Fig. 2.

S1P₁ antagonism by Ex26 induces lymphocyte sequestration in the lymph nodes and thymus. (A) Ex26 induces dose-dependent lymphocyte sequestration 2 hours following i.p. treatment. (B) Lymphopenia induced by 3 mg/kg Ex26 i.p. resolves by 24 hours following treatment. (C and D) Continuous administration of Ex26 in 6-week-old mice by micro-osmotic pumps sequesters T and B cells in the peripheral lymph nodes (pLN) (C), leaving the spleen depleted of lymphocytes (D). pLN cell numbers derive from combined inguinal, axillary, and brachial lymph nodes. (E) Ex26 leads to accumulation of mature CD62L^Hi, but not immature CD62L^Lo, SP thymocytes. All graphs are representative of three experiments, with 3–4 mice per group per experiment. Graphs are plotted as the mean ± S.E.M. *P < 0.05, **P < 0.01 as determined by an unpaired, two-tailed t test.