Interleukin-2 Receptor Alpha (IL2RA), also known as CD25, is a receptor component that binds interleukin-2 (IL-2) and is crucial for T-cell activation, differentiation, and proliferation. IL2RA is expressed on the surface of activated T cells and regulatory T cells, and its expression is often used as a marker in studies of immune responses and autoimmune diseases. ELISA kits for IL2RA are used to measure its soluble form (sIL-2Rα) in biological samples, such as serum, plasma, and cell culture supernatants.

Overview of IL2RA ELISA Kits

• Purpose: To detect and quantify soluble IL2RA (sIL-2Rα) levels in biological fluids. This measurement is useful for research into immune responses, autoimmune diseases, and lymphoid malignancies.
• Assay Principle: Typically a sandwich ELISA. The assay involves capturing sIL-2Rα with a specific antibody coated on a microtiter plate, followed by detection with a secondary antibody conjugated to an enzyme (usually HRP). The enzymatic reaction produces a color change proportional to the amount of sIL-2Rα present in the sample.
• Sensitivity: High sensitivity, often in the picogram per milliliter (pg/mL) range, allowing detection of low levels of sIL-2Rα.
• Specificity: High specificity for sIL-2Rα, with minimal cross-reactivity with other cytokine receptors or proteins.
• Sample Volume: Typically requires 50-100 µL of sample per well.

Content of a Standard IL2RA ELISA Kit

• Microtiter Plate: Pre-coated with an anti-IL2RA antibody.
• Standards: Recombinant sIL-2Rα protein at various concentrations to generate a standard curve.
• Detection Antibody: Biotinylated or enzyme-conjugated anti-IL2RA antibody.
• Enzyme Conjugate: Typically streptavidin-HRP, used to amplify the signal generated by the detection antibody.
• Substrate Solution: Usually TMB (3,3',5,5'-Tetramethylbenzidine), which undergoes a colorimetric change upon reaction with HRP.
• Stop Solution: Often sulfuric acid, which halts the enzymatic reaction and stabilizes the color change.

Key Steps in the Assay Procedure

• Sample/Standard Addition: Standards and samples are added to wells coated with an anti-IL2RA antibody.
• Incubation: The plate is incubated to allow sIL-2Rα in the samples to bind to the capture antibody.
• Washing: Wells are washed to remove unbound components.
• Detection Antibody Addition: A detection antibody specific to sIL-2Rα is added, binding to the captured protein.
• Washing: Excess detection antibody is washed away.
• Enzyme Conjugate Addition: Enzyme-conjugated secondary antibody binds to the detection antibody.

Applications

• Research: Investigating immune system activation, T-cell regulation, and the role of IL2RA in autoimmune diseases such as multiple sclerosis, rheumatoid arthritis, and in lymphoid malignancies like leukemia and lymphoma.
• Clinical Diagnostics: Measuring sIL-2Rα levels can provide insights into immune activation and regulation, which may be relevant for diagnosing and monitoring autoimmune diseases and other immune-related conditions.

IL2RA ELISA kits are important tools for understanding the role of IL2RA in immune regulation and disease. They allow researchers and clinicians to measure sIL-2Rα levels, providing valuable information for both basic research and clinical applications in immunology.