Plant polyphenols induce differential regulation of CD11b expression and function on monocytes and γδ T cells (97.11)

Abstract

Abstract Leukocyte adhesion and migration is partially mediated by CD11b/CD18 (MAC-1, CR3). Earlier studies have demonstrated a role for green tea polyphenols in down-regulating CD11b on monocytes and CD8+ T cells. We have recently shown a stimulatory effect of unripe apple polyphenols (APP) on γδ T cells. Thus, we compared the effect of APP on γδ T cell and monocyte CD11b expression. Purified bovine monocytes and monocyte-depleted peripheral blood lymphocytes were cultured with APP for 24 hours. CD11b levels decreased on monocytes in response to APP. In contrast, a subset of γδ T cells responded to APP by up-regulating CD11b. Consistant with the changes in surface CD11b expression, APP treated γδ T cells showed increased adherence to plastic, whereas monocyte adhesion was reduced. The affects of APP on monocytes could be inhibited by anti-CD11b mAb, whereas the mAb had no effect on the APP response in γδ T cells, suggesting the two cell types respond to APP via different mechanisms. Polyphenols are typically thought of as anti-inflammatory agents, however, these data, as well as other ongoing studies, indicate they have a pro-inflammatory effect on γδ T cells. In vivo, plant polyphenols may enhance γδ T cell migration to sites of inflammation, where they can enact rapid immunoregulatory and innate-like responses. Funded by: NIH –NIAID DAIT-BAA-03 -41