Journal: Scientific Reports
Article Title: Enhanced anti-metastatic bioactivity of an IGF-TRAP re-engineered to improve physicochemical properties
doi: 10.1038/s41598-018-35407-2
Figure Lengend Snippet: SPR direct binding and competition assays show similar ligand binding affinities for IGF-TRAP 3.1 and IGF-TRAP 3.3. Direct ligand binding was measured by first capturing the IGF-TRAP onto an immobilize anti-Fc surface (4000 resonance units (RUs)), and then flowing a dilution series of the ligands indicated over the captured IGF-TRAP. Shown in (A-top) are results of binding sensorgrams of a representative analysis of a total of 3 performed. The kinetic fits used for affinity determination are shown in green. The calculated affinity constants (mean ± SD, n = 3) based on a fit to a 1:1 Langmuir binding model are shown in the Table ( A -bottom). Shown in ( B ) are results of a binding competition assay in which increasing concentrations of IGF-TRAP-3.1 or IGF-TRAP-3.3 were used to compete with binding of constant ligand concentrations to MAb MEDI-573-immobilized onto the SPR surface. The SPR response of IGF binding to MEDI-573 is shown (B-top) with IGF-TRAP-3.1 (in red), IGF-TRAP-3.3 (in green) and using rhIGF-1 (circles) or rhIGF-2 (triangles) as ligands. Shown in (B-bottom) are IC50 values for IGF-TRAP-3.1 and IGF-TRAP-3.3 with the 95% CI (in parentheses) as determined based on the SPR competition binding assays.
Article Snippet: Recombinant human (rh) IGF-1 for KIRA assay was obtained from the National Institute of Biological Standards and Calibrators (NIBSC, Hertfordshire, UK) (02/254). rhIGF-1 and rhIGF-2 and insulin used for surface plasmon resonance (SPR) experiments were from Sigma-Aldrich (Oakville, ON, Canada) and recombinant mouse IGF-1 was from Cedarlane (Burlington, ON, Canada).
Techniques: Binding Assay, Ligand Binding Assay, Competitive Binding Assay
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