IL-7 cannot rescue Notch-dependent TCR-γδ T-cell development. Flow cytometric analysis of human CD34⁺CD1⁻ (A) and CD34⁺CD1⁺ (B) postnatal thymocytes after 3 weeks of coculture on OP9-DL1 stromal cells in the presence of various concentrations of the γ-secretase inhibitor DAPT (GSI) and with increased (50 ng/mL) or reduced (0.5 ng/mL) IL-7 concentrations. Data show TCR-γδ and TCR-αβ cellularity in comparison to normal IL-7 levels (5 ng/mL) as also shown in Figure 3. Data represent mean plus or minus SEM (n = 3).