AJP - Lung Cellular and Molecular Physiology, Vol 273, Issue 6 1258-L1264, Copyright © 1997 by American Physiological Society
Surfactant modifies the lymphoproliferative activity of macrophages in hypersensitivity pneumonitis
E. Israel-Assayag and Y. Cormier
Unite de Recherche, Centre de Pneumologie, Hopital and Universite Laval, Ste.-Foy, Quebec, Canada.
Alveolar macrophages (AM) from normal individuals suppress mitogen-induced
peripheral blood mononuclear cell (PBMC) proliferation, whereas cells from
patients with hypersensitivity pneumonitis (HP) enhance PBMC. Because
surfactant components can interfere with AM functions, we tested the effect
of Survanta (a modified bovine surfactant) and surfactant fractions
isolated from bronchoalveolar lavage of normal subjects and HP patients on
AM-induced lymphoproliferation. Surfactant fractions were isolated from
bronchoalveolar lavage fluids by differential centrifugation into total
aggregates (TA) and large aggregates (LA). Surfactant preparations (200
micrograms/ml) from 10 normal subjects (N) or 12 HP patients or of Survanta
were added to AM-PBMC cocultures stimulated with phytohemagglutinin (PHA)
at 1:1 and 2:1 ratios. Results, expressed as percent of PHA-induced PBMC
proliferation cocultures without surfactant, show that normal surfactant
and Survanta decrease mitogen-induced proliferation of cells to a larger
extent than surfactant from HP patients. For AM-to-PBMC ratios of 1:1, the
results were as follows: N TA 10.58 +/- 2.75% (mean +/- SE), N LA 12.96 +/-
2.78%, HP TA 43.09 +/- 7.81%, HP LA 61.64 +/- 7.77%, and Survanta 16.70 +/-
2.95%. Similar data were obtained in 2:1 cocultures. Because surfactant
components interact with AM, alterations of surfactant composition in
lymphocytic diseases, mainly in the LA fraction, may account for the lack
of suppressive activity in AM of HP patients and the observed alveolitis.
