Fig. 6.

Positive selection and functional testing of the DR^high+CD45RA^- T_reg subset. Magnetically isolated CD4⁺CD127^low+/−CD25⁺ T_reg were stained with anti-CD4, anti-CD25 and anti-human leucocyte antigen D-related (HLA-DR)-specific antibodies and sorted into a population of DR^high+CD45RA^- T_regs (a, R1) and into a population consisting of DR^low+CD45RA^-, DR^-CD45RA^- and naive DR^-CD45RA⁺ T_regs (a, R2). Subsequently, both T_reg populations obtained from three different subjects were analysed concerning their suppressive activity (b). The maximum suppressive activity (T_reg/T_resp = 1/1) and the minimum ratio of T_reg/T_resp (titre) with at least 15% suppression were increased strongly for the DR^high+CD45RA^- T_regs compared to the remaining T_regs (R2) (c).