CHARACTERIZATION OF THE C-TERMINAL DOMAINS OF INTIMIN-LIKE PROTEINS OF ENTEROPATHOGENIC AND ENTEROHEMORRHAGIC ESCHERICHIA-COLI, CITROBACTER-FREUNDII, AND HAFNIA-ALVEI

Surface proteins called intimins (Int), which are homologous to the in vasin protein (Inv) of Yersinia spp., play a role in inducing brush bo rder damage, termed attachment and effacement, which follows infection by enteropathogenic and enterohemorrhagic Escherichia coli, Citrobact er freundii biotype 4280, and Hafnia alvei. Maltose-binding protein (M BP) fusions containing the C-terminal 280 amino acids of Int-like prot eins of strains of enteropathogenic E. coli, enterohemorrhagic E. coli , H. alvei, and C. freundii biotype 4280 and of Yersinia pseudotubercu losis Inv were constructed and purified. The 3' end of the gene for th e H. alvei Int-like protein was sequenced and showed homology to corre sponding regions of other Int-encoding genes. Binding of MBP-Int-like and MBP-Inv fusion proteins to HEp-2 cells was demonstrated by immunof luorescence microscopy and by fluorescence-activated cell sorting. MBP -Inv induced attachment and spreading of HEp-2 cells to plastic-coated wells, but MBP-Int-like fusion proteins did not. Preincubation of HEp -2 cells with MBP-Inv, but not with MBP-Int-like fusion proteins, inhi bited MBP-Inv-induced cell attachment. Fixed staphylococci and fluores cent polymer microspheres coated with both MBP-Int like and MBP-Inv fu sion proteins showed enhanced adhesion to HFp-2 cells. These fusion pr oteins will facilitate studies of the role of intimin in the pathogene sis of diarrhea associated with members of the family Enterobacteriaec eae that induce attachment and effacement.