Enhancement of Interferon-γ Production in Glycyrrhizin-Treated Human Peripheral Lymphocytes in Response to Concanavalin A and to Surface Antigen of Hepatitis B Virus

Abstract

Abstract

The effects of glycyrrhizin, a component of licorice (Glycyrrhiza glabra) roots, on the production of interferon-γ in human peripheral lymphocyte-macrophage cultures by concanavalin A (Con A) was examined. Interferon-γ production in normal lymphocyte-macrophage cultures treated with 10 to 100 μg/ml of glycyrrhizin at 37°C for 12 hr or longer, and then treated with 10 μg/ml of Con A, was enhanced four to eight times compared to control cell cultures. Lymphocyte-macrophage cultures treated with 10 to 100 μg/ml of glycyrrhizin alone did not produce interferon. No significant difference in the adsorption of [³H]Con A to glycyrrhizin-treated and control lymphocyte-macrophage cultures was found, but RNA and protein synthesis of the treated lymphocytes was increased compared to control cells; DNA synthesis, however, was reduced. Collaboration between enriched T-lymphocytes and macrophages, both treated with glycyrrhizin, was needed for the enhancement of interferon-γ production. A smaller increase in interferon production was also observed in the glycyrrhizin-treated peripheral lymphocyte-macrophage cultures derived from an asymptomatic carrier of hepatitis B virus, in response to Con A and surface antigen of hepatitis B virus.