Disruption of colonic barrier function and induction of mediator release by strains of Campylobacter jejuni that invade epithelial cells.
OBJECTIVE
To study the mechanisms by which Campylobacter jejuni (C. jejuni) causes inflammation and diarrhea. In particular, direct interactions with intestinal epithelial cells and effects on barrier function are poorly under-stood.


METHODS
To model the initial pathogenic effects of C. jejuni on intestinal epithelium, polarized human colonic HCA-7 monolayers were grown on permeabilized filters and infected apically with clinical isolates of C. jejuni. Integrity of the monolayer was monitored by changes in monolayer resistance, release of lactate dehydrogenase, mannitol fluxes and electron microscopy. Invasion of HCA-7 cells was assessed by a modified gentamicin protection assay, translocation by counting colony forming units in the basal chamber, stimulation of mediator release by immunoassays and secretory responses in monolayers stimulated by bradykinin in an Ussing chamber.


RESULTS
All strains translocated across monolayers but only a minority invaded HCA-7 cells. Strains that invaded HCA-7 cells destroyed monolayer resistance over 6 h, accompanied by increased release of lactate dehydrogenase, a four-fold increase in permeability to [(3)H] mannitol, and ultrastructural disruption of tight junctions, with rounding and lifting of cells off the filter membrane. Synthesis of interleukin (IL)-8 and prostaglandin E(2) was increased with strains that invaded the monolayer but not with those that did not.


CONCLUSIONS
These data demonstrate two distinct effects of C. jejuni on colonic epithelial cells and provide an informative model for further investigation of initial host cell responses to C. jejuni.
Beltinger
Johannes
J
Wolfson Digestive Diseases Centre, Nottingham University Hospital, QMC Campus, Nottingham NG7 2UH, United Kingdom.
del Buono
Jo
J
Skelly
Maeve M
MM
Thornley
John
J
Spiller
Robin C
RC
Stack
William A
WA
Hawkey
Christopher J
CJ
D000230:Adenocarcinoma / Q000473:pathology*; D018988:Bacterial Translocation / Q000502:physiology*; D016123:Campylobacter jejuni / Q000472:pathogenicity*; D045744:Cell Line, Tumor; D002463:Cell Membrane Permeability / Q000502:physiology*; D003110:Colonic Neoplasms / Q000473:pathology*; D015232:Dinoprostone / Q000378:metabolism; D004847:Epithelial Cells / Q000382:microbiology* / Q000473:pathology*; D006801:Humans; D016209:Interleukin-8 / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008353:Mannitol / Q000378:metabolism; D008954:Models, Biological
D016209:Interleukin-8; D008353:Mannitol; D007770:L-Lactate Dehydrogenase; D015232:Dinoprostone