Lipopolysaccharide and peptidoglycan: CD14-dependent bacterial inducers ofinflammation

Surface structures of bacteria contribute to the microbial pathogenic poten tial and are capable of causing local and generalized inflammatory reaction s, Among these factors, endotoxin and peptidoglycan are of particular medic al importance. Both toxic bacterial polymers are now recognized to interact with the same cellular receptor, the CD14 molecule, which is expressed on different types of immune cells, in particular, monocytes/macrophages. The interaction between these bacterial activators and CD14 leads to the produc tion of endogenous mediators such as tumor necrosis factor alpha interleuki n 1 (IL-1), and IL-6, which are ultimately responsible for phlogistic respo nses. The fact that CD14 recognizes not only endotoxin and peptidoglycan bu t also other glycosyl-based microbial polymers suggests that this cellular surface molecule represents a lectin.