Vaccination of Balb/c mice against enteroviral mediated myocarditis.

A non-virulent strain of Coxsackie B3 (CB3) virus was used to produce a subunit vaccine. It contains the capsid proteins VP1, 2, 3 and probably 4 and can be made RNA-free. It is based on the ISCOM technology ensuring non-toxic properties and good adjuvant effect. Vaccinated animals at doses above 16 ng were completely protected from mortality when challenged with a myocarditic strain of CB3. Histologically no inflammatory lesions were found in the heart. This was corroborated using immune histological techniques with monoclonal antibodies against lymphocyte subsets. Even at a dose of 0.16 ng a delayed mortality was observed. Neutralizing antibody titres rose to 512, thus ensuring a circulating level well above that considered protective. It is suggested that vaccination might be a possible way of prophylaxis for myocarditis and even dilated cardiomyopathy, the latter presently being the chief cause of heart transplantation. By persistence or triggering of autoimmune phenomena Coxsackie virus is incriminated as the first step in pathogenesis.