CD82 Antibody

What is CD82 and why is it an important research target?

CD82 is a member of the tetraspanin superfamily of proteins with a molecular mass of approximately 29.6 kilodaltons, although it typically migrates at 34-50 kDa in gel electrophoresis due to post-translational modifications like glycosylation . Originally identified as an accessory molecule in T-cell activation, its most well-characterized function is mediating integrin-dependent cell adhesion to extracellular matrix components . CD82 also functions as a metastasis suppressor in various cancers, regulates MMP9 activity, and plays crucial roles in hematopoietic stem/progenitor cell interactions with the bone marrow microenvironment . It represents an important target for understanding cancer metastasis, leukemia pathophysiology, and cellular adhesion mechanisms.

What are the primary applications for CD82 antibodies in research?

CD82 antibodies are employed across multiple experimental techniques in research settings:

• Western blotting for protein expression analysis and molecular weight determination

• Immunohistochemistry (IHC) for tissue localization studies

• Enzyme-linked immunosorbent assay (ELISA) for quantitative protein detection

• Flow cytometry for cell surface expression analysis and cell sorting

• Functional studies investigating cell adhesion, migration, and invasion

• In vivo applications such as mobilization of leukemic cells in animal models

The choice of application should dictate antibody selection, as different epitope recognition patterns exist among various commercial antibodies .

What expression patterns does CD82 typically show in human tissues?

CD82 demonstrates distinct expression patterns across different tissues and cell types:

This diverse expression pattern highlights CD82's tissue-specific roles and suggests careful consideration when interpreting experimental results from different tissue sources.

How do different CD82 antibody epitopes affect experimental outcomes?

The epitope recognition pattern of CD82 antibodies critically influences experimental results and interpretations . Research has demonstrated that antibodies recognizing different epitopes can detect distinct forms of CD82:

• Antibodies targeting the large extracellular loop (amino acids 17-82 and 84-242), such as TS82b, can detect both standard (75-100 kDa) and truncated (37-50 kDa) forms of CD82

• Antibodies targeting the C-terminus (amino acid 250 to C-terminus), like Abcam ab66400, only detect the standard form but not the truncated variant lacking an intact C-terminus

This distinction is biologically significant as truncated CD82 forms have been associated with invasive metastasis and poor clinical outcomes . Researchers should carefully select antibodies based on the specific CD82 domains they wish to investigate and validate detection of the appropriate isoforms in their experimental system.

What are the mechanisms behind CD82's observed migration pattern discrepancies in Western blotting?

The discrepancy between CD82's predicted molecular weight (29-30 kDa) and its observed migration pattern (34-100 kDa) in Western blotting results from several factors :

• Post-translational modifications: CD82 contains multiple glycosylation sites that significantly increase its apparent molecular weight

• Protein isoforms: Full-length versus truncated variants of CD82 migrate at different molecular weights (75-100 kDa versus 37-50 kDa)

• Sample preparation conditions: Reducing versus non-reducing conditions affect migration patterns

• Tissue-specific modifications: CD82 from different tissues may undergo distinct post-translational modifications

For accurate interpretation, researchers should:

• Include deglycosylation treatments (such as PNGase F) to assess contribution of glycosylation

• Use multiple antibodies targeting different epitopes to distinguish between isoforms

• Compare migration patterns across multiple tissue types to understand tissue-specific variations

• Include appropriate positive and negative controls from validated sources

How should researchers approach contradictory findings regarding CD82 function across different experimental systems?

CD82 functional studies have yielded seemingly contradictory results across different experimental systems, requiring careful methodological considerations for resolution :

• Cellular context sensitivity: CD82 functions differently in hematopoietic cells versus epithelial cells; for example, it enhances adhesion in acute myelogenous leukemia cells while potentially suppressing adhesion in certain carcinoma cells

• Isoform-specific effects: Truncated versus full-length CD82 exhibit divergent functions, with truncated forms potentially lacking metastasis suppressor activity

• Molecular interaction network variations: CD82 regulates S100 family proteins in certain contexts but may not in others

• Antibody selection impacts: Different antibodies targeting distinct epitopes may neutralize specific functions while sparing others

To reconcile contradictory findings, researchers should:

• Explicitly define the cellular context of their experiments

• Characterize the specific CD82 isoforms present in their experimental system

• Employ multiple complementary techniques (genetic manipulation and antibody-based approaches)

• Validate key findings using in vivo models when possible

What are the optimal methods for generating CD82 knockout models for antibody validation studies?

Generating effective CD82 knockout models requires careful methodological consideration :

• CRISPR/Cas9 approach: Offers precise gene editing but requires specific guide RNA design targeting conserved CD82 exons across potential isoforms

• Flow cytometry-based sorting: While convenient for isolating CD82-negative populations, this method (as noted in research) may result in mixed populations with varying degrees of CD82 expression

• Single-cell clone isolation: Essential for establishing homogeneous CD82-knockout cell lines with consistent phenotypes; research has demonstrated more pronounced effects in single-cell derived CD82-knockout lines compared to mixed populations

• Validation requirements:

  • Confirm knockout at both protein level (using multiple antibodies targeting different epitopes) and mRNA level (RT-PCR)

  • Assess potential compensatory expression of other tetraspanin family members

  • Functionally validate the knockout through appropriate phenotypic assays

Research indicates that single-cell derived knockout lines provide more reliable and pronounced phenotypes for antibody validation studies compared to mixed populations .

