Low-affinity immunoglobulin epsilon Fc receptor and Interleukin-2 receptor subunit alpha (CD23 and CD25)

CD23 (Low-affinity immunoglobulin epsilon Fc receptor) and CD25 (Interleukin-2 receptor subunit alpha) are distinct cell surface glycoproteins that serve as critical regulators of the immune system. CD23 is a C-type lectin primarily expressed on B-cells where it regulates IgE synthesis and B-cell growth, making it a target for treating allergic diseases and B-cell chronic lymphocytic leukemia (B-CLL) (UniProt P06734). CD25 is the alpha subunit of the high-affinity IL-2 receptor, expressed on activated T-cells and regulatory T-cells, and is essential for T-cell proliferation and immune homeostasis (UniProt P01589). In clinical practice, CD25 is targeted by monoclonal antibodies like basiliximab to prevent organ transplant rejection and treat certain lymphomas (PubMed: 10449219). CD23 has been targeted by experimental agents such as lumiliximab to induce apoptosis in malignant B-cells (PubMed: 15155838). Because these two proteins are distinct molecular entities with different biological roles, they are typically considered separate therapeutic targets, though their co-expression is often monitored as a biomarker for lymphocyte activation and hematologic malignancies (PubMed: 11033331).

Other names

FCER2IL2RACD23CD25Low-affinity IgE receptorInterleukin-2 receptor alpha chainp55TAC antigenLymphocyte IgE receptorFCE2

Drugs targeting CD23, such as lumiliximab, bind to the receptor on B-cells to inhibit IgE binding and induce cell death via apoptosis or antibody-dependent cellular cytotoxicity (ADCC). Drugs targeting CD25, such as basiliximab and daclizumab, act as IL-2 receptor antagonists by binding to the alpha subunit, which prevents IL-2 from binding to the high-affinity receptor complex, thereby blocking T-cell activation and proliferation.