(A) CD25^–CD4⁺ T cells from SKG mice were infected with retroviruses of mTAp63KD or nonsilencing (n.s. or NS) in Th17-polarizing conditions, and infected NGFR⁺ cells were sorted (TAp63KD SKG CD4⁺ T cells or n.s. SKG CD4⁺ T cells, respectively) and injected i.v. into SCID mice. Joint swelling was monitored twice a week for 50 days. (B) Changes in ankle thickness (left panel) or arthritis score (right panel) in mice transferred with NS SKG CD4⁺ T cells and TAp63KD SKG CD4⁺ T cells. Each symbol and vertical line represent the mean ± SEM. Data are compiled from 3 independent experiments (n = 7–8 each). *P < 0.05 by 2-way ANOVA. (C and D) Representative photograph of hind paw (C) and photomicrographs of ankle joints (D) of mice injected with PBS, NS SKG CD4⁺ T cells, or TAp63KD SKG CD4⁺ T cells. Scale bar: 100 μm. ***P < 0.001 by 1-way ANOVA followed by Tukey’s test. Histologic scores for the ankle joints of mice injected with PBS, NS SKG CD4⁺ T cells, or TAp63KD SKG CD4⁺ T cells. (E) Representative flow cytometric analyses of RORγt versus Foxp3 and the frequencies of Foxp3⁺ cells, RORγt⁺ cells, and Foxp3⁺RORγt⁺ cells of NGFR⁺CD4⁺ T cells, as well as the ratio of Foxp3⁺ to RORγt⁺ cells (right panel) in NGFR⁺CD4⁺ T cells at the timing of cell transfer. Data are reported as mean ± SEM. n = 5 (NS) and n = 4 (mTAp63KD). (F) Representative flow cytometric analyses of RORγt versus Foxp3 and the frequencies of Foxp3⁺ cells, RORγt⁺ cells, and Foxp3⁺RORγt⁺ cells of NGFR⁺CD4⁺ T cells, as well as the ratio of Foxp3⁺ to RORγt⁺ cells (right panel) in splenic NGFR⁺CD4⁺ T cells 14 days after the cell transfer. Data are reported as mean ± SEM. n = 4 (NS) and n = 6 (mTAp63KD). *P < 0.05 by unpaired t test.