Specific action of c-kit neutralizing antibody in two lines. PDE02 (ES) (A,C,E,G) and 6647 (ES) (B,D,F,H) cultured in complete medium. Cytofluorimetric profile of the propidium iodide staining of DNA content in basal condition (A,B) with 0.4 μg/10⁴ cells of Vβ-8 for 7 days (C,D), with 0.4 μg/10⁴ cells of anti–c-kit neutralizing antibody for 72 hours (E,F) and for 7 days (G,H). The reduction of S phase and the increment of the apoptotic phenomenon appear at 72 hours (E,F) and is more evident after 7 days (G,H) (13% in PDE02 and 46% in 6647). These results were confirmed by TdT assay.