Identification and characterization of mouse small intestine mucosal receptors for Escherichia coli K-12(K88ab).

Adhesion of 3H-labeled Escherichia coli K-12(K88ab) to CD-1 mouse small intestine mucus and brush border preparations, immobilized on polystyrene, was studied. E. coli K12(K88ab) was shown to adhere readily to either crude mucus or brush border preparations, but not to bovine serum albumin. In contrast, the nearly isogenic E. coli K-12 strain, i.e., lacking the K88ab plasmid, did not bind well to either mucus, brush borders, or bovine serum albumin. The adhesion of E. coli K-12(K88ab) to both mucus and brush borders required pilus expression (i.e., growth at temperatures greater than 18 degrees C) and was inhibited by pretreatment of either mucus or brush borders with trypsin, pronase, or sodium metaperiodate and by the presence of D-galactosamine. Crude mucus was fractionated by gel filtration, and the proteins in receptor-containing fractions were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Separated proteins were Western blotted to nitrocellulose. Adhesion of 35SO4-labeled E. coli K-12(K88ab) and 35SO4-labeled E. coli K-12 to Western blots followed by autoradiography revealed two E. coli K-12(K88ab)-specific mucus receptor proteins (57 and 64 kilodaltons). Brush borders contained the same two receptor proteins present in mucus and an additional 91-kilodalton receptor protein.