# CD25 (IL-2 receptor alpha)

Source: https://onco.cc/targets/cd25/  
OnCo record `cd25` (Target). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

CD25 is the part of the interleukin-2 receptor found on activated T cells and on some lymphoma cells; denileukin diftitox uses it as a doorway to deliver a toxin.

## Summary

CD25, the alpha chain of the high-affinity interleukin-2 receptor (IL2RA), is expressed on activated T cells, regulatory T cells and the malignant cells of cutaneous T-cell lymphoma, adult T-cell leukaemia/lymphoma and some Hodgkin and B-cell lymphomas. Denileukin diftitox, a fusion of IL-2 with diphtheria toxin fragments, binds CD25-expressing cells and kills them by blocking protein synthesis; it was approved in 1999, withdrawn in 2014 for manufacturing reasons and reapproved as Lymphir in 2024 for relapsed or refractory stage I to III CTCL. Anti-CD25 antibodies (basiliximab, daclizumab) are used in transplantation and were studied in leukaemia and for regulatory T-cell depletion.

## Fields

- Kind: Target
- Last checked: 2026-09-10
- Tags: surface-antigen
- Symbol: IL2RA
- Class: surface-antigen
- Biology: CD25 confers high-affinity IL-2 binding; its density on regulatory T cells makes it a candidate for depleting immunosuppressive cells in the tumour microenvironment.
- Where found: Cutaneous T-cell lymphoma (about half of cases express CD25); Adult T-cell leukaemia/lymphoma; Hodgkin lymphoma (Reed-Sternberg cells)

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/IL2RA
- NCBI Gene IL2RA: https://www.ncbi.nlm.nih.gov/gene/3559

## Connected records

- cancers: [Hodgkin lymphoma](https://onco.cc/cancers/hodgkin-lymphoma/), [Peripheral T-cell lymphomas (including cutaneous T-cell lymphoma)](https://onco.cc/cancers/peripheral-t-cell-lymphoma/)
- drugs: [Denileukin diftitox](https://onco.cc/drugs/denileukin-diftitox/), [TAK-928](https://onco.cc/drugs/tak-928/)
- people: [Shimon Sakaguchi](https://onco.cc/people/shimon-sakaguchi/)

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JSON: https://onco.cc/api/v1/entities/cd25.json