title: Mechanisms of bacterial opsonization by immune globulin intravenous: correlation of complement consumption with opsonic activity and protective efficacy.
abstract: To study the mechanism of bacterial opsonization by immune globulin intravenous (IGIV) complement consumption and polymorphonuclear leukocyte (PMNL) membrane receptor (FcRlo, CR1, and CR3)-mediated phagocytosis of Staphylococcus epidermidis, Klebsiella pneumoniae, and groups A and B streptococci were examined. IGIV alone did not consume complement and showed no opsonic activity by itself for these organisms. When these bacteria were preopsonized in IGIV, significant amounts of complement were consumed (44%-94%) and the uptake and killing of bacteria occurred. The in vitro opsonic activity of IGIV for these organisms was significantly correlated with the amount of complement consumed by the IGIV-opsonized bacteria (r = .85, P less than .05). The in vivo protective efficacy of IGIV also appeared to be directly associated with its ability to activate and consume complement (r = 1.0, P less than .001). Antibodies to FcRlo (Leu 11) markedly inhibited phagocytosis of bacteria opsonized in IGIV but not that of bacteria opsonized in specific IgM. Both CR1 and CR3 receptors on PMNLs were involved in uptake, but the contribution of each is different with different organisms.
authors.affiliation: Department of Pediatrics, University of Utah School of Medicine, Salt Lake City 84132.
authors.forename: K D
authors.initials: KD
authors.lastname: Yang
authors.forename: J M
authors.initials: JM
authors.lastname: Bathras
authors.forename: A O
authors.initials: AO
authors.lastname: Shigeoka
authors.forename: J
authors.initials: J
authors.lastname: James
authors.forename: S H
authors.initials: SH
authors.lastname: Pincus
authors.forename: H R
authors.initials: HR
authors.lastname: Hill
mesh_terms: D000818:Animals; D001419:Bacteria / Q000276:immunology*; D001667:Binding, Competitive; D003165:Complement System Proteins / Q000276:immunology*; D004195:Disease Models, Animal; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology* / Q000627:therapeutic use; D016756:Immunoglobulins, Intravenous; D007710:Klebsiella Infections / Q000517:prevention & control; D007711:Klebsiella pneumoniae / Q000276:immunology; D009895:Opsonin Proteins / Q000276:immunology*; D010587:Phagocytosis; D051381:Rats; D011919:Rats, Inbred Strains; D011961:Receptors, Fc / Q000276:immunology; D013212:Staphylococcus epidermidis / Q000276:immunology; D013292:Streptococcus agalactiae / Q000276:immunology; D013297:Streptococcus pyogenes / Q000276:immunology
chemical_list: D007074:Immunoglobulin G; D016756:Immunoglobulins, Intravenous; D009895:Opsonin Proteins; D011961:Receptors, Fc; D003165:Complement System Proteins