Suppressive effect of Chinese medicinal herb, Acanthopanax gracilistylus, extract on human lymphocytes in vitro

We studied the effect of a Chinese medicinal herb, Acanthopanax gracilistyl us, extract (AGE), on human lymphocytes in vitro. AGE markedly suppressed t he proliferative responses of human peripheral blood lymphocytes stimulated with mitogens concanavalin A (Con A) and Staphylococcus aurerts Cowan I (S AC). Both T cell and B cell activities-production of interferon-gamma and i mmunoglobulin-were suppressed by AGE. The mechanism of AGE-induced suppress ion of lymphocytes is to arrest the cell cycle at the G(0)/G(1) stage witho ut a direct cytotoxic effect. AGE also suppressed the alloantigen-specific cytotoxic T lymphocyte response. However, natural killer cell activity was less sensitive to the suppressive activity of AGE. In contrast, AGE markedl y enhanced monocyte function to produce cytokines. These activities of AGE were associated with a 60-kD protein which was sensitive to treatment with pronase E, but not with NaIO4. These results suggest that AGE has an immuno modulating activity on human lymphocytes and its properties could be clinic ally applied in the treatment of several diseases such as autoimmune and al lergic diseases.