Mannose‐specific adherence of Escherichia coli to BHK cells that differ in their glycosylation patterns

We measured the mannose-specific adherence of radiolabeled Escherichia coli, carrying type 1 fimbriae, to monolayers of wild-type baby hamster kidney (BHK) cells and to 3 ricin-resistant mutants defective in the synthesis of complex N-linked oligosaccharide units. RicR14, a mutant accumulating N-linked oligomannose units in its glycoproteins at the expense of complex (N-acetyllactosamine) units, bound the largest number of bacteria, about 4 times more than the wild-type cells. The mutant cells in suspension were also readily agglutinated by the bacteria, while no agglutination of wild-type cells occurred under the conditions used. RicR21, a mutant which accumulates hybrid structures, bound about twice as many bacteria as wild-type cells, and was agglutinated by the bacteria to a lesser extent than RicR14. Binding and agglutination of RicR19, also presumed to accumulate hybrid structures, were the same as those of RicR14. These results provide evidence that oligomannose and hybrid units of cell surface glycoproteins serve as preferred receptors for mannose-specific E. coli. Lectin-resistant mutants are therefore useful for the investigation of sugar-specific adherence.