以恶性疟原虫MSP1和AMA1疫苗组合免疫小鼠诱导保护性免疫

目的以MSP1和AMA1的DNA疫苗、重组痘苗病毒疫苗和重组蛋白疫苗组合免疫小鼠,诱导针对疟疾红内期抗原MSP1和AMA1的保护性抗体。方法将编码恶性疟原虫MSP1全片段和AMA1胞外域的DNA免疫质粒(VR1020/190.3和VR1020/E)、痘苗病毒载体(rMVA/190.3和rMVA/E)及重组蛋白(d-GX190H和E)的同种类型疫苗混合,作为核酸疫苗(D)、病毒疫苗(V)及蛋白疫苗(P)按照“初始-强化”策略免疫小鼠。间接ELISA测血清中抗MSP1和AMA1抗体;用免疫血清进行体外原虫入侵红细胞抑制实验;由转基因伯氏疟原虫Pb-PfM19和P.bANKA株分别对免疫鼠进行体内攻击。结果各组免疫血清中均产生了较强的抗体应答,抗MSP1抗体与抗AMA1抗体滴度的变化趋势一致。实验组免疫小鼠血清在体外对两株原虫入侵红细胞均有较大程度的抑制。体内攻击实验中实验组小鼠平均存活时间较对照组略长。结论采用以MSP1和AMA1为基础的DNA、重组痘苗病毒和重组蛋白疫苗的组合免疫小鼠能诱导出有效的保护性抗体。以上结果为疟疾红内期疫苗合理免疫方案提供了重要的实验依据。

Protective immunity induced by the combined vaccination with merozoite surface protein 1 and apical membrane antigen I of Plasmodium falciparum

To investigate the potential of combined vaccination with merozoite surface protein-1(MSP1) and apical membrane antigen I(AMA1) of Plasmodium falciparum to induce the presence of protective antibodies, the prototype vaccines including plasmid.VR1020/190.3 + VR1020/E(DNA vaccine),vaccinia virus plasmid rMVA/190.3 + rMVA/E(viral vaccine)recombinant protein d-GX190H + E(protein vaccine) were immunized to mice under "prime-boost' vaccination strategy.Speicific IgG produced in the immunized mice was determined by ELISA assay,and the in vitro experiment of inhibition of the merozoite invision to red blood cells was performed by using the mouse immune sera.The immunized mice were challenged with parasites Pb-PfMI9 and P.bANKA.It was demonstrated that strong immune responses were produced in the vaccinated groups of mice with a similar tendency of productions in anti-MSP1 and anti-AMA1 antibody titers,and significant inhibition of the merozoite invasion by two strains parasites to red blood cells could be demonstrated with immune sera of the vaccinated group of mice.Although statistics showed that there was no significant difference in the accumulated parasitemia and the survival time between experimental and the control groups of mice,animals receiving vaccination appeared to livelonger upon challenge.It is concluded that protective antibodies specific to MSP1 and AMA1 can be induced simultaneously by the combined use of DNA vaccine viral vaccine and protein vaccine.This strategy used in the present study would be a good help for the further vaccine design.