Kinetics of exfoliation from CX-1 and MIP-101 human colorectal adeno-carcinoma cells. (A) Cumulative radioactivity (cpm) released on shed vesicles collected from 1 × 10⁷surface-¹²⁵I-labeled CX-1 (▪) and MIP-101 (▴) cells after indicated incubation periods was quantified by scintillation counting. (B) Rates of shedding were calculated by dividing total radioactivity (cpm) released by the incubation time. Shown are the means ± SD of three separate experiments. Note that shedding from CX-1 cells is quantitatively increased relative to shedding from MIP-101 cells.