ULBP and NCR ligand surface expression increases on myeloid differentiation of normal BM progenitor cells in vitro. FACS analysis of ULBP1, ULBP2, and ULBP3 surface expression and sNKp30, sNKp44, and sNKp46 binding by freshly isolated CD34+ cells (▪) and after 7 days of culture with growth factors (GFs; SCF + FL + GM-CSF; ▦), GFs together with IFN-γ (□) or together with IL-1β, LPS, and IFN-γ (▨) for an additional 3 days. Results represent the mean ± SEM of 3 BM samples.