Microbiology
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Microbiology 148 (2002), 2055-2064
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
Right arrow Citation Map
Services
Right arrow Email this article to a friend
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 arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via CrossRef
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Song, X.-M.
Right arrow Articles by Potter, A. A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Song, X.-M.
Right arrow Articles by Potter, A. A.
Agricola
Right arrow Articles by Song, X.-M.
Right arrow Articles by Potter, A. A.
Microbiology (2002), 148, 2055-2064.
© 2002 Society for General Microbiology

Research Paper

Bovine immunoglobulin A (IgA)-binding activities of the surface-expressed Mig protein of Streptococcus dysgalactiae

Xin-Ming Song1, Jose Perez-Casal1, Michael C. Fontaine1 and Andrew A. Potter1,2

Veterinary Infectious Disease Organization (VIDO), Saskatoon, Saskatchewan, Canada S7N 5E31
Canadian Bacterial Diseases Network, Calgary, Alberta, Canada2

Author for correspondence: Andrew A. Potter. Tel: +1 306 966 7484. Fax: +1 306 966 7478. e-mail: Potter{at}sask.usask.edu

The Mig protein of Streptococcus dysgalactiae is a type III immunoglobulin G (IgG)-binding protein, expressing IgG- and {alpha}2-macroglobulin ({alpha}2-M)-binding receptors. This study showed that the Mig protein also displays binding activities to bovine immunoglobulin A (B-IgA). Biotin-labelled bovine serum IgA bound immobilized recombinant Mig and {alpha}2-M receptors derived from Mig, as well as the native Mig extracted from the surface of S. dysgalactiae strain SDG8 and the {alpha}2-M receptor released from the isogenic mig mutant strain Mig8-Mt, as determined by Western blotting and ELISA. There was no B-IgA binding activity to the immobilized IgG receptor derived from Mig or the proteins in the culture supernatant from the mig mutant strain Mig7-Mt, in which expression of Mig or Mig-related peptides on the cell surface was completely abolished. In a reciprocal experiment, biotin-labelled Mig was found to bind immobilized bovine serum IgA but not human IgA (H-IgA). The binding of Mig to bovine serum IgA was competitively inhibited by unlabelled Mig, intact and truncated {alpha}2-M receptors, and bovine serum IgA, but not by the Mig-IgG receptor, H-IgA or B-IgG. The binding of Mig and partially purified bovine secretory IgA (B-sIgA) was also characterized by Western blotting. Membrane-immobilized B-sIgA did not react with the biotin-labelled Mig, whereas soluble B-sIgA showed binding activity to the immobilized {alpha}2-M receptor of Mig. It is therefore concluded that the 11 kDa N-terminal region of the {alpha}2-M receptor of the S. dysgalactiae Mig protein specifically binds soluble and immobilized bovine serum IgA, as well as soluble B-sIgA. This is believed to be the first report of a B-IgA-binding protein in S. dysgalactiae.

Keywords: IgG, {alpha}2-macroglobulin, receptor, bovine mastitis

Abbreviations: {alpha}2-M, {alpha}2-macroglobulin; AP, alkaline phosphatase; B-, bovine (immunoglobulins); H-, human (immunoglobulins); sIgA, secretory immunoglobulin A






HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
INT J SYST EVOL MICROBIOL MICROBIOLOGY J GEN VIROL
J MED MICROBIOL ALL SGM JOURNALS
Copyright © 2002 Society for General Microbiology.