The innate immune system is a universal and ancient form of host defense against infection.
Innate immune recognition relies on a limited number of germline-encoded receptors. These
receptors evolved to recognize conserved products of microbial metabolism produced by
microbial pathogens, but not by the host. Recognition of these molecular structures allows
the immune system to distinguish infectious nonself from noninfectious self. Toll-like
receptors play a major role in pathogen recognition and initiation of inflammatory and …