Jagged2 stimulates the development of NK cells from post-5-FU bone marrow MNCs. (A) Retroviral vector–mediated expression of the full-length mJagged2 in OP-9S/LMJSN but not OP-9S/LXSN (negative control). The top panel is a Northern blot hybridized with an mJagged2 cDNA probe. The middle panel is the ethidium bromide–stained gel before blotting. The bottom panel is a Western blot probed with rabbit antiserum against the intracellular domain of mJagged2. The 120-kDa mJagged2 protein is indicated. (B) Expression of NK1.1 versus CD3 and CD19 versus B220 by 5-FU bone marrow MNCs cocultured with OP-9S/LXSN (negative control) or OP-9S/LMJSN (“J2”) in the presence of IL-7 and Flt3L for 19 days without or with IL-2 on days 10 to 19. The percent of CD3^-NK1.1⁺ cells is indicated. (C) Expression of NK1.1 versus CD3 and CD19 versus B220 by post-5-FU bone marrow MNCs cocultured with OP-9S/LXSN or OP-9S/LMJSN (“J2”) in the presence of IL-7 and Flt3L for 28 days without or with IL-2 on days 20 to 28. The percent of CD3^-NK1.1⁺ cells is indicated. Small numbers of CD3⁺NK1.1⁺ cells were present in OP-9S/LMJSN cocultures. They likely represented NKT or cytotoxic lymphocytes that had evolved from pre-existing T cells.