Ninety Cell Cycle inhibitor clinical isolates obtained from gastric diseases were examined by in-house ABA-ELISA to evaluate whether the degree of MBS of BabA and SabA correlated with gastric lesion types. The degree of BabA MBS was significantly greater in the cancer than in

the non-cancer group (0.514 ± 0.360 vs. 0.693 ± 0.354; P= 0.019), whereas there was no significant difference in the degree of SabA MBS between cancer and non-cancer groups (0.656 ± 0.395 vs. 0.689 ± 0.428; P= 0.704) (Fig. 3). Overall, a weak positive correlation between BabA and SabA MBS was found (r= 0.418) (Fig. 4). The positive correlation of the two MBS was higher in the cancer than in the non-cancer group (r= 0.598 and 0.288, respectively). Furthermore, all 90 clinical isolates were classified into two groups by their BabA MBS; more (BabA-high-binding group, n= 41) and less ALK inhibitor (BabA-low-binding

group, n= 49) than the average of the BabA MBS (OD450= 0.600). Interestingly, the mean SabA MBS was significantly higher in the BabA-high-binding than in the BabA-low-binding group (P < 0.0001) (Fig. 4b). In contrast, when the isolates were classified into two groups by their SabA MBS; more (SabA-high-binding group) and less (SabA-low-binding group) than the average of the SabA MBS (OD450= 0.669), no significant difference was found between these two groups in the mean BabA MBS (P= 0.055). The greatest diversity in the babA2 gene was in the nucleotide sequence positioned from 612 to 1046 (86% mean identity) including segment one, corresponding to the predicted amino acids positioned from 306 to 334. Five distinct families of variants were identified; designated allele groups Amrubicin AD1 (babA2 diversity allele 1), AD2, AD3, AD4 and AD5 (24). To determine whether the diversity of the BabA middle region (AD1–5) influences the MBS of BabA, 21 randomly

selected isolates, including strains with high to low BabA functional binding, were subjected to sequence analysis of the babA2 gene. Nineteen isolates belonged to AD2 (90.5%) and two to AD3 (9.5%) (Fig. 5a); their variable BabA functional binding strength (data not shown) suggest there is no relationship between allelic diversity of the BabA middle region and its MBS. Phylogenetic and molecular evolutionary analysis demonstrated that no specific evolutional mutation of BabA correlated with its MBS (Fig. 5b). Major H. pylori adhesins, BabA and SabA, mediate adherence of H. pylori to Leb or sialic acid epitopes, respectively, on human gastric epithelium. The prevalence of babA2 is 85% in Japan (15), 100% in Taiwan (16), 44% in Brazil (10) and 35%∼60% in the European countries (23), indicating it has geographic variation. In this study we examined the prevalence of the babA2 genotype in 120 Japanese isolates, and found it in 97.5% (data not shown).

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