Increased lymphocyte retention in dCLNs following FTY720 treatment of JHMV-infected mice. S1P1 eGFP mice were i.c. infected with JHMV (150 PFU) and treated daily with FTY720 (3 mg/kg) beginning on day 5 p.i. On days 7, 14 and 21 p.i., dCLNs were isolated to examine size, weight and immunophenotype lymphocyte population by flow cytometry. (A) Representative image depicting the increase in size of dCLNs obtained from FTY720-treated mice compared to vehicle control-treated mice at day 7 p.i. (B) Average weight of dCLNs increased in response to FTY720 treatment compared to vehicle (P < 0.05). Treatment with FTY720 resulted in increased retention of B220+ B cells (C), CD4+ T cells (D) and CD8+ T cells (E) at defined times p.i. Data in panels B to E represent average ± SEM obtained from two or three independent experiments with a minimum of four mice/group. *P <0.05, *** P <0.001. cLN, cervical lymph node. dCLN, draining cervical lymph node.