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Inhibition of macrophage migration by virus-induced interferon preparations
Abstract:
It was found that a preparation of mouse L cell interferon induced by Newcastle disease virus (NDV) possessed not only interferon activity but also inhibitory activity upon migration of guinea pig peritoneal macrophages (MIF activity). These activities were also observed in a preparation of human leukocyte interferon induced by NDV. The interferon and MIF activities shared common characteristics in the dose response, time course of in vitro production, thermal stability, sensitivity to trypsin and periodate, and elution pattern in CM-Sephadex column chromatography. However, gel filtration pattern with Sephadex G-100 showed two separate peaks. Fractions collected from the first peak, corresponding to a molecular weight of about 45 000, had only the MIF activity, while those collected from the second peak, corresponding to a molecular weight of about 30 000, had both the interferon and MIF activities. A preparation of mouse brain interferon induced by Japanese encephalitis virus had a much weaker MIF activity than the L cell interferon, although these preparations were equal in interferon activity (5000 units/ml).
Insights
Mouse and human interferons induced by Newcastle disease virus exhibit both interferon and macrophage migration inhibitory factor (MIF) activities. These activities share characteristics but differ in molecular weight, suggesting distinct but related molecules.
Area of Science:
- Immunology
- Virology
- Biochemistry
Background:
- Interferons are crucial antiviral proteins.
- Macrophage migration inhibitory factor (MIF) plays a role in immune responses.
- The relationship between interferon and MIF activities is not fully understood.
Purpose of the Study:
- To investigate the dual activity of interferon preparations.
- To characterize the interferon and MIF activities induced by Newcastle disease virus (NDV).
- To compare these activities with interferon from other sources.
Main Methods:
- Induction of interferon in mouse L cells and human leukocytes using NDV.
- Assays for interferon activity and macrophage migration inhibitory factor (MIF) activity.
- Characterization of shared properties: dose response, production time, thermal stability, enzymatic sensitivity, and chromatography.
- Gel filtration chromatography (Sephadex G-100) to determine molecular weights.
Main Results:
- NDV-induced mouse and human interferon preparations exhibited both interferon and MIF activities.
- Interferon and MIF activities shared several biochemical properties.
- Gel filtration revealed two distinct molecular weight fractions: one with only MIF activity (~45,000 Da) and another with both interferon and MIF activities (~30,000 Da).
- Mouse brain interferon showed significantly weaker MIF activity compared to L cell interferon at equivalent interferon levels.
Conclusions:
- Interferon preparations can possess dual interferon and MIF activities.
- The findings suggest the existence of at least two molecular species responsible for these activities, one potentially being a distinct MIF and the other a molecule with both functions.
- The observed differences highlight the complexity of interferon biology and its interaction with cellular functions like macrophage migration.