44713 Antibody

What is the 44713 Antibody and what epitope does it recognize?

The 44713 Antibody appears to be associated with research on EphA2, a receptor tyrosine kinase involved in cell-cell interactions and potentially tumor suppression. Based on available research information, this antibody likely targets specific epitopes on the EphA2 protein that mediate its adhesion-associated functions. Similar to other EphA2-targeting antibodies like EK166B or B2D6 mentioned in the literature, it may be used to investigate EphA2's role in cell adhesion and metastatic processes .

Research protocols involving this antibody would typically involve:

• Validation through Western blot showing expected molecular weight bands (~130 kDa for EphA2)

• Immunoprecipitation followed by mass spectrometry validation

• Immunofluorescence staining comparing staining patterns with other validated EphA2 antibodies

• Testing for cross-reactivity with other Eph family receptors

How should researchers validate the specificity of 44713 Antibody for experimental use?

Comprehensive validation of the 44713 Antibody requires multiple orthogonal approaches:

• Knockout/knockdown validation: Testing antibody reactivity in EphA2 knockout or knockdown cell lines compared to wild-type cells using Western blot and immunofluorescence.

• Peptide competition assay: Pre-incubating the antibody with purified EphA2 peptide or recombinant protein before application to samples. Loss of signal confirms specificity.

• Cross-platform validation: Confirming target recognition across multiple techniques:

  • Western blot for size-appropriate detection

  • Immunoprecipitation followed by mass spectrometry

  • Immunohistochemistry with proper controls

• Cross-reactivity testing: Evaluating binding to related proteins (e.g., other Eph family members) to establish specificity boundaries.

Similar antibodies in literature undergo rigorous validation protocols, as seen with the 2G4 antibody where researchers established standardized verification workflows including SDS-PAGE, direct and indirect immunofluorescence, and Western blotting to verify both purity and binding capacity .

How can 44713 Antibody be optimally used for detecting EphA2 in metastatic breast cancer samples?

For optimal detection of EphA2 in metastatic breast cancer samples, researchers should implement a multi-step protocol:

• Sample preparation optimization:

  • Fresh-frozen tissues: Standard lysis protocols with phosphatase inhibitors to preserve phosphorylation status

  • FFPE tissues: Antigen retrieval optimization (citrate buffer pH 6.0 typically works for EphA2)

  • Cell lines: Collection at optimal confluence (70-80%) to standardize EphA2 expression levels

• Titration and controls:

  • Perform detailed antibody titration using automated methods similar to those described for CytoFLEX LX systems

  • Include known EphA2-high (e.g., MDA-MB-231) and EphA2-low/negative cell lines as controls

  • Use phosphatase-treated samples as controls when assessing phosphorylation status

• Detection protocols:

  • Immunohistochemistry: Optimize DAB development time for discriminating between high and low expressors

  • Immunofluorescence: Implement dual staining with E-cadherin to assess correlations with cellular localization

  • Flow cytometry: Use dual-color confirmation approach with two different fluorochromes as described for other target-specific antibodies

• Quantification methods:

  • Implement H-score or Allred scoring for clinical samples

  • For research samples, quantify both intensity and subcellular localization

  • Correlate with phosphotyrosine content using parallel phospho-specific antibodies

Research by Kinch et al. demonstrates that subcellular localization and phosphorylation status of EphA2 are critically important parameters that should be monitored alongside total expression levels .

What are the recommended protocol modifications for using 44713 Antibody in phosphorylation status assessment?

When assessing EphA2 phosphorylation status using 44713 Antibody, specific protocol adjustments are essential:

• Sample preparation:

  • Use ice-cold lysis buffers containing phosphatase inhibitor cocktails (sodium orthovanadate, sodium fluoride, and phosphatase inhibitor cocktails)

  • Process samples rapidly to minimize dephosphorylation

  • Consider crosslinking protocols to stabilize phospho-epitopes

• Controls and validation:

  • Include EphA2 aggregation controls using clustering antibodies to induce phosphorylation as described in literature

  • Use lambda phosphatase-treated samples as negative controls

  • Include time-course experiments (0-60 minutes) following EphA2 activation

• Detection methods:

  • Western blot: Use dual detection with total EphA2 and phosphotyrosine-specific antibodies

  • Immunoprecipitate EphA2 first, then blot with anti-phosphotyrosine antibodies (PY20, 4G10)

  • Consider in vitro kinase assays with immunoprecipitated material to assess enzymatic activity

Research shows that EphA2 phosphorylation is significantly reduced in metastatic cells despite equivalent or higher enzymatic activity, highlighting the importance of examining both total and phosphorylated forms of the protein .

How should 44713 Antibody be titrated for optimal signal-to-noise ratio in various applications?

