Purification of Tregs from human blood. Tregs were isolated using the CD4⁺CD25⁺CD127⁻ Treg isolation kit II magnetic MicroBead method (Miltenyi Biotec). The purity of human Tregs and phenotype expression was analyzed as follows: CD4⁺ cells were gated and analyzed for surface expression IL-7 receptorα chain (CD127) and IL-2 receptorα chain (CD25) and for intracellular expression of Foxp3.