Fig. 4

tPA activates CD4⁺ and CD8⁺, but not FoxP3⁺ T cells in vitro by a proteolytic mechanism. Splenocytes from naive mice were activated with anti-CD3 and anti-CD28 antibodies (both 1 μg/m) and treated in the indicated conditions for 4 days. a Proliferation estimated by observation under bright field binocular (left) and representative flow cytometry histograms for CFSE fluorescence (right), indicating the number of cells in proliferation state at the time of the experiment. Quantification of proliferation index (CFSE) and CD25⁺ MFI (as index of activation) for b, c CD4⁺ and d, e CD8⁺ (N = 4–9). f Quantification of proliferation index for FoxP3⁺ T cells (N = 3). Proliferation index are expressed as mean + SEM percentage vs control (Ctrl = 100% baseline). Activation is expressed as mean + SEM percentage of increase of CD25 MFI. g Quantification of CD4⁺/CCR6⁺ T and CD4⁺/CXCR3⁺ T cells (N = 4). b–g ^*P < 0.05, ^**P < 0.01, ^***P < 0.001 vs control. h–j Proliferation index of CD4⁺ and CD8⁺ T cells in the indicated treatment conditions. N = 5–9; ^*P < 0.05, ^**P < 0.01, ^***P < 0.001 vs control; ^#P < 0.05 vs tPA. k, l Cytokine measurements (percentage of control) in activated splenocytes treated in the indicated conditions (N = 4–7). ^*P < 0.05, ^**P < 0.01 vs control; ^#P < 0.05 vs tPA