title: Agonistic Human Antibodies Binding to Lecithin-Cholesterol Acyltransferase Modulate High Density Lipoprotein Metabolism.
abstract: Drug discovery opportunities where loss-of-function alleles of a target gene link to a disease-relevant phenotype often require an agonism approach to up-regulate or re-establish the activity of the target gene. Antibody therapy is increasingly recognized as a favored drug modality due to multiple desirable pharmacological properties. However, agonistic antibodies that enhance the activities of the target enzymes are rarely developed because the discovery of agonistic antibodies remains elusive. Here we report an innovative scheme of discovery and characterization of human antibodies capable of binding to and agonizing a circulating enzyme lecithin cholesterol acyltransferase (LCAT). Utilizing a modified human LCAT protein with enhanced enzymatic activity as an immunogen, we generated fully human monoclonal antibodies using the XenoMouse(TM) platform. One of the resultant agonistic antibodies, 27C3, binds to and substantially enhances the activity of LCAT from humans and cynomolgus macaques. X-ray crystallographic analysis of the 2.45 Å LCAT-27C3 complex shows that 27C3 binding does not induce notable structural changes in LCAT. A single administration of 27C3 to cynomolgus monkeys led to a rapid increase of plasma LCAT enzymatic activity and a 35% increase of the high density lipoprotein cholesterol that was observed up to 32 days after 27C3 administration. Thus, this novel scheme of immunization in conjunction with high throughput screening may represent an effective strategy for discovering agonistic antibodies against other enzyme targets. 27C3 and other agonistic human anti-human LCAT monoclonal antibodies described herein hold potential for therapeutic development for the treatment of dyslipidemia and cardiovascular disease.
authors.affiliation: From Therapeutic Discovery, Amgen Inc., Seattle, Washington 98119.
authors.forename: Ruwanthi N
authors.initials: RN
authors.lastname: Gunawardane
authors.affiliation: Cardiometabolic Disorders.
authors.forename: Preston
authors.initials: P
authors.lastname: Fordstrom
authors.affiliation: Therapeutic Discovery, and.
authors.forename: Derek E
authors.initials: DE
authors.lastname: Piper
authors.affiliation: Therapeutic Discovery, Amgen Inc., Burnaby, British Columbia V5A 1V7, Canada.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Masterman
authors.affiliation: From Therapeutic Discovery, Amgen Inc., Seattle, Washington 98119.
authors.forename: Sophia
authors.initials: S
authors.lastname: Siu
authors.affiliation: Cardiometabolic Disorders.
authors.forename: Dongming
authors.initials: D
authors.lastname: Liu
authors.affiliation: From Therapeutic Discovery, Amgen Inc., Seattle, Washington 98119.
authors.forename: Mike
authors.initials: M
authors.lastname: Brown
authors.affiliation: Therapeutic Discovery, and.
authors.forename: Mei
authors.initials: M
authors.lastname: Lu
authors.affiliation: Therapeutic Discovery, and.
authors.forename: Jie
authors.initials: J
authors.lastname: Tang
authors.affiliation: Therapeutic Discovery, and.
authors.forename: Richard
authors.initials: R
authors.lastname: Zhang
authors.affiliation: From Therapeutic Discovery, Amgen Inc., Seattle, Washington 98119.
authors.forename: Janet
authors.initials: J
authors.lastname: Cheng
authors.affiliation: From Therapeutic Discovery, Amgen Inc., Seattle, Washington 98119.
authors.forename: Andrew
authors.initials: A
authors.lastname: Gates
authors.affiliation: From Therapeutic Discovery, Amgen Inc., Seattle, Washington 98119.
authors.forename: David
authors.initials: D
authors.lastname: Meininger
authors.affiliation: Cardiometabolic Disorders.
authors.forename: Joyce
authors.initials: J
authors.lastname: Chan
authors.affiliation: PKDM Department, Amgen Inc., South San Francisco, California 94080, and.
authors.forename: Tim
authors.initials: T
authors.lastname: Carlson
authors.affiliation: Therapeutic Discovery, and.
authors.forename: Nigel
authors.initials: N
authors.lastname: Walker
authors.affiliation: Cardiometabolic Disorders.
authors.forename: Margrit
authors.initials: M
authors.lastname: Schwarz
authors.affiliation: Therapeutic Discovery, Amgen Inc., Burnaby, British Columbia V5A 1V7, Canada.
authors.forename: John
authors.initials: J
authors.lastname: Delaney
authors.affiliation: Cardiometabolic Disorders, mzhou@amgen.com.
authors.forename: Mingyue
authors.initials: M
authors.lastname: Zhou
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000276:immunology / Q000494:pharmacology; D000936:Antigen-Antibody Complex / Q000097:blood / Q000737:chemistry / Q000276:immunology; D001666:Binding Sites, Antibody; D016466:CHO Cells; D002318:Cardiovascular Diseases / Q000097:blood / Q000188:drug therapy / Q000276:immunology; D008076:Cholesterol, HDL / Q000097:blood / Q000276:immunology; D006224:Cricetinae; D003412:Cricetulus; D050171:Dyslipidemias / Q000097:blood / Q000188:drug therapy / Q000276:immunology; D006801:Humans; D008252:Macaca fascicularis; D051379:Mice; D007862:Phosphatidylcholine-Sterol O-Acyltransferase / Q000037:antagonists & inhibitors / Q000097:blood / Q000737:chemistry / Q000276:immunology; D020836:Protein Structure, Quaternary
chemical_list: D000911:Antibodies, Monoclonal; D000936:Antigen-Antibody Complex; D008076:Cholesterol, HDL; D007862:Phosphatidylcholine-Sterol O-Acyltransferase
keywords: antibody engineering; cholesterol metabolism; drug discovery; enzyme; high density lipoprotein (HDL)