What are the critical controls needed when using CD82 antibodies in immunohistochemistry studies?

Immunohistochemistry studies using CD82 antibodies require rigorous control implementation :

• Negative controls:

  • Omission of primary antibody while maintaining all other steps of the protocol

  • Isotype-matched control antibodies

  • Tissues known to lack CD82 expression (validated independently)

  • CD82 knockout tissues or cells (when available)

• Positive controls:

  • Human tonsil tissue (shows distinct membrane staining of follicular dendritic cells)

  • Placental tissues at appropriate developmental stages (showing known CD82 expression patterns)

  • Cell lines with confirmed CD82 expression

• Protocol validation elements:

  • Antigen retrieval optimization (e.g., CC1 Cell Conditioning Buffer with standard retrieval program)

  • Blocking steps (3% H₂O₂, 4 min, 37°C)

  • Antibody concentration titration (starting with 1:50 to 1:80 dilution)

  • Secondary antibody validation (e.g., Dako swine anti-rabbit at 1:50, 28 min, 37°C)

  • Signal amplification systems (e.g., Streptavidin ABC system)

• Cross-species reactivity assessment:

  • Determine whether the antibody cross-reacts with murine CD82 for animal model studies

  • Western blot analysis comparing human and animal CD82 detection

How should CD82 antibodies be validated for functional blockade studies?

When using CD82 antibodies for functional blockade studies, comprehensive validation is essential :

• Epitope characterization:

  • Verify which domain of CD82 is recognized (extracellular loop vs. C-terminus)

  • Confirm antibody binding to native protein using flow cytometry or microscopy

• Functional validation assays:

  • Cell adhesion assays (CD82 mediates adhesion to fibronectin via VLA-4)

  • Migration/invasion assays (CD82 typically inhibits these processes)

  • Matrix metalloproteinase 9 (MMP9) activity assays (CD82 inhibits MMP9)

  • CXCR4 expression analysis (CD82 positively regulates CXCR4)

• Dose-response relationships:

  • Establish effective concentrations for in vitro studies

  • Determine appropriate dosages for in vivo applications (e.g., 1 μg for mouse studies)

• Time-course experiments:

  • Characterize temporal dynamics of functional blockade

  • Monitor duration of effect (e.g., CD82 mAb mobilization peaks at 3 hours and returns to baseline by 6 hours post-injection)

• Cross-validation with genetic approaches:

  • Compare antibody blockade effects with CD82 knockdown/knockout phenotypes

  • Rescue experiments using CD82 overexpression

How can CD82 antibodies be utilized in developing therapeutic strategies for acute myelogenous leukemia?

CD82 antibodies show promising therapeutic potential for acute myelogenous leukemia (AML) treatment based on key research findings :

• Mobilization mechanism: CD82 antibodies mobilize CD34+ leukemia cells from the bone marrow microenvironment into peripheral blood, making them more accessible to chemotherapeutic agents

• Combinatorial therapy approach:

  • CD82 monoclonal antibody (mAb) combined with cytarabine (AraC) significantly prolonged survival in mice-bearing human AML cells compared to either agent alone

  • This synergistic effect suggests a unique therapeutic strategy combining mobilizing agents with conventional chemotherapy

• Molecular pathway interactions:

  • CD82 positively regulates CXCR4 expression (blocking CD82 may affect CXCR4-mediated bone marrow retention)

  • CD82 supports CD34+/CD38− AML cell survival via the IL-10/STAT5 signaling pathway

  • CD82 inhibits matrix metalloproteinase 9 (MMP9), which is involved in leukemic cell mobility

• Model system translation considerations:

  • Humanized AML murine models show transient (3-hour peak) mobilization of CD34+ leukemia cells following CD82 mAb treatment

  • Optimal timing of chemotherapy administration should coincide with peak mobilization periods

• Dosage optimization requirements:

  • Low-dose CD82 mAb might be insufficient for anti-leukemic effects as a monotherapy

  • Higher doses or optimized scheduling may enhance therapeutic efficacy

What is the significance of truncated CD82 detection in cancer research and how can antibodies help identify these variants?

