Figure 4. Notch signaling enhances CD16 expression prior to KIR expression.

(A) Day 21 UCB CD34-derived (n = 4), (B) PBMC sorted CD56^brightCD3⁻KIR⁻ (n = 8), and (C) PBMC sorted CD56^dimCD3⁻KIR⁻ (n = 8) NK cells were co-cultured with 10 ng/ml IL-15 and OP9-Native, OP9-DLL1, or OP9-DLL4 cells for 7 days and harvested to assess CD16 expression. (D and G) CD16 expression on KIR⁻ or KIR⁺ NK cell populations from UCB NK (n =4), (E and H) CD56^bright NK (n = 8), and (F and I) CD56^dim NK (n = 8) in the same setting described above. (J) KIR and (K) CD16 expression was tested at day 24 (3 days after start of co-culture) of UCB NK culture (instead of day 28) to assess the role of Notch signaling on expression of these molecules at an earlier time point; co-incubation with OP9 cells was started at day 21 as previously described.