Induction of the HP0102 gene in AGS-adhered Helicobacter pylori strains. A, RNA was extracted from H. pylori strain G27 (A) or different H. pylori strains (B) after adherence to AGS cells (adhered) and from unadhered H. pylori incubated under identical conditions without cell line (unadhered - AGS) or collected from the supernatants of infected AGS cells (unadhered + AGS). HP0102 expression was estimated by quantitative reverse transcription polymerase chain reaction analysis. RNA was extracted 2, 5, and 8 hours after adherence of strain G27 to AGS cells and 2 hours after adherence of the other strains. Relative expression levels were calculated as fold induction of gene expression in adhered bacteria, considering the expression in unadhered bacteria grown without AGS at 2 hours arbitrarily as 1. Bar diagram represents the mean value ± SD of at least 3 experiments. The statistical significance of differences (P values) in expression of the HP0102 gene between the unadhered (−AGS) and adhered H. pylori cells were obtained by the Student t test and are indicated. No statistical significance was obtained in differences of HP0102 expression between unadhered (−AGS) bacteria and unadhered (+AGS) bacteria. *P ≤ .05 and **P ≤ .01. Abbreviation: NS, not significant.