[HpaA promotes gastric mucosa injury via stimulating IL-21 secretion of T cells].

: Objective To demonstrate HpaA can intensify the inflammatory response and gastric mucosa injury by IL-21 from induced T cell. Methods Biopsy specimens were taken from gastric mucosa of 56 patients with H.pylori infection before and after H.pylori radical elimination by endoscope. The levels of IL-21, matrix metalloproteinase-2 (MMP2) and MMP9 from the biopsy were detected by reverse transcription PCR and Western blot analysis. Meanwhile, the recombinant HpaA was cloned, expressed and purified to stimulate the magnetic cell sorting CD3+ T cells from healthy donors' peripheral blood mononuclear cells (PBMCs), and the level of IL-21 in the supernatant fluid was detected by ELISA. Thereafter, AGS cells were cultured and Western blot analysis was performed to detect the levels of MMP2 and MMP9 in the AGS cells with human IL-21 and anti-IL-21 antibody treatment for 24 hours. Results The protein levels of IL-21 and MMP2 and MMP9 in gastric mucosa infected with H. pylori was significantly higher than that in gastric mucosa after radical treatment of H. pylori. Meanwhile, the recombinant HpaA promoted IL-21 secretion by induced CD3+T cells in vitro. IL-21 stimulated the expression of MMP2 and MMP9 in AGS cells. When IL-21 was blocked by the antibody, the levels of MMP2 and MMP9 in AGS cells decreased significantly. Conclusion HpaA plays a significant role in the gastric mucosa injury caused by H.pylori infection through IL-21 from induced T cells.