DL1 and DL4 similarly affect human αβ/γδ T-cell differentiation. (A) Flow cytometric analysis of human CD34⁺ postnatal thymocytes after 21 and 29 days of coculture on OP9-hDL1 and OP9-hDL4 stromal cells in the presence of 0 or 1 μM of the γ-secretase inhibitor DAPT (GSI). Numbers in quadrants indicate the percentage of TCR-αβ⁺CD3⁺, TCR-γδ⁺CD3⁺, or CD4⁺CD8β⁺ cells. Results shown are representative for 2 independent experiments. (B) Corresponding TCR-γδ and TCR-αβ cellularity for cultures depicted in panel A, showing mean plus or minus SEM (n = 2). (C) Ratio of TCR-αβ to TCR-γδ T cells after 29 days of culture, derived from data shown in panel B.