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Keywords:

  • cord blood;
  • NADPH oxidase;
  • neutrophil;
  • newborn infants

Abstract

Introduction

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 (Omath image) 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 Omath image at comparable rates to subcellular fractions from healthy adults. However, mixing experiments demonstrated higher Omath image generation with combination of cytosol from adult controls and membrane from cord blood neutrophils and lower Omath image 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 b558 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 b558 in the plasma membrane and decreased levels of cytosolic components p47-phox, p67-phox, and p40-phox. © 2005 Wiley-Liss, Inc.