Immunomodulatory functions of extracts from the Chinese medicinal fungus Cordyceps cicadae.

The effects of Cordyceps cicadae extracted fractions on human mononuclear cells (HMNC) proliferation were determined by tritiated thymidine uptake. The results indicated that aqueous methanol (50%) extracts of C. cicadae ascocarps portion (CC-1-2) enhanced HMNC proliferation activated with phytohemagglutinin (PHA) with an EC(50) of 13.8+/-4.6 micro g/ml. By contrast, the methanol (100%) extracts of C. cicadae insect-body portion (CC-2-1) suppressed HMNC proliferation stimulated by PHA with an IC(50) of 32.5+/-5.2 micro g/ml. Cell viability test indicated that inhibitory effects of CC-2-1 on HMNC proliferation were not through direct cytotoxicity. The action mechanisms of CC-1-2 and CC-2-1 may involve the regulation of interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) production in HMNC. Since CC-2-1 suppressed IL-2 and IFN-gamma production in HMNC induced with PHA. The CC-1-2 enhanced IL-2 and IFN-gamma production of HMNC stimulated with PHA in a concentration dependent manner. Therefore, the results demonstrated that C. cicadae contained growth modulators for HMNC.