Gamma delta T cell stimulatory activity of Tea and Indian herb extracts

Abstract

Herb extracts have been used in Indian traditional medicine (Ayurveda) to treat various ailments and also shown to have immunomodulatory effects. The present study evaluated the ability of these extracts to activate pool of gamma delta (??) T lymphocytes that play an important role in enhancing host responses to infections and cancer. Peripheral blood mononuclear cells (PBMCs) were isolated form peripheral blood of healthy individuals and stimulated with aqueous extracts of herbs, ethylamine, IPP and BrHPP for 12 days. Phenotype of expanded ?? T lymphocytes was determined by dual color flow cytometry using subset specific (V?2+CD3+, V?1+CD3+, ??+CD3+) fluorochrome labeled antibodies. Immunomagnetically purified ?? T lymphocytes were stimulated with herb extracts and IFN-?, TNF-?, IL-4, IL-10 released in cell free supematants was quantitated by ELISA. Our results demonstrate that the aqueous extracts of Jeevani (Tricopus zeylanicus), Black tea (Camellia sinensis) and American ginseng (Panax quinquefolius) exhibited the ability to significantly (P less than 0.05) expand ?? T lymphocytes from PBMC during in vitro culture. The activated ?? T lymphocytes expressed activation markers CD25 and CD69 and released IFN-? and TNF-?. Priming of ?? T lymphocytes with these herb extracts would be a promising approach to enhance immunity to bacterial infections and cancer.