Biological relevance of lipid A variation in Yersinia spp

• Published in: Journal of endotoxin research Vol. 10; no. 5; p. 6
• Main Authors: Ernst, R K, Rebeil, R, Miller, SI, Hinnebusch, B J
• Format: Journal Article
• Language: English
• Published: 01.01.2004
• Subjects: Yersinia enterocolitica; Yersinia pestis; Yersinia pseudotuberculosis
• ISSN: 0968-0519

Important pathogens in the genus Yersinia include the plague bacillus Yersinia pestis and two enteropathogenic species, Yersinia pseudotuberculosis and Yersinia enterocolitica. A shift in growth temperature induced changes in the number and type of acyl groups on the lipid A of all three species. At a temperature that mimics growth with the flea (21 degree C), Y. pestis synthesized a hexa-acylated lipid A molecule that was modified by a C16:1 fatty acid acyl group. In contrast, after growth at mammalian body temperatures (37 degree C) Y. pestis produced predominately tetra- and penta-acylated lipid A structures. Specifically, Y. pestis lipid A consisted of lipid IV sub(A) (a disaccharide precursor of lipid A) and smaller amounts of penta-acylated lipid A structures modified by the addition of either C10:0 or C12:0 fatty acid acyl groups. In contrast, Y. pseudotuberculosis primarily synthesized lipid IV sub(A) modified with C16:0, and Y. enterocolitica produced a unique tetra-acylated lipid A. The acyltransferase genes (htrB and lpxP) required for increased acylation at 21 degree C have been determined. The more complex lipid A made by the three species at 21 degree C stimulated human monocytes to secrete TNF- alpha , but lipid A synthesized at 37 degree C did not. Finally, the Y. pestis phoP gene was required for aminoarabinose modification of lipid A but not for the temperature-dependent acylation changes. Production of a less immunostimulatory form of LPS upon entry into the mammalian host appears to be a conserved pathogenesis mechanism in the genus Yersinia, and species-specific lipid A forms may be important for life cycle and pathogenicity differences.