The Relationship Between Helicobacter Pylori Infection And The Expression Of TGF-β1 And B7-H1 In Gastric Mucosal Epithelial Cells

Objective To explor the influence of different dose of Helicobacter pylori on the expression of transforming growth factor (TGF-β1) and B7-H1 in the infected gastric mucosal epithelial cell and the bacterial factors which influence the expression of TGF-β1. To confirm that H. pylori can induce the expression of TGF-β1 and B7-H1 to inhibit the host immune function in gastric mucosal epithelial cell.Methods①We investigated the expression of TGF-β1 of human gastric mucosal epithelial cells infected with different concentration (1.0×109 CFU/ml, 4.0×109 CFU/ml, 8.0×109 CFU/ml) of H. pylori(NCTC 11637) in different time-point (0h,0.5h,1h,1.5h,2h,4h,8h,12 h ) , and compared with the expression of TGF-β1 between the deactivated H. pylori group and activated H. pylori group. The blank group is the gastric mucosa epithelial cells which does not infect H. pylori. To detect expression of TGF-β1 in infected cell culture supernatant by Chain enzyme immunosorbent assay (ELISA) and the expression of B7-H1 mRNA by in situ hybridization.②At the same time, the middle concentration of deactivated H. pylori and in vitro gastric mucosal cells were incubated for 2 hours and 12 hours , to detect expression of TGF-β1 in the cells and cell culture supernatant.③In vitro gastric mucosal cells were incubated with H. pylori bacterial supernatant and sedimentation by ultrasonic crushing and centrifugation and with H. pylori bacterial supernatant and sedimentation after boiling respectively, to detect expression of TGF-β1 in the cells and cell culture supernatant after 2h,12h.Results①Compared to the control group , the expression of TGF-β1 was significantly increased after stimulation with different concentration of activated H. pylori in different time-point (P <0.05). The expression of TGF-β1 secretion group has a similar dynamic trend, and the highest expression is the middle concentration group (P <0.05);②There was no difference between the middle concentration of deactivated H. pylori group and the same concentration of activated H. pylori group (P﹥0.05).③The expression of TGF-β1 in the H. pylori bacterial supernatant group was significantly increased higher than the blank group and the H. pylori bacterial sedimentation group (P <0.05), and the H. pylori bacterial supernatant group after boiling was significantly lower than the H. pylori bacterial supernatant group (P <0.05), but there was no difference between H.pylori sedimentation group after boiling and not boiling (P﹥0.05). the B7-H1 expressions of different concentration groups which the H. pylori and gastric mucosal epithelial cells co-cultured 12h are higher than the blank group (P<0.05) by in situ hybridization, and the middle concentration group is the highest expression. TGF-β1 and B7-H1 mRNA are positively correlated (rs=0.628, P<0.01).Conclusion H.pylori can induce the gastric mucosal epithelial cells to express the TGF-β1, the factor was the soluble protein in the H. pylori thalline. At the same time, H. pylori can induce the B7-H1 expression increased in gastric mucosal epithelial cells, and TGF-β1 and B7-H1 mRNA are positively correlated .So, H. pylori can inhibit the host immune response and participate the process of immune escape by increased the expressions of TGF-β1 and B7-H1.