title: Effective suppression of C5a-induced proinflammatory response using anti-human C5a repebody.
abstract: The strongest anaphylatoxin, C5a, plays a critical role in the proinflammatory responses, causing the pathogenesis of a number of inflammatory diseases including sepsis, asthma, and rheumatoid arthritis. Inhibitors of C5a thus have great potential as therapeutics for various inflammatory disorders. Herein, we present the development of a high-affinity repebody against human C5a (hC5a), which effectively suppresses the proinflammatory response. A repebody scaffold composed of leucine-rich repeat (LRR) modules was previously developed as an alternative protein scaffold. A repebody specifically binding to hC5a was selected through a phage display, and its affinity was increased up to 5 nM using modular engineering. The repebody was shown to effectively inhibit the production of C5a-induced proinflammatory cytokines by human monocytes. To obtain insight into a mode of action by the repebody, we determined its crystal structure in complex with hC5a. A structural analysis revealed that the repebody binds to the D1 and D3 regions of hC5a, overlapping several epitope residues with the hC5a receptor (hC5aR). It is thus likely that the repebody suppresses the hC5a-mediated immune response in monocytes by blocking the binding of hC5a to its receptor. The anti-hC5a repebody can be developed as a potential therapeutic for C5a-involved inflammatory diseases.
authors.affiliation: Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 305-701, Republic of Korea.
authors.forename: Da-Eun
authors.initials: DE
authors.lastname: Hwang
authors.affiliation: Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 305-701, Republic of Korea.
authors.forename: Jung-Min
authors.initials: JM
authors.lastname: Choi
authors.affiliation: Department of Molecular and Life Sciences, Hanyang University, Ansan, 15588, Republic of Korea.
authors.forename: Chul-Su
authors.initials: CS
authors.lastname: Yang
authors.affiliation: Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 305-701, Republic of Korea.
authors.forename: Joong-Jae
authors.initials: JJ
authors.lastname: Lee
authors.affiliation: Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 305-701, Republic of Korea.
authors.forename: Woosung
authors.initials: W
authors.lastname: Heu
authors.affiliation: Department of Microbiology, Chungnam National University College of Medicine, Daejeon, Republic of Korea.
authors.forename: Eun-Kyeong
authors.initials: EK
authors.lastname: Jo
authors.affiliation: Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 305-701, Republic of Korea. Electronic address: hskim76@kaist.ac.kr.
authors.forename: Hak-Sung
authors.initials: HS
authors.lastname: Kim
mesh_terms: D000911:Antibodies, Monoclonal / Q000008:administration & dosage* / Q000276:immunology; D001665:Binding Sites; D002478:Cells, Cultured; D015936:Complement C5a / Q000737:chemistry* / Q000276:immunology*; D006801:Humans; D007155:Immunologic Factors / Q000737:chemistry / Q000276:immunology; D018836:Inflammation Mediators / Q000737:chemistry / Q000276:immunology*; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000276:immunology; D011485:Protein Binding; D011487:Protein Conformation; D044087:Receptor, Anaphylatoxin C5a / Q000737:chemistry* / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; C488033:C5AR1 protein, human; D007155:Immunologic Factors; D018836:Inflammation Mediators; D044087:Receptor, Anaphylatoxin C5a; D015936:Complement C5a
keywords: C5a; Inflammatory disease; Modular engineering; Repebody