IMMUNOTOXICITY OF SULFURIC-ACID AEROSOL - EFFECTS ON PULMONARY MACROPHAGE EFFECTOR AND FUNCTIONAL ACTIVITIES CRITICAL FOR MAINTAINING HOST-RESISTANCE AGAINST INFECTIOUS-DISEASES

Despite the widespread occurrence of acidic sulfur oxides in the ambie nt environment and their potential risks to human health, effects asso ciated with pulmonary immune defenses have been poorly studied. The cu rrent in vivo study was designed to provide some insight into this rel atively unexplored area by investigating the impact of inhaled sulfuri c acid on immune defense mechanisms critical for maintaining pulmonary resistance against infectious diseases. Results of this study demonst rate that repeated inhalation of sulfuric acid reduces the uptake and intracellular killing of pathogenic bacteria by exposed pulmonary macr ophages, and depresses the activity/production of important biological modifiers critical for maintaining pulmonary immunocompetence. These findings have important implications for human health, and may contrib ute to a better understanding of the possible mechanism(s) underlying the epidemiological evidence which suggests an association between tot al sulfates in the ambient air and increased incidence of acute bronch itis and lower respiratory illness in school-age children.