Journal of Applied Physiology, Vol 54, Issue 1 94-98, Copyright © 1983 by American Physiological Society
Inhibition of pulmonary macrophage function by airway mucus
K. H. Woodside, S. M. Denas, K. L. Smith, C. S. Kim and A. Wanner
As a model for the interaction between macrophages and mucus in the
tracheobronchial tree, we incubated sheep alveolar macrophages in vitro
with and without airway mucus from the same animal and tested their
phagocytic function and rates of general protein synthesis. Airway mucus
was obtained by tracheal suction after previous subcutaneous injection of
the sheep with pilocarpine (0.5 mg/kg) and subsequently diluted. Pulmonary
macrophages were obtained by saline lavage through a balloon-tipped
fiber-optic bronchoscope. In incubated attached macrophages, phenylalanine
incorporation into protein was inhibited 51% by mucus (P less than 0.001).
Phagocytosis of 1.09-microns latex particles was inhibited 75% by mucus at
nonsaturating levels of particles (P less than 0.001) and by 47% at
saturating levels of particles (P less than 0.001). Inhibitory activity for
protein synthesis and phagocytosis was retained in the 104,000 g
supernatant fraction of whole mucus (sol), while the gel fraction inhibited
phagocytosis only. This difference did not appear to be related to physical
factors. We conclude that diluted airway mucus interferes with pulmonary
macrophage function as assessed by rates of general protein synthesis and
phagocytosis.
