The human alveolar macrophage: isolation, cultivation in vitro, and studies of morphologic and functional characteristics

Abstract

A B S T R A C T Human alveolar macrophages were lavaged from surgically resected lungs and from lungs of normal subjects. Macrophages that had been purified by glass adherence were maintained in tissue culture for as long as 54 days. After 3-4 wk in vitro they underwent transformation into multinucleated giant cells. These aged cells had more than 30 times the phagocytic capacity that the same group of cells had had after 1 day in vitro.Phagocytosis of heat-killed Candida albicans was inhibited by iodoacetate, sodium fluoride, potassium cyanide, and low partial pressures of oxygen, suggesting that these cells require both oxidative and glycolytic energy sources for maximal particle ingestion. Alveolar macrophages and monocyte-derived macrophages killed Listeria monocytogenes with similar efficiency, but neutrophils were more efficient than either of the other cell types. Bacterial killing is probably not dependent upon myeloperoxidase in the monocyte-derived macrophage or in the alveolar macrophage since histochemical stains for peroxidase do not stain either cell type. C. albicans blastospores, which are killed by neutrophils and monocytes that contain myeloperoxidase, were not killed by human alveolar macrophages during the 4 hr of observation.Large cells with supernormal phagocytic capacity were recovered from patients with postobstructive pheumonia and from one patient with recurrent bacterial pneumonia, indicating that macrophage function can be altered in certain disease states.Human alveolar macrophages are unique human phagocytes in their dependence on an oxygen tension greater than 25 mm HG for maximal phagocytosis. Carbon dioxide tensions as high as 70 mm Hg did not alter phago-

Interaction between the legionnaires' disease bacterium (Legionella pneumophila) and human alveolar macrophages. Influence of antibody, lymphokines, and hydrocortisone.

“…The resistance of L. pneumophila to killing is perhaps in part due to a low in vitro antibacterial capacity of alveolar macrophages relative to other phagocytes. Although alveolar macrophages in vitro ingest and kill a variety of potential pulmonary pathogens (S. aureus, E. coli, T. gondii, S. pneumoniae, L. monocytogenes, N. asteroides, and K. pneumoniae), their bactericidal capacity against a given target organism is low compared with other phagocytes (17,19,24,(26)(27)(28)(29). Similarly, in our study, alveolar macrophages were unable to reduce CFU of E. coii below the level of the original inoculum, whereas monocytes were able to reduce CFU of E. coli by two logs (99%) in the same assay.…”

“…Examination of a stained cytocentrifuged sample from each lavage revealed that '90-95% of the cells were macrophages of various sizes; the remaining cells were monocytes, lymphocytes, eosinophils, polymorphonuclear leukocytes, and a few bronchial or oral epithelial cells. As it was difficult to distinguish between monocytes and small alveolar macrophages, additional cytocentrifuged samples were stained for myeloperoxidase (16,17). On the average, 95% of these cells were myeloperoxidase negative (alveolar macrophages) and 5% myeloperoxidase positive (monocytes, granulocytes).…”

Alveolar macrophages in pulmonary host defence – the unrecognized role of apoptosis as a mechanism of intracellular bacterial killing

“…Differentiated macrophages of human or rodent origin lack the capacity to generate certain potent ROS species via myeloperoxidase, used by other phagocytes such as neutrophils. However, they can generate hydrogen peroxide through the nicotinamide adenine dinucleotide phosphate (NADPH)-oxidase system [23,24] and ROS via their mitochondria [25]. They can form more potent microbicidal factors though the reaction of ROS with NO generated through the inducible nitric oxide synthase (NOS2/iNOS) system [26].…”

Immunology of the Lower Respiratory Tract

“…Although composed predominantly of macrophages, the cell populations obtained by bronchopulmonary lavage' of several mammalian species, including man, contain morphologically identifiable lymphocytes (7,9,10). After antigenic stimulation of the respiratory tract, cells appear in alveolar spaces, and these have been reported to be capable of both specific antibody synthesis (11) cell) 2 funictionl, anid cell-milediaited imimiunity (6)(7)(8), a thymus-dependent lymplhocyte (,T cell) funiction.…”