Lipopolysaccharides (LPS′s) are complex glycolipids that are characteristic components of the cell wall of Gram-negative bacteria. They consist of a lipid A moiety linked to an antigenic O-polysaccharide.
Proteus mirabilis is a Gram-negative facultative anaerobic rod-shaped bacterium. Bacteria of the genus Proteus of the family Enterobacteriaceae are opportunistic human pathogens responsible for wound and burn infections as well as skin, eye, ear, nose, throat, urinary tract, and gastrointestinal infections and bacteremias.
Lipopolysaccharide (LPS) and its lipid A moiety stimulate cells of the innate immune system by the toll-like receptor 4 (TLR4), a member of the toll-like receptor protein family, which recognizes common pathogen-associated molecular patterns (PAMPs). Lipid A plays a role in the biological properties attributed to endotoxic LPS. LPS is a highly immunogenic antigen that has the ability to enhance immune responses.The outer-membrane lipopolysaccharide is considered an important virulence factor of Proteus. It has been suggested that the immunological response against P. mirabilis, LPS might play a role in rheumatoid arthritis. A possible correlation between the abundance of P. mirabilis in the intestine and obesity was suggested recently. The purified LPS from P. mirabilis OXK is used in the Weil-Felix test for the diagnosis of rickettsiosis (scrub typhus) caused by the bacterium Orientia (Rickettsia) tsutsugamushi.