The proliferation kinetics of pulmonary alveolar macrophages.

In this study the proliferation kinetics of pulmonary alveolar macrophages (PAMs) are determined using [3H]thymidine labeling, flow cytofluorimetry, metaphase arrest, and the percentage of labeled mitoses. The demonstration of in situ PAM proliferation is demonstrated beyond doubt. Comparison of the turnover time, calculated from cell kinetic parameters, with the experimentally determined migration times shows that the contribution proliferating PAMs make to their own population size is significant. Indeed, a strong case may be made to show that some 70% of the PAM population is produced by intra-alveolar divisions of "free" PAMs.