Determination of the proportion of lymphocytes, myelocytes and primitive cells in engrafted mice treated with cytokines. The percentage of lymphoid, myeloid, and CD34⁺cells in the region of human CD45⁺ cells was measured by flow cytometry for each engrafted mouse in each treatment group. The lymphoid gate that contained >90% of CD19⁺ B lymphocytes and the myeloid gate that contained >90% CD33⁺ cells were established based on FSC and SSC characteristics.6 The histogram shows the mean ± SEM for each cell fraction. (A) Flow cytometric analysis of engrafted (>∼1% human cells) mice shown in Fig 1. In all cases, mice were transplanted with mononuclear CB cells except for the FL/SCF/IL-7 group that also contained two of four mice analyzed, which were transplanted with 1 BM sample. (B) Total number of cells present in the BM of the mice shown in A. This calculation was made by multiplying the percentage of cells with the total cell count obtained from four long bones. (C) Mice transplanted with purified CD34⁺Lin⁻ or CD34⁺CD38⁻ cells. Statistically significant differences with the untreated control mice are shown with the *.