Antibody (Ab) Saturation Assay (Sites/cell & Kd)
Multiple concentrations (up to twelve) of the [125I]-Ab are incubated in quadruplicate with a desired cell line containing the target of interest.
After equilibrium has been reached, receptor-bound [125I]-Ab is separated from non-bound radioligand using either:
- Filter-based Separation
- Scintillation Proximity Assay (SPA)
The filters or SPA plate are counted using liquid scintillation counting, or Gamma Counting, to determine the level of receptor-bound radioligand and the results plotted to obtain sites/cell and if desired the Kd for the target-radioligand integration.