PTGDR2 Antibody

What is PTGDR2 and why is it significant in immunological research?

PTGDR2 (Prostaglandin D2 Receptor 2) is a G-protein coupled receptor that serves as a recently identified receptor for prostaglandin D2 (PGD2), functioning alongside the classic prostaglandin D receptor. It is predominantly expressed on Th2 cells, eosinophils, basophils, and monocytes, mediating chemotaxis of these cells in response to PGD2. This receptor plays a key role in allergic responses and inflammation, making it significant for research in asthma, allergies, and inflammatory disorders. Interestingly, PTGDR2-null mice exhibited enhanced eosinophil recruitment in the lungs and increased production of interleukin-5 (IL-5) and IL-3, suggesting that PTGDR2 has a non-redundant role in restricting eosinophilia and allergic responses in vivo . Recent research has also revealed its importance in cancer biology, where it may exert anti-tumor effects, positioning it as a potential therapeutic target for various malignancies .

What are the key considerations when selecting a PTGDR2 antibody for research applications?

When selecting a PTGDR2 antibody, researchers should consider:

• Target specificity: Confirm the antibody recognizes your species of interest (human, mouse, etc.) and verify cross-reactivity data

• Clonality: Choose between polyclonal antibodies (recognizing multiple epitopes, offering signal amplification) and monoclonal antibodies (higher specificity for a single epitope)

• Application compatibility: Ensure the antibody is validated for your intended applications (WB, ELISA, IHC, flow cytometry)

• Epitope location: Consider whether the antibody targets the N-terminal, C-terminal, or internal regions, as this affects antibody performance in different applications

• Conjugation: Determine if you need unconjugated or conjugated (PE, FITC, etc.) versions based on your detection method

• Validation data: Review published literature and manufacturer data showing antibody performance in applications similar to yours

For optimal results in PTGDR2 research, antibodies targeting internal regions of human CD294 (PTGDR2) have demonstrated strong reliability in multiple applications .

How can PTGDR2 antibodies be effectively used to investigate inflammatory responses in allergic disease models?

To effectively study inflammatory responses in allergic disease models using PTGDR2 antibodies:

• Flow cytometry protocol: Use PE-conjugated anti-PTGDR2 antibodies at 1:100 dilution to quantify PTGDR2-expressing cells in bronchoalveolar lavage fluid (BALF) from asthma models. Include proper isotype controls and co-staining with CD4, CCR3, and CD63 to identify Th2 cells, eosinophils, and activated basophils respectively .

• Ex vivo chemotaxis assays: Isolate peripheral blood mononuclear cells (PBMCs) and use anti-PTGDR2 antibodies to track cellular migration in response to PGD2 gradients. Pre-incubate cells with PTGDR2 antagonists to confirm specificity of the response.

• Western blot analysis: Implement a protocol using anti-PTGDR2 antibodies at 1:500-1:2000 dilution to assess receptor expression levels across different tissues or in response to allergic stimuli .

• Immunohistochemistry optimization: For tissue sections from lung biopsies, use antigen retrieval (citrate buffer, pH 6.0) followed by overnight incubation with PTGDR2 antibodies to visualize receptor distribution in airways.

Research has shown that PTGDR2 activation causes early polarization of alveolar macrophages, leading to neutrophil recruitment and increased lung inflammation, while PTGDR2 antagonists can ameliorate allergen-induced skin, lung, and respiratory inflammation .

What are the recommended protocols for evaluating PTGDR2 expression in tumor samples using antibody-based techniques?

