Human blood monocytes, macrophages from pleural effusions, ascites, and alveolar macrophages obtained by bronchopulmonary lavage were investigated. The proliferative activity of these cells was determined by the 3H-thymidine labeling index in vitro (3H-TDR L.I.). The bacteriostatic capacity was measured by the potential of the cells to block DNA-synthesis of proliferating Escherichia coli after phagocytosis. In most cases 3H-TDR L.I. of blood monocytes, macrophages from pleural effusions and ascites was less than 1%. However, macrophages of some patients with neoplastic diseases exhibited 3H-TDR L.I. between 4.0--9.6%. This probably reflected the action of factors, possibly lymphokines, which stimulated macrophage proliferation. In contrast, alveolar macrophages seemed to have almost totally lost their proliferative potential. The bacteriostatic capacity of blood monocytes proved to be significantly lower than that of macrophages. This demonstrates the functional immaturity of blood monocytes. In all type of macrophages investigated the bacteriostatic power was very high. No differences could be detected either between macrophages of different sources or between macrophages of benign, inflammatory, or malignant diseases.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.