The transcription of interleukin-8 in gastric epithelial cells downregulated by ORF10 of cag Ⅱ of Helicobacter pylori / 中华消化杂志

ABSTRACT

Objective Helicobacter pylori (H. pylori )contains more than 30 genes and many of them in cag pathogenicity island (cag PAI) composed of cag Ⅰ and cag Ⅱ are involved in eliciting the transcription of interleikin 8 (IL 8) and the induction of IL 8 protein secretion in gastric epithelial cells, although some genes are not involved. This study was designed to observe the effect of ORF10 of H. pylori cag Ⅱ on the transcription of IL 8 in gastric epithelial cells and to test the possibility that certain genes in the cag PAI also downregulate (modulate) the transcription and expression of IL 8 in gastric epithelial cells. Methods Three strains of H. pylori mutants with deletion of ORF10 gene (ORF10, namely 28 1, 28 2, 28 3) and L5F11 cells containing IL 8 reporter gene were constructed. The constructed L5F11 cells were co cultured with the above strains and the luciferase activity (IL 8 transcription) was measured in a scintillation counter and the concentration of IL 8 protein was assayed by enzyme linked immunosorbent assay (ELISA). Results The activities of luciferase induced by 3 strains of H. pylori mutants with deletion of ORF10 gene were much higher than that of the mother strain 26695 [ 28 1:(1.49 ? 0.27)?10 6 cpm vs. (0.67 ? 0.08 )? 10 6 cpm, P