For evaluating PTGDR2 expression in tumor samples:

• Immunohistochemistry protocol:

  • Formalin-fixed paraffin-embedded (FFPE) sections: Perform heat-induced epitope retrieval

  • Block with 5% normal serum in PBS-T for 1 hour

  • Incubate with anti-PTGDR2 antibody (1:100-1:200) overnight at 4°C

  • Apply appropriate HRP-conjugated secondary antibody

  • Develop with DAB substrate and counterstain with hematoxylin

  • Score based on percentage of positive cells and staining intensity

• Western blot optimization:

  • Extract proteins using RIPA buffer with protease inhibitors

  • Load 30-50 μg protein per lane

  • Use anti-PTGDR2 antibody at 1:500-1:2000 dilution

  • Quantify expression relative to housekeeping proteins like β-actin

• Flow cytometry for dissociated tumor samples:

  • Create single-cell suspensions using appropriate tissue dissociation kits

  • Block Fc receptors and stain with fluorophore-conjugated PTGDR2 antibodies

  • Include markers for tumor cells and immune cell subsets to identify specific PTGDR2-expressing populations

Studies have shown that PTGDR2 expression in tumor samples may correlate with clinical parameters. In gastric cancer patients, PTGDR2 expression significantly correlated with lymph node metastasis, lymphovascular infiltration, and TNM stage. Furthermore, upregulation of PTGDR2 expression was associated with better prognosis .

How can PTGDR2 antibodies be utilized to investigate the PGD2/PTGDR2 signaling pathway in cancer progression?

To investigate the PGD2/PTGDR2 signaling pathway in cancer progression:

• Signaling pathway analysis protocol:

  • Treat cancer cell lines with PGD2 or PTGDR2-specific agonists/antagonists

  • Use phospho-specific antibodies alongside PTGDR2 antibodies to monitor changes in downstream signaling molecules:

    • STAT3 phosphorylation (Tyr705)

    • NF-κB pathway components

    • MAPK/ERK1/2 phosphorylation

    • Akt pathway activation

  • Perform co-immunoprecipitation with anti-PTGDR2 antibodies to identify binding partners

• Proliferation and migration assays:

  • Use PTGDR2 antibodies to confirm receptor expression before and after pathway manipulation

  • Correlate receptor levels with changes in proliferation (MTT/BrdU assays) and migration (wound healing/transwell assays)

• Gene expression analysis:

  • Perform PTGDR2 knockdown or overexpression followed by RNA-seq

  • Validate protein-level changes using PTGDR2 antibodies

  • Identify key affected pathways using pathway enrichment analysis

Recent research has demonstrated that PGD2 signaling through PTGDR2 can directly inhibit cancer cell survival, proliferation, and migration while reducing resistance toward conventional chemotherapeutic agents. The pathway's activity is mechanistically linked to inhibition of classical NF-κB signaling and KRAS, MAPK, ERK1/2, and Akt-mediated transcription factor signaling pathways .

What methodologies can be employed to study the interaction between PTGDR2 and STAT3 in immune cells using antibody-based approaches?

To study PTGDR2-STAT3 interactions in immune cells:

• Proximity ligation assay (PLA) protocol:

  • Fix and permeabilize isolated immune cells or tissue sections

  • Incubate with primary antibodies against PTGDR2 and STAT3/phospho-STAT3

  • Apply PLA probes and perform ligation and amplification steps

  • Analyze fluorescent signals indicating protein-protein proximity (<40 nm)

• Co-immunoprecipitation methodology:

  • Lyse cells in non-denaturing buffer (150 mM NaCl, 50 mM Tris-HCl pH 7.4, 1% NP-40)

  • Pre-clear lysates with protein A/G beads

  • Immunoprecipitate with anti-PTGDR2 antibodies

  • Analyze pulled-down complexes by Western blot for STAT3, JAK2, or IL-6R

• FRET/BRET analysis:

  • Generate fusion constructs of PTGDR2 and STAT3 with appropriate fluorophores

  • Express in relevant immune cell models

  • Measure energy transfer before and after PGD2 stimulation

• ChIP-seq following PTGDR2 activation:

  • Stimulate cells with PGD2

  • Perform chromatin immunoprecipitation with anti-STAT3 antibodies

  • Sequence bound DNA regions to identify altered transcriptional targets

Research has shown that PTGDR2 competitively binds STAT3, potentially interfering with IL-6R or JAK2 binding, which affects STAT3 phosphorylation levels and subsequent production of cytokines such as IFN-γ . Understanding this interaction is crucial for developing targeted therapies for inflammatory diseases and cancer.

