R. Raeder et Mdp. Boyle, ANALYSIS OF IMMUNOGLOBULIN G-BINDING-PROTEIN EXPRESSION BY INVASIVE ISOLATES OF STREPTOCOCCUS-PYOGENES, Clinical and diagnostic laboratory immunology, 2(4), 1995, pp. 484-486
Invasive group A streptococcal isolates collected as part of a Centers
for Disease Control and Prevention surveillance study were analyzed f
or expression of immunoglobulin G (IgG)-binding proteins. Two IgG-bind
ing phenotypes of group A isolates of the M1 serotype were identified
The first group expressed a surface protein that bound all four human
IgG subclasses (type IIo) and was recognized by rabbit anti-serotype M
1-specific antiserum but not by normal rabbit serum. The second group
expressed an IgG-binding protein that was also recognized by the anti-
serotype M1 antiserum but demonstrated significant nonimmune reactivit
y only with human IgG3 (type IIb). Analysis of extracts of the isolate
s for reactivity with human IgA, fibrinogen, and albumin was also perf
ormed The importance of the binding of human plasma Proteins to pathog
enic group A streptococci remains to he established.