CD25 (Interleukin-2 Receptor Alfa Chain (IL2RA))

CD25 also known as Interleukin-2 receptor alfa chain (IL-2RA). This is the high-affinity component of the Interleukin-2 (IL-2) Receptor, which also includes CD122 (Interleukin-2 Receptor Subunit Beta Chain (IL2RB)) and the Interleukin-2 Receptor Gamma Chain (IL2RG). It is upregulated by activated T cells and is constitutively expressed by CD4 + CD25 + high CD45RA - CD45 RO + CD127 low HLA-DR - CD95 + CTLA4 + Ki67 + ICOS +/- FOXP3 + high Effector Regulatory T Cells
Murphy et al. 2022 W.W. Norton & Company ISBN 978-0-393-68093-5

CD25 (Interleukin-2 Receptor Alfa Chain (IL2RA)) is expressed on human Group 2 ILCs (ILC2) in blood, cord blood, tonsil, adenoid
Meininger et al. 2020 Trends in Immunology 41: 902

The constitutive high expression of CD25 is a key feature of Foxp3+ natural Treg cells
Sakaguchi et al. 1995 J Immunol 155(3): 1151-1164