Engineering of Bispecific Antibodies Simultaneously Targeting Human Interleukin 4 Receptor Alpha (IL-4Rα) and Interleukin 5 Receptor Alpha (IL-5Rα) for Treatment of Severe Eosinophilic Asthma

Author(s)
김정은
Advisor
김용성
Department
일반대학원 분자과학기술학과
Publisher
The Graduate School, Ajou University
Publication Year
2021-02
Language
eng
Keyword
Antibody engineeringBispecific antibodyasthma
Alternative Abstract
Asthma is a heterogeneous disease driven by many inflammatory mediators and the severity is threatened a patient’s quality of life. Particularly, most patients with severe asthma showed persistent eosinophilia in blood and airway tissue and diagnosed with severe eosinophilic asthma (SEA). A variety of type 2 cytokines such as interleukin (IL)-4, IL-5 and IL-13 involve in pathways leading to eosinophilia. With the Increased understanding of the biological mechanism of asthma, monoclonal antibodies (mAbs) targeting a specific type 2 inflammatory pathway have been developed. Up to now, five mAbs (omalizumab, mepolizumab, reslizumab, dupilumab and benralizumab) have been licensed for the treatment of patients with severe eosinophilic asthma. However, due to the chronic and multifactorial nature of asthma, the demand for alternative biologics with more potent than conventional mAbs remains high. In chapter 2, I developed mAbs against IL-4 receptor α (IL-4Rα) because it mediates the type 2 inflammatory response of both IL-4 and IL-13 cytokines on a broad range of cells such as immune cells, smooth muscle cells, and endothelial cells. In chapter 3, I generated humanized anti-IL-5Rα mAbs to directly target eosinophils which is a hallmark of severe asthma. To enhance the affinity and antagonistic activity, I engineered complementary-determining regions (CDRs) using yeast surface display technology. Combining proper library construction strategies and screening methods, I successfully generated mAbs with improved affinity and potent antagonistic activity. In these studies, I demonstrated that affinity and binding epitope of mAbs are critical determinants of biological activities. Additionally, I provided potential candidates, 4R.N6 (anti-IL-4Rα mAb) and 5R65.7 (anti-IL-5Rα mAb), as alternative therapeutics for patients with SEA. In chapter 4, I suggested a therapeutic concept using bispecific antibodies (BiAbs) having potential with more potent therapeutic efficacy than mAbs for patients with SEA. Since the heterogeneous and functional redundancy of type 2 cytokines, targeting a specific pathway by mAbs still showed unsatisfactory outcomes to some patients with SEA. In this context, simultaneous targeting both IL-4Rα and IL-5Rα using BiAbs would be more efficacious by concurrently inhibiting multiple type 2 inflammatory pathways. Further, BiAbs also might elicit enhanced antibody-dependent cellular cytotoxicity activity by binding to both IL-4Rα and IL-5Rα expressed on the same cells (e.g. eosinophils). I designed three different formats of bispecific antibodies (BiAbs) using the antigen-binding domain of 4R.N6 and 5R65.7 to explore an optimal format with favorable properties in developability and biological efficacy. The three different formats of BiAbs including bispecific IgG (BsIgG), IgG single-chain Fv (IgG-scFv), and dual-variable domain IgG (DVD-IgG), have distinguishing features such as binding valency for each antigen, the geometry of antigen-binding sites. Since the unnatural format of BiAbs often is an obstacle to further study, I initially analyzed of biochemical properties of BiAbs. The three different formats of BiAbs showed good purification yield and stability. They exhibited different binding kinetics for each antigen, which would lead to different functionality in further studies performing on in vitro and ex vivo.
URI
https://dspace.ajou.ac.kr/handle/2018.oak/20281
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Graduate School of Ajou University > Department of Molecular Science and Technology > 4. Theses(Ph.D)
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