Toll-Like Receptor Signaling Pathways

Members of the Toll-like receptor (TLR) family recognize conserved microbial structures, such as bacterial lipopolysaccharide and viral double-stranded RNA, and activate signaling pathways that result in immune responses against microbial infections. All TLRs activate MyD88-dependent pathways to induce a core set of stereotyped responses, such as inflammation. However, individual TLRs can also induce immune responses that are tailored to a given microbial infection. Thus, these receptors are involved in both innate and adaptive immune responses. The mechanisms and components of these varied responses are only partly understood. Given the importance of TLRs in host defense, dissection of the pathways they…