ANTIGENIC ANALYSIS OF SEXUAL STAGES OF MALARIA PARASITES

我们已经确定了我们的目标，首先，开发一种25 kDa的性阶段抗原， Pfs25，作为潜在的候选疫苗；第二，克隆 其他已知的传播阻断免疫的靶抗原；第三， 在有性期寄生虫上发现新的靶抗原；最后， 了解水稻受精的分子机制 疟疾寄生虫。我们也开始研究寄生虫的作用 葡萄糖-6-磷酸脱氢酶(G6PD)及其在糖尿病发病中的作用 人类G6PD缺乏症提供的保护。 此前，我们已经克隆了编码Pfs25的基因，Pfs25是一种主要的候选抗原 一种传播阻断疫苗。Pfs25现在已经在 细菌、酵母、牛痘病毒感染的哺乳动物细胞和瞬时 转染组COS细胞。来自接种牛痘疫苗的小鼠的数据 Pfs25非常令人鼓舞：来自小鼠的血清要么接种了活的， 重组痘苗或哺乳动物细胞膜提取物免疫 感染重组牛痘阻断了疟疾的传播。要开始 进一步发展Pfs25作为候选疫苗，我们一直致力于 合作研究中的商业生物技术公司数量和 发展协议(CRADA)。克隆其他靶抗原已经被 这是个问题。新的方法，如哺乳动物表达系统，正在被 除了追求以前成功的战略外，还进行了探索，例如 蛋白质微测序和筛选细菌表达文库。一个 已开发出微配子(男性)特异性单抗，并可 为我们理解所涉及的分子机制提供了中心 在疟疾寄生虫中受精。 最后，我们证明了疟疾寄生虫表达G6PD 与宿主的G6PD状态无关。在我们的 在大肠杆菌中通过互补克隆寄生虫G6PD基因的尝试 已经克隆了编码相关酶葡萄糖磷酸异构酶的基因 (PGI)。

We have set our goals on, first, developing a 25 kDa sexual stage antigen, Pfs25, as a potential vaccine candidate; second, cloning the genes for the other known target antigens of transmission blocking immunity; third, identifying new target antigens on sexual stage parasites; and finally, understanding the molecular mechanisms involved in fertilization of malarial parasites. We have also begun to study the role of parasite glucose-6-phosphate dehydrogenase (G6PD) and its role in the putative protection afforded by G6PD deficiency in humans. Previously we had cloned the gene encoding Pfs25, a prime candidate antigen for a transmission blocking vaccine. Pfs25 has now been expressed in bacteria, yeast, vaccinia-infected mammalian cells and transiently transfected COS cells. Data from mice immunized with vaccinia-produced Pfs25 are very encouraging: sera from mice either inoculated with live, recombinant vaccinia or immunized with membrane extracts of mammalian cells infected with recombinant vaccinia block transmission of malaria. To begin further developing Pfs25 as a vaccine candidate, we have pursued engaging a number of commercial biotechnology companies in Cooperative Research and Development Agreements (CRADA). Cloning the other target antigens has been a problem. New approaches, such as mammalian expression systems, are being explored in addition to pursuing strategies previously successful, such as protein microsequencing and screening bacterial expression libraries. A microgamete (male) specific monoclonal antibody has been developed and may provide the entre we need to understand the molecular mechanisms involved in fertilization in the malaria parasite. Finally, we have demonstrated that the malaria parasite expresses G6PD constitutively, and independently of the G6PD status of the host. In our attempt to clone the parasite G6PD gene by complementation in E. coli, we have cloned the gene encoding a related enzyme, glucose phosphate isomerase (PGI).