Prevention of viral myocarditis with recombinant human leukocyte interferon alpha A/D in a murine model.

Effects of recombinant human leukocyte interferon alpha A/D on experimental myocarditis due to encephalomyocarditis virus were investigated. Plaque reduction assays revealed that 50% of plaque formation in vitro in human amnion (FL) cells was inhibited by interferon alpha A/D (9.7 U/ml) when it was administered 24 hours before infection with the encephalomyocarditis virus. Four week old male DBA/2 mice were inoculated intraperitoneally with 10 plaque-forming units (pfu) of encephalomyocarditis virus. Interferon alpha A/D was administered subcutaneously (10(2) U/g body weight per day in Group 1, 10(3) U/g per day in Group 2 and 10(4) U/g per day in Group 3) starting 1 day before infection. It was also administered starting the same day in Group 4 and 1 day after virus inoculation in Group 5 (10(4) U/g per day in both groups). Control mice were injected with saline solution. Each group consisted of 10 mice; they were killed on day 4 for evaluation. Myocardial virus titers were significantly lower in Group 3 (8.2 +/- 25.2 X 10(2) pfu/mg, p less than 0.05) and Group 4 (3.0 +/- 5.5 X 10(3) pfu/mg, p less than 0.05) than in control mice (5.6 +/- 4.1 X 10(4) pfu/mg). Histologic examination showed extensive myocardial necrosis and cellular infiltration in all control mice, but no myocardial necrosis or cellular infiltration in Group 3 and less severe necrosis and infiltration in Group 4. There were no significant differences in myocardial virus titers or histologic changes between control mice and Group 1, 2 or 5.(ABSTRACT TRUNCATED AT 250 WORDS)