Toll Pathway-Dependent Blockade of CD4~+CD25~+ T Cell-Mediated Suppression by Dendritic Cells

摘要

Toll-like receptors (TLRs) control activation of adaptive immune responses by antigen-presenting cells (APCs). However, initiation of adaptive immune responses is also controlled by regulatory T cells (T_R cells), which act to prevent activation of autoreactive T cells. Here we describe a second mechanism of immune induction by TLRs, which is independent of effects on costimulation. Microbial induction of the Toll pathway blocked the suppressive effect of CD4~+CD25~+ T_R cells, allowing activation of pathogen-specific adaptive immune responses. This block of suppressor activity was dependent in part on interleukin-6, which was induced by TLRs upon recognition of microbial products.