Antibody titration is critical for achieving optimal signal-to-noise ratios. For 44713 Antibody, implement the following systematic approach:

• Automated titration protocol:

  • Utilize automated liquid handlers like the Biomek i7 Multichannel workstation integrated with flow cytometry platforms for consistent results

  • Create a minimum 2-fold serial dilution series starting from manufacturer's recommended concentration (typically 5-10 μg/mL for Western blot and 1-5 μg/mL for immunofluorescence)

  • Test at least 6-8 different concentrations

• Application-specific considerations:

  Application	Recommended Dilution Range	Key Optimization Parameters
  Western Blot	1:500-1:5000	Blocking agent composition, incubation time
  IHC/IF	1:50-1:500	Antigen retrieval method, detection system
  Flow Cytometry	1:20-1:200	Fixation/permeabilization protocol
  ELISA	1:1000-1:10000	Coating buffer, incubation temperature

• Analysis methods:

  • Calculate Stain Index (SI) for each concentration using the formula: SI = (MFI positive - MFI negative) / (2 × SD of negative)

  • Plot SI versus antibody concentration to identify the inflection point where additional antibody no longer improves signal significantly

  • Select the concentration just prior to plateau for optimal cost-efficiency

• Validation across samples:

  • Test optimized concentration across multiple sample types (cell lines, tissues)

  • Verify results in samples with varying target expression levels

Automated approaches using integrated systems as described in CytoFLEX LX literature can significantly reduce experimental variability and improve reproducibility of antibody titration results .

What are the common causes of false positives when using 44713 Antibody, and how can they be mitigated?

Several factors can contribute to false positive results when using 44713 Antibody:

• Cross-reactivity issues:

  • With other Eph receptor family members due to structural homology

  • Mitigation: Include knockout/knockdown controls and peptide competition assays

  • Validate results with orthogonal detection methods

• Non-specific binding:

  • Fc receptor interactions on immune cells

  • Mitigation: Include Fc receptor blocking reagents before antibody application

  • Use appropriate isotype controls matched to 44713 Antibody

• Tissue/sample-specific artifacts:

  • Endogenous peroxidase activity in IHC

  • Mitigation: Implement peroxidase quenching steps

  • Include no-primary antibody controls for each tissue type

• Technical artifacts:

  • Inadequate blocking causing high background

  • Mitigation: Optimize blocking protocols (5% BSA or 10% serum from the species of secondary antibody)

  • Test multiple washing solutions and durations

• Epitope masking/unmasking:

  • Improper fixation altering epitope accessibility

  • Mitigation: Compare multiple fixation protocols

  • Optimize antigen retrieval methods (heat-induced vs. enzymatic)

Studies with similar antibodies demonstrate the importance of quality control workflows including purity assessment through SDS-PAGE with purity coefficients >0.8 and verification of binding specificity through multiple methods .

How should researchers interpret differences in EphA2 localization versus phosphorylation status when using 44713 Antibody?

Interpreting the relationship between EphA2 localization and phosphorylation requires sophisticated analysis:

• Integrated analysis approach:

  • Co-stain for EphA2 (using 44713 Antibody), phosphotyrosine content, and membrane markers (E-cadherin)

  • Implement quantitative co-localization analysis using Manders' or Pearson's coefficients

  • Correlate membrane localization with phosphorylation status

• Functional interpretation framework:

  • Membrane-localized, highly phosphorylated EphA2: Typical of non-neoplastic epithelial cells with intact cell-cell contacts

  • Cytoplasmic, poorly phosphorylated EphA2: Associated with metastatic phenotype

  • Differential localization without phosphorylation changes: May indicate alterations in trafficking rather than signaling

• Context-dependent analysis:

  • In confluent epithelial monolayers: Assess co-localization with E-cadherin at cell-cell junctions

  • In sparse cultures: Evaluate distribution between membrane ruffles versus internal compartments

  • In tissues: Compare distribution in relation to tissue architecture and cell polarity

Research indicates that proper EphA2 localization to cell-cell contacts enables interactions with ephrin ligands, promoting phosphorylation. Disrupted localization in metastatic cells correlates with reduced phosphorylation despite equivalent enzymatic activity .

What statistical approaches are most appropriate for quantifying EphA2 expression levels across different sample types?

When quantifying EphA2 expression across different sample types, researchers should employ these statistical approaches:

• Normalization strategies:

  • For Western blot: Normalize to loading controls (β-actin, GAPDH) and include a reference sample on each blot

  • For IHC/IF: Use tissue microarrays with control samples for batch normalization

  • For flow cytometry: Report data as median fluorescence intensity ratio over isotype control

• Appropriate statistical tests:

  • For comparing two groups: Student's t-test (parametric) or Mann-Whitney (non-parametric)

  • For multiple groups: ANOVA with appropriate post-hoc tests (Tukey, Bonferroni)

  • For correlating with clinical parameters: Cox regression for survival analysis

• Data visualization:

  • Box-and-whisker plots to show distribution across sample types

  • Scatter plots with mean ± SD for showing individual sample variation

  • Kaplan-Meier curves for relating expression to patient outcomes

• Advanced analyses:

  • Hierarchical clustering to identify patterns across multiple markers

  • Principal component analysis to reduce dimensionality of complex datasets

  • Machine learning approaches for integrating expression with other molecular features

When analyzing clinical specimens, immunohistochemical analyses should include scoring of multiple fields per sample, with clear criteria for positive versus negative staining and quantification of both intensity and percentage of positive cells .

