Immune responses in mice induced by DNA vaccines containing different glycoprotein C (Gc) gene fragments of Xinjiang hemorrhagic fever virus / 中华微生物学和免疫学杂志

ABSTRACT

Objective To construct two DNA vaccines based on two glycoprotein antigen segments of Xinjiang hemorrhagic fever virus (XHFV) and to evaluate the immune responses in BALB/c mice following vaccination.Methods Two recombinant expression plasmids pVAX1-GcⅠand pVAX1-Gc Ⅱ were constructed by inserting XHFV YL04057 strain Gc Ⅰ (1 229-1 349 aa) and Gc Ⅱ (1 443-1 566 aa) fragments into the eukaryotic expression vector pVAX1 and then were identify by restriction enzyme digestion and sequencing analysis.The recombinant expression plasmids were transfected into mice by hydrodynamics-based transfection.Immune responses induced in mice were evaluated by testing the proliferation of T cells with MTT,measuring serum antibody level with ELISA and detecting cytokines in the supernatant of spleen cell culture with ELISA kit.Results The recombinant expression plasmids were successfully constructed as indicated by the results of restriction enzyme digestion and sequencing analysis.Expression of Gc Ⅰ and Gc Ⅱ genes in mice liver tissues was detected.Antibody titers in mice immunized with pVAX1-GcⅠor pVAX1-Gc Ⅱ were higher than those in mice immunized with pVAX1.Compared with pVAX1,pVAX1-Gc Ⅱ significantly enhanced the proliferation of splenic T lymphocytes and the expression of IFN-γ (P<0.01).Conclusion The constructed two DNA vaccines for XHFV can induce specific humoral and cellular immune responses in mice.pVAX1-Gc Ⅱ is better than pVAX1-GcⅠin immunogenicity and protective efficacy,suggesting that it can be used as a promising candidate for the development of DNA vaccine for XHFV.