FIG. 5.

H. pylori infection induces NF-κB binding activity. (A) Time course of NF-κB activation in MKN45, MKN28, and AGS cells infected with H. pylori, as evaluated by EMSA (left). Nuclear extracts from the indicated cells infected with H. pylori ATCC 49503 for the indicated times were mixed with ³²P-labeled NF-κB probe (MOI, 20:1). Competition assays were performed with nuclear extracts from these cells infected with H. pylori ATCC 49503 for 30 min (right). Where indicated, 100-fold excess amounts of each specific competitor oligonucleotide were added to the reaction mixture with labeled probe NF-κB (lanes 2 to 4). A supershift assay of NF-κB DNA binding complexes in the same nuclear extracts also was performed. Where indicated, appropriate antibodies (Ab) were added to the reaction mixture before the addition of the ³²P-labeled probe (lanes 5 to 9). Arrows indicate the specific complexes, while arrowheads indicate the DNA binding complexes supershifted by antibodies. (B) cag PAI products of H. pylori are required for the induction of NF-κB binding activity in MKN45 cells. Nuclear extracts from MKN45 cells infected with different densities (MOI) of wild-type strain 26695 or the isogenic mutant Δcag PAI for 1 h were analyzed for NF-κB. Representative results of three similar experiments are shown in each panel. WT, wild type.