Dual roles of CD4+CD25+Foxp3+ Tregs in regulating Th17 cells and promoting host resistance to Candida albicans (137.7)

Abstract

Abstract Th17 cells and CD4+CD25+Foxp3+ regulatory T cells (Tregs) are thought to promote and suppress inflammatory responses, respectively. However, their direct interaction in the context of an inflammation is unclear. Here we show that under Th17 conditions, Tregs suppress late but not early Th17 responses. Moreover, Tregs boost IL-17A, IL-17F and IL-22 in Th17 cells at early time-points. Transient up-regulation of Th17 cytokines by Tregs plays a protective role in clearing Candida albicans infection in mice. However, Tregs regain their suppressive functions over time and suppress Th17 cell mediated inflammation in Candida infected mice. Thus, Tregs play dual roles by initially promoting protective Th17 cells, but subsequently reducing the pathology of Th17 driven inflammation.