IL2RB (Ab-364) Antibody

What is IL2RB and why is phosphorylation at Y364 significant?

IL2RB (CD122) is the beta subunit of the interleukin-2 receptor complex that plays a crucial role in IL-2 signaling pathways. The protein functions as part of both the intermediate-affinity IL-2Rβγ receptor (expressed on resting T-cells and NK cells) and the high-affinity trimeric IL-2Rαβγ receptor (found on regulatory T cells and activated lymphocytes) .

Phosphorylation at tyrosine 364 (Y364) represents a critical event in the signal transduction cascade following IL-2 binding. When IL-2 engages with its receptor, it triggers phosphorylation at multiple tyrosine residues on IL2RB, with Y364 being particularly important for downstream activation of the STAT5 pathway . This phosphorylation event serves as a molecular switch that propagates signaling to regulate critical cellular processes including proliferation, differentiation, and cytokine production in immune effector cells. Monitoring Y364 phosphorylation provides a direct measurement of receptor activation status, making it valuable for studying IL-2 signaling dynamics in different experimental conditions.

What are the recommended experimental applications for the IL2RB (Ab-364) antibody?

The IL2RB (Ab-364) antibody has been validated for multiple experimental applications, with particular strength in the following techniques:

The antibody demonstrates robust reactivity against human, mouse, and rat samples, making it versatile for cross-species research applications . When designing experiments, researchers should consider that detection sensitivity may vary between applications, with Western blot typically providing the most definitive results for phosphorylation status assessment. Preliminary titration experiments are recommended to determine optimal antibody concentrations for specific experimental conditions.

How does the IL2RB phosphorylation state correlate with immune cell activation?

Phosphorylation of IL2RB at Y364 serves as a reliable marker of IL-2 receptor activation and correlates strongly with immune effector cell activation states. In resting lymphocytes, basal phosphorylation levels are typically low or undetectable. Upon IL-2 stimulation, rapid phosphorylation occurs within minutes, reaching peak levels at approximately 15-30 minutes post-stimulation before gradually declining.

The phosphorylation dynamics differ significantly between immune cell subsets:

• In CD8+ T cells, robust and sustained phosphorylation at Y364 correlates with proliferative responses and enhanced cytolytic activity .

• NK cells show rapid and potent IL2RB phosphorylation associated with increased cytokine production and target cell killing.

• Regulatory T cells (Tregs) exhibit distinct phosphorylation kinetics, often with more prolonged signaling due to higher expression of the high-affinity IL-2 receptor complex.

These differential phosphorylation patterns provide valuable insights into how IL-2 signaling diverges across immune cell populations, potentially explaining their distinct functional responses to this cytokine . Researchers can leverage these differences to investigate selective targeting of specific immune cell subsets through IL-2 receptor modulation.

What are the optimal sample preparation methods for detecting IL2RB phosphorylation?

Detection of phosphorylated IL2RB at Y364 requires careful sample preparation to preserve phosphorylation status while minimizing background. Follow these methodological guidelines:

• Cell lysis: Use phosphatase inhibitor-supplemented lysis buffers (containing sodium orthovanadate, sodium fluoride, and phosphatase inhibitor cocktails) to prevent dephosphorylation during processing.

• Timing considerations: Process samples rapidly as phosphorylation is transient and sensitive to experimental conditions.

• Stimulation protocols: For positive controls, freshly isolated peripheral blood mononuclear cells (PBMCs) should be stimulated with recombinant human IL-2 (50-100 ng/ml) for 15 minutes at 37°C.

• Protein quantification: Perform accurate protein quantification to ensure equal loading for comparative analyses.

• Storage: If immediate analysis is not possible, snap-freeze lysates in liquid nitrogen and store at -80°C, minimizing freeze-thaw cycles.

These precautions help maintain phosphorylation integrity and improve detection sensitivity, which is essential for accurate quantification of signaling events. Remember that phosphorylation states can rapidly change during sample handling, making swift processing crucial for reliable results .

How can IL2RB (Ab-364) antibody distinguish between IL-2 and other common gamma chain cytokine signaling?

