This review by Satoshi Uematsu and Shizuo Akira focuses on the role of pattern recognition receptors (PRRs) in innate immunity, particularly Toll-like receptors (TLRs). The innate immune system, which includes PRRs, is the first line of defense against microbial infections. TLRs, mammalian homologs of the Drosophila protein Toll, are key recognition structures that can sense a wide range of pathogens, from bacteria to fungi, protozoa, and viruses. They recognize conserved molecular patterns (PAMPs) of microorganisms, which are not produced by the host but are essential for microbial survival. TLRs are activated by specific microbial components, leading to the activation of signal transduction pathways that induce dendritic cell maturation and cytokine production, ultimately fostering adaptive immunity.
The review also discusses other PRRs, such as members of the NACHT-LRR (NLR) family and the RNA helicase RIG-I, which recognize microbial components in the cytosol. TLRs have 13 members, each with its own signaling pathway and specific functions. The cytoplasmic portion of TLRs contains a Toll/IL-1 receptor (TIR) domain, essential for intracellular signaling, while the extracellular region contains leucine-rich repeats (LRRs) that recognize PAMPs. The review details the recognition of various bacterial components by different TLRs, including lipopolysaccharide (LPS), lipoproteins, peptidoglycans, flagellin, and CpG DNA. These interactions trigger immune responses and contribute to the host's defense against microbial infections.This review by Satoshi Uematsu and Shizuo Akira focuses on the role of pattern recognition receptors (PRRs) in innate immunity, particularly Toll-like receptors (TLRs). The innate immune system, which includes PRRs, is the first line of defense against microbial infections. TLRs, mammalian homologs of the Drosophila protein Toll, are key recognition structures that can sense a wide range of pathogens, from bacteria to fungi, protozoa, and viruses. They recognize conserved molecular patterns (PAMPs) of microorganisms, which are not produced by the host but are essential for microbial survival. TLRs are activated by specific microbial components, leading to the activation of signal transduction pathways that induce dendritic cell maturation and cytokine production, ultimately fostering adaptive immunity.
The review also discusses other PRRs, such as members of the NACHT-LRR (NLR) family and the RNA helicase RIG-I, which recognize microbial components in the cytosol. TLRs have 13 members, each with its own signaling pathway and specific functions. The cytoplasmic portion of TLRs contains a Toll/IL-1 receptor (TIR) domain, essential for intracellular signaling, while the extracellular region contains leucine-rich repeats (LRRs) that recognize PAMPs. The review details the recognition of various bacterial components by different TLRs, including lipopolysaccharide (LPS), lipoproteins, peptidoglycans, flagellin, and CpG DNA. These interactions trigger immune responses and contribute to the host's defense against microbial infections.