Influence of acute exposure to cigarette smoke on the alveolar macrophage system

The influence of cigarette smoke on the numbers and viability of alveolar macrophages in the lungs of mice was determined by utilizing techniques for quantitating lung deposition of bacteria and alveolar macrophage harvest. Alveolar macrophages were obtained by pulmonary lavage. The studies were performed under basal conditions, after the inhalation of cigarette smoke and after exposure to bacterial aerosols and cigarette smoke in sequence. Macrophage yields were increased 1.1, 1.2, and 1.5 times basal levels by exposure to cigarette smoke alone for 1, 2, and 4 hours, repectively. The inhalation of Staphylococcus aureus for 30 minutes induced a 2.4-fold increase in macrophage numbers. Within 15 minutes after bacterial deposition, macrophage yields dropped 33 percent, but elevated levels were restored at 30 minutes and then maintained for the remainder of the 4 hour test period. Cigarette smoke introduced immediately after bacterial challenge and maintained for up to 4 hours did not alter the macrophage response provoked by pulmonary deposition of staphylococci. In addition, smoke inhalation had no effect on the cellular characteristics of lung harvests and the viability of alveolar macrophages. These data demonstrate that cigarette smoke provoked an increase in alveolar macrophage numbers and did not have a deleterious effect on the mobilization of alveolar macrophages; namely, the maintenance of a macrophage response in relation to an airborne bacterial challenge.