Normal Human Alveolar Macrophages Have More Ability than Blood Monocytes to Produce Cell-associated Interleukin-1-alpha

Human alveolar macrophages (AM) were obtained by bronchoalveolar lavage from healthy donors, and their abilities to produce extracellular and cell-associated interleukin 1 (IL-1) in response to various activation stimuli were compared with those of autologous blood monocytes. The production of IL-1α and IL-1β by monocytes and AM was examined by thymocyte co-stimulation assay and enzyme immunoassays (EIA). Results showed that when activated with lipopolysaccharide (LPS) or desmethyl muramyl dipeptide (norMDP), AM released much less extracellular IL-1 than did blood monocytes. In contrast, these activated AM produced more cell-associated IL-1 than did blood monocytes. When the IL-1 activity was examined by the thymocyte assay, the extracellular and cell-associated IL-1 produced by the two cell types were largely IL-1β and IL-1α, respectively, as shown by antibody neutralization. The cell-associated IL-1 activity of AM induced by the synergistic actions of suboptimal concentrations of recombinant interferon-...