FIGURE 5.

PIM1 negatively regulates FOXP3-mediated transcriptional regulation. A, in vitro expanded primary Tregs were transduced with lentivirus delivering control shRNA (shCK) or shRNA targeting PIM1 (shPIM1) and then positively selected in the presence of puromycin for 3 days. Samples were harvested for real-time PCR to detect mRNA levels of PIM1, FOXP3, CD25, CTLA4, GITR, and IL-2. B, shCK or shPIM1 transduced human Tregs were coincubated with CFSE-labeled PBMCs at the indicated ratios for 3 days before detection of the proliferation status in the viable CD8⁺ T cell population by flow cytometry. C, percentages of suppression in each sample were analyzed. Data are mean ± S.E. of three separate experiments. **, p < 0.01; ns, not significant.