Increased activity of the respiratory burst in cord blood neutrophils: kinetics of the NADPH oxidase enzyme system in subcellular fractions

• Published in: Pediatric research Vol. 21; no. 2; pp. 205 - 210
• Main Authors: AMBRUSO, D. R, STORK, L. C, GIBSON, B. E, THURMAN, G. W
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD Lippincott Williams & Wilkins 01.02.1987
• Subjects: Alkaline Phosphatase - blood; Biological and medical sciences; Fetal Blood - cytology; Fetal Blood - enzymology; Fundamental and applied biological sciences. Psychology; Fundamental immunology; General aspects. Ontogeny. Phylogeny; Humans; Immunobiology; Infant, Newborn; Kinetics; Lactoferrin - blood; NADH, NADPH Oxidoreductases - metabolism; NADPH Oxidases; Neutrophils - enzymology; Oxygen Consumption; Peroxidase - blood; Subcellular Fractions - enzymology; Human; Leucocyte function; Enzyme; Membrane fraction; Neutrophile; Granulocyte; Respiratory burst; New born; Kinetic parameter; Metabolism
• ISSN: 0031-3998; 1530-0447
• DOI: 10.1203/00006450-198702000-00019

Previous studies with neutrophils from newborn infants compared to neutrophils from healthy adults have documented increased respiratory burst activity including enhanced superoxide anion (O2-) production, nitroblue tetrazolium dye reduction, and hexose monophosphate shunt activity. To investigate the biochemical basis for these observations, we examined oxidative metabolism in membrane-rich fractions of neutrophils. Neutrophils from cord blood of vaginally delivered term infants or healthy adults were disrupted by nitrogen cavitation and subcellular fractions collected on discontinuous sucrose density gradients. Subcellular fractions of newborn neutrophils separated in a fashion identical with samples from healthy adults. Activity of alkaline phosphatase, a plasma membrane marker, was increased 4- to 5-fold in disrupted cells free from nuclei (postnuclear supernatant) as well as plasma membrane fractions from newborn samples compared to those from healthy adults. Content of lactoferrin, a specific granule marker, was decreased in postnuclear supernatants but equivalent in specific granule fractions of newborn cells compared to those from adults. No differences were noted in myeloperoxidase content of postnuclear supernatants or any other subcellular fraction. Plasma membrane fractions from phorbol myristate acetate-stimulated cord blood neutrophils made significantly more O2- than samples from adults (newborn 32.9 +/- 8.1 nmol O2-/min/mg protein mean +/- SEM, n = 3 versus adult 10.8 +/- 4.2, n = 3; p less than 0.05). Plasma membrane-rich fractions were also collected by the technique of differential centrifugation and kinetic parameters of the NADPH-dependent oxidase enzyme(s) were measured for vaginally delivered newborn and adult samples.