TS2 Antibody

What are the main types of TS2 antibodies used in immunological research?

The TS2 antibody family includes several important monoclonal antibodies used in immunological research, with the three most commonly used being:

• TS2/18 - Targets CD2 on T cells and inhibits T cell activation by binding to an epitope on the distal domain at amino acids 87-99

• TS2/16 - Targets CD29 (integrin beta 1) and possesses activating activity for beta 1 integrins

• TS2/4 - Binds to the alpha L subunit of integrins and is often used as a conformation-insensitive antibody that recognizes all LFA-1 molecules regardless of activation state

Each of these antibodies has distinct applications in studying cell adhesion, signal transduction, and lymphocyte function .

How do I determine which TS2 antibody is appropriate for my specific research question?

Selecting the appropriate TS2 antibody depends on your research target and experimental goal:

• Choose TS2/18 (anti-CD2) when investigating T cell activation mechanisms, cytokine synthesis inhibition, or CD2-mediated signaling pathways

• Select TS2/16 (anti-CD29) when studying integrin-mediated cell adhesion, beta 1 integrin activation, or extracellular matrix interactions

• Use TS2/4 (anti-integrin alpha L) when quantifying total LFA-1 expression regardless of conformational state or when a conformation-insensitive control is needed for studies of integrin activation

Consider the specific epitope recognition, functional effects (inhibitory vs. activating), and compatibility with your experimental system when making your selection .

What epitope does TS2/18 recognize on the CD2 molecule?

TS2/18 binds to an epitope located on the distal domain of the CD2 molecule specifically at amino acids 87-99. This specific epitope recognition is critical for understanding how TS2/18 exerts its inhibitory effects on T cell activation and cytokine synthesis. The epitope location has been confirmed through multiple studies and is considered a key functional region of CD2 involved in its signaling capabilities .

How does TS2/18 affect T cell function when used in experimental settings?

TS2/18 is a potent inhibitor of T cell cytokine synthesis. When added to T cells stimulated with CD2 monoclonal antibody pairs like OKT11-VIT13, TS2/18 efficiently blocks the induction of cytokine synthesis. Mechanistically, it inhibits increases in protein tyrosine phosphorylation and the accumulation of phosphatidic acid induced by either OKT11-VIT13 or cross-linked CD3 mAb. Additionally, TS2/18 disrupts CD2 clusters induced by OKT11-VIT13, suggesting it blocks cytokine synthesis by interfering with early signal transduction events, possibly by impairing the formation of signal-transducing molecular complexes on the T cell surface .

How can I use TS2/18 to investigate the role of CD2 clustering in T cell signaling pathways?

To investigate CD2 clustering using TS2/18, implement this experimental approach:

• Induce CD2 clustering using established CD2 mAb pairs like OKT11-VIT13 at 37°C

• Add TS2/18 (typically at 5-10 μg/ml) at different time points to determine when cluster disruption most impacts signaling

• Visualize cluster formation and disruption using confocal microscopy with fluorescently-labeled secondary antibodies

• Correlate cluster disruption with biochemical signaling events by analyzing protein tyrosine phosphorylation patterns

• Confirm specificity by comparing TS2/18's effects to isotype-matched control antibodies

• Use phosphospecific antibodies to identify which specific signaling molecules are affected by TS2/18-mediated cluster disruption

This approach allows for both spatial and temporal analysis of how CD2 clustering contributes to T cell activation .

What is the relationship between CD2 and anti-tumor immune responses, and how can TS2/18 be used to study this?

The CD2-CD58 interaction plays a significant role in anti-tumor immune responses. Research has shown that reduced CD58 signaling is associated with immune escape of tumor cells in various hematological and lymphoid malignancies, while restoration of this signal promotes an anti-tumor response. Additionally, following cytomegalovirus (CMV) infection, CD2's binding to upregulated CD58 on CMV-infected cells is crucial for the activation and function of adaptive NK cells in the anti-viral response.

TS2/18 can be used to study these interactions by:

• Blocking CD2-CD58 interactions in co-culture systems with tumor cells and immune effectors

• Examining how disruption of this axis affects cytotoxic activity and cytokine production

• Comparing TS2/18 blockade effects in different tumor types with varying CD58 expression levels

This research approach may reveal insights into potential therapeutic strategies for cancer immunotherapy .

