Cell Surface Signalling Laboratory, Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1HH, UK.
Nature. 2011 Nov 9;480(7378):534-7. doi: 10.1038/nature10606.
Erythrocyte invasion by Plasmodium falciparum is central to the pathogenesis of malaria. Invasion requires a series of extracellular recognition events between erythrocyte receptors and ligands on the merozoite, the invasive form of the parasite. None of the few known receptor-ligand interactions involved are required in all parasite strains, indicating that the parasite is able to access multiple redundant invasion pathways. Here, we show that we have identified a receptor-ligand pair that is essential for erythrocyte invasion in all tested P. falciparum strains. By systematically screening a library of erythrocyte proteins, we have found that the Ok blood group antigen, basigin, is a receptor for PfRh5, a parasite ligand that is essential for blood stage growth. Erythrocyte invasion was potently inhibited by soluble basigin or by basigin knockdown, and invasion could be completely blocked using low concentrations of anti-basigin antibodies; importantly, these effects were observed across all laboratory-adapted and field strains tested. Furthermore, Ok(a-) erythrocytes, which express a basigin variant that has a weaker binding affinity for PfRh5, had reduced invasion efficiencies. Our discovery of a cross-strain dependency on a single extracellular receptor-ligand pair for erythrocyte invasion by P. falciparum provides a focus for new anti-malarial therapies.
疟原虫红细胞入侵是疟疾发病机制的核心。入侵需要一系列红细胞受体与疟原虫裂殖子(即入侵形式的寄生虫)表面配体之间的细胞外识别事件。已知的少数几个受体-配体相互作用并非所有寄生虫株都需要,这表明寄生虫能够利用多种冗余的入侵途径。在这里,我们表明已经鉴定出一对受体-配体,它们是所有测试的恶性疟原虫株红细胞入侵所必需的。通过系统筛选红细胞蛋白文库,我们发现了血型抗原 Ok,即 basigin,是 PfRh5 的受体,PfRh5 是寄生虫配体,对红内期生长至关重要。可溶性 basigin 或 basigin 敲低可显著抑制红细胞入侵,并且低浓度的抗 basigin 抗体可完全阻断入侵;重要的是,在所有经过实验室适应和野外株测试中都观察到了这些效应。此外,表达与 PfRh5 结合亲和力较弱的 basigin 变体的 Ok(a-)红细胞的入侵效率降低。我们发现恶性疟原虫红细胞入侵对单一细胞外受体-配体对的交叉株依赖性,为新的抗疟治疗提供了一个重点。