Human alveolar macrophage and blood monocyte interleukin-6 production.
Interleukin-6 (IL-6) modulates a number of processes relevant to host immunity and inflammation. We investigated the capacity of the human alveolar macrophage to elaborate IL-6 in response to lipopolysaccharide (LPS), recombinant interleukin-1 (rIL-1), and recombinant tumor necrosis factor (rTNF), and compared macrophage IL-6 production to that of blood monocytes and lung fibroblasts. Unstimulated and TNF-stimulated alveolar macrophages and monocytes produced little or no detectable IL-6. In contrast, macrophages and monocytes produced large amounts of IL-6 in response to LPS and monocytes produced lesser but readily detectable amounts in response to rIL-1. Monocytes and alveolar macrophages differed significantly in their capacity to produce IL-6, with macrophages making more IL-6 in response to LPS and less IL-6 in response to rIL-1 than autologous blood monocytes. Monocytes aged in vitro produced little detectable IL-6 in response to LPS or rIL-1, suggesting that differences in cell maturity may account for the diminished capacity of the alveolar macrophage to produce IL-6 in response to IL-1 but not its enhanced capacity to produce IL-6 in response to LPS. Mononuclear phagocytes and lung fibroblasts also differed in their ability to produce IL-6. Lung fibroblasts produced more IL-6 in response to rIL-1 and less IL-6 in response to LPS than monocytes and macrophages. In addition, monocytes and macrophages elaborated electrophoretically identical IL-6 moieties that differed from those produced by lung fibroblasts. These differences could be at least partially attributed to differences in sialylation and/or glycosylation.(ABSTRACT TRUNCATED AT 250 WORDS)
Kotloff
R M
RM
Department of Internal Medicine, Hospital of the University of Pennsylvania, Philadelphia.
Little
J
J
Elias
J A
JA
D002454:Cell Differentiation; D004591:Electrophoresis, Polyacrylamide Gel; D005347:Fibroblasts / Q000378:metabolism; D006031:Glycosylation; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology; D015850:Interleukin-6 / Q000096:biosynthesis* / Q000097:blood; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism*; D009000:Monocytes / Q000187:drug effects / Q000378:metabolism*; D019158:N-Acetylneuraminic Acid; D010586:Phagocytes / Q000378:metabolism; D011650:Pulmonary Alveoli / Q000276:immunology*; D011994:Recombinant Proteins / Q000494:pharmacology; D012794:Sialic Acids / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D007375:Interleukin-1; D015850:Interleukin-6; D008070:Lipopolysaccharides; D011994:Recombinant Proteins; D012794:Sialic Acids; D014409:Tumor Necrosis Factor-alpha; D019158:N-Acetylneuraminic Acid