IL 2r Antibody, FITC
Description
Definition and Target Specificity
IL-2R Antibody, FITC refers to monoclonal antibodies targeting specific subunits of the IL-2 receptor, conjugated to FITC for fluorescence-based detection. The IL-2R comprises three subunits:
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CD25/IL-2Rα (high-affinity subunit)
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CD122/IL-2Rβ (intermediate-affinity subunit)
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CD132/IL-2Rγ (common γ-chain shared with other cytokine receptors)
FITC-conjugated antibodies primarily target CD25 or CD122, enabling differentiation between cell populations expressing high-affinity (αβγ trimer) vs. low-affinity (βγ dimer) IL-2Rs .
Mechanism of Action
FITC-labeled IL-2R antibodies bind to extracellular epitopes of their target subunits, facilitating:
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Flow cytometry: Quantification of IL-2Rα⁺ regulatory T cells (Tregs) or activated lymphocytes .
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Receptor blocking: Some antibodies (e.g., JES6-5H4) partially inhibit IL-2 binding to CD25 or CD122, modulating downstream signaling .
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Dynamic studies: Intramolecular FRET assays using dual-labeled antibodies reveal conformational changes in IL-2Rα upon ligand binding .
Treg Expansion and Autoimmunity
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CD25-targeted complexes: IL-2/FITC-antibody complexes (e.g., UFKA-20) preferentially expand Tregs by stabilizing IL-2 binding to CD25⁺ cells, showing efficacy in type 1 diabetes and experimental autoimmune encephalomyelitis models .
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Therapeutic selectivity: Antibodies like F5111.2 reduce IL-2Rβ binding, enhancing Treg specificity while minimizing effector T cell activation .
Vaccine Adjuvant Effects
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Enhanced CD8⁺ T cell responses: IL-2/anti-IL-2 antibody complexes increase IFN-γ⁺ CD8⁺ T cells by 2-fold post-vaccination, though effects diminish within 12 days .
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Mechanistic insight: Complexes bypass Fc receptors, relying on CD122 binding for prolonged IL-2 half-life (143 hours vs. 2 hours for free IL-2) .
Technical Considerations
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Staining protocols: Optimal dilution ranges from 0.125 μg/10⁶ cells (mouse spleen) to 5 μL/100 μL whole blood .
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Cross-reactivity: Some antibodies (e.g., B1.49.9) react with non-human species, including mink and squirrel monkey .
Challenges and Limitations
Product Specs
Product Science Overview
The Mouse Anti-Human Interleukin-2 (IL-2) Receptor FITC is a monoclonal antibody that specifically targets the IL-2 receptor, also known as CD25. This antibody is conjugated with Fluorescein Isothiocyanate (FITC), a fluorescent dye, which allows for the detection and analysis of the IL-2 receptor on the surface of cells using flow cytometry.
The IL-2 receptor is a type I transmembrane glycoprotein that plays a crucial role in the immune response. It consists of three polypeptide chains: α (CD25), β (CD122), and γ (CD132). These chains can form different combinations to create receptors with varying affinities for IL-2:
- Low-affinity receptor: Composed of the α chain (CD25) alone.
- Intermediate-affinity receptor: Formed by the β and γ chains.
- High-affinity receptor: Consists of all three chains (α, β, and γ).
The high-affinity IL-2 receptor is primarily involved in intracellular signal transduction, which is essential for T-cell proliferation and differentiation .
CD25 is expressed on the surface of various immune cells, including:
- Activated T cells: Upon activation by antigens or mitogens, T cells upregulate CD25 expression.
- Regulatory T cells (Tregs): These cells constitutively express high levels of CD25 and play a key role in maintaining immune tolerance.
- Activated B cells and monocytes: CD25 expression can also be induced in these cells under certain conditions .
In normal peripheral blood, a variable percentage (approximately 3-25%) of lymphoid cells express CD25 .
The IL-2 receptor is critical for the immune system’s function. IL-2 binding to its receptor triggers a cascade of intracellular signaling events that lead to:
The expression of CD25 is tightly regulated and can be induced by various stimuli, including:
The Mouse Anti-Human IL-2 Receptor FITC antibody is widely used in research and clinical diagnostics. Its applications include:
