Objective  To compare the effect of macrophage-derived chemokine (MDC) and Shiga toxin B subunit (STxB) gene on the neutralizing antibodies and specific CTL response induced by Coxasckievirus B3 (CVB3) VP1 fusion DNA vaccine

as wells as the protective effect of the genes on the mice challenged with CVB3.   Methods  Male BALB/c mice were divided into 6 groups randomly

20 for each

an

d injected imtramuscularly (i.m.) pcDNA3

pcDNA3/MDC

pcDNA3/STxB

pcDNA3/VP1

pcDNA3/MDC-VP1

pcDNA3/STxB-VP1

once for 3 weeks

totally for 3 times. Serum samples 20 d after each injection were taken and detected for the neutralizing antibody against CVB3 by micro-neutralization test. Three weeks after the third immunization

splenocytes from 3 mice of each group were isolated to detect specific CTL response by CCK-8 assay. The mice were challenged with 10LD

50

of CVB3 after the 3 injections. The survival time and survival rate were observed.   Results  Neutralizing antibodies were induced in pcDNA3/VP1

pcDNA3/STxB-VP1 and pcDNA3/MDC-VP1 groups

and the antibody titers were increased with the increasing number of injections except pcDNA3/STxB-VP1 group. After the third inoculation

the mean neutralizing antibody titers in pcDNA3/MDC-VP1 group were higher than pcDNA3/VP1 and pcDNA3/STxB-VP1 groups (P0.05). Up to the 21st day after CVB3 challenge

the survival rates of pcDNA3/MDC-VP1 group were better than others (P0.05).  However

neutralizing antibody and survival rate had no significant changes in pcDNA3/VP1 and pcDNA3/STxB-VP1 groups.   Conclusion  pcDNA3/MDC-VP1 vaccine can induce a stronger immunological effect

result in a higher survival rate

and had better influence than pcDNA3/STxB-VP1.