Survival and homeostatic expansion of mature NK cells on transfer to alymphoid Rag°γ_c° recipient mice. (A) Kinetics of CFSE dilution of splenic and hepatic NK cells at various times after transfer. An electronic gate was set on CD122⁺ (IL-2Rβ⁺) cells. Boxes indicate percentages of CFSE⁺ NK cells that have not divided. (B) Absolute numbers of recovered splenic CD122⁺NK1.1⁺ NK cells at indicated times after transfer. Black bars (▪) indicate nondivided donor NK cells and open bars (□) indicate NK cells with more than one division. Error bars denote standard deviations. (C) Phenotype of adoptively transferred NK cells. An electronic gate was set on NK1.1⁺ NK cells. Boxes indicate the percentages of cells staining positive above background levels for the given marker. (D) Long-term survival of adoptively transferred NK cells. Absolute numbers of recovered splenic CD122⁺NK1.1⁺ NK cells at indicated times after transfer. Error bars denote standard deviations.