Comparison of CD25⁺HLA-DR⁺ expression and CFSE^dim as measures for antigen-induced activation and regulation of T cells.

CFSE-labelled PBMC from 28 HIV-infected individuals were stimulated for 6 days with peptides encoding either HIV p24 consensus regions (HIV Ag) or a pool of commonly encountered non-HIV viral peptides (Non-HIV Ag). A. Co-expression of CD25 and HLA-DR on live CD8⁺CD3⁺ T cells on non-divided CFSE^high (left panel) and proliferated CFSE^dim T cells (right panel), showing excessive difference in fractions of CD25⁺HLA-DR⁺ in the activated subset to the right. B. Scatter plots of activation measured in the same culture by CFSE^dim or HLA-DR⁺CD25⁺, respectively, to non-HIV (+) and HIV antigen (□) within the CD8⁺ (left panel) and CD4⁺ (right panel) T cell subsets. Significant and high correlations obtained for both Non-HIV antigens (CD8⁺, r = 0.92, p<0.001: CD4⁺ r = 0.64, p<0.001) and HIV Gag p24 (CD8⁺, r = 0.90, p<0.001: CD4⁺ r = 0.71, p<0.001).