The IL-2 receptor shares the common gamma chain (γc) with several other cytokine receptors including IL-4R, IL-7R, IL-9R, and IL-21R, creating potential challenges in distinguishing specific signaling pathways . The IL2RB (Ab-364) antibody offers specificity advantages for dissecting these pathways through several mechanisms:

• Selective recognition: The antibody specifically targets the phosphorylated Y364 residue on IL2RB, which is not present in other common gamma chain-associated receptors. Bispecific binding analyses confirm that the antibody does not cross-react with other common gamma chain partners .

• Comparison with STAT phosphorylation patterns: While multiple γc cytokines activate STAT5, the pattern and kinetics of IL2RB Y364 phosphorylation is distinctively associated with IL-2 signaling.

• Sequential immunoprecipitation: Researchers can perform sequential immunoprecipitation with IL2RB (Ab-364) followed by immunoblotting for other signaling components to delineate pathway-specific complexes.

To experimentally discriminate between IL-2 and other cytokine signals, researchers should design experiments including appropriate cytokine controls alongside specific receptor blockade approaches. The selective nature of the IL2RB (Ab-364) antibody makes it valuable for distinguishing IL-2-specific signaling events in complex experimental systems involving multiple cytokine stimuli .

What are the considerations for using phospho-IL2RB (Y364) antibody in comparison with bispecific IL-2R agonist antibodies?

Recent advances in immunotherapy have led to the development of bispecific antibodies that simultaneously target IL-2Rβ and IL-2Rγ to mimic IL-2 activity while avoiding preferential activation of regulatory T cells . When using phospho-IL2RB (Y364) antibody to study these novel therapeutics, several considerations are critical:

• Binding site competition: Some bispecific IL-2R agonist antibodies may bind at or near the Y364 region of IL2RB, potentially masking the epitope recognized by the phospho-specific antibody. Epitope mapping or sequential staining experiments should be conducted to assess potential interference.

• Differential phosphorylation kinetics: Bispecific agonists may induce phosphorylation patterns distinct from native IL-2. Research indicates that bispecific IL-2Rβγ antibodies can induce phosphorylation of STAT5 with varying EC50 values, some comparable to rhIL-2 (e.g., BsAb-1, BsAb-3, BsAb-4) .

• Cell type-specific responses: Document the differential responses across cell populations:

• Validation strategies: Use phospho-flow cytometry in parallel with Western blot analysis to correlate Y364 phosphorylation with downstream STAT5 activation when studying bispecific antibody effects .

The phospho-IL2RB (Y364) antibody serves as a valuable tool for characterizing the mechanistic activity of these bispecific agonists, helping researchers understand how their signaling properties compare to natural cytokine activity.

How does IL2RB Y364 phosphorylation contribute to different functional outcomes in immune cell subsets?

The phosphorylation of IL2RB at Y364 contributes to divergent functional outcomes across immune cell populations through differential coupling to downstream signaling networks. These differences help explain the pleiotropic effects of IL-2 in the immune system:

• CD8+ T cells: Y364 phosphorylation strongly activates the JAK-STAT5 pathway, promoting expression of genes associated with proliferation and cytolytic function. The phospho-flow cytometry data shows that bispecific IL-2Rβγ antibodies can stimulate STAT5 phosphorylation in CD8+ T cells with EC50 values comparable to rhIL-2 .

• NK cells: In these cells, Y364 phosphorylation couples more robustly to both STAT5 and MAP kinase pathways, enhancing cytotoxicity and IFN-γ production. Experimental data demonstrates that IL-2Rβγ bispecific antibodies induce dose-dependent increases in NK cell proliferation .

• Regulatory T cells: Despite lower expression of IL2RB compared to IL2RA, Y364 phosphorylation still occurs but links to different transcriptional programs supporting suppressive functions.

To experimentally investigate these differential outcomes, researchers can employ:

• Phospho-proteomics to map the complete signaling network activated downstream of Y364 in different cell types

• Chromatin immunoprecipitation to identify STAT5 binding sites following IL2RB activation

• Single-cell analysis correlating Y364 phosphorylation with functional outcomes

These approaches can reveal how the same phosphorylation event translates into context-dependent biological responses, providing insights for targeted immunomodulatory strategies.

