Coxsackievirus B3 (CVB3) causes viral
myocarditis and can ultimately result in
dilated cardiomyopathy. However, there is no
vaccine available for clinical use. In this study, we assessed the protection provided by three immunization strategies against CVB3
infection. Vaccination was performed with
a DNA vaccine expressing the cloned capsid gene VP1 or a
vaccine developed from purified VP1
protein. Third, a strategy of vaccination was attempted with the
DNA vaccine followed by two boosts with the
recombinant protein vaccine (DNA prime-
protein boost
vaccine). Followed immunization, mice were challenged with CVB3
infection. Improved induction of CVB3-specific
antibodies and
neutralizing antibodies were found in mice immunized by the
DNA prime-
protein boost regimen. Furthermore, virus-specific cytotoxic activity of spleen cells derived from
DNA prime-
protein boost vaccinated mice was elicited. In addition, the
DNA prime-
protein boost
vaccine resulted in protection of 75% of mice from lethal CVB3 challenge and a significant reduction of viral load in sera of immunized mice after acute CVB3
infection. There was a significant reduction in myonecrosis and infiltrating myocardial immune cells indicating reduced severity of
myocarditis in surviving mice. These findings demonstrated that
a DNA prime-
protein boost immunization strategy, but not
a DNA vaccine or
protein vaccine alone, was effective in eliciting both humoral and cell-mediated immune responses against CVB3
infection in mice and might be a promising
vaccine candidate.