FIGURE 5.

PRMT5 is required for the proliferation of naïve T cells in response to TCR stimulation in vitro. CTV-labeled naïve CD8⁺ and CD4⁺ T cells from control and CD4^Cre PRMT5^fl/fl mice were stimulated for 3 d with anti-CD3 and anti-CD28-coated beads in the presence or absence of anti-IL-2 blocking antibody or IL-2, and analyzed by flow cytometry. (A) The frequency of live cells (Live/Dead near-IR^–) among CD8⁺ T cells (TCRβ⁺ CD8a⁺) and CD4⁺ T cells (TCRβ⁺ CD4⁺) is plotted as mean ± SEM. (B) The counts of live T cells are normalized to the initial (day 0) counts and plotted as mean ± SEM. (C) Representative plots show the dilution of CTV and expression of PRMT5. The CTV dilution of PRMT5^– cells among CD4^Cre PRMT5^fl/fl T cells were overlayed on the CTV dilution profile of control T cells. The data are representative of three independent experiments. *P < 0.05, **P < 0.01, ***P < 0.001, by unpaired two-tailed Student’s t-test. NS, not significant.