Toll-like receptors. I. Structure, function and their ligands

The innate immune system senses invading microorganisms by a phylogenetically conserved family of proteins PRRs of which TLRs are ones of the most important. There are at least 10 different TLRs in humans and 11 in mice. They have in the course of evolution specialized for the recognition of conserved structures among microorganisms called PAMPs. Activation of TLRs results in induction of innate immunity mechanisms as well in development of antigen-specific adaptive immune responses, thus bridging innate and adaptive immunity.