[Construction and expression of Schistosoma japonicum bivalent DNA vaccines and their efficiencies of protective immunity].
OBJECTIVE
To study the efficiency of protective immunity afforded by the constructed bivalent DNA vaccines of Schistosoma japonicum.


METHODS
The plasmids pVIVO2-mcs-SjFABP-Sj23 and pVIVO2-mes-Sj23-SjFABP, co-expressed bivalent DNA vaccines, were constructed and identified. The presence of bivalent DNA vaccine in the mouse muscle cells was also tested by indirect immunofluorescent antibody tests (IFAT). 70 BALB/c mice were randomly divided into seven groups to be injected with normal saline, pVIVO2-mcs, pVIVO2-mcs-Sj23, pVIVO2-mcs-SjFABP, pVIVO2-mcs-Sj23-SjFABP, pVIVO2-mcs-SjFABP-Sj23 plasmid DNA, and a mixture of pVIVO2-mcs-Sj23-SjFABP plasmid DNA and amylose adjuvant, respectively. At day 45 after challenge the mice were sacrificed. The number of adult worms and hepatic eggs were counted.


RESULTS
Successful construction of co-expressed bivalent DNA vaccines were identified by restriction analysis and sequencing. It was confirmed by IFAT that the bivalent DNA vaccine was expressed in the plasma and on the surface of muscle cells from mouse. The worm reduction rate was 41.20%-53.85% and the egg reduction rate was 47.02%-53.83% bivalent DNA groups. Furthermore, the worm and egg reduction rates in pVIVO2-mcs-Sj23-SjFABP plasmid DNA and amylose adjuvant group were 68.89% and 84.04% respectively, significantly higher than single antigenic DNA vaccine and bivalent DNA vaccine (P < 0.05).


CONCLUSIONS
The co-expressed bivalent DNA vaccines of Schistosoma japonicum can induce immune protection in mice. The protective immunity of amylose adjuvant group is higher than that of the univalent DNA and bivalent vaccines.
Hu
Yuan
Y
Department of Parasitology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
Shi
You-en
YE
Zhu
Xiao-hua
XH
Ning
Chang-xiu
CX
Zhu
Hong-gang
HG
D000818:Animals; D019084:Fluorescent Antibody Technique, Indirect; D015870:Gene Expression; D015801:Helminth Proteins / Q000235:genetics; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D010957:Plasmids / Q000235:genetics; D011897:Random Allocation; D012549:Schistosoma japonicum / Q000235:genetics / Q000276:immunology*; D012554:Schistosomiasis japonica / Q000276:immunology* / Q000469:parasitology / Q000517:prevention & control; D019444:Vaccines, DNA / Q000235:genetics / Q000276:immunology* / Q000627:therapeutic use
D015801:Helminth Proteins; D019444:Vaccines, DNA