A Spin Label Study of the Effects of NO2, SO2 and pH Upon the Pulmonary Alveolar Macrophage

Much of the in vivo research that has been conducted on the health effects of pollutants such as SO₂ and NO₂ has been concerned with their effects upon lung defense systems, with particular reference to their effect on functional properties of the alveolar macrophage (AM). The lungs are constantly exposed to the external environment with its variable content of irritants and infectious agents. Agents deposited in or below the region of the respiratory bronchioles are phagocytized by the AM. The specific capacity of the AM to perform its task is subject to many factors. Gaseous air pollutants have been shown to affect the functional state of the cells^(1). Phagocytosis is an energy dependent process and plasma membrane ATPase has been suggested to act as a mechanoenzyme making phagocytosis possible through the conversion of chemical energy in the form of ATPase to the mechanical energky required for attachement and ingestion ⁽²⁾. Since the bulk of the cellular ATPase activity is located in the plasma membrane of the AM⁽³⁾ the enzyme is easily accessible to inhaled pollutants. Furthermome, the activity of ATPase and other membrane bound enzymes is well know to be dependent upon the fluidity of membrane lipids.