Fig. 3.
Effect of D2C treatment on the growth and viability of K562 cells. a Cells were incubated with an increasing concentration of D2C, monoclonal antibody against Transferrin receptor (TfR), or non-specific human IgG (50 μg/ml, isotypism control 1) or non-specific mouse IgG (50 μg/ml, isotypism control 2) control. Cell growth was determined in triplicate cultures 48 h after co-culture using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reagent as described in “Materials and methods”. Each value represents the mean±SD of three independent experiments. Absorbance values obtained with untreated cells maintaining under identical experimental conditions were taken as 100%. b Harvested during the logarithm growth period, 1×105 cells of K562 were plated into 24-well plate and then incubated with D2C in the titration as described in above graph, non-specific human IgG (50 μg/ml, isotypism control 1) or non-specific mouse IgG (50 μg/ml, isotypism control 2). Total cell amount of each well was calculated by trypan blue staining through optical microscope (×100) each day for a week. Because the proximity results of three groups (untreated, isotypism control 1 and isotypism control 2) were presented in the parallel growth curves, they have overlapped and could not been differentiate. Photomicrographs of K562 cells after a 72 h coculture with (c) RPMI 1640, (d) D2C, or (e) monoclonal antibody against TfR. Cells treated with RPMI 1640 is specular globular, whereas most of the cells treated with D2C or monoclonal antibody against TfR is displayed many particles. (Original magnification, ×400)