GLP1 Antibody
Description
Definition and Target Profile
GLP1 antibodies are immunoglobulin-based molecules designed to either:
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Bind GLP1 directly (e.g., neutralizing or detection antibodies)
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Target GLP1R (e.g., antagonistic or agonistic antibodies modulating receptor activity)
These antibodies enable precise investigation of GLP1/GLP1R signaling and therapeutic interventions in metabolic disorders .
Monoclonal Antibodies
Polyclonal Antibodies
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Bioss bs-0038R: Targets GLP1 (7-36), used in ELISA and immunofluorescence .
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R&D Systems MAB110299: Detects human GLP1 with high specificity for assay development .
Mechanisms of Action
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Antagonism: Block GLP1R activation by endogenous GLP1 or synthetic agonists (e.g., liraglutide) .
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Inverse Agonism: Suppress basal receptor activity (e.g., TB-222-023 reduces insulin secretion in hyperinsulinism models) .
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Detection: Enable GLP1 quantification in plasma or tissue samples (e.g., Bioss bs-0038R) .
In Vitro Studies
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Receptor Signaling: Antibodies like Glp1R0017 inhibit GLP1-induced cAMP production in CHO cells .
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Beta-Cell Function: TB-222-023 reduces insulin secretion in pancreatic islets from hyperinsulinism patients .
In Vivo Studies
| Model | Antibody | Outcome | Citation |
|---|---|---|---|
| Sur1 −/− mice | TB-222-023 | Hypoglycemia resolution | |
| C57BL/6 mice | Glp1R0017 | Reversed glucose-lowering effects |
Therapeutic Potential
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Metabolic Diseases: Antagonistic antibodies may mitigate hypoglycemia in hyperinsulinism .
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Drug Development: Bispecific antibodies (e.g., AMG 133) combine GLP1R agonism with GIPR antagonism for obesity treatment .
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Diagnostics: Antibody pairs (e.g., MAB110299 + MAB12492) enhance GLP1 detection in clinical assays .
Challenges and Innovations
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Specificity: Cross-reactivity with GIPR or glucagon receptor requires rigorous validation .
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Formulation: Long half-life variants (e.g., AMG 133) enable monthly dosing for sustained weight loss .
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Oral Delivery: Small-molecule GLP1R agonists (e.g., danuglipron) aim to improve patient compliance .
Future Directions
Product Specs
Constituents: 50% Glycerol, 0.01M Phosphate Buffered Saline (PBS), pH 7.4
Target Background
Q&A
How are GLP-1R antagonistic antibodies generated and characterized in vitro?
Basic Research Focus
Antibody generation typically involves phage display libraries screened against GLP-1R extracellular domains (ECDs). For example:
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Selection: Biopanning with biotinylated human GLP-1R ECDs or cell surface selections on GLP1R-overexpressing CHO cells .
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Affinity maturation: ScFvs (single-chain variable fragments) are converted to IgG1 format, improving potency (e.g., Glp1R0017 IC50 reduced from 238 nM to 5.2 nM post-conversion) .
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Functional assays:
Key Data Table:
| Assay Type | Target Cell Line | IC50 (Glp1R0017) | Citation |
|---|---|---|---|
| cAMP Inhibition (ScFv) | mGLP1R-CHO | 238 nM | |
| cAMP Inhibition (IgG1) | mGLP1R-CHO | 5.2 nM | |
| Insulin Secretion Block | INS-1 832/3 | >50% inhibition |
What methods validate GLP-1 antibody specificity across species?
Basic Research Focus
Cross-species reactivity is critical for translational studies:
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In vitro receptor panels: Test antagonism against homologous receptors (e.g., GIPR, GCGR) using cAMP assays .
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Immunostaining: Validate tissue-specific binding (e.g., pancreatic islets in WT vs. Glp1r KO mice) .
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Species-specific cell lines: Use CHO/HEK293T cells expressing human, mouse, rat, or monkey GLP1R .
How to address discrepancies between in vitro and in vivo efficacy of GLP-1 antibodies?
Advanced Research Focus
Discrepancies arise due to pharmacokinetics or receptor dynamics:
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Dose-response profiling: Compare in vitro IC50 with in vivo glucose tolerance tests (IPGTT/OGTT). For example, Glp1R0017 reversed liraglutide’s glucose-lowering effect in mice at 10 mg/kg .
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Pharmacodynamic markers: Monitor cAMP suppression duration and receptor occupancy via radiolabeled ligand competition assays .
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Tissue penetration studies: Use fluorescently labeled antibodies to quantify pancreatic vs. CNS biodistribution .
What strategies enhance GLP-1 antibody stability and half-life?
Advanced Research Focus
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Albumin-binding domains: Fusion with DARPin (designed ankyrin repeat proteins) extends half-life via HSA binding .
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Linker engineering: Rigid helical linkers (e.g., (EAAAK)₃) reduce steric hindrance between antibody and payload .
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In vivo antibody painting: Covalent attachment of GLP-1 agonists to endogenous IgGs reduces required doses by 75% in mice .
Example:
How do GLP-1 antibodies inform receptor internalization mechanisms?
Advanced Research Focus
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β-arrestin recruitment assays: Measure EC50 for β-arrestin vs. cAMP pathways (e.g., GLP1R partial agonists with β-arrestin EC50 >1 µM) .
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Fluorescence microscopy: Track pHrodo-labeled antibodies to visualize endosomal trafficking post-binding .
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Kinetic modeling: Use rate constants for antibody-receptor dissociation to predict internalization efficiency .
What are design considerations for bispecific GLP-1/GIPR antibodies?
Advanced Research Focus
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Epitope binning: Ensure non-overlapping binding sites for GLP1R and GIPR to avoid steric clashes .
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Linker optimization: Flexible (GGGGS)₃ linkers enable simultaneous receptor engagement .
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Functional validation:
How to assess cross-reactivity with homologous receptors like GIPR?
Basic Research Focus
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Competitive binding assays: Use ⁵¹I-labeled GLP-1 or GIP to quantify displacement by antibodies .
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Structural modeling: Compare antibody paratopes with conserved GLP1R/GIPR residues (e.g., transmembrane domain 2) .
What mechanisms underlie GLP-1 antibody-mediated metabolic effects in neurological models?
Advanced Research Focus
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Blood-brain barrier (BBB) penetration: Assess via intracerebroventricular injection vs. systemic administration .
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Receptor dimerization: Probe GLP1R-GLP2R heterodimerization in hippocampal neurons using FRET .
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Behavioral endpoints: Measure cognitive function (Morris water maze) and neuroinflammation (GFAP/Iba1 staining) .
