Figure 4.

FTY720-induced homing of CCR7^−/− T cells is pertussis toxin sensitive. Splenocytes from CCR7^−/− donor animals were labeled with CFDA-SE. Cells were treated ex vivo with FTY720 (0.5 μM, 37°C, 3 h), and/or pertussis toxin (PTX; 20 ng/ml, 37°C, 3 h) or incubated in medium only (37°C, 3 h) and injected into wild-type recipient mice. Recipient mice receiving FTY720 treated cells were given FTY720 once orally by gavage (6 μg/animal) 2 h before transfer of labeled cells. Recipient mice receiving cells not treated with FTY720 were given vehicle only by gavage. 4 h after the transfer, LNs were obtained by dissection and the number of CD4⁺ CFSE stained T cells was determined by cell counting and flow cytometry. Mean values of six LNs from three animals are shown, error bars indicate SD.