Differentiation of non–T-lineage cells is significantly lower after IT administration of WT BM progenitors. (A) ZAP-70^−/− mice were injected with WT CD45.1⁺ lin⁻ BM progenitor cells (2 × 10⁵) by either intravenous (IV) or IT routes. Animals were killed 20 to 25 weeks later, and donor cells in the spleen were assessed by CD45.1 staining. Within the CD45.1⁺ gate, the relative percentages of granulocyte (Gr1^high) and B-lineage (CD19⁺) donor cells (top) as well as CD4 and CD8 T cells (bottom) in representative WT mice as well as ZAP-70^−/− mice reconstituted by intravenous (IV) and IT administration of donor progenitors are indicated. (B) The graphs show the absolute numbers of LN donor B lymphocytes, granulocytes, and T cells in ZAP-70^−/− mice reconstituted by IV (n = 8) and IT (n = 9) injection of donor progenitors. *P = .01-.015; **P = .008.