Healer Julie, Chiu Chris Y, Hansen Diana S
The Walter and Eliza Hall Institute of Medical Research,1G Royal Parade, Parkville, Victoria 3052,Australia.
Parasitology. 2018 Jun;145(7):839-847. doi: 10.1017/S0031182017001949. Epub 2017 Nov 16.
Malaria is one the most serious infectious diseases with over 200 million clinical cases annually. Most cases of the severe disease are caused by Plasmodium falciparum. The blood stage of Plasmodium parasite is entirely responsible for malaria-associated pathology. The population most susceptible to severe malaria are children under the age of 5, with low levels of immunity. It is only after many years of repeated exposure that individuals living in endemic areas develop clinical immunity. This form of protection prevents clinical episodes by substantially reducing parasite burden. Naturally acquired immunity predominantly targets blood-stage parasites with antibody responses being the main mediators of protection. The targets of clinical immunity are the extracellular merozoite and the infected erythrocyte surface, with the extremely diverse PfEMP1 proteins the main target here. This observation provides a strong rationale that an effective anti-malaria vaccine targeting blood-stage parasites is achievable. Thus the identification of antigenic targets of naturally acquired immunity remains an important step towards the formulation of novel vaccine combinations before testing their efficacy in clinical trials. This review summarizes the main findings to date defining antigenic targets present on the extracellular merozoite associated with naturally acquired immunity to P. falciparum malaria.
疟疾是最严重的传染病之一,每年有超过2亿例临床病例。大多数重症病例由恶性疟原虫引起。疟原虫的血液阶段完全导致了与疟疾相关的病理状况。最易患重症疟疾的人群是5岁以下免疫力低下的儿童。只有经过多年反复接触,生活在疟疾流行地区的个体才会产生临床免疫力。这种保护形式通过大幅降低寄生虫负担来预防临床发作。自然获得的免疫力主要针对血液阶段的寄生虫,抗体反应是保护的主要介导因素。临床免疫的靶点是细胞外裂殖子和被感染红细胞表面,这里极其多样的恶性疟原虫红细胞膜蛋白1(PfEMP1)是主要靶点。这一观察结果有力地证明了,开发一种针对血液阶段寄生虫的有效抗疟疾疫苗是可行的。因此,在临床试验中测试新型疫苗组合的疗效之前,确定自然获得性免疫的抗原靶点仍然是朝着开发新型疫苗组合迈出的重要一步。本综述总结了迄今为止确定与恶性疟原虫疟疾自然获得性免疫相关的细胞外裂殖子上存在的抗原靶点的主要研究结果。