Specific uptake mediated by cell-surface DHCR24.

<p>(<i>a</i>) HCC cell lines (HuH-7, Hep3B, and PLC/PRF/5) and HeLa cells were incubated with 2-152a MAb at 4°C (a temperature that inhibits endocytosis) or 37°C (physiological temperature) for 2 h, and then incubated with an Alexa Fluor 488-conjugated goat anti-mouse IgG at 4°C for 1 h. The cells were then analyzed by flow cytometry. (<i>b</i>) HuH-7 cells were seeded at a density of 5 × 10³ cells/well in 96-well tissue culture plates. After incubation for 24 h, serial dilutions of 2-152a MAb or mouse IgG were added in the presence of saporin-conjugated anti-mouse IgG (1 μg/mL). After 72 h, cell viability was then assessed using the BrdU ELISA assay kit. Average viability was calculated relative to the viability of untreated cells, which was set at 100%. (<i>c</i>) HeLa, Hep3B, and PLC/PRF/5 cells were treated with 2-152a MAb or mouse IgG (10 μg/mL) in the presence or absence of saporin-conjugated anti-mouse IgG (1 μg/mL). After 72 h, cell viability was determined using a BrdU ELISA assay kit. Percent viability was calculated relative to the viability of untreated cells, which was set at 100%. *, <i>p</i> < 0.05.