Comparative Analysis of the Interaction of Helicobacter pylori with Human Dendritic Cells, Macrophages, and Monocytes

Cytokines released by monocytes treated with H. pylori. A total of 5 × 10⁵ monocytes were infected with H. pylori (MOI of 10; circles) for 1 h; the bacteria was washed out, and the cells were afterwards incubated for 24 h. Controls included monocytes treated with 100 ng/ml LPS (squares) or incubated with medium alone (diamonds). Concentrations of cytokines in the supernatants were determined by ELISA. Each symbol per condition represents the data obtained with cells from one donor. Horizontal lines show the median values of 10 experiments. *, P < 0.05 (Friedman test and Dunn's multiple comparison test).

H. pylori-activated DCs are characterized by impaired phagocytosis, enhanced proliferation of allogeneic CD4⁺ and CD8⁺ T cells, and secretion of proinflammatory cytokines as well as IL-10, but reduced production of MIF. A total of 5 × 10⁵ immature DCs were incubated with H. pylori (MOI of 10; circles), LPS (100 ng/ml; squares), recombinant cytokines ([CKT] 352 ng/ml prostaglandin E2, 10 ng/ml TNF-α, 10 ng/ml IL-1β, and 10 ng/ml IL-6; triangles), or medium alone (diamonds) for 1 h and afterwards cultured for 24 h. (A) The cells were incubated with FITC-labeled dextran for 30 min at 37°C and washed, and the uptake was determined by flow cytometry. Bars indicate the mean values ± standard deviations of data obtained for seven donors (values for unspecific binding at 4°C were subtracted). (B) DCs were incubated with allogeneic CFSE-labeled, HLA-DR-depleted T cells in graded ratios for 6 days. Percentages of proliferated T cells (CD4⁺ CD8⁺) were determined by FACS as CFSE^low cells. Each symbol represents an experiment using cells from one individual donor. Horizontal lines show the median values of at least 10 experiments. (C) Concentrations of cytokines in the supernatants determined by ELISA. Each symbol per condition represents data obtained for one donor. Horizontal lines indicate the median of nine experiments.*, P < 0.05 (Friedman test and Dunn's multiple comparison test).

H. pylori-activated M1 macrophages are characterized by impaired phagocytosis, enhanced proliferation of allogeneic CD8⁺ T cells, and secretion of mainly proinflammatory cytokines. A total of 5 × 10⁵ M1 macrophages were incubated with H. pylori (MOI of 10; circles), LPS (100 ng/ml; squares), or medium alone (diamonds) for 1 h and afterwards cultured for 24 h. (A) The cells were incubated with FITC-labeled dextran for 30 min at 37°C and washed, and the uptake was determined by flow cytometry. Bars indicate the mean values ± standard deviations of data obtained for seven donors (values for unspecific binding at 4°C were subtracted). (B) M1 macrophages were cocultured with allogeneic CFSE-labeled, HLA-DR-depleted T cells in graded ratios for 6 days. Percentages of proliferated T cells (CD4⁺ CD8⁺) were determined by FACS as CFSE^low cells. Each symbol represents an experiment using cells from one individual donor. Horizontal lines indicate the median of at least six experiments. (C) Concentrations of cytokines in the supernatants determined by ELISA. Each symbol per condition represents data obtained for one donor. Horizontal lines show the median values of eight experiments.*, P < 0.05 (Friedman test and Dunn's multiple comparison test).