A3D8 and J173 antibodies have different binding abilities to HL-60, SKNO-1 and NB4 cells. (A) Western blot analysis of CD44 protein levels. Cellular lysates were isolated from HL-60, SKNO-1 and NB4 cells, subjected to 8% SDS-gel electrophoresis and then probed with either A3D8 or J173 antibody. (B) Cell surface CD44 binding of A3D8 and J173. HL-60, SKNO-1 and NB4 cells were incubated with mouse IgG, A3D8 and J173 first and then FITC labeled secondary antibody. The fluorescence strength was determined by FACS.