Fig. 5: ADM promotes IFN-γ-producing T-cell responses via PI3K–AKT and STAT3 activation.

a Representative immunofluorescence staining images showing RAMP2-expressing (red) CD3⁺ T cells (green) and IFN-γ-expressing (red) CD3⁺ T cells (green) in gastric mucosa of H. pylori-infected patients. Scale bars: 20 µ (left), 100 µ (right). b The correlation between ADM expression and IFN-γ expression in gastric mucosa of patients was analyzed. c, d T cells were stimulated with ADM (10, 50, and 100 nM) (c), or pretreated with Wortmannin (a PI3K–AKT inhibitor) and FLLL32 (a STAT3 inhibitor), and then stimulated with ADM (100 nM) (d) for 5 days as described in “Materials and methods”. T-cell proliferation and IFN-γ production was assessed by flow cytometry and statistically analyzed (n = 3). The results are representative of three independent experiments. e T cells were stimulated with the culture supernatants from WT H. pylori-infected human primary gastric epithelial cells in the presence or absence of ADM fragment 22–52 (an ADM receptor antagonist) (AMA) for 5 days as described in Methods. T-cell proliferation and IFN-γ production was assessed by flow cytometry and statistically analyzed (n = 3). The results are representative of three independent experiments. f T cells were stimulated with ADM (100 nM) at different time points, or pretreated with Wortmannin (a PI3K–AKT inhibitor) or FLLL32 (a STAT3 phosphorylation inhibitor), and then stimulated with ADM (100 nM) for 6 h. AKT and p-AKT proteins, and STAT3 and p-STAT3 proteins, were analyzed by western blot. Spearman rank-correlation analysis was used for c, *P < 0.05, and **P < 0.01 for groups connected by horizontal lines compared. sup supernatants.