This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Zhang, W.
Right arrow Articles by Francis, D. H.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Zhang, W.
Right arrow Articles by Francis, D. H.

 Previous Article  |  Next Article 

Infection and Immunity, February 2009, p. 699-706, Vol. 77, No. 2
0019-9567/09/$08.00+0     doi:10.1128/IAI.01165-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Characterization of the Binding Specificity of K88ac and K88ad Fimbriae of Enterotoxigenic Escherichia coli by Constructing K88ac/K88ad Chimeric FaeG Major Subunits{triangledown}

Weiping Zhang,* Ying Fang, and David H. Francis

The Center for Infectious Disease Research & Vaccinology, Department of Veterinary Science, South Dakota State University, Brookings, South Dakota 57007

Received 17 September 2008/ Returned for modification 19 October 2008/ Accepted 12 November 2008

Enterotoxigenic Escherichia coli (ETEC) strains expressing K88 (F4) fimbriae are the major cause of diarrhea in young pigs. Three antigenic variants of K88 fimbriae (K88ab, K88ac, and K88ad) have been identified among porcine ETEC strains. Each K88 fimbrial variant shows a unique pattern in binding to different receptors on porcine enterocytes. Such variant specificity in fimbrial binding is believed to be controlled by the major subunit (FaeG) of the K88 fimbriae, because the genes coding for the only other fimbrial subunit are identical among the three variants. Uniqueness in binding to host receptors may be responsible for differences in the virulence levels of porcine diarrhea disease caused by K88 ETEC strains. To better understand the relationships between the structure of FaeG proteins and fimbrial binding function, and perhaps virulence in disease, we constructed and expressed various K88ac/K88ad faeG gene chimeras and characterized the binding activity of each K88 chimeric fimbria. After verifying biosynthesis of the chimeric fimbriae, we examined their binding specificities in bacterial adherence assays by using porcine brush border vesicles that are specific to either the K88ac or K88ad fimbria. Results showed that each fimbria switched binding specificity to that of the reciprocal type when a peptide comprising amino acids 125 to 163 was exchanged with that of its counterpart. Substitutions of a single amino acid within this region negatively affected the binding capacity of each fimbria. These data indicate that the peptide including amino acids 125 to 163 of the FaeG subunit is essential for K88 variant-specific binding.

* Corresponding author. Mailing address: Veterinary Science Department, Box 2175, South Dakota State University, Brookings, SD 57006. Phone: (605) 688-4317. Fax: (605) 688-6003. E-mail: weiping.zhang{at}sdstate.edu

{triangledown} Published ahead of print on 17 November 2008.

Editor: A. J. Bäumler

Infection and Immunity, February 2009, p. 699-706, Vol. 77, No. 2
0019-9567/09/$08.00+0     doi:10.1128/IAI.01165-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.





Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»