Biochemical and biological properties of the binding of human fibrinogen to M protein in group A streptococci - PubMed (original) (raw)

Biochemical and biological properties of the binding of human fibrinogen to M protein in group A streptococci

E Whitnack et al. J Bacteriol. 1985 Oct.

Abstract

Fibrinogen is known to bind to group A streptococci and precipitate with extracts containing streptococcal M protein. We have previously shown that the binding of fibrinogen to M-positive streptococci prevents opsonization by complement and protects that organism from phagocytosis in nonimmune blood. In the present study, we used 3H-labeled fibrinogen, a highly purified peptide fragment of type 24 M protein (pep M24), and anti-pep M sera to show that fibrinogen binds to M-positive streptococci with high affinity (dissociation constants, 1 to 5 nM); occupation of the high-affinity binding sites suffices to protect the organism from phagocytosis; proteolytic treatments that remove M protein from streptococcal cells abolish binding; binding is competitively inhibited by anti-pep M sera; pep M24 precipitates fibrinogen; and binding to type 24 cells is inhibited by pep M24. We conclude that M protein is the cell surface structure principally responsible for binding fibrinogen on the surface of M-positive streptococci and that this binding contributes to the known antiopsonic property of M proteins.

PubMed Disclaimer

Comment in

Similar articles

Cited by

References

    1. J Exp Med. 1976 Apr 1;143(4):759-71 - PubMed
    1. Nature. 1970 Aug 15;227(5259):680-5 - PubMed
    1. Acta Pathol Microbiol Scand B. 1981 Apr;89(2):49-55 - PubMed
    1. Proc Natl Acad Sci U S A. 1978 Jul;75(7):3163-7 - PubMed
    1. J Cell Biol. 1980 Jul;86(1):104-12 - PubMed

Publication types

MeSH terms

Substances

LinkOut - more resources