What are the optimal fixation and antigen retrieval methods for PTGDR2 immunohistochemistry in different tissue types?

Optimal fixation and antigen retrieval methods for PTGDR2 immunohistochemistry vary by tissue type:

For frozen sections across all tissue types, acetone fixation for 10 minutes at -20°C followed by air drying provides adequate antigen preservation while maintaining PTGDR2 immunoreactivity. When troubleshooting, the most common issues include:

• False negatives: Often resolved by extending antigen retrieval time or using a combination of heat and enzymatic retrieval methods

• Background staining: Minimize by extending blocking steps (5% BSA in PBS with 0.3% Triton X-100) to 2 hours and including an avidin/biotin blocking step

• Membrane vs. cytoplasmic staining: PTGDR2 may show different localization patterns depending on cell activation state - use confocal microscopy to confirm

What strategies can address non-specific binding when using PTGDR2 antibodies in flow cytometry applications?

To address non-specific binding in flow cytometry with PTGDR2 antibodies:

• Optimized blocking protocol:

  • Incubate cells in 10% normal serum (from the species of secondary antibody) for 30 minutes

  • Add 5% BSA to blocking buffer to reduce hydrophobic interactions

  • Include 1-5% human AB serum when working with human samples to block Fc receptors

  • For mouse samples, use anti-CD16/CD32 (Fc block) antibodies at 1 μg per million cells

• Titration strategy:

  • Perform antibody titration experiments (typically 1:25 to 1:400 dilutions)

  • Calculate signal-to-noise ratio at each concentration

  • Select optimal concentration with highest specific signal and lowest background

• Validation controls:

  • Include fluorescence minus one (FMO) controls

  • Use isotype-matched control antibodies at identical concentrations

  • Include PTGDR2-negative cell populations as biological negative controls

  • For competitive blocking, pre-incubate antibody with immunizing peptide

• Buffer optimization:

  • Use buffers containing 0.1-0.5% saponin for intracellular PTGDR2 detection

  • Add 0.1% sodium azide to prevent antibody internalization during staining

  • Include 2 mM EDTA to prevent cell clumping

• Technical adjustments:

  • Reduce autofluorescence by including 1% Tween-20 in wash buffers

  • For fixed cells, use 50 mM NH₄Cl to quench aldehyde-induced fluorescence

  • Consider using Brilliant Violet or PE-conjugated antibodies for better signal separation

These strategies have been shown to significantly improve the specificity of PTGDR2 detection in complex immune cell populations, particularly in samples with high eosinophil content where autofluorescence can be problematic.

How should researchers interpret apparently contradictory findings regarding PTGDR2 function in inflammatory conditions versus cancer models?

Researchers should consider the following framework when interpreting contradictory findings about PTGDR2:

• Context-dependent signaling:

  • In allergic inflammation: PTGDR2 activation typically promotes Th2 cell, eosinophil, and basophil recruitment, contributing to allergic responses

  • In cancer biology: The same receptor exhibits apparent anti-tumor effects by inhibiting cell proliferation and migration

• Methodological analysis:

  • Examine differences in experimental models (cell lines vs. primary cells vs. in vivo models)

  • Assess antibody clone specificity – different antibodies may recognize distinct isoforms or conformational states

  • Consider the timing of analysis – PTGDR2 may have biphasic effects

• Molecular explanation framework:

  • PTGDR2 signaling affects multiple downstream pathways (STAT3, NF-κB, MAPK)

  • Cell-type specific expression of signaling partners may determine net outcome

  • PGD2 metabolites (like 15-d-PGJ2) may activate different receptors with opposing effects

• Reconciliation approach:

  • In inflammatory conditions: Initial PTGDR2 activation may promote inflammation, while sustained signaling may trigger resolution pathways

  • In cancer: PTGDR2 may inhibit tumor progression by modulating the tumor microenvironment and immune infiltration

Research has shown that PTGDR2 knockdown enhanced inflammatory responses in macrophages and increased mortality in bleomycin-induced pulmonary fibrosis models, suggesting anti-inflammatory functions . Simultaneously, in cancer studies, reduced PGD2 expression correlated with poor prognosis in gastric, breast, lung, and pancreatic cancers, suggesting anti-tumor activity . These apparently contradictory findings highlight the complex, context-dependent biology of PTGDR2 signaling.

