Helicobacter pylori infection leads to chronic gastric inflammation. The current study determined the response of human immune system to this bacterium in vitro. Therefore we have established a Model that is composed of three kinds of immune cells: These are dendritic cells, NK-cells and T-cells. Human monocyte-derived dendritic cells (Mo-DC) were incubated with bacteria for 48 h. Intact H. pylori at a multitude of infection 5 (MOI 5) stimulated the expression of MHC class II (4- to 7-fold), CD80, and CD86 (10- to 12-fold) and the CD83 costimulatory molecule (>30-fold) as well as IL-12 secretion (>50-fold) in DCs, and thereby, strongly induced their maturation and activation. CD56+/CD16+ NK cells, as well as CD4+/CD45RA+ naive T cells, were isolated and incubated with DCs pulsed with intact bacteria or different cellular fractions. Co-culture of H. pylori-pulsed DCs with NK cells strongly induced the secretion of TNF-á and IFN-ã. Co-culture of naive T cells with H. pylori-pulsed DCs significantly enhanced TNF-á, IFN-ã and IL-2 secretion as well as T-bet mRNA levels, while GATA-3 mRNA was lowered. However, the effect appeared attenuated compared with co-culture with E. coli. A greater stimulation was seen with naive T cells and DCs pulsed with H. pylori membrane preparations. Intact H. pylori potently induced the maturation and activation of human monocyte-derived DC and thereby promote NK and Th1 responses. Th1-polarized T cells were induced especially by incubation with membrane preparations of H. pylori, suggesting that membrane proteins may account for the specific adaptive immune response.
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Helicobacter pylori infection leads to chronic gastric inflammation. The current study determined the response of human immune system to this bacterium in vitro. Therefore we have established a Model that is composed of three kinds of immune cells: These are dendritic cells, NK-cells and T-cells. Human monocyte-derived dendritic cells (Mo-DC) were incubated with bacteria for 48 h. Intact H. pylori at a multitude of infection 5 (MOI 5) stimulated the expression of MHC class II (4- to 7-fold), CD8...
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