Plasmodium vivax invasion of human erythrocytes inhibited by antibodies directed against the Duffy binding protein
Plasmodium vivax invasion of human erythrocytes inhibited by antibodies directed against the Duffy binding protein
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DOI：
10.1371/journal.pmed.0040337
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发表时间：
2007-12-01
期刊：
影响因子：
15.8
通讯作者：
King, Christopher L.
中科院分区：
文献类型：
--
作者：
Grimberg, Brian T.;Udomsangpetch, Rachanee;King, Christopher L.
间日疟原虫入侵需要红细胞表面的人类Duffy抗原与其表达的间日疟原虫Duffy结合蛋白(PvDBP)相互作用。鉴于Duffy阴性个体是耐药的，Duffy阴性杂合子对血期感染的易感性降低，我们假设针对间日疟原虫Duffy结合蛋白(PvDBPII)第二区域的抗体可以抑制间日疟原虫对人红细胞的侵袭。方法和发现利用间日疟原虫Duffy结合蛋白(RPvDBPII)的一个重组区域，从免疫的兔身上制备多克隆抗体，并从14名暴露于间日疟原虫的巴布亚新几内亚人的混合血清中纯化亲和力。用ELISA法和流式细胞术分别检测到兔抗体和人抗体均能抑制rPvDBPII与Duffy抗原N端区和Duffy阳性人红细胞的结合。此外，使用免疫荧光显微镜，抗体被证明附着在间日疟原虫裂殖子顶端的天然PvDBP上。用泰国Mae Sot地区个人的血液分离进行的体外侵袭分析表明，加入兔抗PvDBPII抗体或血清(针对间日疟原虫Duffy结合蛋白第二区域的抗体或含有抗体的血清)(1：100)可将寄生虫入侵的次数减少高达%，而来自间日疟原虫接触者的混合PvDBPII抗血清可使间日疟原虫的侵袭减少高达54%。结论这些结果首次表明，针对间日疟原虫的兔抗体和人抗体都降低了从感染患者分离的野生间日疟原虫的侵袭效率并表明以PvDBP为基础的疫苗可能会减少人类血液期间日疟原虫的感染。
BackgroundPlasmodium vivax invasion requires interaction between the human Duffy antigen on the surface of erythrocytes and the P. vivax Duffy binding protein (PvDBP) expressed by the parasite. Given that Duffy-negative individuals are resistant and that Duffy-negative heterozygotes show reduced susceptibility to blood-stage infection, we hypothesized that antibodies directed against region two of P. vivax Duffy binding protein (PvDBPII) would inhibit P. vivax invasion of human erythrocytes.Methods and FindingsUsing a recombinant region two of the P. vivax Duffy binding protein (rPvDBPII), polyclonal antibodies were generated from immunized rabbits and affinity purified from the pooled sera of 14 P. vivax-exposed Papua New Guineans. It was determined by ELISA and by flow cytometry, respectively, that both rabbit and human antibodies inhibited binding of rPvDBPII to the Duffy antigen N-terminal region and to Duffy-positive human erythrocytes. Additionally, using immunofluorescent microscopy, the antibodies were shown to attach to native PvDBP on the apical end of the P. vivax merozoite. In vitro invasion assays, using blood isolates from individuals in the Mae Sot district of Thailand, showed that addition of rabbit anti-PvDBPII Ab or serum ( antibodies against, or serum containing antibodies against, region two of the Plasmodium vivax Duffy binding protein) ( 1: 100) reduced the number of parasite invasions by up to 64%, while pooled PvDBPII antisera from P. vivax-exposed people reduced P. vivax invasion by up to 54%.ConclusionsThese results show, for what we believe to be the first time, that both rabbit and human antibodies directed against PvDBPII reduce invasion efficiency of wild P. vivax isolated from infected patients, and suggest that a PvDBP-based vaccine may reduce human blood-stage P. vivax infection.