Construction and expression of DNA vaccine pIRES-Sj97-Sj14-Sj26 and its immunogenicity in mice

Abstract

To find a new preventive strategy for the infection of Schistosoma japonica, plasmid pIRES-Sj97-Sj14-Sj26 that contains fatty binding protein (Sj14), GST (Sj26) and paramyocin (Sj97) that are expressed on the membrane, was constructed. RT-PCR was used to detect the expression of Sj14 mRNA, Sj26 mRNA and Sj97 mRNA in the Hela cells, the indirect immunofluorescent test was employed for the detection of the expression of trans-membrane Sj26 after the plasmid was transfected into Hela cells. Fifty BALB/c mice were randomly divided into 5 groups and pIRES-Sj97-Sj14-Sj26 plasmid DNA, pIRES-Sj14-Sj26 plasmid DNA, pIRES-Sj26 plasmid DNA, pIRES blank vector and normal saline were respectively injected into the quadriceps muscles of thigh. Eight weeks after the immunization the mice were killed and significantly higher level of IgG was detected in the pIRES-Sj97-Sj14-Sj26 group as compared with the pIRES blank vector, normal saline and pIRES-Sj26 groups (P<0.01) and the pIRES-Sj14-Sj26(P<0.05). Single splenocyte suspension was prepared to detected the level of IFN-γ by ELISA and the lymphocyte stimulating index (SI) by MTT. SI was significantly higher of in the pIRES-Sj97-Sj14-Sj26 group than in other groups (P<0.01), while the IFN-γ level was significantly higher the pIRES-Sj97-Sj14-Sj26 group than in pIRES blank vector and normal saline groups (P<0.01), but no significant differences were found when compared with pIRES-Sj14-Sj26 and pIRES-Sj26 groups. Flow cytometery showed that the percent-ages of CD4+ and CD8+ T cells were much higher in the pIRES-Sj97-Sj14-Sj26 group (P< 0.01, P<0.05). It was concluded that pIRES-Sj97-Sj14-Sj26 vaccine may induce stronger immune response in BALB/c mice.

References

[1] GurunathanS., KlinmanD., SederR.. DNA vaccines: immunology, application and optimization. Annu Rev Immunol, 2000, 18: 927-974

[2] NascimentoE, LeaiI C, PereiraV R. Protective immunity of single and multi-antigen DNA vaccine againse schistosomiasis. Mem Inst Oswaldo Cruz, 2002, 1: 105-109

[3] Da’daraA. A., SkellyP. J., FatakdawalaM., et al.. Comparative efficacy of the Schistosome mansoni nucleic acid vaccine, Sm23, following microseeding or gene gun delivery. Parasite Immunol, 2002, 24(4): 179-187

[4] YangW., JacksonD. C., ZengQ., et al.. Multi-epitope schistosome vaccine candidates tested for protective immunogenicity in mice. Vaccine, 2000, 19(1): 103-113

[5] BergquistR., Al-SherbinyM., BarakatR., et al.. Blueprint for schistosomasis vaccine development. Acta Trop, 2002, 82(2): 183-192

[6] LiuJ. M., CaiX. Z., LinJ. J., et al.. Gene cloning, expression and vaccine testing of Schistosoma japonicum SjFABP. Parasite Immunol, 2004, 26: 351-358

[7] HernandezM. G.. Paramyosin is a major target of the human IgA response against Schistosoma japonicum. Parasite Immunol, 1999, 21(12): 641-648

[8] ForusX., EmersonS. U., TobinG. J., et al.. DNA immunization of mice and macaques with plasmids encoding hepatitis C virus envelop Ez protein expressed intracelluarlly and on the cell surface. Vaccine, 1999, 17: 1992-2002

[9] SimmondsR. S., ShearerM. H., KennedyR. C.. DNA vaccine-from principle to practice. Parasitol Today, 1997, 13(9): 328-331

[10] WaineG. J., McManusD. P.. Schistosomiasis vaccine development-the current picture. Bioassays, 1997, 19(5): 435-443

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Huazhong University of Science and Technology