ELUCIDATING & DISRUPTING PLASMODIUM RECEPTOR-LIGAND INTERACTIONS

 描述(由申请人提供)：关于疟原虫入侵红细胞所必需的相互作用是如何介导的，以及针对这些相互作用的抗体如何阻止寄生虫进入，在知识上存在根本差距。这些差距阻碍了我们为全球健康问题疟疾设计有效干预措施的能力。长期目标是确定受体-配体相互作用是如何在分子水平上调节的，以及如何将其用于预防、治疗和诊断目的。这项应用的目的是了解关键寄生虫配体识别受体的分子基础，并建立针对这些蛋白的中和性单抗的抑制模式。该应用的中心假设是，寄生虫配体的结合域是保守的，但创建了不同的受体结合口袋来识别不同的受体，而抑制性抗体针对结合口袋，防止它们的形成或可获得性。拟议研究的理由是，一旦确定了功能区， 通过将免疫反应专门集中在目标功能区，可以将寄生虫配体的一部分用于新的基于蛋白质的干预和疫苗。在先前发表的工作和强大的初步数据的支持下，这一假说将通过追求两个特定的目标来检验：1)确定寄生虫配体的受体特异性和选择性的决定因素；2)确定抗体介导的抑制侵袭的结构基础和机制。在第一个目标下，将利用结构、功能和机理研究来全面确定受体-配体相互作用的分子细节。在第二个目标下，结构和相互作用图谱研究将揭示中和抗体瞄准的寄生虫配体的表位，以确定具有最大中和潜力的表位。这种方法是创新的，因为它将揭示一个关键的寄生虫配体家族的第一个结构信息。利用人类细胞系的创新蛋白质生产系统已经建立，以正确地产生翻译后修饰的受体，因为这些修饰对受体识别至关重要。开发了一种发现抗体表位的创新方法，增加了在给定时间可以研究的抗体的数量，包括难于结晶的抗体。这项拟议的研究具有重要意义，因为它有望促进和扩大我们对受体-配体相互作用、抗体-抗原相互作用和微生物发病机制的了解。预计这些知识将有助于直接制定疟疾的诊断、预防和治疗干预措施。

 DESCRIPTION (provided by applicant): There are fundamental gaps in knowledge of how interactions essential for erythrocyte invasion by Plasmodium parasites are mediated and how antibodies that target these interactions prevent parasite entry. These gaps hinder our ability to design effective interventions for the global health problem malaria. The long- term goal is to determine how receptor-ligand interactions are mediated at the molecular level and how they can be exploited for preventative, therapeutic and diagnostic purposes. The objectives of this application are to understand the molecular basis of receptor recognition by critical parasite ligands and to establish the mode of inhibition of neutralizing monoclonal antibodies that target these proteins. The central hypothesis of the application is that the binding domains of parasite ligands are conserved yet create distinct receptor-binding pockets to recognize diverse receptors, and that inhibitory antibodies target binding pockets, preventing their formation or accessibility. The rationale for the proposed research is that, once identified, functional regions of parasite ligands can be exploited for novel protein-based interventions and vaccines by focusing the immune response to target functional regions exclusively. Supported by prior published work and strong preliminary data, this hypothesis will be tested by pursuing two specific aims: 1) define the determinants for receptor specificity and selectivity of parasite ligands; and 2) determine the structural basis and mechanism for antibody-mediated inhibition of invasion. Under the first aim, structural, functional and mechanistic studies will be used to comprehensively determine the molecular details of receptor-ligand interactions. Under the second aim, structural and interaction mapping studies will reveal epitopes of parasite ligands targeted by neutralizing antibodies towards identifying epitopes that have the greatest neutralizing potential. The approach is innovative as it will reveal the first structural informatin for a key family of parasite ligands. Innovative protein production systems that exploit human cells lines have been established to produce correctly post- translationally modified receptors as these modifications are critical for receptor-recognition. An innovative approach for antibody epitope discovery has been developed that increases the number of antibodies that can be studied at a given time, including antibodies refractory to crystallization. The proposed research is significant because it is expected to advance and expand our knowledge of receptor-ligand interactions, antibody-antigen interactions, and microbial pathogenesis. It is anticipated that thi knowledge will aid in the direct development of diagnostics, preventative and therapeutic interventions for malaria.