A. (Top) USP44 transcript levels across CD4+ T cell populations. Suspension of the lymph node and spleen cells of 6-8 week old female C57BL/6 mice (n= 5 experiments) were obtained, and naïve (CD62Lhigh/CD25-) CD4+ T cells and nTregs (CD4+/CD25high) were obtained by FACS. The indicated effector T cell populations were generated by activating 1x10^6 naïve CD4+ T precursors with anti-CD3 and anti-CD28 antibodies (1 and 4 ug/ml, respectively) for 4 days under the indicated in vitro skewing conditions (described in the Methods section). After harvesting RNA by Trizol reagent and generating cDNA, the Usp44 mRNA levels expressed by the resulting Teff and iTreg, as well as freshly isolated nTreg cells were determined by qRT-PCR. (Bottom) Suspension of lymph node and spleen cells of 6-8 week old female C57BL/6 mice were obtained, and naïve (CD62LhighCD25-) CD4+ T cells and nTregs (CD4+/CD25high) were sorted by FACS. iTregs were generated by activating 1x10^6 naïve CD4+ T cells with anti-CD3 and anti-CD28 antibodies (1 and 4 ug/ml, respectively) for 4 days in the presence of IL-2 (100u/ml) and TGF-β (5ng/ml) before the cells were harvested for SDS-PAGE. Panels A and B depict the mean mRNA expression normalized to the housekeeping gene GAPDH. 