title: A dual-monoclonal, sandwich immunoassay specific for glucagon like peptide-19-36/7 (GLP-19-36/7).
abstract: OBJECTIVE
  Glucagon-like peptide-1 (GLP-1) is a peptide hormone secreted by intestinal L-cells which stimulates glucose-dependent insulin secretion. GLP-1 is initially secreted as the active peptide GLP-17-36/7, but rapidly undergoes cleavage by dipeptidyl peptidase 4 (DPP4) to yield the inactive form, GLP-19-36/7. Despite a reduced affinity for the GLP-1 receptor, GLP-19-36/7 may have cardioprotective properties. There is currently no described immunoassay capable of specifically measuring GLP-19-36/7.
  
  
  METHODS
  We generated a monoclonal antibody specific for the N-terminal neoepitope of GLP-19-36/7. After affinity maturation, we paired this capture antibody with an anti-total GLP-1 monoclonal detection antibody to create a sandwich ELISA specific for GLP-19-36/7.
  
  
  RESULTS
  The sandwich ELISA was highly specific for GLP-19-36/7 and did not recognize GLP-17-36 or GLP-17-37. The ELISA exhibited a broad dynamic range and a lower limit of detection (LLOD) of 3.17ng/L. In healthy volunteers, concentrations of GLP-19-36/7 increased dramatically in the postprandial state compared to the fasted state and were markedly elevated at both 30 and 120-minute postprandial time points.
  
  
  CONCLUSIONS
  The optimization of an N-terminal-specific monoclonal antibody for GLP-19-36/7 enabled the development of a sensitive and specific sandwich ELISA assay capable of measuring physiological concentrations of GLP-19-36/7. This ELISA may have the potential to help expand our knowledge of GLP-1 biology.
authors.affiliation: From the Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, 46285, USA. Electronic address: osborne_robert@lilly.com.
authors.forename: Robert I
authors.initials: RI
authors.lastname: Osborne
authors.affiliation: From the Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, 46285, USA.
authors.forename: Wenyu
authors.initials: W
authors.lastname: Ming
authors.affiliation: From the Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, 46285, USA.
authors.forename: Jason S
authors.initials: JS
authors.lastname: Troutt
authors.affiliation: From the Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, 46285, USA.
authors.forename: Robert W
authors.initials: RW
authors.lastname: Siegel
authors.affiliation: From the Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, 46285, USA.
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Konrad
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D015415:Biomarkers / Q000097:blood*; D001786:Blood Glucose / Q000032:analysis; D018819:Dipeptidyl Peptidase 4 / Q000097:blood* / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005215:Fasting; D052216:Glucagon-Like Peptide 1 / Q000097:blood* / Q000276:immunology; D064368:Healthy Volunteers; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D019518:Postprandial Period; D012372:ROC Curve; D011817:Rabbits
chemical_list: D000911:Antibodies, Monoclonal; D015415:Biomarkers; D001786:Blood Glucose; D052216:Glucagon-Like Peptide 1; C042807:DPP4 protein, human; D018819:Dipeptidyl Peptidase 4
keywords: Diabetes; GLP-1(9–36/7); Glucagon; Incretin; Insulin; Peptide