TY - JOUR
T1 - Inhibition of alternative complement pathway opsonization by group a streptococcal M protein
AU - Peterson, Phillip K.
AU - Schmeling, David
AU - Cleary, Paul P.
AU - Wilkinson, Brian J.
AU - Kim, Youngki
AU - Quie, Paul G.
PY - 1979/5
Y1 - 1979/5
N2 - Group A streptococcal M protein is known to be antiphagocytic; however, the exact basis for this property has not been established. In this study the hypothesis was tested that cell wall-associated M protein inhibits phagocytosis by interfering with bacterial opsonization. Two strains of group A Streptococcus pyogenes, CS44 (M+) and CS64 (an M variant of CS44), were radiolabeled, and after incubation in serum these organisms were exposed to human polymorphonuclear leukocytes. Phagocytosis was quantitated by measurement of leukocyte-associated radioactivity. The contributions of complement and of immunoglobulin to streptococcal opsonization were evaluated by use of serum from a variety of sources. The results revealed that the M strain was efficiently opsonized via the alternative complement pathway in a relative absence of immunoglobulins. In contrast, the M+ strain was poorly opsonized by all sera tested. These findings suggest that streptococcal M protein in some way prevents bacterial opsonization via the alternative complement pathway and that this property of M protein may partly explain its antiphagocytic characteristic.
AB - Group A streptococcal M protein is known to be antiphagocytic; however, the exact basis for this property has not been established. In this study the hypothesis was tested that cell wall-associated M protein inhibits phagocytosis by interfering with bacterial opsonization. Two strains of group A Streptococcus pyogenes, CS44 (M+) and CS64 (an M variant of CS44), were radiolabeled, and after incubation in serum these organisms were exposed to human polymorphonuclear leukocytes. Phagocytosis was quantitated by measurement of leukocyte-associated radioactivity. The contributions of complement and of immunoglobulin to streptococcal opsonization were evaluated by use of serum from a variety of sources. The results revealed that the M strain was efficiently opsonized via the alternative complement pathway in a relative absence of immunoglobulins. In contrast, the M+ strain was poorly opsonized by all sera tested. These findings suggest that streptococcal M protein in some way prevents bacterial opsonization via the alternative complement pathway and that this property of M protein may partly explain its antiphagocytic characteristic.
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U2 - 10.1093/infdis/139.5.575
DO - 10.1093/infdis/139.5.575
M3 - Article
C2 - 374652
AN - SCOPUS:0018347233
SN - 0022-1899
VL - 139
SP - 575
EP - 585
JO - Journal of Infectious Diseases
JF - Journal of Infectious Diseases
IS - 5
ER -