Select Procyanidins induce gammadelta T cell activation and proliferation

Abstract

Many pharmaceutical drugs in use today were originally identified in plants from traditional medicine. However, there remain many plants in traditional medicine that produce confusing immune responses and are therefore unlikely candidates for pharmaceutical drugs. The effects of some of the traditional medicines that induce these confusing immune responses may now be explained by recent advances in the characterization of our immune system, namely in our understanding of the unique functions of the gammadelta T cell. These gammadelta T cell functions include tissue repair and homeostasis, cancer infiltration and clearance, pathogen detection and cytokine response, and antigen presentation. Although there are currently therapies being studied to increase the effector function of gammadelta T cells, these techniques are only active on a limited population of gammadelta T cells, the human Vdelta2 subset. Although these cells are potent effectors against pathogens and some cancers, Vdelta2 T cells demonstrate a restricted tissue distribution and limited effector function in other gammadelta T cell host defense responses. As such, we screened compound libraries and traditional medicines for agonists with activity encompassing alternative gammadelta T cell subsets. Tannins derived from select plant species are able to fulfill this role as demonstrated by the activation and expansion of gammadelta T cell subsets not responsive to current gammadelta T cell expansion therapies. The ability of tannins to expand these gammadelta T cell populations will potentially increase the therapeutic range of gammadelta T cells and may be used as treatments for wound healing as well as in the clearance of solid tumor cancers.