Validating Technology To Optimize Antibody Affinity For Targeting Therapeutics

描述（由申请人提供）：基于抗体的治疗方法现已在临床上成功用于多种癌症的治疗和诊断。抗体对靶配体的亲和力和特异性决定了治疗递送的特异性和靶外副作用。发现和优化针对重要癌症靶点的高亲和力抗体对于开发新的临床方法至关重要，但仍然是一项非常具有挑战性的任务。一种与噬菌体和酵母展示相媲美的强大的真核技术将克服微生物蛋白质翻译的限制，从而提高所展示抗体的多样性，这些抗体可以被筛选和优化，并更无缝地过渡到用于临床生产的大规模哺乳动物表达系统。我们的长期目标是通过提高递送特异性和靶向性来改善癌症治疗的靶向性

DESCRIPTION (provided by applicant): Antibody-based therapeutics have now had success in the clinic for the treatment and diagnosis of a variety of cancers. The affinity and specificityof the antibody for the target ligand determines the specificity of therapeutic delivery and off-targe side effects. The discovery and optimization of high affinity antibodies to important cancer targets is critical for the development of new clinical approaches but is still a very challenging task. A robust, eukaryotic technology that is comparable to phage and yeast display would overcome the protein translation limitations of microorganisms and thereby improve the diversity of the displayed antibodies that can be screened and optimized as well as more seamlessly transition into a large-scale mammalian expression sys- tem for clinical production. Our long-term goal is to improve the targeting of cancer therapeutics by increasing delivery specificity and distribution in the target tissue thereby improving efficacy while reducing/eliminating off-target side effects. The overall objective of this application is to validate the utility and efficiency o a novel antibody display platform based on the eukaryotic retrovirus, Avian Leukosis Virus (ALV), to affinity optimize anti- bodies in eukaryotic cells, and to advance the development of the technology for initial antibody discovery and improved library screening. Our central hypothesis is: the characteristics of ALV replication and ALV polypeptide display offer a robust, eukaryotic version of bacteriophage display, thereby enabling an improvement in the diversity of properly processed and functional scFv variants that can be screened and affinity optimized to improve promising antibody candidates compared to antibody display and affinity maturation using microorganisms. We plan to test our central hypothesis and, thereby, attain the objective of the application by pursuing the following specific aims: Aim 1: Validate the utility of ALV virus display technology for antibody affinity optimization. Aim 2: Advance the development of the ALV antibody display platform. Aim 3: Evaluate the specificity, cytotoxicity, and biodistribution o affinity-matured antibody fragments in relevant cancer models. We will affinity mature a series of lead scFvs and single-domains that recognize two newly emerging cancer targets, glypican-3 (liver cancers) and mesothelin (mesothelioma, ovarian cancer) and demonstrate superior cancer cell killing with targeting using the optimized antibody fragments. The rationale for the proposed experiments is to solve the need for a robust eukaryotic polypeptide display platform for the discovery and affinity maturation of antibodies, offering a powerful addition to the existig display technologies that use microorganisms. The significance of our contribution here is supplying just such a technology. The research proposed in this application is innovative because it represents a new and substantive departure from the status quo of antibody display using platforms based on microorganisms, providing a significant improvement and extension of mammalian cell display by offering both virus and cell display platforms in a eukaryotic expression system.