FIG. 2.

The cag PAI of H. pylori is required for induction of MCP-1 expression in MKN45 cells. (A) cag PAI⁺ H. pylori strains (ATCC 49503, OHPC0001, and OHPC0003) are capable of inducing MCP-1 mRNA expression in MKN45 cells compared with a cag PAI⁻ H. pylori strain (OHPC0002). Total RNA was extracted from the cells infected with H. pylori for 6 h and used for RT-PCR. (B) Role of cag PAI in H. pylori-induced MCP-1 promoter and enhancer activity. MKN45 cells were transfected with 1 μg of either pGLM-PRM or pGLM-ENH firefly luciferase reporter and 2 μg of the pRL-TK Renilla luciferase reporter as an internal control. Twenty-four hours later, cells were treated with medium alone (control), with medium containing H. pylori, or with medium containing H. pylori culture supernatants. MKN45 cell lysates were prepared 6 h after stimulation and analyzed for luciferase activity. Data represent means ± standard deviations from three independent experiments and are expressed as fold induction relative to the basal level measured in cells treated with medium alone (control).