Combined treatment with anti-CD44 mAbs (H90 or A3D8) and RA induces the differentiation of KG1a cells.
(A) Increased expression of lineage differentiation antigens. Cells were labeled in triplicate with FITC-conjugated mAbs directed to CD15 and CD11b. The percentage of CD11b+ and CD15+cells was determined by flow cytometry relative to isotypic controls. (B) Induction of NBT-reducing ability. Data are the percentage of NBT+ cells. They are mean values ± 1 SD of triplicate samples from a representative of 3 experiments. (C) May-Grünwald Giemsa–stained cytosmears of KG1a cells. Cells were treated for 6 days with H90 (20 μg/mL) plus RA (10−7 M/L) or J173 (controls). Control cells showed an immature myeloblastic phenotype: high nucleus-cytoplasmic ratio and numerous nucleoli. Treated cells showed a decrease in nucleus-cytoplasmic ratio, chromatin condensation, and a pale cytoplasm with irregular contours, all typical of maturing monocytes. Cells treated with A3D8 (2.5 μg/mL) and RA displayed similar features. Magnification: × 630.
