Plasmodium yoelii sporozoites with simultaneous deletion of P52 and P36 are completely attenuated and confer sterile immunity against infection
Plasmodium yoelii sporozoites with simultaneous deletion of P52 and P36 are completely attenuated and confer sterile immunity against infection
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DOI：
10.1128/iai.00225-07
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发表时间：
2007-08-01
影响因子：
3.1
通讯作者：
Kappe, Stefan H. I.
中科院分区：
文献类型：
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作者：
Labaied, Mehdi;Harupa, Anke;Kappe, Stefan H. I.
当蚊子叮咬时，子孢子传播到哺乳动物宿主时，疟疾感染开始。子孢子进入血液循环，到达肝脏，感染肝细胞。寄生虫液泡（PV）的形成建立了它们的细胞内生态位。最近，6-Cys结构域蛋白家族的两个成员，P52和P36，每个都被证明在伯氏疟原虫子孢子对啮齿动物宿主的感染性中发挥重要的作用，尽管不是必需的。在这里，我们产生p52/p36缺陷型约氏疟原虫寄生虫的同时删除两个基因，使用一个单一的遗传操作。p52/p36缺陷型寄生虫在血液阶段感染、传播给蚊子、蚊子阶段发育和唾液腺的子孢子感染期间的生命周期中表现出正常进展。p52/p36缺陷的子孢子也表现出正常的运动性和细胞穿越活性。然而，免疫荧光分析和电子显微镜观察显示，p52/p36缺陷型寄生虫在体外和体内的肝细胞内没有形成PV。p52/p36缺陷型寄生虫定位为宿主细胞质或宿主细胞核质中的游离实体，并且不发育为肝脏阶段。因此，即使在高子孢子接种剂量下，它们也不会引起血液期感染。用p52/p36缺陷子孢子免疫的小鼠完全保护免于感染性子孢子攻击。我们的研究结果首次证明了双位点基因缺失减毒寄生虫的产生，其感染肝脏但不进展为血液阶段感染。这项研究将严格指导恶性疟原虫减毒疟疾活疫苗的设计。
Malaria infection starts when sporozoites are transmitted to the mammalian host during a mosquito bite. Sporozoites enter the blood circulation, reach the liver, and infect hepatocytes. The formation of a parasitophorous vacuole (PV) establishes their intracellular niche. Recently, two members of the 6-Cys domain protein family, P52 and P36, were each shown to play an important albeit nonessential role in Plasmodium berghei sporozoite infectivity for the rodent host. Here, we generated p52/p36- deficient Plasmodium yoelii parasites by the simultaneous deletion of both genes using a single genetic manipulation. p52/p36- deficient parasites exhibited normal progression through the life cycle during blood-stage infection, transmission to mosquitoes, mosquito-stage development, and sporozoite infection of the salivary glands. p52/p36-deficient sporozoites also showed normal motility and cell traversal activity. However, immunofluorescence analysis and electron microscopic observations revealed that p52/p36-deficient parasites did not form a PV within hepatocytes in vitro and in vivo. The p52/p36-deficient parasites localized as free entities in the host cell cytoplasm or the host cell nucleoplasm and did not develop as liver stages. Consequently, they did not cause blood-stage infections even at high sporozoite inoculation doses. Mice immunized with p52/p36-deficient sporozoites were completely protected against infectious sporozoite challenge. Our results demonstrate for the first time the generation of two-locus gene deletion- attenuated parasites that infect the liver but do not progress to blood-stage infection. The study will critically guide the design of Plasmodium falciparum live attenuated malaria vaccines.