Toll-like receptor(TLR) is a pathogen recognition receptor and is the item of research in recent years.It discriminates different pathogen-associated molecular patterns(PAMPs) and activates signaling cascades leading to immune responses.The specific TLR signal is conducted by adaptor proteins containing toll-interleukin1 receptor(TIR) domains.The function is carried out by MYD88 or no-MYD88/TRIF pathway involving five TIR adaptors: MYD88,MAL,TRIF,TRAM and SARM.