Figure 1.

Surface expression of Flt3 by mouse BM cells and by different hemopoietic precursor populations. Total BM cells were stained with PE-conjugated anti-Flt3 antibody together with other fluorescence-conjugated antibodies against different surface molecules expressed by BM cells including CD19, B220, CD3, Mac-1, Gr-1, MHC class II, and c-kit. The expressions of these molecules on the gated Flt3⁺ BM cells are shown in A. The solid lines represent the staining of different surface molecules and the dashed lines represent the isotype controls. The precursor populations from mouse BM or thymus were first enriched for lineage marker–negative cells and then distinguished by four color fluorescence staining as (B) CLP (c-kit⁺ CD127⁺), (C) CMP (CD34⁺ CD16/32^lo) and GMP (CD34⁺ CD16/32^hi), (D) intrathymic CD4^lo lymphoid precursors (c-kit⁺ Thy-1^lo), and (E) BM pro-B precursors (c-kit⁺ CD19⁺). The surface expression of Flt3 by each precursor population was then examined. The contour plots display the gating for each precursor population (cells within the boxes). The histograms show the Flt3 expression on each gated precursor population. The solid lines represent the Flt3 staining and the dashed lines represent the isotype controls. Data presented in this figure is representative of at least three similar experiments on each precursor population.