Changes in CD8α/CD27 expression on proliferating T-helper cell subsets. (A) Violet proliferation dye-labelled CD4+CD8α-CD27+- (left panel; naïve), CD4+CD8α+CD27+- (middle panel; CD27+) and CD4+CD8α+CD27--sorted (right panel, CD27-) cells were stimulated with ConA/rhIL-2 in presence of 10% CD172a+ APCs for 4 days. Microcultures in Medium served as controls (embedded density plots). Four-colour FCM analysis was performed to analyse Violet-dye dilution (x-axes) versus CD8α and CD27 expression (y-axes) after four days of cultivation. See main text for description of arrow heads and numbers. Data of one representative animal is shown. Per sample at least 2 x 104 cells were recorded. (B) Percentage of naïve, CD27+ and CD27- sorted T helper cells that expressed CD8α (left graph, y-axis) and CD27 (right graph, y-axis) in relation to cell division (x-axes). Percent values of the respective cell generations were calculated by FlowJo software. The graphs show mean values + standard deviations of three animals tested in separate experiments.