Antibody-independent activation of C1 by type Ia group B streptococci
| Autor: | Carol J. Baker, Michael E. Eads, Nancy J. Levy, Anne Nicholson-Weller, Dennis L. Kasper |
|---|---|
| Rok vydání: | 1982 |
| Předmět: |
biology
Phagocytosis food and beverages Complement C4 Complement C3 Complement C2 Opsonin Proteins C3-convertase Complement system Microbiology Streptococcus agalactiae Antibody opsonization Infectious Diseases Species Specificity Complement C1 biology.protein Immunology and Allergy Complement Pathway Classical Antibody Opsonin Pathogen Complement C3 Convertases Complement Activation |
| Zdroj: | The Journal of infectious diseases. 146(5) |
| ISSN: | 0022-1899 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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