Purification and characterization of the CFA/I antigen of enterotoxigenic Escherichia coli.

摘要: The fimbral colonization factor antigen CFA/I of enterotoxigenic Escherichia coli was purified and characterized. initial purification step release these fimbriae from the bacterial cells by homogenization with a Waring blender. Common flagellar were avoided careful control growth conditions use nonmotile (H-) mutant prototype strain H-10407 (O78:H11). essential steps membrane filtration (Millipore Corp.), ammonium sulfate fractionation, negative diethylaminoethyl-Sephadex column chromatography. Yields approximately 4.0 mg protein per g (wet weight) bacteria. Purified is fimbrial molecule 7.0 nm in diameter has an average molecular weight 1.6 X 10(6), as determined sedimentation equilibrium. polymer identical subunits 23,800 N-terminal valine, 37% hydrophobic amino acid residues, 11 residues proline mol. retains its morphology, antigenicity, biological activity. exhibits mannose-resistant hemagglutination human group A, bovine, chicken erythrocytes, do CFA/I-positive This demonstrated sensitizing latex microbeads since cell-free not hemagglutinate erythrocytes. Thus, detached bacteria are monovalent; however, affinity for epithelial rabbit small intestine blocks adhesion These results demonstrate that good candidate oral vaccine immunoprotection against diarrhea caused E. coli.