EFFECTS OF LEVAMISOLE, AN IMMUNOMODULATOR, UPON MURINE ENCEPHALOMYOCARDITIS VIRUS MYOCARDITIS

To test the therapeutic efficacy of levamisole, 5-week-old DBA/2 mice were inoculated intraperitoneally with 10 plaque-forming units of ence phalomyocarditis virus. Levamisole (2.5 mg/kg/per day) was administere d intraperitoneally daily, starting simultaneously with the virus inoc ulation, in experiment I for 14 days, and daily on days 14 to 28 in ex periment II in mice that survived to 14 days after virus inoculation. In experiment I, survival was higher, the severity of myocarditis was less, and myocardial virus titers were lower in treated than in untrea ted animals. In experiment II, levamisole was not effective. No signif icant changes in serum neutralizing antibody titers occurred in either experiment. Furthermore, levamisole prevented associated lymphoid org an atrophy induced by the virus infection. An additional in vitro stud y revealed the absence of anti-viral activity of the drug. Thus, levam isole may have favorable effects upon encephalomyocarditis virus myoca rditis by preventing the virus-induced lymphoid organ atrophy and redu cing myocardial virus replication in the acute stage.