Characterization of Plasmodium GAPDH as a candidate for development of a malaria pre-erythrocytic vaccine

 描述（由申请人提供）：疟疾仍然是最具破坏性的传染病之一。它每年造成约100万人死亡，同时在全世界造成巨大痛苦和经济损失。对抗这种疾病的两种主要武器--杀死蚊子媒介的杀虫剂和杀死感染者体内寄生虫的药物--对遏制这种疾病有很大的贡献。然而，必须制定更多的措施，如疫苗，以消除并最终根除这一疾病。当被受感染的蚊子叮咬期间，子孢子沉积在 被咬者的皮肤。其次，子孢子进入循环，必须离开它在肝脏继续他们的周期。肝血管由两种类型的细胞-内皮细胞和枯否细胞-内衬，子孢子通过优先穿过枯否细胞离开血管。使用噬菌体肽展示文库，我们已经鉴定了三种肽- P39、P61和P52 -其特异性结合枯否细胞，并且通过这样做，在体外（枯否细胞培养物）和体内（活小鼠）抑制子孢子穿越。进一步的工作确定了肽与CD 68 Kupffer细胞表面受体蛋白结合。此外，肽在结构上模拟伯氏疟原虫甘油醛3-磷酸脱氢酶（PbGAPDH）的结构域，所述蛋白质存在于子孢子表面上。此外，我们已经表明，CD 68和PbGAPDH蛋白直接相互作用。该项目旨在鉴定PbGAPDH蛋白介导与CD 68受体相互作用的结构域。这些蛋白质结构域将用作抗原以免疫小鼠。预期免疫小鼠的抗体将干扰库普弗细胞的子孢子穿越，并以这种方式阻止肝脏感染。本研究中鉴定的抗原 这项研究可以想象地用于增强RTS，S红细胞前疫苗的有效性，该疫苗在III期试验中已被证明是部分有效的。

 DESCRIPTION (provided by applicant): Malaria remains one of the most devastating infectious diseases. It kills around a million people every year while causing immense suffering and economic losses worldwide. The two main weapons to fight the disease - insecticides that kill the mosquito vector and drugs that kill the parasites in infected individuals - significantly contribute to contain the disease. However, it is imperative that additional measures, such as vaccines, be developed for the elimination and eventual eradication of the disease. Human infection is initiated when during a bite by an infected mosquito, sporozoites are deposited in the skin of the bitten person. Next, sporozoites enter the circulation and must leave it in the liver t continue their cycle. Liver vessels are lined by two cell types - endothelial cells and Kupffer cels - and sporozoites exit the vessels by preferentially traversing Kupffer cells. Using a phage peptide display library we have identified three peptides - P39, P61 and P52 - that bind specifically to Kupffer cells and by doing so, inhibit sporozoite traversal both in vitro (Kupffer ell cultures) and in vivo (live mice). Further work determined that the peptides bind to the CD68 Kupffer cell surface receptor protein. Moreover, the peptides structurally mimic domains of Plasmodium berghei glyceraldehyde 3-phosphate dehydrogenase (PbGAPDH), a protein present on the surface of sporozoites. In addition, we have shown that the CD68 and PbGAPDH proteins interact directly. This project aims at identifying domains of the PbGAPDH protein that mediate interactions with the CD68 receptor. These protein domains will be used as antigens to immunize mice. It is expected that the antibodies of immune mice will interfere with sporozoite traversal of Kupffer cells and in this way, thwart liver infection. The antigens identified in this study may conceivably be used to enhance the effectiveness of the RTS,S pre-erythrocytic vaccine, which in phase III trials has proven to be partially effective.