What experimental design considerations are necessary when investigating the two known isoforms of PTGDR2 using antibody-based methods?

When investigating the two known isoforms of PTGDR2:

• Isoform-specific antibody selection:

  • Verify epitope mapping data from manufacturers to ensure recognition of specific isoforms

  • Use antibodies targeting unique regions of each isoform

  • Consider developing custom antibodies against isoform-specific junctions

• Comprehensive experimental design:

  • Implement Western blotting with high-resolution gels (10-12% acrylamide) to distinguish isoforms based on molecular weight differences

  • Include positive controls with recombinant proteins of each isoform

  • Use siRNA or CRISPR targeting isoform-specific sequences as validation controls

• RNA-level validation:

  • Design RT-PCR primers spanning unique exon junctions for each isoform

  • Perform qPCR to quantify relative expression of each isoform

  • Correlate protein detection with mRNA expression patterns

• Functional characterization protocol:

  • Compare ligand binding affinities between isoforms using competitive binding assays

  • Assess differential signaling by measuring cAMP levels, Ca²⁺ flux, and downstream phosphorylation events

  • Evaluate isoform-specific protein-protein interactions using proximity ligation assays

• Tissue and cell-type distribution mapping:

  • Create comprehensive expression maps of each isoform across tissues and cell types

  • Use flow cytometry with isoform-specific antibodies to quantify expression at single-cell level

  • Perform immunofluorescence co-localization studies to determine subcellular localization patterns

When interpreting results, consider that different PTGDR2 isoforms may have distinct signaling properties, subcellular localization patterns, and responses to ligands. For example, one isoform might preferentially couple to different G proteins or exhibit altered internalization kinetics. This could explain some of the context-dependent functions observed in different experimental models .

How can researchers integrate PTGDR2 antibody data with genomic and transcriptomic analyses for comprehensive pathway understanding?

To integrate PTGDR2 antibody data with genomic and transcriptomic analyses:

• Multi-omics integration protocol:

  • Perform parallel analyses on the same samples:

    • Protein expression: Quantitative Western blot/flow cytometry with PTGDR2 antibodies

    • mRNA expression: RNA-seq or qPCR for PTGDR2 and pathway components

    • Genomic analysis: WGS/WES to identify variants in PTGDR2 and related genes

  • Use computational tools (e.g., mixOmics, MultiPLIER) to correlate findings across platforms

• Correlation analysis methodology:

  • Calculate Pearson/Spearman correlations between PTGDR2 protein levels and expression of genes in STAT3, NF-κB, and MAPK pathways

  • Perform weighted gene co-expression network analysis (WGCNA) to identify gene modules correlated with PTGDR2 protein expression

  • Use these correlations to generate testable hypotheses about pathway interactions

• Functional validation approach:

  • Select top correlating genes for validation experiments

  • Perform siRNA knockdown or CRISPR knockout of these genes

  • Assess impact on PTGDR2 expression and signaling using antibody-based methods

  • Conduct reciprocal experiments (PTGDR2 manipulation followed by assessment of correlated genes)

• Pathway visualization and analysis:

  • Map integrated data onto pathway diagrams using tools like Cytoscape

  • Identify feedback loops and cross-talk with other signaling networks

  • Create interactive visualizations connecting genomic variants with protein expression changes

Researchers have used this approach to identify that in gastric cancer, PTGDR2 expression correlates with better prognosis and is associated with specific gene expression patterns. This integration of protein-level data with genomic and transcriptomic analyses has revealed that PTGDR2 signaling interacts with multiple pathways including STAT3, NF-κB, KRAS, and ERK1/2 , providing a more comprehensive understanding of its role in disease processes.