Nanobody mediated inhibition of attachment of F18 Fimbriae expressing Escherichia coli

PLoS One. 2014 Dec 11;9(12):e114691. doi: 10.1371/journal.pone.0114691. eCollection 2014.

Abstract

Post-weaning diarrhea and edema disease caused by F18 fimbriated E. coli are important diseases in newly weaned piglets and lead to severe production losses in farming industry. Protective treatments against these infections have thus far limited efficacy. In this study we generated nanobodies directed against the lectin domain of the F18 fimbrial adhesin FedF and showed in an in vitro adherence assay that four unique nanobodies inhibit the attachment of F18 fimbriated E. coli bacteria to piglet enterocytes. Crystallization of the FedF lectin domain with the most potent inhibitory nanobodies revealed their mechanism of action. These either competed with the binding of the blood group antigen receptor on the FedF surface or induced a conformational change in which the CDR3 region of the nanobody displaces the D″-E loop adjacent to the binding site. This D″-E loop was previously shown to be required for the interaction between F18 fimbriated bacteria and blood group antigen receptors in a membrane context. This work demonstrates the feasibility of inhibiting the attachment of fimbriated pathogens by employing nanobodies directed against the adhesin domain.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adhesins, Bacterial / chemistry
  • Adhesins, Bacterial / immunology
  • Adhesins, Bacterial / metabolism
  • Animals
  • Bacterial Adhesion / immunology*
  • Binding, Competitive
  • Camelids, New World / immunology
  • Camelids, New World / microbiology
  • Carbohydrate Metabolism
  • Enterocytes / microbiology
  • Escherichia coli / cytology*
  • Escherichia coli / immunology
  • Escherichia coli / physiology*
  • Escherichia coli Proteins / chemistry
  • Escherichia coli Proteins / immunology
  • Escherichia coli Proteins / metabolism
  • Fimbriae, Bacterial / immunology
  • Fimbriae, Bacterial / metabolism*
  • Gene Expression
  • Models, Molecular
  • Protein Conformation
  • Single-Domain Antibodies / genetics
  • Single-Domain Antibodies / immunology*
  • Swine / immunology
  • Swine / microbiology

Substances

  • Adhesins, Bacterial
  • Escherichia coli Proteins
  • FedF protein, E coli
  • Single-Domain Antibodies

Grant support

K.M. was a doctoral fellow of the Fonds voor Wetenschappelijk Onderzoek (FWO) – Vlaanderen. H.R. is supported by a VIB Young PI project grant and the Odysseus program of the FWO-Vlaanderen. E.P. is supported by grant 7/40 of the Interuniversity Attraction Poles (IAP) Program of the Belgian Science Policy Office. The authors are grateful to the beamline staff of the Swiss Light Source (SLS; Switzerland), Diamond Light Source (England) and Soleil (France) for support with data collection and processing. This research was granted by FWO project G030411N and equipment grant UABR/09/005 from the Hercules Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.