IL-2 & IL-15 Reporter HEK 293 Cells - CD25 high / CD122/CD132 low

Cell line description

HEK-Blue™ IL-2Rα/β/γ cells were generated by stable transfection of the human embryonic kidney HEK293 cell line with the genes encoding for the human CD25 (IL-2Rα), CD122 (IL-2Rβ), and CD132 (IL-2Rγ) subunits. These cells were engineered to express high levels of CD25 together with low levels of CD122 and CD132, enabling preferential detection of high-affinity IL-2 signaling. They also feature stable expression of human JAK3 and STAT5 to obtain a fully functional IL-2/IL-15 signaling pathway, as well as a STAT5-inducible secreted embryonic alkaline phosphatase (SEAP) reporter. The binding of IL-2 or IL-15 to their receptors triggers a signaling cascade leading to the activation of STAT5 and the subsequent production of SEAP. This can be readily assessed in the supernatant using QUANTI-Blue™ Solution, a SEAP detection reagent.

HEK-Blue™ IL-2Rα/β/γ cells strongly respond to human IL-2 and display lower responsiveness to IL-15, consistent with their high CD25 and low CD122/CD132 expression profile. Owing to their elevated CD25 expression, HEK-Blue™ IL-2Rα/β/γ cells are particularly suitable for evaluating CD25-targeted therapeutics, high-affinity IL-2 biologics, and CD25-dependent IL-2 signaling. They can also be used to assess IL-15 bioactivity and compare IL-2- and IL-15-induced STAT5 signaling in a high-CD25 receptor environment. In addition, these cells can be used to validate the functionality, potency, toxicity, and dose-dependent effects of IL-2- and IL-15-based biologics. 

IL-2 and IL-15 background

Interleukin-2 (IL-2) and interleukin-15 (IL-15) are closely related cytokines that play central roles in the regulation of innate and adaptive immune responses [1,2]. Both cytokines signal through receptor complexes containing the CD122 and CD132 subunits, while their biological specificity is conferred by distinct α receptor chains: CD25 (IL-2Rα) for IL-2 and CD215 (IL-15Rα) for IL-15 [1,3]. The incorporation of CD25 into the receptor complex generates the highest-affinity IL-2 receptor. This enables cells expressing elevated CD25 levels to respond efficiently to low concentrations of IL-2 [3,4].

The binding of IL-15 and IL-2 to their heterodimeric or heterotrimeric receptors activates JAK1/JAK3-STAT5 signaling together with the PI3K/AKT/mTOR and MAPK pathways, resulting in cellular responses such as proliferation, survival, differentiation, and immune effector functions [1,3]. IL-2 is a key regulator of activated T cells and regulatory T cells (Tregs), whereas IL-15 plays an important role in the development, maintenance, and activation of natural killer (NK) cells and memory CD8+ T cells [1,2].

Aberrant IL-2 and IL-15 signaling has been associated with T-cell large granular lymphocytic leukemia, cutaneous T-cell lymphoma, adult T-cell leukemia/lymphoma, multiple myeloma, celiac disease, rheumatoid arthritis, psoriasis, and inflammatory bowel disease, while CD25 overexpression has been reported in several hematological malignancies and solid tumors [1-4]. Consequently, IL-2-, IL-15-, and CD25-directed therapies are being actively developed for the treatment of cancer, autoimmune disorders, and chronic inflammatory diseases [1-4].

1. Sindaco P, et al., 2023. The role of interleukin-15 in the development and treatment of hematological malignancies. Front Immunol. 14:1141208
2. Propper DJ & Balkwill FR, 2022.  Harnessing cytokines and chemokines for cancer therapy. Nat. Rev. Clin. Oncol. 19:237-253.
3. Peng Y, et al., 2022. CD25: A potential tumor therapeutic target. Int J Cancer. 151:1617-1626.
4. Al Nasar M, et al., 2024. The T-Cell Growth Factor Interleukin-2, Which Is Occasionally Targeted by Autoantibodies, Qualifies as Drug for the Treatment of Allergy, Autoimmunity, and Cancer: Collegium Internationale Allergologicum (CIA) Update 2024. Int Arch Allergy Immunol. 185:286-300.