Construction of the multivalent DNA vaccine pVIVO_2SjFABP-23 and its immuno-protection in mice

The multivalent DNA vaccine pVIVO_2SjFABP-23 was constructed and its immuno-protection to Schistosoma japonicum was investigated in mice,in which two couples of specific primers were designed according to gene sequences of Sj-FABP(fatty acid binding protein) and Sj-23(23kDa membrane protein),and these two gene fragments were spliced through a linker sequence by recombinant PCR technique to obtain the fusion gene Sj-FABP-23,which was inserted into vector pGEM-T,identified by restriction analysis digested with BamHI and EcoR1 and then cloned into expression plasmid pVIVO_2/MCS and transformed to E.coli GT110.The recombinant plasmid pVIVO_2-SjFABP-23 was extracted,purified and then inoculated to BALB/c mice through intramuscular route.Mice were challenged with cercariae of S.japonicum 4 weeks after inoculation,and killed to get specimens to count the adult worms and eggs.The experimental results showed that a target fragment with an obvious band of 1.1 kb demonstrated by electrophoresis of SjFABP-23 on 0.7% agarose gel could be amplified by PCR,and inoculation with this fragment into mice induced the reduction of the adult worm counts up to 52.14% and those of eggs up to 60.93% in comparison with those of control group of mice inoculated with blank plasmid pVIVO_2 intrtamuscularly at the same dosage of 100 μ per mouse.It is concluded that the multivalent DNA vaccine expressing SjFABP-23 was successfully constructed and this DNA vaccine demonstrates certain immuno-protection to S.japonicum infection in mice.