Ginger extract inhibits macrophage activation and T cell co‐stimulation

Abstract

Ginger is widely used as an alternative herbal remedy and is reported to have anti-inflammatory as well as anti-atherogenic properties. Ginger extract has been reported to inhibit LPS induced expression of pro-inflammatory cytokines. However, the effects of ginger extract on the expression of co-stimulatory molecules and its impact on T cell signaling is not known. The present study examined the effects of ginger extract on macrophage activation and the ability of macrophages to stimulate T cells. Murine peritoneal macrophages were treated with ginger (10μl/ml, 1μl/ml) extract in the presence of LPS (100ng/ml) for 24h. Expression of CD80, CD86 and MHC II were analyzed by flow cytometry. Macrophage induced T cell activation was examined with a mixed lymphocyte reaction assay. Macrophages were with vehicle or ginger extract for 24h. and cultured with CD4+ cells in the presence of alloantigen for 5 days. The cell supernatants were collected for IFN-γ and IL-2 assay by ELISA and cell proliferation was determined by the MTS assay. Ginger extract attenuated the LPS induced expression of CD80, CD86 and MHC II in macrophages. Similarly, ginger extract significantly inhibited the ability of macrophages to stimulate T cell proliferation by 65%. Further, ginger extract significantly inhibited the release of IL-2 and IFN-γ from macrophage stimulated T cells and complete inhibition of IL-2 (control = 2 pg/ml, ginger extract treated = 0 pg/ml) and IFN-γ (control = 43 pg/ml, ginger extract treated = 0 pg/ml). The present study demonstrates that ginger extract inhibits macrophage activation and inhibits the ability of macrophages to stimulate T cell proliferation in vitro. Supported by NIH grant no. 1 R21 AT01221-01A2.