Aim: To immunize the mice using the rAd/MDC-VP1 prime-pcDNA3/MDC-VP1 boost strategy and observe its immunological effect against Coxsackievirus B3(CVB3).
Methods: BALB/c mice were randomly divided into four groups: PBS group, rAd/MDC-VP1 group, pcDNA3/MDC-VP1 group and rAd/MDC-VP1 prime-pcDNA3/MDC-VP1 boost group. Mice in each group were immunized intramuscularly. The titers of serum IgG and neutralizing antibody were tested by ELISA and trace neutralization assays respectively. The Lymphocytes proliferation activity and specific CTL cytotoxic activity were tested by CCK-8 assay. The mice in each group were challenged with lethal dose of CVB3, and the serum virus titer was assayed and the protection efficacy against Coxsackievirus infection was observed.
Results: It was observed that the titers of CVB3 VP1 specific IgG and neutralizing antibody, non-specific lymphocytic proliferation activity and specific lymphocytic CTL cytotoxic activity of the rAd/MDC-VP1 prime-pcDNA3/MDC-VP1 boost group were much higher than those of the rest groups(P<0.05), what's more, after CVB3 challenged, the serum virus titer of this group was lower and the protection rate(41.67%) was higher (P<0.05).
Conclusion: Both the cellular and humoral immune responses in mice could be significantly enhanced by the rAd/MDC-VP1 prime-pcDNA3/MDC-VP1 boost strategy and the protection rate after challenged by lethal dose of virus could be increased.