BACKGROUND Helicobacter pylori(H.pylori)colonizes the human stomach and is a major cause of peptic ulcer disease and gastric cancer.However,although the prevalence of H.pylori is high in Africa,the incidence of gastri...BACKGROUND Helicobacter pylori(H.pylori)colonizes the human stomach and is a major cause of peptic ulcer disease and gastric cancer.However,although the prevalence of H.pylori is high in Africa,the incidence of gastric cancer is low,and this phenomenon is called to be African enigma.The CagA protein produced by H.pylori is the most studied virulence factor.The carcinogenic potential of CagA is associated with the Glu-Pro-Ile-Tyr-Ala(EPIYA)patterns and CagAmultimerization(CM)motifs.AIM To better understand the EPIYA patterns and CM motifs of the cagA gene.METHODS Gastric mucosal biopsy specimens were obtained from 258 patients with dyspepsia living in the Dominican Republic,from which 120 H.pylori strains were cultured.After the bacterial DNA extraction,the EPIYA pattern and CM motif genotypes were determined using a polymerase chain reaction-based sequencing.The population structure of the Dominican Republic strains was analyzed using multilocus sequence typing(MLST).Peptic ulcer disease and gastric cancer were identified via endoscopy,and gastric cancer was confirmed by histopathology.Histological scores of the gastric mucosa were evaluated using the updated Sydney system.RESULTS All CagA-positive strains carried the Western-type CagA according to the identified EPIYA patterns.Twenty-seven kinds of CM motifs were observed.Although the typical Western CM motif(FPLKRHDKVDDLSKVG)was observed most frequently,the typical East Asian CM motif(FPLRRSAAVNDLSKVG)was not observed.However,“FPLRRSAKVEDLSKVG”,similar to the typical East Asian CM motif,was found in 21 strains.Since this type was significantly more frequent in strains classified as hpAfrica1 using MLST analysis(P=0.034),we termed it Africa1-CM(Af1-CM).A few hpEurope strains carried the Af1-CM motif,but they had a significantly higher ancestral Africa1 component than that of those without the Af1-CM motif(P=0.030).In 30 cagA-positive strains,the"GKDKGPE"motif was observed immediately upstream of the EPIYA motif in the EPIYA-A segment,and there was a significant association between strains with the hpAfrica1 population and those containing the“GKDKGPE”motif(P=0.018).In contrast,there was no significant association between the CM motif patterns and histological scores and clinical outcomes.CONCLUSION We found the unique African CM motif in Western-type CagA and termed it Africa1-CM.The less toxicity of this motif could be one reason to explain the African enigma.展开更多
AIMTo develop a novel Helicobacter pylori(H.pylori)CagA antibody enzyme-linked immunosorbent assay(ELISA)suitable for detecting serum anti-CagA antibodies with high sensitivity.METHODSRecombinant East Asian-type CagA ...AIMTo develop a novel Helicobacter pylori(H.pylori)CagA antibody enzyme-linked immunosorbent assay(ELISA)suitable for detecting serum anti-CagA antibodies with high sensitivity.METHODSRecombinant East Asian-type CagA protein was purified and immobilized for ELISA.Serum samples from 217 Vietnamese individuals(110 H.pylori-infected and 107 uninfected individuals)were applied.Conventional ELISA from Western-type CagA and our East Asian-type CagA ELISA were evaluated by comparing 38 subjects with the Western-type genotype and 72 subjects with the East Asian-type cagA genotype.Histological scores of the gastric mucosa were determined using the updated Sydney System to examine the relationship with anti-CagA antibody titers.RESULTSRecombinant 70-100 kDa fragments were immobilized on the ELISA plate.In ROC analysis,the area under the curve of our East Asian-type CagA ELISA was comparable to that of conventional CagA ELISA.The sensitivity of the two ELISAs differed depending on the cagA genotype.The sensitivity of East Asian-type CagA ELISA was higher for subjects infected with East Asian-type cagA H.pylori(P<0.001),and the sensitivity of the conventional CagA ELISA tended to be higher for subjects infected with Western cagA H.pylori(P=0.056).The titer of anti-CagA antibody tended to correlate with monocyte infiltration scores(r=0.25,P=0.058)and was inversely correlated with H.pylori density(r=-0.26,P=0.043).CONCLUSIONThe novel ELISA is useful to detect anti-CagA antibodies in East Asian countries,and the titer may be a marker for predicting chronic gastritis.展开更多
基金Supported by The Grants-in-aid for Scientific Research from the Ministry of Education,Culture,Sports,Science,and Technology of Japan,No.16H05191,No.221S0002,No.16H06279,No.18KK0266 and No.19H03473(partly)the National Fund for Innovation and Development of Science and Technology from the Ministry of Higher Education Science and Technology of the Dominican Republic,No.2012-2013-2A1-65 and No.2015-3A1-182(MC).
