INHIBITORY ROLE OF ALVEOLAR MACROPHAGES IN COLONY-STIMULATING FACTOR PRODUCTION BY THE LUNG-TISSUE FROM BACILLUS-CALMETTE-GUERIN-TREATED ANIMALS

Production of colony-stimulating factors (CSF) by lung tissue from rat s injected by bacillus Calmette-Guerin (BCG) and the role of alveolar macrophages (AM) in this process was studied. Injection of BCG at 10, 100, or 1,000 mg/kg changed the CSF production by the lung in a time-d ependent manner. Maximum stimulation was observed at 10 mg/kg and 3 da ys of interval between BCG injection and animal sacrifice. Longer peri ods or higher concentrations had no effect or actually depressed CSF p roduction. BCG injection also changed the number of AM in a time- and dose-dependent manner. When AM from BCG-treated animals were lavaged o ut and the AM-depleted lung tissues were cultured, an increase in CSF production with respect to controls was observed at 10 mg/kg of BCG. O n the other hand, in control animals removal of AM had no effect on CS F production by the lung. The results suggest that BCG treatment alter s the number of AM and CSF production by the lung. AM, in BCG-injected animals, inhibit CSF production by the lung tissue while in non-injec ted animals they do not play any role in this process.