Kinetics of expression of different activation markers in human lymphoid tissue ex vivo. Tissues from 8 to 22 different donors were immunostained for different activation markers (CD69, CD25, and HLA-DR). The graphs represent the means (± SEM) of T cells expressing these markers at days 1, 6, 9, and 12 after the beginning of culture. Shown are the fractions of cells positive for CD25, CD69, and HLA-DR expression.