Bcl-2 downmodulation by CD4XL in PBMC is restricted to CD4⁺ T cells. Intracytoplasmic Bcl-2 staining was performed on day 3 in combination with surface CD8 and CD3 staining in the CD4XL-PBMC. Histograms representing the Bcl-2 expression in (CD3⁺CD8⁺, and CD3⁺CD8^-) gated populations are shown. The vertical line indicates the notch of the Bcl-2 downmodulation in CD3⁺CD8^- cells.