What is the specificity and reactivity profile of the TS2/16 antibody?

The TS2/16 monoclonal antibody specifically reacts with human CD29 (integrin beta 1), an approximately 130 kDa single-pass transmembrane glycoprotein. It recognizes epitope A2 on the CD29 molecule. This antibody shows high specificity for human samples and has been validated for applications including:

• Flow cytometric analysis

• Immunoprecipitation

• Immunohistochemical staining of acetone-fixed frozen tissue sections

TS2/16 has notable functional activity as it possesses activating properties for beta 1 integrins, making it valuable not only for detection but also for functional studies of integrin-mediated processes .

How is TS2/16 typically used in flow cytometry experiments?

For flow cytometric analysis using TS2/16, the recommended procedure is:

• Use 5 μL (0.25 μg) of antibody per test, where a test is defined as staining a cell sample in a final volume of 100 μL

• Cell numbers can range from 10^5 to 10^8 cells per test, though optimal cell concentration should be determined empirically

• For fluorochrome-conjugated versions (like FITC-TS2/16), incubate cells with the antibody for 20-30 minutes at 4°C in buffer containing 1-2% serum proteins

• For unconjugated TS2/16, use a secondary detection antibody appropriate for the TS2/16 isotype

• The antibody works well for staining various cell types including lymphocytes and monocytes, with optimal performance in PBS buffer supplemented with 0.5-2% BSA

This approach provides reliable detection of CD29 expression across different cell types .

How can integrin activation be experimentally induced and measured using TS2/16?

To induce and measure integrin activation using TS2/16:

• Induction protocol: Incubate cells with 1/10 dilution of TS2/16 hybridoma supernatant (or 1-10 μg/ml purified antibody) for 10 minutes at 37°C before attachment assays

• Measuring activation: Compare cell adhesion to integrin ligands (e.g., fibronectin) between TS2/16-treated and untreated cells

• Quantification methods:

  • Adhesion assays using labeled cells (fluorescent or radioactive)

  • Analysis of focal adhesion formation using immunofluorescence microscopy

  • Measurement of downstream signaling events like FAK phosphorylation

For optimal results, pre-warm all reagents to 37°C, as temperature significantly impacts integrin conformational changes. Include controls like Mn²⁺ stimulation or DTT treatment for comparison with TS2/16-induced activation .

What experimental approaches should be used to differentiate between the activating effects of TS2/16 and physiological integrin activation mechanisms?

To differentiate between TS2/16-induced and physiological integrin activation, employ these experimental approaches:

• Perform side-by-side comparisons using physiological activators (Mn²⁺, DTT, activating mutations) alongside TS2/16 and measure binding to immobilized ligands

• Use FRET-based biosensors incorporating the integrin cytoplasmic domains to determine whether TS2/16 induces the same conformational changes as inside-out signaling

• Conduct binding studies with soluble ligands in the presence of TS2/16 versus physiological stimuli to assess affinity changes

• Apply point mutations in the integrin that specifically disrupt inside-out signaling to determine if TS2/16 can bypass these requirements

• Perform time-resolved studies comparing activation kinetics between TS2/16 and physiological stimuli like chemokines or growth factors

This approach will help distinguish between the external conformational changes induced by TS2/16 and the internal signaling cascades that drive physiological integrin activation .

What are the binding characteristics and applications of the TS2/4 antibody?

TS2/4 is a monoclonal antibody that binds to the alpha L subunit of human integrins (CD11a). Key characteristics include:

• It's conformation-insensitive, recognizing all LFA-1 molecules regardless of activation state

• Useful for quantifying total LFA-1 present on cells (typically ~27,000-34,000 sites per T cell)

• Binding is not significantly affected by divalent cations like Mg²⁺ or Mn²⁺

• Commonly used at 5-10 μg/ml for flow cytometry and immunostaining applications

• Available as a recombinant mouse monoclonal antibody with IgG2a isotype and kappa light chain

These properties make TS2/4 particularly valuable as a tool for assessing total integrin expression in various experimental contexts .

How does TS2/4 complement activation-specific antibodies in studies of integrin conformational changes?

