Characterization of haptoglobin-binding properties of streptococci of serological group G.
Two group G streptococcal cultures (G 10187, G 11122) with surface antigen T4 possess surface receptors for human haptoglobin (Hp). G 10187 additionally interacted with immunoglobulin G and albumin, G 11122 with fibrinogen and fibronectin. Binding of 125I-Hp 2-1 was time-dependent, saturable, reversible in the presence of unlabelled Hp and could be inhibited by unlabelled human-Hp 2-1, -Hp 2-2, -Hp 1-1, Hp-hemoglobin complexes and by Hp preparations from pigs, horses and rabbits. The Hp binding sites could be destroyed by heat treatment (95 degrees C) and by proteolytic treatment of the bacteria. Hp binding sites were solubilized from group G streptococcal surface by heat treatment of the bacteria at acid pH and subsequently isolated by affinity chromatography on Hp 2-1 sepharose. SDS-PAGE and Western blotting of the Hp binding proteins revealed numerous protein bands with 125I-Hp 2-1 binding activity. Specific antibodies against G streptococcal binding proteins prepared in chickens inhibited binding of 125I-Hp to group G and group A streptococci, but not to Actinomyces pyogenes.
Lämmler
C
C
Institut für Bakteriologie und Immunologie, Justus-Liebig-Universität Giessen.
Guszczynski
T
T
Dobryszycka
W
W
D000418:Albumins / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D005340:Fibrinogen / Q000378:metabolism; D005353:Fibronectins / Q000378:metabolism; D006242:Haptoglobins / Q000378:metabolism*; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism; D013291:Streptococcus / Q000378:metabolism*
D000418:Albumins; D005353:Fibronectins; D006242:Haptoglobins; D007074:Immunoglobulin G; D005340:Fibrinogen