Viability of leukemia cell lines treated with imatinib-encapsulated liposomes. SUP-B15 Ph⁺ ALL cells (A; bcr-abl⁺, CD19⁺), CML-BC K562 cells (B; bcr-abl⁺, CD19^–), Burkitt lymphoma Daudi cells (C; bcr-abl^–, CD19⁺), and APL NB4 cells (D; bcr-abl^–, CD19^–) were cultured with or without the indicated imatinib-encapsulated liposomes. Viability of cells was evaluated 8 days after the start of culture. (E) Time course of the viability of SUP-B15 cells treated with imatinib-CD19-liposomes or free imatinib at a concentration of 0.1 or 1 μM is shown. Data represent mean ± SD of triplicate experiments.