How can 44713 Antibody be used to investigate the relationship between EphA2 and E-cadherin in metastatic progression?

Investigating the EphA2/E-cadherin relationship in metastasis requires sophisticated experimental approaches:

• Co-localization studies:

  • Perform dual immunofluorescence staining with 44713 Antibody and E-cadherin antibodies

  • Use super-resolution microscopy (STORM, STED) to visualize nanoscale interactions

  • Implement live-cell imaging to monitor dynamics of interaction during cell migration

• Protein-protein interaction analysis:

  • Co-immunoprecipitation with 44713 Antibody followed by E-cadherin detection

  • Proximity ligation assay (PLA) to visualize and quantify direct interactions in situ

  • FRET/FLIM microscopy to measure direct molecular interactions in living cells

• Functional studies:

  • Manipulate E-cadherin levels (knockdown/overexpression) and assess effects on EphA2 phosphorylation

  • Use calcium chelation to disrupt E-cadherin-mediated junctions and monitor EphA2 redistribution

  • Employ microfluidic devices to apply mechanical forces to cell-cell junctions while monitoring EphA2/E-cadherin dynamics

Research has demonstrated that EphA2 and E-cadherin show overlapping distribution at lateral membranes within sites of cell-cell contact, with E-cadherin potentially regulating EphA2 function . This relationship appears disrupted in metastatic cells, where altered localization correlates with reduced phosphorylation.

What approaches can be used to study EphA2 clustering and its impact on receptor activation when using 44713 Antibody?

EphA2 clustering is a critical mechanism regulating its activation. Researchers can investigate this using:

• Antibody-mediated clustering protocols:

  • Implement the two-step clustering approach using anti-EphA2 primary and secondary antibodies as described in literature

  • Monitor time-course of phosphorylation after clustering (0-60 minutes)

  • Compare effects of clustering with soluble versus membrane-bound ephrin ligands

• Advanced imaging approaches:

  • Single-particle tracking to monitor EphA2 diffusion and clustering dynamics

  • Quantum dot-labeled antibody fragments to visualize receptor nanoclusters

  • TIRF microscopy to visualize clustering events at the plasma membrane

• Biochemical assessment methods:

  • Blue native PAGE to preserve and analyze receptor complexes

  • Chemical crosslinking followed by immunoprecipitation to stabilize transient complexes

  • In vitro kinase assays with clustered versus monomeric receptors

• Functional correlation:

  • Monitor downstream signaling events after clustering (MAPK pathway, Rho GTPase activation)

  • Assess changes in cell behavior (adhesion, migration) following controlled receptor clustering

  • Compare clustering dynamics in non-metastatic versus metastatic cell models

Research shows that antibody-mediated clustering can restore phosphorylation of EphA2 in metastatic cells to levels comparable with non-neoplastic cells, highlighting the importance of receptor aggregation rather than simple antibody binding for activation .

How can researchers use 44713 Antibody for identifying and isolating EphA2-positive cells from heterogeneous populations?

For isolating EphA2-positive cells from heterogeneous populations:

• Flow cytometry-based isolation:

  • Implement dual antigen-specific labeling using two fluorochromes to reduce background, as recommended for rare cell isolation

  • Use viability dyes to exclude dead cells that often bind antibodies non-specifically

  • Establish clear positive/negative gating using FMO (Fluorescence Minus One) controls

  • Sort cells under conditions that maintain viability (low pressure, appropriate media)

• Magnetic separation techniques:

  • Conjugate 44713 Antibody to magnetic beads using commercial kits

  • Optimize antibody-to-bead ratio for highest specificity

  • Implement a two-step enrichment process with decreasing bead size for higher purity

• Validation of isolated populations:

  • Perform post-sort analysis for purity assessment

  • Validate EphA2 expression by Western blot or RT-PCR

  • Assess functional characteristics of isolated cells (migration, invasion, sphere formation)

• Single-cell applications:

  • Following sorting, perform single-cell RNA-seq to characterize transcriptional heterogeneity

  • Establish clonal derivatives to assess phenotypic stability

  • Trace lineages using genetic barcoding to monitor clonal dynamics

Similar approaches with antigen-specific cell isolation have shown ≥99% positivity in controlled systems, as demonstrated with Dsg3-specific hybridoma B cells using dual fluorochrome labeling .