Induction of interleukin-8 secretion from gastric epithelial cells by a cagA negative isogenic mutant of Helicobacter pylori.
The ability of Helicobacter pylori strains to induce interleukin-8 (IL-8) gene expression and protein secretion from gastric epithelial cell lines in vitro is variable. This cellular response is associated with bacterial expression of the CagA protein present in type I H pylori strains. To determine the role of CagA in this host cell response, an isogenic cagA negative mutant, N6.XA3, was constructed. The cagA negative isogenic mutant and the wild-type parental cagA positive strain, N6, were cocultured with AGS, ST-42 and KATO-3 gastric epithelial cell lines and secreted interleukin-8 assayed by enzyme linked immunosorbent assay. In all three cell lines there was no significant difference in the IL-8 secretion induced by the cagA negative isogenic mutant, N6.XA3, and the wild-type parent strain, N6. These studies show that CagA is not the inducer of IL-8 secretion from gastric epithelial cells. As all wild-type CagA positive strains studied to date induce IL-8, the bacterial factor(s) inducing this inflammatory response is closely associated with the expression of CagA.
Division of Medicine, St James's University Hospital, Leeds.
J E
JE
Crabtree
Z
Z
Xiang
I J
IJ
Lindley
D S
DS
Tompkins
R
R
Rappuoli
A
A
Covacci
D000942:Antigens, Bacterial; D001426:Bacterial Proteins / Q000502:physiology*; D002478:Cells, Cultured / Q000378:metabolism; D005753:Gastric Mucosa / Q000378:metabolism*; D015870:Gene Expression; D016480:Helicobacter pylori / Q000737:chemistry*; D016209:Interleukin-8 / Q000235:genetics / Q000378:metabolism*
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D016209:Interleukin-8; C080866:cagA protein, Helicobacter pylori