title: Involvement of lipooligosaccharide heptose residues of Haemophilus parasuis SC096 strain in serum resistance, adhesion and invasion.
abstract: Haemophilus parasuis is the causative agent of Glässer's disease. To investigate the role of lipooligosaccharide (LOS) in H. parasuis infection, ΔopsX, ΔrfaF and ΔwaaQ mutants defective in expressing opsX, rfaF and waaQ heptosyltransferases were constructed by transformation. Compared to the wild-type SC096 strain, the ΔopsX and ΔrfaF mutants, but not the ΔwaaQ mutant, produced severely truncated LOS. The mutants exhibited various degrees of reduction in resistance to complement-mediated killing in porcine and rabbit sera. In addition, the ΔopsX and ΔrfaF mutant strains showed impaired ability to adhere to and invade porcine kidney epithelial cells (PK-15) and porcine umbilical vein endothelial cells, indicating roles for heptose I and II residues in the interaction with host cells. The ΔwaaQ mutant strain, with no obvious truncation of LOS structure, did not exhibit significant defects in adhesion to and invasion of host cells. This study provides insight into the contribution of the inner core oligosaccharide, especially heptose I and heptose II residues, to the virulence-associated properties of H. parasuis.
authors.affiliation: Key Laboratory of Veterinary Vaccine Innovation of the Ministry of Agriculture, College of Veterinary Medicine, South China Agricultural University, Guangzhou 510642, People's Republic of China.
authors.forename: Chenggang
authors.initials: C
authors.lastname: Xu
authors.forename: Lingyun
authors.initials: L
authors.lastname: Zhang
authors.forename: Bin
authors.initials: B
authors.lastname: Zhang
authors.forename: Saixiang
authors.initials: S
authors.lastname: Feng
authors.forename: Suming
authors.initials: S
authors.lastname: Zhou
authors.forename: Jingyi
authors.initials: J
authors.lastname: Li
authors.forename: Yi
authors.initials: Y
authors.lastname: Zou
authors.forename: Ming
authors.initials: M
authors.lastname: Liao
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D044137:Haemophilus parasuis / Q000276:immunology* / Q000502:physiology*; D006539:Heptoses / Q000737:chemistry / Q000276:immunology* / Q000502:physiology*; D009154:Mutation; D009844:Oligosaccharides / Q000737:chemistry / Q000378:metabolism*; D011817:Rabbits; D013552:Swine
chemical_list: D006539:Heptoses; D009844:Oligosaccharides