Homing cells are SRC/stem cells.

(A) BM and spleen cells of mice that were transplanted with human CD34⁺-enriched cells were harvested at indicated time points and assayed for colony formation. Data represent mean ± SE from 6 experiments, n = 12 mice. (B) NOD/SCID mice used as primary recipients were transplanted with 10⁶ CD34⁺cells/mouse. Secondary recipients NOD/SCID/B2m^null mice were transplanted either with BM (2 × 10⁶ cells/mouse) or spleen cells (4.5 × 10⁶ cells/mouse) from one primary recipient. BM cells of secondary-transplanted recipients were assayed for lymphoid (R1), nonlymphoid (R2) cell differentiation (B), erythroid and myeloid progenitor cells (C), and human DNA levels (D). A representative experiment is shown of 3 performed, n = 12 mice.