Figure 4.

Large LTC cells are highly endocytic. Protein uptake was measured by pulsing cells with OV-FITC. (A) Histograms represent FITC⁺ small vs. large cells at 6 h after incubation. At 6 h, 15.8 ± 3.7% (mean ± SE, where n = 3) of small cells were FITC⁺, whereas 84.8 ± 5.0% of large cells were FITC⁺. The protein uptake of cells kept on ice was taken as background (dotted line). (B) Data points represent the percentage of FITC⁺ cells at 0.5, 1, 3, 6, 12, and 24 h after incubation at 37°C in the presence of labeled protein for each of three replicate experiments (background control not shown). Open symbols represent small cells; closed symbols represent large cells.