CYTOADHERENCE-BLOCKING PEPTIDES AS A THERAPY FOR MALARIA

细胞粘附阻断肽作为疟疾的治疗方法

• 批准号: 2067953
• 负责人: Irwin W Sherman
• 金额: $ 15.87万
• 依托单位: UNIVERSITY OF CALIFORNIA RIVERSIDE
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-12-01 至 1996-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2067953
• 关键词: Aotus; Plasmodium falciparum; Primates; Saimiri; cell adhesion; chemical conjugate; enzyme linked immunosorbent assay; epitope mapping; high performance liquid chromatography; human subject; inhibitor /antagonist; laboratory mouse; malaria; malaria vaccines; monoclonal antibody; nonhuman therapy evaluation; parasitic disease chemotherapy; peptide chemical synthesis; synthetic peptide

Plasmodium falciparum, the most malignant of the four human malarias, contributes to 1-2 million deaths annually. The hallmark of P. falciparum infections is sequestration - the attachment of erythrocytes infected with mature stage parasites (trophozoites/schizonts) to endothelial cells lining the post-capillary venules. Sequestration in the brain microvessels - cerebral malaria--may totally occlude blood flown and result in deep coma and death. Through the use of murine monoclonal antibodies (Mabs) it has been possible to show that parasite-induced modifications in the erythrocyte membrane protein band 3 are directly involved in in vitro adhesion (cytoadherence); it is conceivable these proteins also play a role in vivo (sequestration/cerebral malaria). Based on molecular mapping of the modified forms of band 3 with these anti- adhesion Mabs, peptides were synthesized. Several of these peptides inhibited cytoadherence. To precisely define the sequences critical to adhesion, overlapping peptides corresponding to the amino acids surrounding and included within the binding region of these peptides will be prepared by solid phase synthesis. Peptides will be tested singly and in combination for their capacity to inhibit cytoadherence, and those with the greatest inhibitory activity will be administered to P. falciparum-infected monkeys to determine their capacity for reversal of sequestration. Antisera to the peptides will be prepared in mice, and peptides will be used to vaccinate monkeys. The antisera will be used for epitope mapping and for assessment of strain specificity; anti- sequestering activity of the antisera will be determined, both in vitro and by passive transfer experiments in monkeys. The ligand to which the adhesin binds will be identified using anti-idiotype antibodies and affinity chromatography with immobilized peptide. The administration of adhesion-inhibiting peptides to comatose cerebral malaria patients should unplug microvessels containing packed parasitized red cells and bring the patient out of coma Anti-adhesion therapy and/or vaccination would be ideal in areas where malaria is hyperendemic, since it would reduce both mortality and morbidity in those individuals who were most susceptible-- young children without any natal immunity.

恶性疟原虫是四种人类疟疾中最恶性的一种， 每年造成1-2百万人死亡。恶性疟原虫的标志 感染是隔离-红细胞的附着感染 与成熟期寄生虫（滋养体/寄生虫）一起感染内皮细胞 排列在毛细血管后小静脉上大脑中的隔离 微血管-脑型疟疾-可能完全阻塞血液流动， 导致深度昏迷和死亡通过使用鼠单克隆抗体 抗体（单克隆抗体），它已经有可能表明，寄生虫诱导的 红细胞膜蛋白带3的修饰直接 参与体外粘附（细胞粘附）;可以想象， 蛋白质也在体内发挥作用（隔离/脑型疟疾）。基于 在分子映射的修改形式的带3与这些反 粘附单克隆抗体，合成肽。这些肽中有几种 抑制细胞粘附。为了精确地定义关键的序列， 粘附，对应于氨基酸的重叠肽 包围并包括在这些肽的结合区内的肽将 通过固相合成制备。肽将单独测试， 由于其抑制细胞粘附的能力， 将具有最大抑制活性的药物施用给P。 恶性疟原虫感染的猴子，以确定他们的能力，逆转 隔离将在小鼠中制备肽的抗血清， 肽将用于给猴子接种疫苗。抗血清将用于 表位作图和评估菌株特异性;抗 将测定抗血清的螯合活性， 以及在猴子身上进行的被动转移实验。配体， 将使用抗独特型抗体鉴定粘附素结合， 用固定化肽进行亲和层析。管理 粘附抑制肽对昏迷脑型疟疾患者应 拔出含有堆积的寄生虫红细胞的微血管， 患者脱离昏迷抗粘连治疗和/或疫苗接种将是 这是疟疾高发地区的理想选择，因为它可以减少 死亡率和发病率， 没有任何纳塔尔免疫力的幼儿。