E. Expression of FOXP3 protein and mRNA by adoptively transferred Tregs. Mesenteric lymph nodes were excised from the recipients of WT and USP44-/- Tregs in A. FOXP3 protein was detected by intracellular immunostaining and flow cytometry (left). Shown are events within the gate for transferred Tregs (CD4+/CD45.1+). Transferred Tregs were also recovered from mesenteric lymph node cell suspensions by staining for the congenic marker and CD4 followed by FACS, and Foxp3 mRNA was measured in these recovered Tregs by RT-PCR (right). 