Toll-like receptors

This chapter deals with the toll-like receptors, which represent the first point of meaningful physical contact between pathogens and the host. They are the "eyes" of the innate immune system, and they supply the information upon which the host must rely in forming an immune response, with all of the benefits, and potential problems that such a response entails. While other innate immune mechanisms work in parallel with the TLRs, and support their function, the overall pattern of the response to a pathogen is cast in stone from the moment the TLRs are activated. More specifically, it is far from deciphering the molecular events that transpire in TLR signal transduction. While all of the human TLRs have been identified, other proteins may participate in forming the macromolecular complex that detects pathogens at the surface of innate immune cells. Some of these proteins may be detected through direct biochemical techniques, and others may be identified only through mutagenesis.