International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi 110067, India.
Infect Immun. 2010 Feb;78(2):872-83. doi: 10.1128/IAI.00427-09. Epub 2009 Nov 23.
A chimeric gene, MSP-Fu(24), was constructed by genetically coupling immunodominant, conserved regions of the two leading malaria vaccine candidates, Plasmodium falciparum merozoite surface protein 1 (C-terminal 19-kDa region [PfMSP-1(19)]) and merozoite surface protein 3 (11-kDa conserved region [PfMSP-3(11)]). The recombinant MSP-Fu(24) protein was produced in Escherichia coli cells and purified to homogeneity by a two-step purification process with a yield of approximately 30 mg/liter. Analyses of conformational properties of MSP-Fu(24) using PfMSP-1(19)-specific monoclonal antibody showed that the conformational epitopes of PfMSP-1(19) that may be critical for the generation of the antiparasitic immune response remained intact in the fusion protein. Recombinant MSP-Fu(24) was highly immunogenic in mice and in rabbits when formulated with two different human-compatible adjuvants and induced an immune response against both PfMSP-1(19) and PfMSP-3(11). Purified anti-MSP-Fu(24) antibodies showed invasion inhibition of P. falciparum 3D7 and FCR parasites, and this effect was found to be dependent on antibodies specific for the PfMSP-1(19) component. The protective potential of MSP-Fu(24) was demonstrated by in vitro parasite growth inhibition using an antibody-dependent cell inhibition (ADCI) assay with anti-MSP-Fu(24) antibodies. Overall, the antiparasitic activity was mediated by a combination of growth-inhibitory antibodies generated by both the PfMSP-1(19) and PfMSP-3(11) components of the MSP-Fu(24) protein. The antiparasitic activities elicited by anti-MSP-Fu(24) antibodies were comparable to those elicited by antibodies generated with immunization with a physical mixture of two component antigens, PfMSP-1(19) and PfMSP-3(11). The fusion protein induces a protective immune response with human-compatible adjuvants and may form a part of a multicomponent malaria vaccine.
一个嵌合基因 MSP-Fu(24) 通过基因偶联两种领先的疟疾候选疫苗的免疫显性、保守区域构建而成，这两种疫苗候选物分别是恶性疟原虫裂殖子表面蛋白 1（C 端 19-kDa 区域 [PfMSP-1(19)]）和裂殖子表面蛋白 3（11-kDa 保守区域 [PfMSP-3(11)]）。重组 MSP-Fu(24) 蛋白在大肠杆菌细胞中产生，并通过两步纯化过程（产量约为 30 毫克/升）进行纯化至均一性。使用 PfMSP-1(19)-特异性单克隆抗体分析 MSP-Fu(24) 的构象特性表明，PfMSP-1(19)中可能对寄生虫产生免疫反应至关重要的构象表位在融合蛋白中保持完整。重组 MSP-Fu(24) 与两种不同的与人相容的佐剂联合使用时，在小鼠和兔子中具有高度免疫原性，并诱导针对 PfMSP-1(19)和 PfMSP-3(11)的免疫反应。纯化的抗 MSP-Fu(24) 抗体显示出对恶性疟原虫 3D7 和 FCR 寄生虫的入侵抑制作用，并且这种作用被发现依赖于针对 PfMSP-1(19)成分的抗体。通过使用抗 MSP-Fu(24) 抗体的抗体依赖性细胞抑制 (ADCI) 测定法，在体外寄生虫生长抑制中证明了 MSP-Fu(24) 的保护潜力。总体而言，寄生虫的抗寄生虫活性是由 MSP-Fu(24) 蛋白的 PfMSP-1(19)和 PfMSP-3(11)成分产生的生长抑制性抗体的组合介导的。抗 MSP-Fu(24) 抗体引起的寄生虫活性与用两种成分抗原 PfMSP-1(19)和 PfMSP-3(11)的物理混合物免疫引起的抗体产生的寄生虫活性相当。该融合蛋白与人相容的佐剂一起诱导保护性免疫反应，并且可能成为多成分疟疾疫苗的一部分。