What experimental approaches can validate IL2RB antibody specificity in complex biological samples?

Validating antibody specificity is crucial for reliable research outcomes. For the IL2RB (Ab-364) antibody, several complementary validation approaches are recommended:

• Phosphatase treatment controls: Treating parallel samples with lambda phosphatase before immunoblotting should eliminate the signal if the antibody is truly phospho-specific.

• Peptide competition assays: Pre-incubating the antibody with phosphorylated and non-phosphorylated peptides spanning the Y364 region can demonstrate binding specificity. Signal abolishment should only occur with the phospho-peptide.

• Genetic validation approaches:

  • CRISPR/Cas9-mediated introduction of Y364F mutation in the IL2RB gene

  • siRNA knockdown of IL2RB followed by reconstitution with wild-type or Y364F mutant

• Immunoprecipitation-mass spectrometry: Confirming that proteins pulled down by the antibody are indeed IL2RB through mass spectrometry analysis.

• Correlation with functional readouts: Demonstrating that Y364 phosphorylation correlates with downstream STAT5 phosphorylation and functional outcomes.

What are the optimal protocols for using IL2RB (Ab-364) antibody in Western blot analysis?

Western blot analysis is a primary application for detecting IL2RB Y364 phosphorylation. The following optimized protocol enhances detection sensitivity while minimizing background:

Sample Preparation:

• Stimulate cells with IL-2 (50-100 ng/ml) for 15 minutes to induce IL2RB phosphorylation

• Lyse cells in buffer containing 50 mM Tris-HCl (pH 7.4), 150 mM NaCl, 1% NP-40, 0.5% sodium deoxycholate, 0.1% SDS, 1 mM EDTA, supplemented with:

  • 1 mM sodium orthovanadate

  • 5 mM sodium fluoride

  • Phosphatase inhibitor cocktail

  • Protease inhibitor cocktail

• Clear lysates by centrifugation (14,000 × g, 15 min, 4°C)

Western Blot Procedure:

• Separate 20-40 μg protein on 8% SDS-PAGE gels (IL2RB has a calculated molecular weight of 61,117 Da)

• Transfer to PVDF membrane (wet transfer recommended)

• Block with 5% BSA in TBST (not milk, which contains phosphatases)

• Incubate with IL2RB (Ab-364) antibody at 1:1000 dilution in 5% BSA/TBST overnight at 4°C

• Wash membranes 4 × 5 min with TBST

• Incubate with HRP-conjugated anti-rabbit secondary antibody (1:5000) for 1 hour at room temperature

• Develop using enhanced chemiluminescence with exposure optimization

Critical Considerations:

• Include positive controls (IL-2 stimulated samples) and negative controls (unstimulated or phosphatase-treated samples)

• Stripping and reprobing with total IL2RB antibody allows normalization of phospho-signal to total protein

• For precious samples, consider multiplexing with different fluorescent secondary antibodies to detect both phosphorylated and total IL2RB simultaneously

This methodology has been validated to detect phosphorylated IL2RB from human, mouse, and rat samples with high specificity .

How should researchers optimize immunofluorescence protocols using this antibody?

Immunofluorescence (IF) applications with the IL2RB (Ab-364) antibody require specific optimization to preserve phospho-epitopes while achieving clean signal detection:

Cell Preparation:

• Culture cells on poly-L-lysine coated coverslips

• For stimulation experiments, treat with IL-2 (100 ng/ml) for 15 minutes

• Fix cells immediately with 4% paraformaldehyde (10 min, room temperature)

• Permeabilize with 0.2% Triton X-100 in PBS (10 min, room temperature)

Staining Procedure:

• Block with 5% normal goat serum plus 1% BSA in PBS (1 hour, room temperature)

• Incubate with IL2RB (Ab-364) antibody at 1:200 dilution in blocking buffer (overnight, 4°C)

