Fig. 4. Optimized cytokines enhance T cell development.

(A) Predicted optima for PSC-derived T cell differentiation compared with previously identified optima for UCB-derived HSPC differentiation to the T lineage. (B) To validate predictions, CD34⁺ cells were cultured in EHT conditions for 7 days and then transferred to cytokines optimized for PSC- or cord blood–derived cells. In addition, CD34⁺ cells were placed directly into PSC optima without the EHT step. (C) Total viable cell yield for each test condition per input CD34⁺ cell (n = 3). (D) Representative flow cytometry of CD7⁺, CD5⁺ T cell progenitors at day 8 + 14. (E) Quantification of the frequency and yield of CD7⁺, CD5⁺ T cell progenitors (yield is reported as number of CD5⁺, CD7⁺ cells per CD34⁺ input cell, n = 3, mean ± SD). (F) Representative flow cytometry of CD4⁺, CD8⁺ DP cells at day 8 + 28. (G) Quantification of the frequency and yield of CD4⁺, CD8⁺ DP cells (yield is reported as number of CD4⁺, CD8⁺ cells per CD34⁺ input cell, n = 3, mean ± SD). (H) Representative flow cytometry at day 8 + 35 after stimulation with anti-CD2/3/28 antibodies in the presence of + IL-21. (I) Quantification of the frequency and yield of the phenotypes shown in (H). Yield is reported as abundance of indicated cell population per CD34⁺ input cell (n = 3, mean ± SD).