NONLETHAL ADHERENCE TO HUMAN NEUTROPHILS MEDIATED BY DR ANTIGEN-SPECIFIC ADHESINS OF ESCHERICHIA-COLI

Uropathogenic Escherichia call strains express a variety of adhesins, including members of the Dr adhesin family such as the Dr hemagglutini n, AFAI, and AFAIII. Certain E. coli adhesins (e.g., type 1 and S fimb riae) are known to mediate adherence to human polymorphonuclear leukoc ytes (PMNs). The receptor on erythrocytes for Dr family adhesins, deca y accelerating factor, is also present on PMNs. To determine whether D r family adhesins mediate adherence to PMNs and to characterize the sp ecificity and consequences of such adherence, we studied agglutination of PMNs and adherence to PMNs by recombinant E. call strains expressi ng various mannose-resistant or mannose-sensitive adhesins, in the pre sence or absence of inhibitors of adherence. Dr family adhesins, like type 1 fimbriae, mediated concentration-dependent adherence to PMNs. A dherence to PMNs was mannose sensitive for type 1 fimbriae but mannose resistant for Dr family adhesins, Chloramphenicol inhibited PMN adher ence for the Dr hemagglutinin with the same potency as that with which it inhibited hemagglutination, but it was inactive against PMN adhere nce and hemagglutination mediated by other members of the Dr adhesin f amily. In contrast to PMN adherence mediated by type 1 fimbriae, adher ence mediated by the Dr hemagglutinin did not lead to significantly in creased bacterial killing. These data suggest that Dr family adhesins mediate a novel pattern of adherence to PMNs, probably by recognizing decay accelerating factor, with minimal consequent bacterial killing.