ANTIGENIC ANALYSIS OF SEXUAL STAGES OF MALARIA PARASITES

四种潜在的靶抗原(Pfs25/Pgs25、Pfs28、Pfs40和Pfs230) 的传播阻断抗体现在已经在我们的 实验室，以及第五个(寄生虫产生的几丁质酶)和第六个(a 蚊子产生的蛋白酶)已被鉴定。在四个目标中 已经被克隆的抗原，都在一个或多个 重组表达系统，但只有重组Pfs25(RPfs25)具有 在实验动物中诱导传播阻断抗体。我们的 近期目标是1)在人类身上测试安全性、免疫原性和 Pfs25亚单位疫苗的效力，并设计一种测试方法 这种传播阻断疫苗的现场效果，2)表示 Pfs28作为一种重组蛋白，其形式可引发传播- 阻断抗体并检测rPfs25和rPfs28的各种组合 在鸡尾酒疫苗中，以确定组合是否会导致更长的时间 持久的或更高滴度的传播阻断抗体，3)确定 钙结合蛋白Pfs40在性行为中的作用 开发并确定Pfs40是否为传输阻断目标 抗体，4)鉴定并以重组蛋白形式表达B细胞 Pfs230中负责传递阻断活性的表位 我们的抗Pfs230，5)的单抗确定是否有抗体 完全由寄生虫产生的几丁质酶或蚊子产生的蛋白酶 阻断传播，如果是的话，分离并表达编码基因 这些酶，并分离出这五种寄生虫的相似基因 来自间日疟原虫的蛋白质，如果它们存在的话。我们更长远的目标包括 鉴定有性期寄生虫的新靶抗原，并确定 疟疾寄生虫受精的分子机制。

Four potential target antigens (Pfs25/Pgs25, Pfs28, Pfs40, and Pfs230) of transmission-blocking antibodies have now been cloned in our laboratory, and a fifth ( parasite-produced chitinase) and a sixth (a mosquito-produced protease) have been identified. Of the four target antigens that have been cloned, all have been expressed in one or more recombinant expression systems, but only recombinant Pfs25 (rPfs25) has induced transmission-blocking antibodies in laboratory animals. Our immediate goals are to 1) test in humans the safety, immunogenicity, and efficacy of a Pfs25 subunit vaccine and design a means of testing the efficacy of such a transmission-blocking vaccine in the field, 2) express Pfs28 as a recombinant protein in a form that elicits transmission- blocking antibodies and test various combinations of rPfs25 and rPfs28 in a cocktail vaccine to determine if the combination elicits longer lasting or higher titer transmission-blocking antibodies, 3) determine the role, if any, that the calcium-binding Pfs40 plays in sexual development and ascertain if Pfs40 is a target of transmission-blocking antibodies, 4) identify and express as recombinant protein the B-cell epitopes in Pfs230 responsible for the transmission-blocking activity of our monoclonal antibodies to Pfs230, 5) determine if antibodies to parasite-produced chitinease or mosquito-produced protease completely block transmission, and if so, isolate and express the genes encoding these enzyme, and 6) isolate analogous genes to these five parasite proteins, if they exist, from P. vivax. Our more long term goals include identifying new target antigens on sexual stage parasites, and defining the molecular mechanisms involved in fertilization of malarial parasites.