Autoantibodies against vimentin in a murine model of myocarditis

The presence of autoantibodies in the sera of patients with myocarditis has suggested that autoimmunity is a sequela of myocarditis. In this study, we examined anti-vimentin antibodies in a murine model of myocarditis. Four-week-old male DBA/2 mice were inoculated intraperitoneally with 10 plaque-forming units of encephalomyocarditis (EMC) virus. The surviving mice were killed on Days 0 (n = 7), 2 (n = 6), 5 (n = 6), 7 (n = 6), 9 (n = 6), 14 (n = 5), 60 (n = 6) and 540 (n = 3) after virus inoculation. The presence of anti-vimentin autoantibodies in the sera of mice was determined by ELISA. The optical density (OD) of anti-vimentin IgG and IgM autoantibodies of day 0 mice was 0.03 +/- 0.03 and 0.12 +/- 0.08, respectively, when positive antibody was defined as over the mean value plus 2-standard deviations of the sera of day 0 mice, anti-vimentin IgG antibodies were negative before day 5 but positive in all mice on day 9. Both IgG and IgM OD of the sera from day 9 mice (IgG; 0.26 +/- 0.12, IgM; 0.30 +/- 0.08) were significantly higher than those of the sera from day 0 mice (p < 0.005) and decreased thereafter on day 14. In the chronic stage, five of six mice were positive on day 60 and two of three mice were positive on day 540. Although further studies are needed to elucidate the pathogenetic role of anti-vimentin antibodies, these antibodies may be a parameter of the interstitial injury.