恶性疟原虫抗原—痘苗病毒重组活疫苗株的实验室评价

以恶性疟原虫保护性抗原复合基因—痘苗病毒重组活疫苗候选株为研究对象 ,探索其免疫血清及IgG的体外抗疟原虫能力、保护性细胞免疫反应及换人血猕猴模型动物抗攻击能力试验。结果表明 ,受检免疫血清及IgG具有一定的体外抑制恶性疟原虫增殖作用。家兔及大白鼠免疫后 4～ 6周血清中可产生明显的IL 2活性 ,免疫后 6周家兔、大白鼠及小白鼠血清IFN的活性水平比免疫前明显升高。免疫后 1个月攻虫 ,免疫猴从第 3天一直到第 12天血检中均未发现疟原虫 ;而非重组痘苗病毒免疫猴第 3天后原虫感染率上升 ,第 6天原虫感染率最高达到 6 0 % ,而后原虫感染率逐渐下降 ,持续 13d ;空白对照猴第 3天后原虫感染率也上升 ,第 8天原虫感染率最高达到 2 5 % ,而后原虫感染率逐渐下降 ,持续 12d。结果初步表明该候选疫苗株具有一定的诱发体液免疫、细胞免疫反应及抗虫体攻击能力 ,值得做进一步的研究。

Laboratory Evaluation of a Vaccinia Virus Vectored Multi-epitope Live Vaccine Candidate for Plasmodium falciparum

A vaccine virus vectored multi epitope live vaccine candidate containing HGFSP gene encoding circumsporazoite protein(CSP),major merozoite surface antigen 1(MSA1),major merozoite surface antigen 2(MSA2),ring infected erythrocyte surface antigen(RESA) of Plasmodium falciparum and interleukin 1(IL 1) as well as tetanus toxin(TT) epitopes was constructed previously The anti plasmodium activities of the immune sera against this recombinant live vaccine and its IgG were determined in this study Experimental results showed that this vaccine had some inhibitory activity to inhibit the growth of plasmodium in vitro The sera of rabbits and rats immunized with this vaccine showed obvious activity of IL 2 in 4～6 days after immunization,and the IFN levels in sera of rabbit,rat and mice after immunization were significantly higher than those before immunization These results indicated that this recombinant vaccine could stimulate cell mediated immunity(Th1 cell response) in the immunized animals and had inhibitory effect on the multiplication of cultured Plasmodium falciparum in vitro Also,it was demonstrated that this vaccine conferred protection against the challenge of blood stage Plasmodium falciparum in the human blood transfused Macaca monkey models The results of these experiments indicate that this recombinant live vaccine is an appropriate vaccine candidate for further investigation