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.
«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...
»