ET2 expression at the LMPP stage inhibits myeloid development and enhances B-cell production. (A) GFP-positive (ET2⁺) and -negative (ET2⁻) total LSK, Flt3^HiLSK (LMPP), and Flt3^−/loLSK were isolated from mice as described for Figure 4 and seeded at 300 cells/well in media containing SCF, IL-3, IL-6, and G-CSF. Four days later, cells were analyzed with the indicated antibodies. The number of Mac-1⁺ cells produced from each progenitor subset is shown in the bar graph on the right (n = 3). (B) The same subsets of progenitors were also placed at 1250 cells/well in media containing SCF, Flt3-L, and IL-7 and cultured for 16 days. Cells were stained with indicated antibodies and analyzed by flow cytometry. Average numbers of B220⁺CD19⁺ cells are shown in bar graphs with SD (n = 3).