Interaction of fimbriae of Haemophilus influenzae type B with heparin-binding extracellular matrix proteins

The interaction of the fimbriae of Haemophilus influenzae type b (Hib) with two heparin-binding extracellular matrix proteins, human fibronectin (Fn) and heparin-binding growth-associated molecule (HB-GAM) from mouse, were st udied. The fimbriated Hib strain 770235 fim+, as well as the recombinant st rain E. coli HB101(pMH140), which expressed Hib fimbriae, adhered strongly to Fn and HB-GAM immobilized on glass. Purified Hib fimbriae bound to Fn an d HB-GAM, and within the Fn molecule, the binding was localized to the N-te rminal 30,000-molecular-weight (30K) and 40K fragments, which contain hepar in-binding domains I and II, respectively. Fimbrial binding to Fn, HB-GAM, and the 30K and the 40K fragments was inhibited by high concentrations of h eparin, The results show that fimbriae of Hib interact with heparin-binding extracellular matrix proteins. The nonfimbriated Hib strain 770235 fim- ex hibited a low level of adherence to Fn but did not react with HB-GAM, indic ating that Hib strains also possess a fimbria-independent mechanism to inte ract with Fn.