T-cell activation and cell division following mitogen stimulation. (A) Representative plots and (B) cumulative percentage of (top) CD25 expression, (middle) Ki67 expression, and (bottom) CFSE staining in CD4⁺ T cells from controls (solid gray) or CD3G patients (red) in unstimulated samples or following activation with PHA, anti-CD3, or anti-CD3/CD28. (C) Representative plots and (D) cumulative data for (top) CD25 expression, (middle) Ki67 expression, and (bottom) CFSE staining in CD8⁺ T cells from controls (solid gray) or patients (red) among the indicated groups. (A-D) Response to anti-CD3+anti-CD28 was studied in 5 patients (P1-P5) because not enough cells were available from P6. Dose titration curve of CFSE dilution among (E) CD4⁺ and (F) CD8⁺ T cells following stimulation with PHA (top) or anti-CD3 (bottom) for patient P6 (red line) and control sample (blue line). Unstim, unstimulated.