Expression Of B7-1、B7-2and CD28in Peripheral Blood Mononuclear Cells And Gastric Antral Mucosa Of Patients With HP Infection

Objective:To explore the mechanism of helicobacter pylori infection in peptic ulcer, we compared the expression levels of B7-1、B7-2and CD28in peripheral blood mononuclear cells(PBMC) and distal gastric mucosal cells between Hp-infected groups (with/without peptic ulcer) and normal control group.Methods:Sixty children with gastrointestinal tract symptoms were selected, and then accepted gastroscopy and biopsy, the specimens got from gastric antrum. Blood samples were also needed.60patients were divided into three groups:group(A):children with gastrointestinal tract symptoms, and gastroscopy showed gastric ulcer, with HP-positive,20cases; group(B):children with gastrointestinal tract symptoms, but gastroscopy showed basically normal, with HP-positive,20cases; control group(C): children with gastrointestinal tract symptoms, gastroscopy and Hp were both negative,20cases. The expression of B7-1, B7-2, CD28mRNA in peripheral blood mononuclear cells and gastric antrum mucosal cells, the levels of relevant coding proteins in gastric antrum mucosal cells were detected through immunohistochemistry and semi-quantitative reverse transcriptase polymerase chain reaction. Then compared whether there were differences among the indices. Finally, linear regression analysis was used to analyze the correlation between B7-1, B7-2, CD28mRNA and relevant coding proteins.Results:1. The immunohistochemistry showed that B7-1and B7-2proteins mainly expressed in the epithelium cells of antral mucosa and mononuclear cells of lamina propria, while CD28protein mainly expressed in mononuclear cells. The amount of mononuclear cells of lamina propria was larger in group A and group B than group C. In group A and B, the level of B7-1and CD28proteins were significantly higher than group C (P<0.05), but no significant differences between group A and group B (P>0.05); the expression of B7-2protein in three groups had no significant differences (P>0.05).2. The expression of B7-1and CD28mRNA in distal gastric mucosal cells was higher in group A and B than in group C (P<0.05), however the expression had no differences in group A and group B(P>0.05). The expression of B7-2mRNA in three groups was the same level.3. The expression of B7-1, B7-2and CD28mRNA had no difference in the three groups.4. Linear regression analysis showed that there were positive correlation between transcription levels (RT-PCR) and relevant coding protein levels (immunohistochemistry) of the three co-stimulatory molecules in local gastric antral mucosa.Conclusion:1. The immunohistochemistry shows that, the expression of B7-1, B7-2and CD28proteins can be found in the lamina propria of the Hp-infected children, so the results explain that Hp can stimulate the host to produce specific immune response.2. The transcription and translation levels of B7-1and CD28have increased in the lamina propria of Hp-infected children, while the level of B7-2has no change, this indicates that local cellular immune acts as the main factor in the inflammatory injury process after Hp infection.3. The level of B7-1, B7-2and CD28mRNA does not change a lot in peripheral blood mononuclear cells (PBMC) after Hp-infection, so the conclusion shows that immune response takes place in local lamina propria, with no serious influence to the whole body.