title: Assessment of Haemophilus influenzae type b opsonins by neutrophil chemiluminescence.
abstract: A luminol-enhancement chemiluminescence assay and a radiolabeled uptake assay were developed to assess opsonins for Haemophilus influenzae type b. Opsonins in acute and convalescent sera from 17 children with H. influenzae type b meningitis, along with pooled normal human sera, were evaluated and compared with anti-polyribosephosphate antibody concentrations. Five children had a rise in the chemiluminescence-area under the curve for convalescent compared with acute sera. Patient chemiluminescence--area-under-the-curve values were significantly (P less than 0.05) more likely to exceed 50% of normal human serum values if sera contained greater than or equal to 0.1 microgram of anti-polyribosephosphate antibody per ml. Magnesium ethylene glycol tetraacetic acid chelation and heat inactivation of patient and normal human sera significantly (P less than 0.05) reduced chemiluminescence--area-under-the-curve activity. Thus, complement appears to contribute significantly to the opsonization of H. influenzae type b in sera of children. Two of nine children had increases in opsonins as assayed by 3H-labeled H. influenzae type b uptake. After natural systemic H. influenzae type b infection, young children are unable to respond acutely with an increase in anti-polyribosephosphate antibody or serum opsonic activity.
mesh_terms: D000907:Antibodies, Bacterial / Q000032:analysis; D001681:Biological Assay; D002675:Child, Preschool; D006193:Haemophilus influenzae / Q000145:classification / Q000276:immunology*; D006801:Humans; D007223:Infant; D008163:Luminescent Measurements; D008583:Meningitis, Haemophilus / Q000276:immunology*; D009504:Neutrophils / Q000502:physiology; D009895:Opsonin Proteins / Q000032:analysis*; D011135:Polysaccharides, Bacterial / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D009895:Opsonin Proteins; D011135:Polysaccharides, Bacterial