Fig. 2. The fraction of ligand that is captured decreases as ligand release increases. Cells that had been induced to release ligand at different rates using tetracycline and a ligand-release inhibitor were allowed to condition their medium for 8-14 hours. The medium was collected and assayed for EGF by ELISA. The concentration of EGF was then converted to a ligand secretion rate. The total ligand secretion rate, V_LT, was calculated from samples containing 5.0 µg/ml 225 mAb during cell medium conditioning. Fraction ligand captured is determined by comparing ligand secretion rates calculated from samples without 5.0 µg/ml 225 mAb to those with 5.0 µg/ml 225 mAb during cell medium conditioning. The error bars represent the s.e.m. of a set of data points taken and analyzed in duplicate.