Fig. 2.

FTY720 (FTY) treatment alters the number and ratio of lymphocyte populations in the peripheral blood of type II collagen–immunized mice. Peripheral blood lymphocytes (PBLs) were recovered from mice treated with FTY720 at 24 h, 72 h, and 120 h after a single 1 mg/kg treatment, and the cells were stained with antibodies specific for CD19, CD3, CD4, and CD8. All data were gated on the basis of live cells (4′,6-diamidino-2-phenylindole–negative) and forward versus side scatter to identify the lymphoid population. The CD4⁺ and CD8⁺ populations were generated as subpopulations of CD3⁺ cells. a and b The number of cells per microliter of blood was determined by adding CountBright beads to the samples before analyses, as described in the Methods section. Closed stars in (a) indicate statistically significant changes (p < 0.01). c–f Change in the subpopulation distribution of B cells and T cells in the peripheral blood. Antibody staining and analysis of the flow cytometry data were done as indicated in each panel, with statistically significant differences of p < 0.05 denoted by closed stars. Open bars indicate 1.0 mg/kg FTY720 treatment, and closed bars represent vehicle control. Error bars depict standard deviations