文摘BACKGROUND Helicobacter pylori(H.pylori)colonizes the human stomach and is a major cause of peptic ulcer disease and gastric cancer.However,although the prevalence of H.pylori is high in Africa,the incidence of gastric cancer is low,and this phenomenon is called to be African enigma.The CagA protein produced by H.pylori is the most studied virulence factor.The carcinogenic potential of CagA is associated with the Glu-Pro-Ile-Tyr-Ala(EPIYA)patterns and CagAmultimerization(CM)motifs.AIM To better understand the EPIYA patterns and CM motifs of the cagA gene.METHODS Gastric mucosal biopsy specimens were obtained from 258 patients with dyspepsia living in the Dominican Republic,from which 120 H.pylori strains were cultured.After the bacterial DNA extraction,the EPIYA pattern and CM motif genotypes were determined using a polymerase chain reaction-based sequencing.The population structure of the Dominican Republic strains was analyzed using multilocus sequence typing(MLST).Peptic ulcer disease and gastric cancer were identified via endoscopy,and gastric cancer was confirmed by histopathology.Histological scores of the gastric mucosa were evaluated using the updated Sydney system.RESULTS All CagA-positive strains carried the Western-type CagA according to the identified EPIYA patterns.Twenty-seven kinds of CM motifs were observed.Although the typical Western CM motif(FPLKRHDKVDDLSKVG)was observed most frequently,the typical East Asian CM motif(FPLRRSAAVNDLSKVG)was not observed.However,“FPLRRSAKVEDLSKVG”,similar to the typical East Asian CM motif,was found in 21 strains.Since this type was significantly more frequent in strains classified as hpAfrica1 using MLST analysis(P=0.034),we termed it Africa1-CM(Af1-CM).A few hpEurope strains carried the Af1-CM motif,but they had a significantly higher ancestral Africa1 component than that of those without the Af1-CM motif(P=0.030).In 30 cagA-positive strains,the"GKDKGPE"motif was observed immediately upstream of the EPIYA motif in the EPIYA-A segment,and there was a significant association between strains with the hpAfrica1 population and those containing the“GKDKGPE”motif(P=0.018).In contrast,there was no significant association between the CM motif patterns and histological scores and clinical outcomes.CONCLUSION We found the unique African CM motif in Western-type CagA and termed it Africa1-CM.The less toxicity of this motif could be one reason to explain the African enigma.
基金the National Institutes of Health,No.DK62813Grants-in-Aid for Scientific Research from the Ministry of Education,Culture,Sports,Science,and Technology of Japan(in part),No.25293104,No.26640114 and No.15H02657)theJapan Society for the Promotion of Science Institutional Program for Young Researcher Overseas Visits and the Strategic Funds for the Promotion of Science and Technology from the Japan Science and Technology Agency
文摘AIMTo develop a novel Helicobacter pylori(H.pylori)CagA antibody enzyme-linked immunosorbent assay(ELISA)suitable for detecting serum anti-CagA antibodies with high sensitivity.METHODSRecombinant East Asian-type CagA protein was purified and immobilized for ELISA.Serum samples from 217 Vietnamese individuals(110 H.pylori-infected and 107 uninfected individuals)were applied.Conventional ELISA from Western-type CagA and our East Asian-type CagA ELISA were evaluated by comparing 38 subjects with the Western-type genotype and 72 subjects with the East Asian-type cagA genotype.Histological scores of the gastric mucosa were determined using the updated Sydney System to examine the relationship with anti-CagA antibody titers.RESULTSRecombinant 70-100 kDa fragments were immobilized on the ELISA plate.In ROC analysis,the area under the curve of our East Asian-type CagA ELISA was comparable to that of conventional CagA ELISA.The sensitivity of the two ELISAs differed depending on the cagA genotype.The sensitivity of East Asian-type CagA ELISA was higher for subjects infected with East Asian-type cagA H.pylori(P<0.001),and the sensitivity of the conventional CagA ELISA tended to be higher for subjects infected with Western cagA H.pylori(P=0.056).The titer of anti-CagA antibody tended to correlate with monocyte infiltration scores(r=0.25,P=0.058)and was inversely correlated with H.pylori density(r=-0.26,P=0.043).CONCLUSIONThe novel ELISA is useful to detect anti-CagA antibodies in East Asian countries,and the titer may be a marker for predicting chronic gastritis.
