Name: PE Human CD25 (IL-2Rα) Protein (C-Fc)
Brand: InnoCyto
SKU: 813001
Price: 245 USD
Availability: InStock

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PE Human CD25 (IL-2Rα) Protein (C-Fc)

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Cat #	Size	Price	Quantity
813001	25 ug	$245
813002	100 ug	$595

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Product Details

Application	Flow Cytometry
Format	Liquid, PE
Expression Host	CHO
Target Name	IL2RA, CD25, p55
Species	Human
Sources	Recombinant Human CD25 (Glu22-Cys213) with C-terminus Fc-tag is expressed in CHO cell and conjugated to PE.
Accession Number	P01589
Molecular Weight	The protein has a predicted molecular weight of 48.0 kDa. Under DTT-reducing conditions, it migrates at approximately 65 kDa on SDS-PAGE prior to conjugation.
Affinity Tag	C-Fc
Regulatory Status	RUO
Formulation	1xPBS buffer, pH7.4, 0.09% NaN3 with a carrier protein
Endotoxin level	Not tested
Protein Concentration	25µg size is bottled at 0.1mg/mL concentration. 100 µg size is bottled at lot specific concentration.
Storage and Handling	Briefly centrifuge the vial upon receipt. An unopened vial may be stored at 2–8°C for up to six months.
Research Areas	T cells, Tregs, T cell Activation, Adaptive Immunity, Autoimmunity, Cancer Marker, Dendritic cells

Background Information

CD25, also known as the interleukin-2 receptor alpha chain (IL-2Rα), is a transmembrane glycoprotein that plays a central role in regulating immune responses. It functions as part of the interleukin-2 (IL-2) receptor complex, which is essential for T cell proliferation, survival, and differentiation. CD25 itself has low affinity for IL-2 when expressed alone, but when combined with IL-2 receptor beta (CD122) and the common gamma chain (CD132), it forms the high-affinity IL-2 receptor complex capable of effective signal transduction.

Structurally, CD25 is a single-pass type I membrane protein composed of an extracellular domain of approximately 219 amino acids responsible for IL-2 binding, a hydrophobic transmembrane segment, and a short cytoplasmic tail that lacks intrinsic signaling domains. The extracellular region is heavily glycosylated, which stabilizes its conformation and facilitates ligand interaction. Because the alpha chain alone is not signaling-competent, it acts primarily to increase the receptor complex’s affinity for IL-2 and to expand the range of cells responsive to low cytokine concentrations.

CD25’s main ligand, IL-2, is a cytokine crucial for T lymphocyte expansion and immune tolerance. Engagement of IL-2 with the high-affinity receptor triggers the JAK-STAT signaling pathway, leading to cell proliferation, differentiation, and regulatory T cell (Treg) function. CD25 is constitutively expressed on Tregs and upregulated on activated CD4+ and CD8+ T cells, making it a marker of immune activation as well as immune regulation.

Aberrant CD25 expression or IL-2 signaling contributes to immune dysregulation and disease. In autoimmune disorders such as multiple sclerosis and type 1 diabetes, alterations in the IL-2/CD25 axis impair Treg function and tolerance mechanisms. Elevated CD25 expression is also found in certain malignancies, particularly adult T-cell leukemia/lymphoma and Hodgkin lymphoma, where it may serve as a biomarker of malignant proliferation. Moreover, soluble CD25, released from cell surfaces, can act as a decoy receptor, modulating IL-2 availability and contributing to immune suppression in cancer and chronic inflammation.

Therapeutically, CD25 is a prominent target for immune modulation. Monoclonal antibodies such as basiliximab and daclizumab have been developed to block IL-2 binding, preventing T cell activation and mitigating graft rejection in organ transplantation. Conversely, IL-2 or CD25-targeted therapies that enhance regulatory T cell function are being explored to treat autoimmune diseases and promote immune tolerance. Thus, CD25 remains a critical immunological node, balancing activation and regulation within the immune system.

Frequently Asked Questions

How is a fluorescence labeled recombinant protein different from a labeled antibody for the same target?

A labeled protein (e.g., a fluorescent ligand or receptor domain) binds its natural counter-receptor or binding partner directly, making it useful for functional binding assays, competition/blocking studies, and receptor occupancy measurements — whereas an antibody typically binds a specific epitope regardless of the protein's natural binding activity. Choose the labeled protein format when you need to assess biologically relevant binding interactions rather than simple target detection.

Can these proteins be used in flow cytometry, and are they compatible with other panel reagents?

Yes, fluorescence labeled proteins are commonly used in flow cytometry panels to detect receptor expression or ligand binding on live cells, and are designed to be compatible with standard antibody panels. As with any multicolor panel, confirm spectral compatibility and run proper compensation controls when combining labeled proteins with labeled antibodies.

What controls should I use with fluorescence labeled recombinant proteins?

Recommended controls include an unlabeled/unconjugated version of the same protein (for competition/blocking controls), an irrelevant labeled protein of the same conjugate as a background control, and standard unstained/FMO controls for gating. Species- or format-matched controls are noted on the product page where available.

What applications are these proteins validated for?

Common applications include receptor binding assays, flow cytometry-based ligand-receptor studies, ELISA-based detection, and blocking/competition assays to study receptor occupancy or antagonist activity. Specific validated applications and recommended usage concentrations vary by product and are detailed on the individual product page.

Have a product or application question? Consult our FAQs or contact us.

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