T-cell reconstitution by LSK cells cultured on immobilized Delta1^ext-IgG compared with noncultured LSK cells. (A) Lethally irradiated Ly5.1 C57BL/6 recipients received 5 × 10³ noncultured LSK cells or 1 × 10⁶ Ly5.2 Delta1^ext-IgG-cultured cells along with 1 × 10⁵ Ly5.1 BM cells. FACS analysis and CBCs were performed on blood samples obtained at 3 weeks after HCT to determine the number of Ly5.2⁺ CD3⁺, CD4⁺, CD8⁺, CD19⁺, GR1⁺, and F4/80⁺ cells in mice that received LSK cells cultured on Delta1^ext-IgG (closed bars) compared with noncultured LSK cells (open bar). (B) FACS analysis and CBCs were performed on blood samples obtained at various times after HCT to determine the number of Ly5.2⁺ CD3⁺ cells in mice that received LSK cells cultured on Delta1^ext-IgG (•) compared with noncultured LSK cells (▵). (C-E) FACS analysis was performed on thymuses at 1 week (C), 2 weeks (D), and 3 weeks (E) after HCT to determine the total number of Ly5.1 host and Ly5.2 donor DN1, DN2, DN3, CD4⁺, CD8⁺, or DP cells in mice that received noncultured Ly5.2 LSK cells or Ly5.2 LSK cells cultured on Delta1^ext-IgG. Data represent mean plus or minus SEM of 3 separate experiments (n = 10-15).