• Wash 3 × 5 min with PBS

• Incubate with fluorophore-conjugated secondary antibody (1:500, 1 hour, room temperature, protected from light)

• Counterstain nuclei with DAPI (1 μg/ml, 5 min)

• Mount with anti-fade mounting medium

Advanced Optimization Strategies:

• Phospho-epitope preservation: Add phosphatase inhibitors (1 mM sodium orthovanadate, 5 mM NaF) to all buffers through the fixation and permeabilization steps

• Signal amplification: For weak signals, employ tyramide signal amplification

• Multiplexed detection: Combine with markers for cell type identification or activation status

• Controls: Include blocking peptide controls and non-stimulated samples

For tissue sections, additional antigen retrieval steps may be necessary, preferably using citrate buffer (pH 6.0) rather than EDTA-based buffers which may disrupt phospho-epitopes. When analyzing IF results, researchers should evaluate both signal intensity and subcellular localization, as receptor internalization following activation can alter distribution patterns .

What controls are essential when using IL2RB (Ab-364) antibody in experimental designs?

Rigorous control strategies are critical for generating reliable data with phospho-specific antibodies. When working with IL2RB (Ab-364) antibody, the following controls should be incorporated:

Essential Technical Controls:

• Phosphorylation state controls:

  • Positive control: Cells treated with IL-2 (50-100 ng/ml, 15 min)

  • Negative control: Unstimulated cells

  • Dephosphorylation control: Lysate treated with lambda phosphatase

• Antibody specificity controls:

  • Blocking peptide competition using phosphorylated peptide

  • Non-phosphorylated peptide competition (should not block signal)

  • Secondary antibody-only control

• Expression controls:

  • Cell lines with known IL2RB expression (e.g., NK-92 cells)

  • IL2RB-knockout or siRNA-treated cells

Biological Validation Controls:

• Signaling pathway controls:

  • JAK inhibitor treatment (e.g., Tofacitinib) should prevent IL2RB phosphorylation

  • Correlation with downstream STAT5 phosphorylation

• Cross-species validation:

  • The antibody reacts with human, mouse, and rat IL2RB , enabling validation across model systems

  • Species-specific positive controls should be included

• Cell-type specific controls:

  • NK cells (high IL2RB expression)

  • Resting T cells (intermediate expression)

  • Non-lymphoid cells (negative control)

Experimental Design Considerations:

Implementing these controls helps distinguish specific signals from background and artifacts, ensuring that observed IL2RB phosphorylation reflects genuine biological events rather than technical variables.

How should researchers interpret discrepancies between IL2RB phosphorylation and downstream STAT5 activation?

Discrepancies between IL2RB Y364 phosphorylation and downstream STAT5 activation may reflect important biological regulatory mechanisms rather than technical artifacts. Researchers should consider several potential explanations when encountering such inconsistencies:

• Temporal dynamics: IL2RB phosphorylation typically precedes STAT5 activation, with peak IL2RB phosphorylation occurring at approximately 5-15 minutes post-stimulation, while maximum STAT5 phosphorylation may take 15-30 minutes. Time-course experiments are essential for accurate correlation.

• Threshold effects: Partial IL2RB phosphorylation may be insufficient to trigger robust STAT5 activation, suggesting non-linear relationship between receptor phosphorylation and downstream signaling.

• Pathway cross-regulation: Other cytokine receptors or signaling molecules may impact STAT5 activation independently of IL2RB. For instance, bispecific IL-2Rβγ agonist antibodies showed variable STAT5 phosphorylation patterns across different bispecific formats despite targeting the same receptor complex .

• Negative regulators: Induction of SOCS proteins or activation of phosphatases may suppress STAT5 phosphorylation despite persistent IL2RB phosphorylation.

• Cell type-specific factors: The expression ratio between IL-2R subunits varies among cell types, with CD4+ T-cells showing approximately twofold higher expression of IL-2Rβγ than CD8+ T-cells, potentially affecting signaling efficiency .

