Partial purification and characterization of two non K99 mannose-resistant haemagglutinins of Escherichia coli B41.

A K99-variant of Escherichia coli B41 was produced by growing the parent strain in the presence of antiserum to E. coli K12K99. Two mannose-resistant and eluting (MRE) haemagglutinins with molecular weights greater than 20 x 10(6) were extracted from the cell surface of the variant. One was an anionic antigen, partially purified by ammonium sulphate and isoelectric point precipitation, which adhered to calf intestinal brush borders; it was a protein composed of subunits with mol. wt 34000. Electron microscopy showed that this material did not have a regular fimbrial appearance, but contained some fine fibrillar structures. A second MRE haemagglutinin which was also partially purified by ammonium sulphate precipitation, had a definite fimbrial structure, being a protein composed of two subunits of mol. wt 49500 and 48000. This antigen was probably responsible for the fimbrial appearance of the K99-variant, but it was antigenically distinct from the anionic adhesin and did not adhere to calf intestinal brush borders.