代谢途径图.pdfVIP

INFECTION AND IMMUNITY, July 1999, p. 3302–3307 Vol. 67, No. 7 0019-9567/99/$04.00 0 Copyright © 1999, American Society for Microbiology. All Rights Reserved. Role of Lactosyl Glycan Sequences in Inhibiting Enteropathogenic Escherichia coli Attachment ROSA P. VANMAELE, LOUIS D. HEERZE, AND GLEN D. ARMSTRONG* Department of Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada Received 23 December 1998/Returned for modification 24 February 1999/Accepted 12 April 1999 Previously, we found that asialo-lactosamine sequences served as receptors for enteropathogenic Escherichia coli (EPEC) binding to Chinese hamster ovary (CHO) cells. In the present report, we have extended these earlier results by examining the ability of lactosamine- or fucosylated lactosamine-bovine serum albumin (BSA) glycoconjugates to inhibit EPEC, strain E2348/69, binding to HEp-2 cells. We found that, consistent with our previous findings with CHO cells, N -acetyllactosamine-BSA was the most effective inhibitor of EPEC localized adherence to HEp-2 cells, with Lewis X-BSA being the next best inhibitor. Further investigation revealed that coincubating EPEC E2348/69 with these BSA glycoconjugates alone caused a decrease in the expression of the bundle-forming pilus structural subunit (BfpA) and intimin by the bacteria. BfpA and intimin expression were reduced to the greatest extent by N -acetyllactosamine–BSA and Lewis X-BSA, respectively. These results suggest that the glycocon