Journal: Scientific Reports
Article Title: A novel label-free method to determine equilibrium dissociation constants of antibodies binding to cell surface proteins
doi: 10.1038/s41598-024-82288-9
Figure Lengend Snippet: Biacore and MSD-CAT affinity data for the binding of anti-CD123 to human antigen-full length (CD123 SP1) and its truncated variant (CD123 SP2). For the SPR experiment recombinant CD123 SP1 or CD123 SP2 were used for complex formation. For the MSD-CAT experiments reported in the last column, complex formation was obtained by incubating antibodies or Fabs with cells expressing human CD123 SP1 or CD123 SP2, or cynomolgus full length CD123. Detection of antibody in the cell-antibody equilibrated mixture was performed by capturing free antibody in the supernatant with biotinylated recombinant CD123 SP1 or CD123 SP2 which has been previously captured on a streptavidin MSD-plate.
Article Snippet: To detect free (unbound) antibody in solution using the (ECLIA) assay, MSD SA-STD plates were blocked with 50 μL per well of assay buffer (PBS containing 0.2% BSA, 0.05% Tween 20) for at least 5 min. Plates were turned over to remove assay buffer and tapped on paper towels and 50 μL per well of 0.7 μg/mL biotinylated human CD123 SP1 (huCD123 SP1, R&D Systems cat 301-R3/CF, lot# LV091112A or LV081110A) or human CD123 SP2 BlueSky Lot #120,503-CP05057h or 6519A) in assay buffer were added and the plates were allowed to incubate overnight in the refrigerator.
Techniques: Binding Assay, Variant Assay, Recombinant, Expressing