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CagA-positive H. pylori is reported to be associate d with gastroduode nal dise ase in We ste rn countrie s. To evaluate the relationship between CagA and dise ase , cloning of the entire cagA gene (3771 bp) , insertion of a partial fragment (1272 bp) into an expre ssion vector, purification of the recombinant prote in, production of an antibody against the recombinant CagA prote in through rabbits, and use of the recombinant CagA prote in as an antige n, de tection of the anti-CagA antibody by western blotting were all pe rformed. Sera of 132 H. pylori-infected patie nts unde rgoing endoscopy were studied. Anti-CagA antibodie s were de tected in 90%, 87%, 90%, 94%, and 93% of patients with gastric ulce r (N 5 34) , duode nal ulce r (N 5 27) , chronic gastritis (N 5 31) , gastric cance r (N 5 17) , and normal mucosa (N 5 15) , respective ly. High seropositivity of anti-CagA antibody even in individuals with normal mucosa indicate d that CagA may not be a unique marke r for dise ase by H. pylori infection in Japan.
KEY WORDS: Helicobacter pylori; cagA; recombinant protein; anti-CagA antibody; gastroduodenal disease.
Helicobacter pylori is closely associate d with chronic active gastritis, peptic ulcers, and gastric cance r (1-4). Although the pathoge nesis of H. pylori infection is not well unde rstood, seve ral potential virule nce factors may contribute to mucosal damage induce d by H. pylori infection.
CagA prote in is associate d with the production of vacuolating cytotoxin. This prote in was found in 60 -70% of H. pylori strains in We ste rn countrie s and is strongly associated with gastroduode nal disease (5-7). Cove r et al (7) reported that seropositivity for anti-CagA antibody was 88% (28 of 32) for patients with duode nal ulce r and only 56% (22 of 39) for patie nts with nonulce r dyspepsia. Ching et al (6) showed that seropositivity for anti-CagA antibody was 84% (165 of 197) for patients with duode nal ulcer and only 56% (25 of 45) for patie nts with nonulce r dyspepsia.
Neutrophilic infiltration into the gastric epithe lium, which may be due to increased gastric mucosal production...