Human PBMCs were stimulated with soluble anti-CD3+ anti-CD28, SEB, or PMA + ionomycin for 10 hours (protein secretion inhibitors were added during the last 8 hours). CD69 staining increased on almost all anti-CD3/CD28-and P+I-stimulated cells, and a subset of SEB-stimulated cells ( Figure 1A ). AR staining was increased, only in the CD69+ population, and this increase was most obvious in the P+I-stimulated cells. For all three stimulation conditions, the staining intensity for AR increased for the whole CD69+ population, i.e. separate positive and negative populations were not resolved, and so the percentage of cells in the AR+ gate may be an underestimate of the total number of cells expressing AR. The specificity of AR staining was demonstrated by using a control goat antiserum (right column). Similar results were obtained with CD8 T cells ( Figure 1A) .