Author
WU, DAYONG - TUFTS/HNRCA | |
CRUPI, KATIE - TUFTS/HNRCA | |
HAN, SUNG - TUFTS/HNRCA | |
MEYDANI, SIMIN - TUFTS/HNRCA |
Submitted to: Journal of Federation of American Societies for Experimental Biology
Publication Type: Abstract Only Publication Acceptance Date: 1/19/2005 Publication Date: 3/7/2005 Citation: Wu, D., Crupi, K., Han, S.N., Meydani, S. 2005. Effect of in vitro supplementation with tea catechin, epigallocatechin-3-gallate (egcg), on t cell mediated immune response. Journal of Federation of American Societies for Experimental Biology. 19:A1344. Interpretive Summary: Technical Abstract: Studies have suggested a benefit of consuming green tea in promoting general health and reducing the risk of certain diseases. However, little is known about the effect of tea on immune function. Majority of in vitro studies reported so far have used EGCG, the major active component of tea, at higher doses than those achievable in body tissues through oral intake (<10 microM). In this in vitro study, we used a wide range of doses (0.25 to 50 microM) to determine the effect of EGCG on T cell-mediated response in spleen cells isolated from C57BL mice. T cell proliferation was not affected by EGCG at low doses (0.25 to 1 microM) but at higher doses (2.5 to 50 microM), EGCG caused a dose-dependent inhibition of T cell proliferation. The EGCG-induced inhibition of cell proliferation was not due to increased oxidative stress as previously suggested by others because: 1) H2O2 production was not elevated in cultures supplemented with less than 20 microM EGCG, and 2) addition of antioxidants (glutathione or vitamin E) or catalase in the culture did not prevent this EGCG-induced inhibition. Glutathione or vitamin E alone enhanced T cell proliferation. These results indicate that EGCG at high physiologically relevant levels (2.5 to 10 microM) may have an adverse effect on T cell function. The underlying mechanisms as well as the in vivo effects of tea catechins deserve further investigation. |