ML120B sensitizes bone marrow granulocytes and B-cell progenitors to killing by TNFα. (A) Bone marrow cells were isolated and incubated in media, ML120B alone (30 μM), murine TNFα alone (100 ng/mL), or ML120B + TNFα for 4 hours and then analyzed by flow cytometry for annexin with granulocyte marker GR-1 or B-cell marker B220. (B) Percent live granulocytes (GR-1+ annexin^–) and live B cells (B220⁺annexin^–) after 4 hours of culture. Values are averages of triplicates; error bars indicate SD. (C) Bone marrow cells were cultured in increasing concentrations of ML120B in the presence or absence of murine TNFα (100 ng/mL) for 4 hours then washed and plated in culture conditions for myeloid colony growth or B-cell colony growth. Colonies were scored 7 days after plating. All cultures contained 0.5% DMSO. (D) Percent live thymocytes (annexin^–) after 6 hours of culture. Values are averages of triplicates; error bars indicate SD. One representative experiment of 3 with similar results is shown.