Characterization of flgK gene and FlgK protein required for H pylori Colonization-from cloning to clinical relevance

• Published in: World journal of gastroenterology : WJG 2006-07, Vol.12 (25), p.3989-3993
• Main Authors: Wu, Jiunn-Jong, Sheu, Bor-Shyang, Huang, Ay-Huey, Lin, Shin-Ting, Yang, Hsiao-Bai
• Format: Article
• Language: English
• Subjects: Animals; Bacterial Proteins - genetics; Bacterial Proteins - immunology; Bacterial Proteins - physiology; Cell Movement - physiology; Cloning, Molecular; Flagellin - immunology; H Pylori; Helicobacter Infections - microbiology; Helicobacter pylori - genetics; Helicobacter pylori - physiology; Helicobacter pylori - ultrastructure; Humans; Male; Mice; Mice, Inbred BALB C; Molecular Sequence Data; Mutagenesis; Prospective Studies; Sequence Analysis, DNA; 临床表现; 基因表达; 幽门螺杆菌; 细菌感染
• ISSN: 1007-9327; 2219-2840
• DOI: 10.3748/wjg.v12.i25.3989

AIM： To characterize the role of flgK and its protein product in Hpylori colonization. METHODS： The PCR cloning method identified the flgK gene. An isogenic flgK mutant was constructed by gene replacement and confirmed by Southern blot analysis and PCR analysis. The recombinant FlgK protein （r-FlgK） was purified. Electron microscopy （EM） was applied to demonstrate the flagella of H pylori. An in vitro motility test was assessed in semisolid medium. The densities of H pylori colonization with either the wild-type strain or its flgK mutant were compared among BALB/c mice with or without pre-immunization with r-FlgK. The serological responses to r-FlgK were analyzed for 70 clinical patients with different densities of H pylori colonization. RESULTS： From a duodenal ulcer strain, the flgK gene was cloned and it contained 1821 bp, with a 95.7% identity to the published sequences. No flagella were observed under EM for the mutant strain, which had a loss of motility. Hpylori density was lower in the BALB/c mice inoculated by the mutant or with pre-immunization with r-FlgK compared to unimmunized mice or mice inoculated by the wild-type strain （P 〈 0.05）. In the H pylori-infected patients, the serological responses to r-FlgK were uniformly low in titer. CONCLUSION： FlgK encoded by flgK is important for flagella formation and H pylori motility. Deficiency in FlgK or an enhanced serological response to r-FlgK can interfere with Hpylori colonization. FlgK of Hpylori could be a novel target for vaccination.