EFFECT OF CLOSTRIDIUM-DIFFICILE TOXIN-A ON HUMAN INTESTINAL EPITHELIAL-CELLS - INDUCTION OF INTERLEUKIN-8 PRODUCTION AND APOPTOSIS AFTER CELL DETACHMENT
Yr. Mahida et al., EFFECT OF CLOSTRIDIUM-DIFFICILE TOXIN-A ON HUMAN INTESTINAL EPITHELIAL-CELLS - INDUCTION OF INTERLEUKIN-8 PRODUCTION AND APOPTOSIS AFTER CELL DETACHMENT, Gut, 38(3), 1996, pp. 337-347
Clostridium difficile is the aetiological agent of pseudomembranous co
litis, and animal studies suggest the essential role of secreted toxin
A in inducing disease. This study examined the biological responses t
o toxin A by human intestinal epithelial cells. Confluent monolayers o
f Caco2, HT29, and T84 cells and primary epithelial cells in organ cul
tures of human colonic biopsy specimens and after detachment with EDTA
were studied. Interleukin 8 was assayed using enzyme linked immunosor
bent assay (ELISA). Purified C difficile toxin A induced cell rounding
and detachment of monolayers of the epithelial cell lines. Cells in d
etached monolayers initially remained viable while adherent to each ot
her. Subsequently, an increasing number of apoptotic cells appeared in
suspension. Exposure to toxin A for 24 hours induced interleukin 8 pr
oduction in T84 and HT29 cells. Toxin A also induced epithelial cell r
ounding, detachment, and apoptosis in organ cultures of human colonic
biopsy specimens. During culture (in medium only), EDTA detached colon
ic epithelial cells produced interleukin 8 and cell death occurred by
apoptosis. Colonic disease by C difficile may be initiated by toxin A
mediated induction of epithelial cell interleukin 8 production and apo
ptosis after cell detachment from the basement membrane. Studies on is
olated (toxin untreated) colonic epithelial cells suggest that interle
ukin 8 production and apoptosis occur as a consequence of cell injury
and detachment.