Interleukin-8 response of gastric epithelial cell lines to Helicobacter pylori stimulation in vitro.
Gastric infection with Helicobacter pylori activates a mucosal inflammatory response by mononuclear cells and neutrophils that includes expression of cytokines interleukin-1 beta (IL-1 beta), IL-6, tumor necrosis factor alpha, and IL-8. In this study, we analyzed the IL-8 response of human gastric cancer cell lines (Kato III, AGS, and MKN28) to H. pylori infection in vitro. IL-8 mRNA expression was detected by reverse transcription-PCR amplification of RNA extracted from epithelial cells after incubation with different H. pylori wild-type and mutant strains, and IL-8 secretion was measured by an enzyme-linked immunosorbent assay. Exposure to viable H. pylori induced IL-8 mRNA and protein synthesis in all three gastric cell lines but not in nongastric epithelial cell lines. Heat-killed H. pylori and a crude cytotoxin preparation did not induce significant IL-8 secretion. IL-8 mRNA peaked between 2 and 4 h postinfection, and IL-8 protein production was maximal 24 h postinfection. Exposure of gastric carcinoma cells to other gastrointestinal bacteria, such as Pseudomonas aeruginosa, Campylobacter jejuni, and Escherichia coli, but not Campylobacter fetus, induced IL-8 synthesis. Wild-type strains that expressed the vacuolating cytotoxin (Tox+) and a cytotoxin-associated gene (cagA) product (CagA+) induced significantly more IL-8 than did CagA- Tox- strains. However, there was no decrease in IL-8 induction by isogenic mutants of CagA-, Tox-, or Cag- Tox- strains or by a mutant lacking the urease subunits. These results indicate that exposure to H. pylori and other gram-negative organisms that do not colonize the gastric mucosa induces IL-8 production by gastric carcinoma cells in vitro. Although the CagA+ Tox+ phenotype of H. pylori is associated with enhanced IL-8 production by gastric cell lines, other bacterial constituents are clearly essential.
Sharma
S A
SA
Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee 37232-2605, USA.
Tummuru
M K
MK
Miller
G G
GG
Blaser
M J
MJ
D000942:Antigens, Bacterial; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001427:Bacterial Toxins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D003603:Cytotoxins / Q000235:genetics / Q000378:metabolism; D004848:Epithelium / Q000378:metabolism; D005753:Gastric Mucosa / Q000276:immunology*; D015870:Gene Expression; D016480:Helicobacter pylori / Q000276:immunology*; D006801:Humans; D016209:Interleukin-8 / Q000096:biosynthesis* / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D012333:RNA, Messenger / Q000032:analysis; D013045:Species Specificity; D013274:Stomach Neoplasms; D014018:Tissue Distribution; D014407:Tumor Cells, Cultured
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D003603:Cytotoxins; D016209:Interleukin-8; D012333:RNA, Messenger; C074689:VacA protein, Helicobacter pylori; C080866:cagA protein, Helicobacter pylori