Lack of contribution of myeloid cells to lymph S1P. (A) Flow cytometric analysis of enzyme-digested LN cells to detect CD11b and CD11c. (B) LYVE-1 or control antibody staining of the six cell populations shown in A. (C) The proportion of each subpopulation replaced by donor-derived cells in lethally irradiated CD45.2⁺ Lyve-1 Cre⁺ Sphk-deficient mice reconstituted with wild-type CD45.1⁺ BM. Numbers refer to the percentage of cells in the indicated gates. (D) S1P1 on CD4⁺ CD62L^hi T cells from the lymph and LNs of mice that had been reconstituted with wild-type BM as in C. Sphk Δ indicates the Lyve-1 Cre⁺ Sphk-deficient host; C indicates the control host. The shaded histogram shows staining of LN cells from an FTY720-treated mouse. (E) Bioassay measurement of S1P in lymph and plasma from the chimeric mice. Data in A–E are representative of three experiments with three mice. MFI, mean fluorescence intensity.