Bacterial cell wall macroamphiphiles: Pathogen-/microbe-associated molecular patterns detected by mammalian innate immune system
Aurélie Ray, Marlène Cot, Germain Puzo, Martine Gilleron, Jérôme Nigou
CNRS, IPBS (Institut de Pharmacologie et de Biologie Structurale), Toulouse, France.
Innate immune system is the first line of host defense against invading microorganisms. It relies on a limited number of germline-encoded pattern recognition receptors that recognize conserved molecular structures of microbes, referred to as pathogen-/microbe-associated molecular patterns (PAMPs/MAMPs). Bacterial cell wall macroamphiphiles, namely Gram-negative bacteria lipopolysaccharide (LPS), Gram-positive bacteria lipoteichoic acid (LTA), lipoproteins and mycobacterial lipoglycans, are important molecules for the physiology of bacteria and evidently meet PAMP/MAMP criteria. They are well suited to innate immune recognition and constitute non-self signatures detected by the innate immune system to signal the presence of an infective agent. They are notably recognized via their lipid anchor by Toll-like receptors (TLRs) 4 or 2. Here, we review our current knowledge of the molecular bases of macroamphiphile recognition by TLRs, with a special emphasis on mycobacterial lipoglycan detection by TLR2.