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Ig-binding surface proteins of Streptococcus pyogenes also bind human C4b-binding protein (C4BP), a regulatory component of the complement system

Thern, Anette; Stenberg, Lars LU ; Dahlbäck, Björn LU and Lindahl, Gunnar LU (1995) In Journal of Immunology 154(1). p.375-386
Abstract
Streptococcus pyogenes, an important human pathogen, expresses several proteins that interact with the immune system of the host. Among the proteins isolated from different bacterial strains are antiphagocytic M proteins, Ig Fc-binding proteins and exotoxins that act as superantigens. Here we report a novel interaction between S. pyogenes and the human immune system, the ability of most S. pyogenes strains to bind human C4BP (C4b-binding protein), a 570-kDa serum protein that inhibits the classical pathway of complement activation. Molecular analysis of three different streptococcal strains demonstrated that C4BP binds to protein Arp or protein Sir, two Ig-binding cell surface molecules that are members of the M protein family. These... (More)
Streptococcus pyogenes, an important human pathogen, expresses several proteins that interact with the immune system of the host. Among the proteins isolated from different bacterial strains are antiphagocytic M proteins, Ig Fc-binding proteins and exotoxins that act as superantigens. Here we report a novel interaction between S. pyogenes and the human immune system, the ability of most S. pyogenes strains to bind human C4BP (C4b-binding protein), a 570-kDa serum protein that inhibits the classical pathway of complement activation. Molecular analysis of three different streptococcal strains demonstrated that C4BP binds to protein Arp or protein Sir, two Ig-binding cell surface molecules that are members of the M protein family. These bacterial proteins have separate high affinity binding sites for Ig and for C4BP, as demonstrated by inhibition tests and binding assays with purified components. A single streptococcal cell surface molecule, Arp or Sir, therefore combines the abilities to bind Ig and C4BP, two high m.w. components of the immune system. Two bacterial strains expressing Arp or Sir were shown to selectively bind C4BP in whole human serum, suggesting that S. pyogenes also binds C4BP in the infected host. When bound to streptococcal cells, C4BP retained its ability to act as a cofactor in the degradation of C4b by factor I. These results indicate that many strains of S. pyogenes interfere with the classical pathway of complement activation by binding C4BP to the bacterial cell surface. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Immunology
volume
154
issue
1
pages
375 - 386
publisher
American Association of Immunologists
external identifiers
  • pmid:7995956
  • scopus:0028831310
ISSN
1550-6606
language
English
LU publication?
yes
id
259051fa-9db8-4d08-9f3a-7e1b4038b7ee (old id 1109098)
alternative location
http://www.jimmunol.org/cgi/reprint/154/1/375
date added to LUP
2008-07-25 13:29:20
date last changed
2017-04-23 04:17:51
@article{259051fa-9db8-4d08-9f3a-7e1b4038b7ee,
  abstract     = {Streptococcus pyogenes, an important human pathogen, expresses several proteins that interact with the immune system of the host. Among the proteins isolated from different bacterial strains are antiphagocytic M proteins, Ig Fc-binding proteins and exotoxins that act as superantigens. Here we report a novel interaction between S. pyogenes and the human immune system, the ability of most S. pyogenes strains to bind human C4BP (C4b-binding protein), a 570-kDa serum protein that inhibits the classical pathway of complement activation. Molecular analysis of three different streptococcal strains demonstrated that C4BP binds to protein Arp or protein Sir, two Ig-binding cell surface molecules that are members of the M protein family. These bacterial proteins have separate high affinity binding sites for Ig and for C4BP, as demonstrated by inhibition tests and binding assays with purified components. A single streptococcal cell surface molecule, Arp or Sir, therefore combines the abilities to bind Ig and C4BP, two high m.w. components of the immune system. Two bacterial strains expressing Arp or Sir were shown to selectively bind C4BP in whole human serum, suggesting that S. pyogenes also binds C4BP in the infected host. When bound to streptococcal cells, C4BP retained its ability to act as a cofactor in the degradation of C4b by factor I. These results indicate that many strains of S. pyogenes interfere with the classical pathway of complement activation by binding C4BP to the bacterial cell surface.},
  author       = {Thern, Anette and Stenberg, Lars and Dahlbäck, Björn and Lindahl, Gunnar},
  issn         = {1550-6606},
  language     = {eng},
  number       = {1},
  pages        = {375--386},
  publisher    = {American Association of Immunologists},
  series       = {Journal of Immunology},
  title        = {Ig-binding surface proteins of Streptococcus pyogenes also bind human C4b-binding protein (C4BP), a regulatory component of the complement system},
  volume       = {154},
  year         = {1995},
}