The effects of sodium concentration on human neutrophil
bactericidal functions.
Mizgerd, Joseph P., Lester Kobzik, Angeline E. Warner, and Joseph D.
Brain.
Physiology Program, Harvard School of Public Health, Boston, MA
02115
APStracts 2:0085L, 1995.
What are the ionic requirements for neutrophil (PMN) function and how
might altered electrolyte concentrations contribute to airway
disease? The in vitro killing of Pseudomonas aeruginosa by human
peripheral white blood cells (WBCs) was progressively compromised as
Na+ concentration was lowered from 124 to 62 mM; at 62 mM Na+,
bactericidal activity was 28.8+/-7.4% (SE) of normal. In contrast,
Cl- concentration affected killing only when lowered to 8 mM. We
examined phagocytosis and oxidative metabolism in response to P.
aeruginosa or particles opsonized with either immunoglobulin G (IgG)
or complement (C'). Phagocytosis of P. aeruginosa and of IgG-coated
particles was Na+-dependent (31.2+/-3.1% and 58.6+/-14.2% of normal,
respectively, at 62 mM Na+). However, no effect on uptake of C'
-coated particles was observed, and the respiratory burst at 70 mM Na+
was normal regardless of stimuli. Thus, low Na+ concentration
compromises select PMN functions. These results may help explain why
airways of cystic fibrosis (CF) patients become colonized with
bacteria such as P. aeruginosa. Perhaps the low concentration of Na+
reported for some CF respiratory secretions inhibits bactericidal
functions of PMNs, predisposing these patients to airway infections.
Received 12 August 1994; accepted in final form 26 April 1995.
APS Manuscript Number L233-4.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 26 May 1995.