Infusion of donor alloreactive NK cells accelerates post-BMT immune reconstitution. (A) H-2^b recipient mice were conditioned with TBI+IL2-activated alloreactive NK cells (NK^allo) from H-2^d mice or with TBI+IL2-activated syngeneic (nonalloreactive) H-2^b NK cells (NK^syn). Mice were then transplanted with T-cell–depleted BM from H-2^d mice. (B) Recovery of BM B220⁺/cytoplasmic μ (Cμ)− pro-B cells (light green bars), B220⁺/Cμ⁺/surface immunoglobulins (SIg)⁻ pre-B cells (blue bars), and B220⁺/SIg⁺ B cells (red bars). (C) Recovery of splenic B220⁺/SIg⁺ B cells. (D) Recovery of CD4⁺/CD8⁺ double-positive (red bars), CD4⁺ single-positive ( blue bars), and CD8⁺ single-positive (light green bars) thymocytes. (E) Recovery of splenic CD3⁺ T cells, including γ/δ T cells, regulatory T cells (Tregs), effector memory (EM) T cells, central memory (CM) T cells, and naïve T cells. (F) Splenic CD3⁺ T-cell proliferation in response to allogeneic H-2^b splenocytes and anti-CD3 antibody stimulation at 35 days after transplant. (G) Recovery of BM CD11c⁺ DCs. (H) Recovery of splenic CD11c^int/B220⁺/GR1⁺ plasmacytoid DCs (red bars) and CD11c^high/B220⁻/GR1⁻ myeloid DCs (blue bars). (I) Recovery of thymic CD11c^high/CD8⁺ DCs (red bars) and CD11c^high/CD8⁻ DCs (blue bars). Bars: mean ± standard deviation of at least 3 independent experiments; statistics were performed with a Student t test (GraphPad Prism 5). ∗P < .05, ∗∗P < .01. Cntrl, cell counts in transplant donors.