Tl. Mynott et al., DETECTION OF ATTACHMENT OF ENTEROTOXIGENIC ESCHERICHIA-COLI (ETEC) TOHUMAN SMALL-INTESTINAL CELLS BY ENZYME-IMMUNOASSAY, FEMS immunology and medical microbiology, 10(3-4), 1995, pp. 207-218
Simple immunoassays were developed to study the binding between entero
cytes of the small intestine and other cell types, and enterotoxigenic
Escherichia coil (ETEC). CFA/I or CFA/II pilus protein or CFA-positiv
e E. coil bacteria were immobilised in wells of microtitre plates and
incubated with vesicles or crude mucus prepared from human brush borde
r enterocytes. Binding of the cell preparations was detected by adding
specific rabbit anti-brush border IgG followed by urease-labelled goa
t anti-rabbit IgG and urea substrate. The binding of purified CFA/I to
human or rabbit small intestine, human oral epithelial cells or Caco-
2 cells was detected with specific anti-CFA/I IgG. Both human brush bo
rder and mucus-derived preparations were able to attach to ETEC. The b
inding was CFA-specific and strong enough to withstand several washing
s. In contrast, CFA/I did not bind to small intestinal cells of non-hu
man small intestinal origin, indicating that there may be important di
fferences in affinity between receptors present on human small intesti
nal cells and cells of non-human small intestinal origin. Antibodies d
irected against human small intestinal and non-small intestinal cells
did not cross-react with either preparation, indicating that receptors
between these different cell sources are different. The EIA proved us
eful during the identification of a newly-recognised 15 kDa bacterial
surface component of ETEC strain H10407P, which may function as a puta
tive attachment factor. The EIAs developed in this study were easy to
perform and multiple tests could be performed on small samples, includ
ing biopsy samples obtained during endoscopy.