[HTML][HTML] Toll-dependent control mechanisms of CD4 T cell activation

C Pasare, R Medzhitov - Immunity, 2004 - cell.com
Immunity, 2004cell.com
Toll-like receptors (TLRs) detect microbial infection and play an essential role in the
induction of innate and adaptive immune responses. The mechanisms of TLR-mediated
control of adaptive immunity are not yet fully understood. Induction of dendritic cell (DC)
maturation is essential for activation of naive T cells. Here, we demonstrate that TLR-
induced DC maturation and migration to the lymph nodes, in the absence of TLR-induced
inflammatory cytokines, are not sufficient for T cell activation in vivo. We show that transient …
Abstract
Toll-like receptors (TLRs) detect microbial infection and play an essential role in the induction of innate and adaptive immune responses. The mechanisms of TLR-mediated control of adaptive immunity are not yet fully understood. Induction of dendritic cell (DC) maturation is essential for activation of naive T cells. Here, we demonstrate that TLR-induced DC maturation and migration to the lymph nodes, in the absence of TLR-induced inflammatory cytokines, are not sufficient for T cell activation in vivo. We show that transient depletion of regulatory T (Tr) cells recovers the primary CD4 T cells response in MyD88-deficient mice, demonstrating that a major mechanism of TLR-mediated activation of T cell responses is the blocking of suppression by regulatory T cells. In addition we show that a TLR-induced signal(s) is required for memory CD4 T cell differentiation, but not for activation of memory T cells.
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