Pre-exposure of murine macrophages to lipopolysaccharide inhibits the induction of nitric oxide synthase and reduces leishmanicidal activity
| Autor: | Catherine A. O'Donnell, Damo Xu, Alison Severn, David W. Moss, Jacqueline Doyle, Sara J. Brett, Ludmila M. C. C. Leal, Foo Y. Liew |
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| Rok vydání: | 1993 |
| Předmět: |
Cytotoxicity
Immunologic Lipopolysaccharides Cellular immunity Lipopolysaccharide Immunology Leishmaniasis Cutaneous Stimulation Nitric Oxide Nitric oxide Cell Line chemistry.chemical_compound Mice Immunology and Allergy Macrophage Animals Leishmania major biology Tumor Necrosis Factor-alpha Macrophages biology.organism_classification Molecular biology Nitric oxide synthase Biochemistry chemistry Leishmania tropica Enzyme Induction biology.protein Mice Inbred CBA lipids (amino acids peptides and proteins) Tumor necrosis factor alpha Amino Acid Oxidoreductases Nitric Oxide Synthase |
| Zdroj: | European journal of immunology. 23(7) |
| ISSN: | 0014-2980 |
| Popis: | Murine macrophages produce nitric oxide (NO) from L-arginine on stimulation with lipopolysaccharide (LPS), alone or with interferon-gamma (IFN-gamma). The effect of incubation of macrophages with low concentrations of LPS on NO synthesis on subsequent stimulation was investigated, using a murine macrophage cell line, J774, and peritoneal macrophages from CBA mice. Cells which had been incubated with LPS produced significantly lower amounts of NO, and expressed lower levels of NO synthase activity, following stimulation with IFN-gamma and LPS, or with a high concentration of LPS. This effect was not reversed by tumor necrosis factor-alpha. The ability of CBA macrophages to kill the intracellular parasite Leishmania major was markedly reduced by pre-incubation with LPS. Reduced NO production by macrophages previously exposed to LPS is a manifestation of endotoxin tolerance, and may represent an important means of regulation of NO synthesis and thus a survival mechanism for intracellular parasites. |
| Databáze: | OpenAIRE |
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