Functional heterogeneity of rabbit peritoneal and alveolar macrophages activated with Mycobacterium bovis BCG.

The biological activity of rabbit peritoneal and alveolar macrophages activated with M. bovis BCG was investigated by use of tests measuring their phagocytic and staphylocidal properties. Macrophages were separated in a discontinuous albumin gradient which yielded 4 to 5 bands depending on the source of the exudate. The peritoneal exudate had about 40% of cells recovered in band E and the alveolar exudate had about 35% in band C. There were not significant differences between the uptake by three subpopulations of macrophages. The alveolar macrophages from normal rabbits were less active than peritoneal macrophages. They were also less active those from vaccinated animals. Subpopulations of band B macrophages killed S. aureus more efficient than those from band C. Such differences reflect the number of mature or immature cells in each subpopulations. Mature cells (bond B and C) possess phagocytic and bactericidal activities whereas immature cells (bond D) are capable of ingesting bacteria but no killing them.