THE ROLE OF ALVEOLAR MACROPHAGES IN THE PRODUCTION OF COLONY –STIMULATING FACTOR BY THE LUNG

The role of alveolar macrophages in the production of granulocyte/ macrophage colony-stimulating factor(s) by the rat lung was investigated. Lavaged lungs, when incubated at proper weight per volume of culture medium, produced the same amount of colony-stimulating factor as unlavaged ones. Both lavaged and unlavaged lungs produced similar types of colony-stimulating factor (s). Prolonged incubation of lavaged and unlavaged lung tissues did not result in higher levels of activity beyond that produced by 48 hrs of incubation. Alveolar macrophages recovered from the lung did not produce colony-stimulating factors when they were cultured unstimulated and under similar conditions as lung conditioned medium. The results indicated that alveolar macrophages did not play a significant role in colony stimulating factor (s) production by the lungs and when unstimulated, they did not produce colony-stimulating factors directly.