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Updated: Aug 19, 2026
Dissecting Innate Immune Signaling in Viral Evasion of Cytokine Production
Published on: March 2, 2014
Natural antiviral activity of mouse macrophages against encephalomyocarditis virus
Abstract:
Resident mouse peritoneal cells (PC) express a significant antiviral activity against encephalomyocarditis virus (EMCV) in vitro, as judged by decreased virus yield from infected mouse embryo fibroblasts (MEF). This natural antiviral activity of PC was not due either to enhanced lysis of virus-infected cells, as these were protected from lysis rather than destructed by PC, or to interferon (IFN) production, as no direct correlation between IFN and anti-EMCV activity was found. Among PC, macrophages (M phi) appear to be responsible for the anti-EMCV activity, which was indeed attributable to a Thy 1.2-negative, adherent mononuclear cell. Moreover, M phi-defective C3H/HeJ mice showed a significant impairment of anti-EMCV activity, whereas M phi of mice defective for natural killer (NK) activity (bg/bg, SJL/J) or for mature T cells (nu/nu) possessed an intact antiviral capacity.
Insights
Resident mouse peritoneal cells exhibit antiviral activity against encephalomyocarditis virus (EMCV). Macrophages within these cells are identified as the primary mediators of this natural antiviral defense, distinct from interferon production.
Area of Science:
- Virology
- Immunology
- Cell Biology
Background:
- Resident mouse peritoneal cells (PC) demonstrate natural antiviral activity against encephalomyocarditis virus (EMCV) in vitro.
- This activity is crucial for understanding innate immune responses to viral infections.
Purpose of the Study:
- To elucidate the cellular mechanisms underlying the antiviral activity of mouse peritoneal cells against EMCV.
- To identify the specific cell types within peritoneal exudate responsible for this antiviral effect.
- To differentiate the antiviral mechanism from interferon (IFN) production and cell lysis.
Main Methods:
- In vitro antiviral assays using mouse peritoneal cells (PC) and infected mouse embryo fibroblasts (MEF).
- Characterization of antiviral cells based on adherence, morphology, and surface markers (Thy 1.2).
- Assessment of antiviral activity in immunodeficient mouse models (C3H/HeJ, bg/bg, nu/nu) with defects in macrophages, NK cells, or T cells.
Main Results:
- PC significantly reduced EMCV yield in MEF, indicating antiviral activity.
- The antiviral effect was not mediated by enhanced lysis of infected cells or by interferon production.
- Macrophages (M phi), specifically Thy 1.2-negative, adherent mononuclear cells, were identified as the primary effector cells.
- M phi-deficient C3H/HeJ mice showed impaired antiviral activity, while mice with NK or T cell deficiencies retained intact antiviral capacity.
Conclusions:
- Macrophages are the key cellular component of peritoneal exudate responsible for natural antiviral activity against EMCV.
- This antiviral mechanism operates independently of interferon and direct cell killing.
- The findings highlight the critical role of macrophages in innate antiviral immunity against EMCV.
