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Murine Kupffer cells. Mononuclear phagocytes deficient in the generation of reactive oxygen intermediates
Abstract:
Murine Kupffer cells (KC) were isolated by a high yield collagenase perfusion technique. The morphology, surface markers, and secretory products were typical of macrophages in other tissues. However, KC released negligible levels of H2O2 and O-2, in contrast to peritoneal macrophages. KC oxygen consumption was not increased by agents triggering a respiratory burst in peritoneal cells. Moreover, KC capacity to secrete reactive oxygen intermediates (ROI), in contrast to Ia antigen expression, was not enhanced by exposure to lymphokines or recombinant gamma interferon. The selective defect in KC oxidative response was paralleled by impaired in vitro killing of Toxoplasma gondii trophozoites and Leishmania donovani promastigotes and amastigotes. Deficient secretion of ROI by KC might protect hepatocytes and erythrocytes from injury during endocytosis by KC, but might render the liver more susceptible to parasitization by organisms that are primarily killed through oxygen-dependent mechanisms.
Insights
Murine Kupffer cells (KC) exhibit a defective oxidative response, releasing minimal reactive oxygen intermediates (ROI). This impairment affects their ability to kill parasites, potentially impacting liver susceptibility to infections.
Area of Science:
- Immunology
- Cell Biology
- Hepatology
Background:
- Kupffer cells (KC) are resident macrophages in the liver sinusoids.
- Macrophages typically utilize reactive oxygen intermediates (ROI) for pathogen killing.
- Previous studies have not fully characterized the oxidative burst capacity of KC.
Purpose of the Study:
- To investigate the oxidative response of murine Kupffer cells (KC).
- To compare KC ROI secretion with peritoneal macrophages.
- To assess the functional consequences of KC oxidative defects on parasite killing.
Main Methods:
- Isolation of murine KC using collagenase perfusion.
- Assessment of hydrogen peroxide (H2O2) and superoxide anion (O-2) release.
- Measurement of oxygen consumption in response to respiratory burst stimuli.
- Evaluation of ROI secretion and Ia antigen expression after lymphokine/interferon exposure.
- In vitro killing assays using Toxoplasma gondii and Leishmania donovani.
Main Results:
- KC morphology, surface markers, and general secretory products were typical of macrophages.
- KC released negligible H2O2 and O-2, unlike peritoneal macrophages.
- KC oxygen consumption was not enhanced by respiratory burst-inducing agents.
- KC ROI secretion, but not Ia antigen expression, was not increased by lymphokines or gamma interferon.
- KC demonstrated impaired in vitro killing of Toxoplasma gondii and Leishmania donovani.
Conclusions:
- Murine KC possess a selective defect in their oxidative response pathway.
- This deficiency in ROI secretion may protect host cells but compromises the liver's defense against certain intracellular parasites.
- The findings highlight a unique functional characteristic of Kupffer cells compared to other macrophages.