Phagocytosis of Escherichia coli mediated by mannose resistant non-fimbrial haemagglutinin (NFA-1).

We examined the interaction between a urinary isolate of E. coli carrying non-fimbrial MR adhesin (NFA-1) and human polymorphonuclear leukocytes (PMN). We found that the organisms attach to PMN and the attachment was dose dependent and saturable. It was inhibited by isolated NFA-1, but not by mannoside. Recombinant plasmid encoding NFA-1 adhesin conferred binding capacity on a non-adhesive strain. The attachment of the bacteria carrying NFA-1 to PMN was associated with oxidative burst and inhibited by isolated NFA-1. The data taken together suggest that NFA-1 mediates the attachment of the bacteria to PMN. The attachment is followed by ingestion and killing of the organisms, but at a slower rate than with bacteria bound via type 1 fimbriae.