Immunosuppressive activity of Pollen Typhae ethanol extract on the immune responses in mice

The immunosuppressive activity of the ethanol extract of Pollen Typhae (EEPT) consisting of a mixture of flavonoids, steroids and volatile oils was studied on the immune responses in mice. EEPT significantly suppressed concanavalin A (Con A)- and lipopolysaccharide (LPS)-stimulated splenocyte proliferation in vitro in a concentration-dependent manner. ICR mice were immunized subcutaneously with OVA on days 0 and 14. Beginning on the day of immunization, the mice were administered intraperitoneally with EEPT at a single dose of 0.25, 0.5, and 1.0 mg at intervals of 7 days for a total of five doses. On day 28, antigen-specific antibodies in serum, and mitogen- and OVA-induced splenocyte proliferation were measured. EEPT significantly suppressed Con A-, LPS- and OVA-induced splenocyte proliferation in the OVA-immunized mice in a dose-dependent manner. Moreover, the OVA-specific total IgG, IgG1 and IgG2b levels in the OVA-immunized mice were significantly reduced by EEPT. The results suggest that EEPT could suppress the cellular and humoral response in mice, and deserve further researches to be developed as immunosuppressant.