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Oxidase activity in cord blood neutrophils: A balance between increased membrane associated cytochrome b 558 and deficient cytosolic components
Author(s) -
Chudgar Urmish H.,
Thurman Gail W.,
Ambruso Daniel R.
Publication year - 2005
Publication title -
pediatric blood and cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.116
H-Index - 105
eISSN - 1545-5017
pISSN - 1545-5009
DOI - 10.1002/pbc.20340
Subject(s) - cord blood , cytosol , nadph oxidase , medicine , superoxide , respiratory burst , oxidase test , whole blood , immunology , andrology , enzyme , biochemistry , chemistry
Newborn infants are prone to develop life‐threatening pyogenic infections. Alterations in the function of neonatal phagocytes, including the activity of the neutrophil NADPH oxidase, have been suggested as one cause of increased susceptibility to such infections. Methods In the present study, comprehensive analysis of NADPH oxidase enzyme system was performed in cord blood neutrophils from vaginally and cesarean section (CS) delivered, healthy, full‐term infants. Results Superoxide anion (O 2 − ) production by intact neutrophils from cord blood in response to soluble stimuli was equal to or increased compared to levels generated by cells from adult controls. In the sodium dodecyl sulfate (SDS) cell‐free system, cytosol and plasma membrane from cord blood neutrophils generated O 2 −at comparable rates to subcellular fractions from healthy adults. However, mixing experiments demonstrated higher O 2 −generation with combination of cytosol from adult controls and membrane from cord blood neutrophils and lower O 2 −production with combination of cytosol from cord blood neutrophils and membrane from adult controls. Kinetic parameters for cord blood specimens were no different from those obtained for fractions from adult controls. Quantitative analysis of cytosolic components showed moderately reduced amount of p40‐phox, p47‐phox, and p67‐phox in neutrophils from cord blood. In contrast, cytochrome b 558 content of plasma membrane of cord blood neutrophils was ∼2‐fold higher compared to adult controls. Conclusion The normal to increased respiratory burst of intact cord blood neutrophils is the result of alterations to oxidase components: increased content of cytochrome b 558 in the plasma membrane and decreased levels of cytosolic components p47‐phox, p67‐phox, and p40‐phox. © 2005 Wiley‐Liss, Inc.