TLR3 Is a Negative Regulator of Immune Responses Against.

Abstract

Toll-like receptors (TLRs) comprise the best-characterized pattern-recognition receptor (PRR) family able to activate distinct immune responses depending on the receptor/adaptor set assembled. TLRs, such as TLR2, TLR4 and TLR9, and their signaling were shown to be important ininfections. However, the role of the endosomal TLR3 in experimental paracoccidioidomycosys remains obscure.assays, macrophages of the bone marrow of WT or TLR3mice were differentiated for evaluation of their microbicidal activity., WT or TLR3mice were infected intratracheally withyeasts for investigation of the lung response type induced. The cytotoxic activity of CD8T cells was assessed by cytotoxicity assay. To confirm the importance of CD8T cells in the control of infection in the absence of tlr3, a depletion assay of these cells was performed. Here, we show for the first time that TLR3 modulate the infection againstby dampening pro-inflammatory response, NO production, IFNCD8T, and IL-17CD8T cell activation and cytotoxic function, associated with granzyme B and perforin down regulation. As conclusion, we suggest that TLR3 could be used as an escape mechanism of the fungus in an experimental paracoccidioidomycosis.