Antibody-independent activation of C1 by type Ia group B streptococci.
J Infect Dis
; 146(5): 665-72, 1982 Nov.
Article
em En
| MEDLINE
| ID: mdl-6752296
ABSTRACT
A prototype fresh clinical isolate of type Ia group B streptococci (strain 515) can be opsonized by serum containing low levels of antibody. This opsonizing process can also occur in hypogammaglobulinemic serum, confirming its antibody independence, but it does require Ca++ ions and the second component of complement (C2). When formalin-fixed organisms are reacted with whole serum, C4 and C3 are cleaved. These data are strong evidence that this organism can directly activate C1 in the absence of antibody and that this activation leads to the formation of a classical C3 convertase (C4b2a), which cleaves C3. The observation that opsonization can occur in hypogammaglobulinemic serum suggests that complement alone, presumably the fixation of C3b, is sufficient for phagocytes to ingest this pathogen.
Buscar no Google
Base de dados:
MEDLINE
Assunto principal:
Fagocitose
/
Streptococcus agalactiae
/
Ativação do Complemento
/
Via Clássica do Complemento
Idioma:
En
Ano de publicação:
1982
Tipo de documento:
Article