Truncated CD82 variants have emerging significance in cancer research with important implications for diagnosis and prognosis :

• Biological significance:

  • Truncated CD82 proteins lacking intact C-terminus correlate with invasive metastasis and poor patient outcomes

  • The 37-50 kDa truncated CD82 variant may lack the metastasis suppressor function associated with full-length CD82

• Detection strategy using complementary antibodies:

  • Antibodies recognizing the large extracellular loop (e.g., TS82b targeting amino acids 17-82 and 84-242) detect both full-length and truncated variants

  • C-terminus-specific antibodies (e.g., ab66400 targeting amino acid 250 to C-terminus) detect only the full-length protein

  • Using both antibody types enables discrimination between variants

• Experimental validation approach:

  • Western blotting with and without deglycosylation treatment (PNGase F)

  • Comparison of banding patterns between different antibodies

  • Correlation with functional assays (migration, invasion)

• Clinical correlation analysis:

  • Patient samples showing only truncated CD82 may indicate poorer prognosis

  • Ratio of truncated to full-length CD82 may serve as a potential biomarker

• Cancer type considerations:

  • Initially observed in squamous cell carcinoma (SCC)

  • Further investigation needed to determine if this mechanism generalizes across other cancer types

How do CD82 antibodies help elucidate the relationship between CD82 and S100 family proteins in cancer biology?

CD82 antibodies have been instrumental in uncovering the relationship between CD82 and S100 family proteins, with significant implications for cancer biology :

• Expression correlation findings:

  • Research using CD82 antibodies in immunoblotting and immunohistochemistry demonstrated that CD82 expression positively correlates with S100 family members (S100A7, S100A7A, S100A6, S100A8, and S100A9)

  • CD82 knockout models confirmed that loss of CD82 leads to significant downregulation of these S100 proteins

• Functional relationship assessment:

  • S100 proteins are calcium-binding proteins involved in cellular processes including proliferation, differentiation, and migration

  • CD82 may regulate S100 protein expression, potentially affecting downstream cellular processes

  • This relationship has implications for understanding cancer cell migration and invasion

• Methodological approaches using antibodies:

  • Real-time PCR combined with Western blotting using CD82 antibodies to correlate mRNA and protein expression levels

  • CD82 knockout models validated with antibodies to confirm complete protein ablation

  • Immunohistochemistry to assess co-localization patterns

• Cancer type considerations:

  • The CD82-S100 relationship has been observed in squamous cell carcinoma

  • Further research needed to establish if this relationship exists in other cancer types

• Therapeutic implications:

  • The CD82-S100 axis may represent a novel therapeutic target

  • Monitoring both CD82 and S100 proteins may provide more comprehensive prognostic information

What are the optimal protocols for detecting CD82 in Western blotting applications?

Optimized Western blotting protocols for CD82 detection require careful attention to several technical factors :

• Sample preparation considerations:

  • Reducing conditions are necessary for proper denaturation

  • Include protease inhibitors to prevent degradation

  • Consider deglycosylation treatments (PNGase F) to resolve glycosylation-dependent migration patterns

• Gel selection and running conditions:

  • 10-12% SDS-PAGE gels provide optimal resolution for CD82 (29-100 kDa range)

  • Use gradient gels when detecting both truncated and full-length variants simultaneously

• Antibody selection strategy:

  • For detecting all CD82 forms: use antibodies targeting the large extracellular loop (e.g., TS82b)

  • For full-length CD82 specific detection: use C-terminus-specific antibodies (e.g., ab66400)

  • Recommended starting concentration: 1 μg/mL for most applications

• Expected band patterns:

  • Predicted molecular weight: 29 kDa

  • Observed molecular weights:

    • Full-length glycosylated: 75-100 kDa

    • Truncated glycosylated: 37-50 kDa

    • Deglycosylated: closer to 34 kDa

• Optimization considerations:

  • Blocking: 3% BSA in TBST generally provides better results than milk-based blockers

  • Secondary antibody: HRP-conjugated anti-rabbit IgG (1:3000 dilution)

  • Exposure time: Start with 2 minutes and adjust as needed

What tissue processing techniques yield optimal results for CD82 immunohistochemistry?

Optimal tissue processing for CD82 immunohistochemistry involves several critical steps :

• Fixation protocol:

  • Formaldehyde fixation has been validated for CD82 detection

  • Fixation time should be optimized (typically 12-24 hours) to preserve epitope integrity

• Antigen retrieval methods:

  • Heat-mediated antigen retrieval is essential

  • CC1 Cell Conditioning Buffer using standard retrieval program shows good results

  • pH considerations: slightly alkaline conditions (pH 8-9) often improve signal

• Blocking steps:

  • Peroxidase blocking (3% H₂O₂, 4 min, 37°C)

  • Protein blocking to reduce nonspecific binding

  • Blocking duration and temperature optimization improves signal-to-noise ratio

• Antibody incubation parameters:

  • Primary antibody dilutions: 1:50 to 1:80 provide optimal results

  • Incubation time and temperature: 1 hour at 37°C works well

  • Secondary antibody: Dako swine anti-rabbit (1:50, 28 min, 37°C)

• Detection system selection:

  • Streptavidin ABC system (16 min, 37°C) provides good signal amplification

  • DAB as chromogen offers stable staining with good contrast

  • Consider signal amplification for tissues with low CD82 expression