Expression of Interleukin-18, a Th1 cytokine, in human gastric mucosa is increased in Helicobacter pylori infection.
Interleukin-18 (IL-18), a cytokine that promotes Th1 responses, is processed to the active mature protein by caspase-1. The effects of Helicobacter pylori infection on gastric IL-18 and caspase-1 were examined. In antral mucosa, IL-18 mRNA expression was greater (P<.01) in H. pylori-positive (n=40) than in H. pylori-negative patients (n=29) with normal mucosa. Inactive precursor (24 kDa) and mature (18 kDa) IL-18 were present in antral biopsy specimens from uninfected and infected subjects. In corpus mucosa, mature IL-18 and a 16-kDa protein, corresponding to inactive IL-18, were present. Active caspase-1 p20 subunit was detected in antral and corpus mucosa of infected and uninfected subjects. These data show that, although H. pylori infection is associated with increased antral IL-18 mRNA expression, mature IL-18 protein and active caspase-1 p20 are present in mucosa of both H. pylori-infected and -uninfected subjects. IL-18 may have an important role in promoting gastric Th1 responses in H. pylori infection.
Tomita
T
T
Molecular Medicine Unit, St. James's University Hospital, Leeds LS9 7TF, United Kingdom.
Jackson
A M
AM
Hida
N
N
Hayat
M
M
Dixon
M F
MF
Shimoyama
T
T
Axon
A T
AT
Robinson
P A
PA
Crabtree
J E
JE
D000328:Adult; D000368:Aged; D000942:Antigens, Bacterial; D001426:Bacterial Proteins / Q000378:metabolism; D020170:Caspase 1 / Q000378:metabolism; D002460:Cell Line; D004847:Epithelial Cells; D005260:Female; D005753:Gastric Mucosa / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology*; D005756:Gastritis / Q000175:diagnosis; D016481:Helicobacter Infections / Q000276:immunology* / Q000382:microbiology; D016480:Helicobacter pylori / Q000276:immunology*; D006801:Humans; D020382:Interleukin-18 / Q000096:biosynthesis* / Q000235:genetics; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D020382:Interleukin-18; D012333:RNA, Messenger; C080866:cagA protein, Helicobacter pylori; D020170:Caspase 1