title: C-reactive protein reactivity with complement and effects on phagocytosis.
abstract: In the studies described here we have attempted to evaluate the hypothesis that CRP may function in host defense using two systems in which CRP in the presence of C appears to have opsonic properties. In the first, CRP and C were found to stimulate ingestion of erythrocytes by human monocyte or mouse macrophages in vitro, and to alter clearance patterns in vivo. In the second, we have studied opsonization of S. pneumoniae by CRP and C. Experiments with human neutrophils indicate that although CRP and C can enhance opsonization of S. pneumoniae, this effect is more pronounced in the absence of antibody. In vivo CRP was found to protect mice against intravenous infection with S. pneumoniae.
mesh_terms: D000818:Animals; D001770:Blood Bactericidal Activity; D002097:C-Reactive Protein / Q000378:metabolism / Q000502:physiology*; D003171:Complement Pathway, Classical; D003165:Complement System Proteins / Q000378:metabolism*; D006801:Humans; D009895:Opsonin Proteins; D010587:Phagocytosis; D011008:Pneumococcal Infections / Q000276:immunology; D011135:Polysaccharides, Bacterial / Q000378:metabolism; D011485:Protein Binding; D013296:Streptococcus pneumoniae / Q000276:immunology
chemical_list: D009895:Opsonin Proteins; D011135:Polysaccharides, Bacterial; C027158:polysaccharide C-substance (Streptococcus); D003165:Complement System Proteins; D002097:C-Reactive Protein