A DNA vaccine to prevent transmission of human malaria

描述（由申请人提供）：当前申请是根据编号为no - od -058的题为“使rpg能够利用NCRR中心和类似中心的项目”的通知提交的。母基金RO1AI0470889的研究重点是开发针对人类疟疾的疫苗。疟疾传播阻断疫苗（TBVs）旨在诱导对感染蚊子的寄生虫各阶段产生免疫力，从而减少或阻止疟疾传播。靶抗原包括配子体中合成的蛋白（受精前抗原，恶性疟原虫中：Pfs230和Pfs48/45）和受精卵-卵母细胞中合成的蛋白（受精后抗原，恶性疟原虫中：Pfs25和Pfs28），传播阻断抗体识别的表位本质上是富含半胱氨酸的还原敏感构象。在母体资助中提出的研究旨在(1)鉴定受精前抗原的免疫学相关结构域，(2)通过在阳离子脂质中配制疫苗和通过体内电穿孔给药来优化受精前和受精后抗原的组合。(3)在非人灵长类动物（猕猴）体内电穿孔法评估候选DNA疫苗，并利用Aotus恶性疟原虫感染模型，在自然感染期间增强对受精前抗原的免疫，以验证这一概念。此外，与标准的体外膜饲养试验相比，转基因Pfs25的开发将为基于Pfs25的人疟疾TBV的体内评估提供一种方法。由于大多数疫苗在非人灵长类动物中都经过免疫原性和功能评估（只要生物学上可行），因此现在建议修改亲本资助的范围，以开发表达Pfs25的转基因非人疟疾寄生虫，从而促进基于Pfs25的TBV的优化和评估。

DESCRIPTION (provided by applicant): The current application is submitted in response to the notice number NOT-OD-058 entitled "Enabling RPGs to Leverage NCRR Center and Centers-like Programs". The research focus of the parent grant RO1AI0470889 is to develop a vaccine targeting human malaria. Transmission blocking vaccines (TBVs) against malaria are intended to induce immunity against the stages of the parasite that infect mosquitoes so that malaria transmission is reduced or halted. The target antigens include proteins synthesized in the gametocytes (pre-fertilization antigens, in P. falciparum: Pfs230 and Pfs48/45) and in the zygotes-ookinetes (post-fertilization antigens, in P. falciparum: Pfs25 and Pfs28) and the epitopes recognized by transmission blocking antibodies are cysteine-rich reduction-sensitive conformational in nature. Studies proposed in the parent grant were aimed at (1) identifying immunologically relevant domains in the pre- fertilization antigens, (2) optimizing the combination of pre- and post-fertilization antigens by vaccine formulation in cationic lipids and vaccine delivery by in vivo electroporation, (3) evaluating a candidate DNA vaccine by in vivo electroporation in nonhuman primates (Macaca mulatta) and testing the concept that immunity against pre-fertilization antigens can be maintained by boosting during natural infection using an Aotus model for P. falciparum infection. Moreover, the development of Pfs25 transgenic P. berghei will provide an approach for in vivo evaluation of human malaria TBV based on Pfs25, as compared to a standard in vitro membrane feeding assay. Since most vaccines go through immunogenicity and functional evaluation (wherever biologically feasible) in nonhuman primates, it is now proposed to revise the scope of the parent grant to develop transgenic nonhuman malaria parasite expressing Pfs25 which would then facilitate optimization and evaluation of Pfs25-based TBV. PUBLIC HEALTH RELEVANCE: Malaria causes more than 300 million infections worldwide. Our long term goal is to develop a vaccine to stop transmission of malaria. Research proposed in this application, in particular, will result in the development of a nonhuman primate model to test such human malaria transmission blocking vaccines.