To systematically address these discrepancies, researchers should:

• Perform detailed time-course experiments

• Analyze multiple nodes in the signaling pathway simultaneously

• Consider cell type-specific response patterns

• Investigate the role of negative regulators

These approaches can transform apparent discrepancies into insights about pathway regulation and cell type-specific signaling mechanisms.

What are common technical challenges with phospho-IL2RB detection and their solutions?

Phospho-specific detection presents unique technical challenges. Here are common issues encountered with IL2RB (Ab-364) antibody and their solutions:

Challenge 1: Weak or absent signal

• Potential causes: Rapid dephosphorylation, insufficient stimulation, low protein loading

• Solutions:

  • Enhance phosphatase inhibition (increase concentration or use alternative inhibitors)

  • Optimize stimulation conditions (increase IL-2 concentration to 100-200 ng/ml)

  • Increase antibody concentration (1:500 instead of 1:1000)

  • Use signal enhancement systems (HRP polymer detection)

  • Try alternative lysis buffers with stronger detergents

Challenge 2: High background

• Potential causes: Insufficient blocking, excessive antibody concentration, non-specific binding

• Solutions:

  • Increase blocking time (overnight at 4°C)

  • Use alternative blocking agents (5% BSA with 1% normal serum)

  • Reduce antibody concentration (1:2000 dilution)

  • Add 0.1% Tween-20 to antibody dilution buffer

  • Increase washing stringency (higher salt concentration in wash buffer)

Challenge 3: Multiple bands or unexpected band sizes

• Potential causes: Cross-reactivity, protein degradation, post-translational modifications

• Solutions:

  • Add protease inhibitors to prevent degradation

  • Validate with IL2RB knockdown controls

  • Use gradient gels to improve resolution

  • Compare with total IL2RB antibody pattern

  • Consider native vs. denatured conditions (some phospho-epitopes are conformation-sensitive)

Challenge 4: Poor reproducibility

• Potential causes: Variation in cell activation status, inconsistent sample handling

• Solutions:

  • Standardize cell culture conditions (density, passage number)

  • Establish consistent stimulation protocol (timing, temperature)

  • Prepare master mixes of antibody dilutions

  • Include internal normalization controls

  • Consider automated Western blot systems for consistency

The antibody has been validated for Western blot, immunofluorescence, and ELISA applications, but researchers should optimize conditions for their specific experimental systems to achieve optimal results .

How can IL2RB phosphorylation data be normalized for cross-experiment comparison?

Normalizing phospho-IL2RB data is essential for reliable cross-experiment comparisons. Implement these methodological approaches to enhance data consistency and interpretability:

1. Total protein normalization approaches:

• Total IL2RB normalization: Calculate the ratio of phospho-IL2RB to total IL2RB for each sample

• Loading control normalization: Use housekeeping proteins (β-actin, GAPDH) only when total IL2RB antibody is unavailable

• Total protein staining: Techniques like Ponceau S, SYPRO Ruby, or stain-free technology provide more reliable normalization than single housekeeping proteins

2. Internal reference sample strategies:

• Include a common "reference sample" (IL-2 stimulated PBMC lysate) across all experiments

• Express all experimental values as a percentage or fold change relative to this reference

• Prepare large batches of reference lysate, aliquot and store at -80°C

3. Quantification methodologies:

• Use digital imaging systems rather than film for wider dynamic range

• Apply local background subtraction for each lane

• Establish signal linearity by running a dilution series

• Consider using fluorescent secondary antibodies for more precise quantification

4. Statistical normalization approaches:

• For flow cytometry data, use median fluorescence intensity (MFI) rather than mean

• Calculate stimulation index: (Stimulated sample MFI) ÷ (Unstimulated sample MFI)

• For complex datasets, consider Z-score normalization to facilitate cross-experiment comparison

5. Experimental design considerations:

• Run time-matched controls for each experiment

• Include both technical and biological replicates

• Randomize sample order to avoid systematic bias

• Consider batch effects in analysis

By implementing these normalization strategies, researchers can generate more robust, reproducible, and comparable data sets across different experimental conditions, time points, and laboratory settings, enhancing both the internal validity and broader applicability of their findings.