Attenuation of coxsackievirus B3 by VP2 mutation and its application as a vaccine against virus-induced myocarditis and pancreatitis.

Coxsackievirus B3 (CVB3) is a common agent of viral myocarditis, a major cause of sudden cardiac death, and ultimately dilated cardiomyopathy. However, there is no vaccine in clinical use. In this study, we identified the conserved amino acid sequences in the C-terminal region of the VP2 of the coxsackievirus B group and some echoviruses. The mutant virus, YYFF, with phenylalanines substituted for two tyrosines in these conserved sequences was highly attenuated in vivo and could induce a high neutralizing antibody titer and a cytotoxic T-lymphocyte response against CVB3. Thereby, mutant-virus-immunized mice showed a 100% survival rate and protection against inflammation of the heart and pancreas after lethal dose challenge. Thus, this mutant virus is a good candidate for an attenuated CVB3 vaccine.