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Viral and host genetic factors influence encephalomyocarditis virus-induced polymyositis in adult mice
Abstract:
Recent research findings implicate picornaviruses in the etiology of human polymyositis/dermatomyositis and suggest that genetic factors play a role in susceptibility to these diseases. We compared 2 variants of encephalomyocarditis (EMC) virus for their ability to induce polymyositis in adult mice, and evaluated what role the genetic background of the host plays in the degree of myositis induced. While BALB/c mice developed minimal myositis when infected with a diabetogenic variant (EMC-D), the same strain inoculated with a newly isolated myopathic variant (EMC-221A) developed viral dose-dependent elevations in muscle-associated enzymes, bilateral limb muscle weakness, and the histopathologic changes of severe polymyositis. Mice with different genetic backgrounds showed significantly different susceptibilities to EMC-221A. These data suggest that the severity of polymyositis induced by EMC virus is influenced by both the viral and host genomes.
Insights
Picornaviruses may cause polymyositis. Researchers found that a specific encephalomyocarditis (EMC) virus variant caused severe polymyositis in mice, with disease severity influenced by both viral and host genetics.
Area of Science:
- Virology
- Immunology
- Genetics
Background:
- Recent findings suggest picornaviruses contribute to polymyositis/dermatomyositis etiology.
- Genetic factors are implicated in disease susceptibility.
Purpose of the Study:
- To compare the myositis-inducing potential of two encephalomyocarditis (EMC) virus variants.
- To assess the influence of host genetic background on EMC virus-induced myositis severity.
Main Methods:
- Adult mice (BALB/c and other strains) were infected with either EMC-D (diabetogenic) or EMC-221A (myopathic) virus variants.
- Disease severity was evaluated by measuring muscle enzymes, observing muscle weakness, and performing histopathological analysis.
Main Results:
- BALB/c mice infected with EMC-221A developed dose-dependent polymyositis, including elevated muscle enzymes, weakness, and histopathological changes.
- Mice with different genetic backgrounds exhibited varying susceptibility to EMC-221A-induced myositis.
- EMC-D variant induced minimal myositis in BALB/c mice.
Conclusions:
- The severity of EMC virus-induced polymyositis is determined by both viral and host genetic factors.
- Specific viral variants and host genetic background significantly influence disease development and severity.