AIM:To evaluate the prevalence of Helicobacter pylori(H.pylori ) babA2 ,babB and a recombinant gene between babA2 and babB(babA2/B ),and their role in the development of atrophic gastritis in Costa Rican and Japanese ...AIM:To evaluate the prevalence of Helicobacter pylori(H.pylori ) babA2 ,babB and a recombinant gene between babA2 and babB(babA2/B ),and their role in the development of atrophic gastritis in Costa Rican and Japanese clinical isolates.METHODS:A total of 95 continuous H.pylori-positive Costa Rican(41 males and 54 females;mean age,50.65 years;SD,± 13.04 years) and 95 continuous H.pylori-positive Japanese(50 males and 45 females;mean age,63.43;SD,± 13.21 years) patients underwent upper endoscopy from October 2005 to July 2006.They were enrolled for the polymerase chain reaction(PCR)-based genotyping of the H.pylori babA2 ,babB and babA2/B genes.Statistical analysis was performed using the χ2 test and the Fisher's exact probability test and multivariate analysis was performed by logistic regression adjusting for gender and age.P < 0.05 was regarded as statistically significant.RESULTS:The PCR-based genotyping of 95 Costa Rican and 95 Japanese isolates showed a higher prevalence of babA2 in Japan(96.8%) than in Costa Rica(73.7%),while that of babA2/B was higher in Costa Rica(11.6%) than in Japan(1.1%).In Costa Rican isolates only,babA2 was significantly associated with atrophic gastritis(P = 0.01).CONCLUSION:These results suggest that the status of babA2 and babA2/B shows geographic differences,and that babA2 has clinical relevance in Costa Rica.展开更多
Interactions between BabA and Lewis b (Leb) related antigens are the best characterized adhesin-receptor interactions in Helicobacter pylori (H pylori). Several mechanisms for the regulation of BabA expression are pre...Interactions between BabA and Lewis b (Leb) related antigens are the best characterized adhesin-receptor interactions in Helicobacter pylori (H pylori). Several mechanisms for the regulation of BabA expression are predicted, including at both transcriptional and translational levels. The formation of chimeric proteins (babA /B or babB /A chimeras) seems to play an especially important role in translational regulation. Chimeric BabB/A protein had the potential to bind Leb; however, protein production was subject to phase variation through slipped strand mispairing. The babA gene was cloned initially from strain CCUG17875, which contains a silent babA1 gene and an expressed babA2 gene. The sequence of these two genes differs only by the presence of a 10 bp deletion in the signal peptide sequence of babA1 that eliminates its translational initiation codon. However, the babA1 type deletion was found only in strain CCUG17875. A few studies evaluated BabA status by immunoblot and confirmed that BabA-positive status in Western strains was closely associated with severe clinical outcomes. BabA-positive status also was associated with the presence of other virulence factors (e.g. cagA-positive status and vacA s1 genotype). A small class of strains produced low levels of the BabA protein and lacked Leb binding activity. These were more likely to be associated with increased mucosal inflammation and severe clinical outcomes than BabA-positive strains that exhibited Leb binding activity. The underlying mechanism is unclear, and further studies will be necessary to investigate how the complex BabA-receptor network is functionally coordinated during the interaction of H pylori with the gastric mucosa.展开更多
基金Supported by (in part) A Grant-in-Aid for Scientific Research from the Ministry of Education,Science and Culture of Japan(21590631)the Project Research Fund from the Kochi University
文摘AIM:To evaluate the prevalence of Helicobacter pylori(H.pylori ) babA2 ,babB and a recombinant gene between babA2 and babB(babA2/B ),and their role in the development of atrophic gastritis in Costa Rican and Japanese clinical isolates.METHODS:A total of 95 continuous H.pylori-positive Costa Rican(41 males and 54 females;mean age,50.65 years;SD,± 13.04 years) and 95 continuous H.pylori-positive Japanese(50 males and 45 females;mean age,63.43;SD,± 13.21 years) patients underwent upper endoscopy from October 2005 to July 2006.They were enrolled for the polymerase chain reaction(PCR)-based genotyping of the H.pylori babA2 ,babB and babA2/B genes.Statistical analysis was performed using the χ2 test and the Fisher's exact probability test and multivariate analysis was performed by logistic regression adjusting for gender and age.P < 0.05 was regarded as statistically significant.RESULTS:The PCR-based genotyping of 95 Costa Rican and 95 Japanese isolates showed a higher prevalence of babA2 in Japan(96.8%) than in Costa Rica(73.7%),while that of babA2/B was higher in Costa Rica(11.6%) than in Japan(1.1%).In Costa Rican isolates only,babA2 was significantly associated with atrophic gastritis(P = 0.01).CONCLUSION:These results suggest that the status of babA2 and babA2/B shows geographic differences,and that babA2 has clinical relevance in Costa Rica.
基金(in part) National Institutes of Health Grants, R01 DK62813
文摘Interactions between BabA and Lewis b (Leb) related antigens are the best characterized adhesin-receptor interactions in Helicobacter pylori (H pylori). Several mechanisms for the regulation of BabA expression are predicted, including at both transcriptional and translational levels. The formation of chimeric proteins (babA /B or babB /A chimeras) seems to play an especially important role in translational regulation. Chimeric BabB/A protein had the potential to bind Leb; however, protein production was subject to phase variation through slipped strand mispairing. The babA gene was cloned initially from strain CCUG17875, which contains a silent babA1 gene and an expressed babA2 gene. The sequence of these two genes differs only by the presence of a 10 bp deletion in the signal peptide sequence of babA1 that eliminates its translational initiation codon. However, the babA1 type deletion was found only in strain CCUG17875. A few studies evaluated BabA status by immunoblot and confirmed that BabA-positive status in Western strains was closely associated with severe clinical outcomes. BabA-positive status also was associated with the presence of other virulence factors (e.g. cagA-positive status and vacA s1 genotype). A small class of strains produced low levels of the BabA protein and lacked Leb binding activity. These were more likely to be associated with increased mucosal inflammation and severe clinical outcomes than BabA-positive strains that exhibited Leb binding activity. The underlying mechanism is unclear, and further studies will be necessary to investigate how the complex BabA-receptor network is functionally coordinated during the interaction of H pylori with the gastric mucosa.
