HeJ mice which do not respond to the stimulation with LPS. A well known biological response modifier (BRM), Krestin (PSK), had no ability in inducing either T or B lymphocyte activation in vitro as shown by AIL.(ABSTRACT TRUNCATED AT 250 WORDS)