Related Experiment Videos
Cellular immune responses in mice challenged with an amyocarditic variant of Coxsackievirus B3
Abstract:
An amyocarditic variant of a temperature-sensitive (ts) mutant derived from the parent myocarditic variant Coxsackievirus B3 (CVB3m) was studied in a murine model of CVB3m-induced myocarditis to assess virus-induced antigens and their possible role in the disease process. Amyocarditic variant ts5R induced a heart tissue antigen(s), extractable by hypertonic KC1, which inhibited migration of peritoneal exudate cells from CVB3-inoculated myocarditic mice in an agarose droplet cell-migration-inhibition assay. The ts5R variant was amyocarditic at inoculum doses of 10(3) to 10(8) plaque-forming units per mouse, but in cyclophosphamide-immunosuppressed mice, ts5R induced myocarditis. Viable ts5R served as a vaccine and protected mice against CVB3m-induced myocarditis. Murine neonatal skin fibroblasts (MNSF) infected with either virus served as in vitro targets and were lysed by splenic cytotoxic T lymphocytes from mice inoculated with either virus variant. ts5R and CVB3m replicated to similar titers in murine neonatal skin fibroblasts (MNSF) at 24 hr postinoculation (pi), but differences in titers were found by 72 hr pi. Levels of natural killer cell activities in spleens of ts5R-inoculated mice were slightly lower than in spleens of CVB3m-inoculated mice at 7 days pi. The data suggest that viral induction of new antigens on target cells and viral induction of specific cytotoxic T lymphocytes that recognize these antigenic changes do not always result in induction of myocarditis.
Insights
An amyocarditic variant of Coxsackievirus B3 (CVB3m), ts5R, induced heart antigens but did not cause myocarditis in healthy mice. However, ts5R acted as a vaccine, protecting against CVB3m-induced myocarditis.
Area of Science:
- Virology
- Immunology
- Cardiovascular Research
Background:
- Coxsackievirus B3 myocarditis (CVB3m) is a significant cause of heart disease.
- Understanding the role of viral antigens in disease pathogenesis is crucial.
Purpose of the Study:
- To investigate the role of virus-induced antigens in CVB3m-induced myocarditis.
- To evaluate the amyocarditic potential and vaccine efficacy of a temperature-sensitive mutant (ts5R).
Main Methods:
- A murine model of CVB3m-induced myocarditis was used.
- Cell migration inhibition assays assessed antigenicity.
- Cytotoxic T lymphocyte and natural killer cell activities were measured.
- Viral replication in murine neonatal skin fibroblasts (MNSF) was quantified.
Main Results:
- The ts5R variant induced heart tissue antigens that inhibited cell migration.
- ts5R was amyocarditic in immunocompetent mice but induced myocarditis in immunosuppressed mice.
- Viable ts5R demonstrated vaccine potential, protecting against CVB3m-induced myocarditis.
- Both viruses induced cytotoxic T lymphocytes that lysed infected MNSF.
Conclusions:
- Viral induction of new antigens and specific cytotoxic T lymphocytes does not invariably lead to myocarditis.
- The ts5R mutant offers a potential vaccine candidate for preventing CVB3m-induced myocarditis.