title: Antibody to the outer membrane proteins is the dominant opsonic antibody in normal human serum against H. influenzae type b.
abstract: We hypothesized that the predominant opsonic antibody of normal serum is directed against outer membrane proteins (OMP). Sera from 10 normal adults were tested for their opsonic capacity against Haemophilus influenzae b (Eagan strain) by the luminol-enhanced neutrophil chemiluminescence elicited on incubation with serum-opsonized bacteria, and the ability to deposit C3 on the bacterial surface. Peak chemiluminescence correlated with the amount of C3 on the bacterial surface (r = 0.71, P less than 0.025) and this, in turn, correlated with the concentration of IgG directed against outer membrane proteins, (r = 0.75, P less than 0.01), but not with the concentration of anticapsular polysaccharide antibody. Two groups of sera were easily distinguished based on the chemiluminescence experiments: a high opsonic group (greater than 50,000 peak counts per second; c.p.s.) and a low opsonic group (less than 10,000 c.p.s.). The IgG fraction from the high opsonic sera could augment C3 deposition when added to a low opsonic serum, but could not after absorption of the anti-OMP antibody by affinity chromatography. We conclude that the predominant opsonin of normal serum is antibody to outer membrane proteins, a finding which could be significant for the development of future vaccines against H. influenzae b.
authors: Department of Pediatrics, Albany Medical College, New York 12208.
authors: S V
authors: SV
authors: Hetherington
mesh_terms: D000907:Antibodies, Bacterial / Q000276:immunology*; D001425:Bacterial Outer Membrane Proteins / Q000276:immunology*; D003176:Complement C3 / Q000378:metabolism; D006193:Haemophilus influenzae / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D009895:Opsonin Proteins / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D001425:Bacterial Outer Membrane Proteins; D003176:Complement C3; D007074:Immunoglobulin G; D009895:Opsonin Proteins