JAC Advance Access published online on July 10, 2007
Journal of Antimicrobial Chemotherapy, doi:10.1093/jac/dkm251
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Inhibition of P-fimbriated Escherichia coli adhesion by multivalent galabiose derivatives studied by a live-bacteria application of surface plasmon resonance
1 Department of Medical Biochemistry and Molecular Biology, University of Turku, FI-20520 Turku, Finland 2 Department of Medicinal Chemistry, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, PO Box 80082, NL-3508 TB Utrecht, The Netherlands 3 Institute for Molecular Biology of Infectious Diseases, University of Würzburg, D-97070 Würzburg, Germany
Received 9 March 2007; returned 22 May 2007; revised 12 June 2007; accepted 15 June 2007
* Corresponding author. Tel: +358-2-3337240; Fax: +358-2-3337229; E-mail: jukka.finne{at}utu.fi
Objectives: Uropathogenic P-fimbriated Escherichia coli adheres to host cells by specific adhesins recognizing galabiose (Gal
1-4Gal)-containing structures on cell surfaces. In search of agents inhibiting this first step of infection, the inhibition potency of a set of synthetic mono- and multivalent galabiose compounds was evaluated. In order to mimic the flow conditions of natural infections, a live-bacteria application of surface plasmon resonance (SPR) was established.
Methods and results: For the measurement of the binding of E. coli to a surface containing galabiose, live bacteria were injected over the flow cell, and the inhibition of adhesion caused by the galabiose inhibitors was recorded. Quantitative binding data were recorded in real-time for each inhibitor. The results were compared with those of conventional static haemagglutination and ELISA-based cell adhesion assays. Compared with the Gram-positive Streptococcus suis bacteria, which also bind to galabiose and whose binding inhibition is strongly dependent on the multivalency of the inhibitor, E. coli inhibition was only moderately affected by the valency. However, a novel octavalent compound was found to be the most effective inhibitor of E. coli PapGJ96 adhesion, with an IC50 value of 2 µM.
Conclusions: Measurement of bacterial adhesion by SPR is an efficient way to characterize the adhesion of whole bacterial cells and allows the characterization of the inhibitory potency of adhesion inhibitors under dynamic flow conditions. Under these conditions, multivalency increases the anti-adhesion potency of galabiose-based inhibitors of P-fimbriated E. coli adhesion and provides a promising approach for the design of high-affinity anti-adhesion agents.
Key Words: anti-adhesion , glycodendrimers , oligovalent inhibitors , Streptococcus suis