CagA/cytotoxic strains of Helicobacter pylori and interleukin-8 in gastric epithelial cell lines.
OBJECTIVE
To investigate: (1) whether Helicobacter pylori directly induces interleukin-8 (IL-8) message expression and protein secretion in established gastric epithelial cell lines; and (2) if CagA/cytotoxin positive and negative strains of H pylori differ in their ability to induce epithelial IL-8.


METHODS
Gastric epithelial cell lines were co-cultured with H pylori NCTC 11637 and 10 clinical isolates (four cytotoxic, six non-cytotoxic) and secreted IL-8 was measured by enzyme linked immunosorbent assay (ELISA). Specific induction of gastric epithelial IL-8 mRNA was examined by reverse transcription and polymerase chain reaction (RT-PCR) amplification.


RESULTS
H pylori (NCTC 11637) induced IL-8 secretion from three gastric epithelial cell lines (KATO-3, ST42, AGS) but not from MKN 45 (gastric) or intestinal (SW480, HT29) cell lines. H mustelae did not stimulate IL-8 secretion from KATO-3, ST42, and AGS cells. H pylori induced IL-8 secretion was reduced by heat killing, sonication, freeze thawing or formalin fixation of the bacteria. CagA/cytotoxin positive strains of H pylori induced significantly higher IL-8 secretion than CagA/cytotoxin negative strains in the three positive gastric epithelial cell lines (KATO-3, ST42: p < 0.01; AGS: p < 0.02). A significant increase (p < 0.01) in the expression of IL-8 mRNA relative to G3PDH mRNA was observed in KATO-3 cells after three hours of co-culture with CagA/cytotoxin positive strains.


CONCLUSIONS
H pylori directly increases gastric epithelial IL-8 mRNA expression and IL-8 protein secretion in a strain specific manner. Induction of epithelial IL-8 by CagA/cytotoxin positive strains is likely to result in neutrophil chemotaxis and activation and thus mucosal damage. These observations on epithelial IL-8 may explain the association between CagA/cytotoxin positive strains and gastroduodenal disease.
Department of Clinical Medicine, St James's University Hospital, Leeds.
J E
JE
Crabtree
S M
SM
Farmery
I J
IJ
Lindley
N
N
Figura
P
P
Peichl
D S
DS
Tompkins
D000818:Animals; D000942:Antigens, Bacterial / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D001431:Bacteriological Techniques; D002460:Cell Line; D004847:Epithelial Cells; D004848:Epithelium / Q000276:immunology / Q000382:microbiology; D015964:Gene Expression Regulation, Bacterial; D016480:Helicobacter pylori / Q000276:immunology / Q000378:metabolism*; D016209:Interleukin-8 / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis*; D013270:Stomach / Q000166:cytology / Q000276:immunology / Q000382:microbiology*
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D016209:Interleukin-8; D012333:RNA, Messenger; C080866:cagA protein, Helicobacter pylori