The innate immune system uses a variety of pattern-recognition receptors (PRRs) that recognize conserved microbial structures or pathogen-associated molecular patterns, such as those that occur in the bacterial cell-wall components peptidoglycan and lipopolysaccharide. PPRs are classified as:1)Membrane bound PRRs: These are referred to as toll-like receptors (TLRs). Eleven such receptors have been identified in mammals. TLRs are transmembrane receptors which use adapter proteins like TRAF6 and Myd88 to initate NF-κB and other signaling pathways that induce pro-inflammatory cytokines. 2)Extracellular PRRs: These include the complement proteins, pentraxins and collectins...