GP96_(NTD)-CSP重组DNA疟疾疫苗诱导小鼠产生保护性免疫的研究

Partial protective immunity induced by malaria DNA vaccine GP96_(NTD)-CSP

目的探讨pFLAG CMV8 gp96NTD-CSP重组DNA疟疾疫苗免疫能否诱导小鼠产生保护性免疫及其效应机制。方法以pFLAG CMV8质粒为载体,构建免疫用重组质粒,按照DNA疫苗免疫方法免疫小鼠;野生子孢子进行攻击后,采用Real-time PCR和吉氏染色观察被攻击小鼠的肝脏虫荷和原虫血症,即免疫小鼠抵御野生子孢子攻击的能力;并通过ELISA和ELISPOT方法探讨免疫小鼠保护性免疫的可能机制。结果核酸疫苗pFLAG CMV8 gp96NTD-CSP免疫小鼠能显著抵御野生子孢子的攻击,并且能诱导小鼠产生较高的抗体水平和较高的CSP特异的CD8+T细胞频率。结论 pFLAG CMV8 gp96NTD-CSP重组DNA疫苗可能通过诱导小鼠CSP特异抗体和CSP特异的CD8+T细胞的产生,一定程度上抵御野生子孢子的攻击。

In this study,we aimed to investigate the protective immune response induced by malaria DNA vaccine GP96NTD-CSP.Firstly,we constructed the recombination plasmids used for immunizing mice.Two weeks after final immunization with the plasmids,WT and immunized mice were challenged with wild-type Plasmodium yoelii BY265 sporozoites via tail vein.Then,the protective effect of all mice was determined according to parasitemia and liver parasite burden.And the level of CSP-specific antibody and the frequency of IFN-γ-secreted-CSP-specific CD8＋ T cells were measured by ELISA and ELISPOT assay,respectively.We found that mice immunized with pFLAG CMV8 gp96NTD-CSP had much lower liver parasite burden and parasitemia after the challenge of wild-type Plasmodium yoelii BY265 sporozoites.Interestingly,both the level of CSP-specific antibody and the frequency of IFN-γ-secreted-CSP-specific CD8＋ T cells were much higher in mice immunized with pFLAG CMV8 gp96NTD-CSP,as compared with control.All the results suggest that immunization of pFLAG CMV8 gp96NTD-CSP could induce partial protection against the malaria parasite challenge,might through inducing high level of CSP-specific antibody and high frequency of CSP-specific CD8＋T cells.