In studies of integrin activation, TS2/4 is primarily used as a control antibody to determine the total amount of LFA-1 present, against which the binding of activation-dependent antibodies can be normalized. A typical experimental design includes:

• Staining cells with FITC-conjugated TS2/4 (10 μg/ml) for 20 minutes at 37°C to measure total LFA-1

• In parallel samples, staining with activation-dependent antibodies (like KIM127 or AL-57)

• Comparing binding before and after stimulation with activators such as PMA or chemokines

• Calculating the percentage of integrins activated by dividing the MFI or site number of activation-specific antibody by the TS2/4 signal

This approach revealed that only about 10% of total LFA-1 molecules become activated upon stimulation, as shown in this quantitative analysis:

This data demonstrates that activation-dependent epitopes are expressed on subpopulations of approximately 10% of total LFA-1 molecules on stimulated T cells .

What are the critical considerations for designing experiments to monitor the kinetics of integrin activation using TS2/4 and activation-specific antibodies?

When designing experiments to monitor integrin activation kinetics, consider these critical factors:

• Temporal resolution: For capturing rapid conformational changes, add activation-specific antibodies (e.g., AL-57 Fab-Alexa Fluor 488) 2 minutes before the end of stimulation time points

• Fixation protocol: Immediately fix cells in cold 2% formaldehyde after the stimulation period to capture the activation state at that precise moment

• Temperature control: Maintain consistent temperature (37°C) during stimulation as integrin activation is temperature-sensitive

• Stimulation conditions: For chemokines like CXCL-12, use 50-100 ng/ml in HBSS containing 2% glucose, 2% BSA, 1 mM MgCl₂, and 1 mM CaCl₂

• Antibody format: Use Fab fragments rather than whole IgG for activation-specific antibodies to prevent artificial clustering or activation

• Controls: Include both TS2/4 staining and appropriate isotype controls at each time point

This approach has revealed that integrin activation peaks within 2-5 minutes after chemokine stimulation and becomes undetectable after 10 minutes, demonstrating the transient nature of the conformational change .

How are TS2 antibodies used in studying tuberous sclerosis complex (TSC) pathophysiology?

Tuberous sclerosis complex (TSC) is caused by mutations in either the TSC1 or TSC2 genes. Anti-TSC2 antibodies are critical tools for studying this disorder:

• Protein detection: Anti-TSC2 antibodies like the one from R&D Systems (AF4040) can detect TSC2 protein in Western blots at approximately 200 kDa. These antibodies are typically used at 0.5-1 μg/mL concentration .

• Localization studies: TSC2 can be detected in tissue sections (e.g., human kidney) using immunohistochemistry protocols with anti-TSC2 antibodies at 3 μg/mL, revealing specific localization to epithelial cells .

• Functional studies: Research has shown that biallelic mutations in TSC2 lead to mTORC1 hyperactivation, which can be detected using phospho-specific antibodies against downstream targets like S6 (pS6 S240/244) and 4EBP1 (pS65 4EBP1) .

• Therapeutic assessment: Treatment with rapamycin reduces neuronal activity and partially reverses gene expression abnormalities in TSC2-mutant neurons, which can be monitored using anti-TSC2 antibodies in combination with functional assays .

What experimental approaches can distinguish between phenotypes caused by monoallelic versus biallelic TSC2 mutations?

Recent research has demonstrated important differences between cells with heterozygous (one functional allele) versus homozygous (no functional alleles) TSC2 mutations. To experimentally distinguish these phenotypes:

• Protein expression analysis: Use Western blotting with anti-TSC2 antibodies to quantify TSC2 protein levels, which will be reduced in heterozygous mutations and absent in homozygous mutations

• mTOR pathway activation: Measure phosphorylation of downstream targets (pS6, p4EBP1) using antibodies against these phospho-epitopes:

  • Anti-pS6 S240/244 (1:1000; Cell Signaling Technology)

  • Anti-S6 (1:200; Santa Cruz Biotechnology)

  • Anti-pS65 4EBP1 (1:1000, Cell Signaling)

  • Anti-4EBP1 (1:1000, Cell Signaling)

• Neuronal activity measurements: Studies have shown that only neurons with biallelic mutations of TSC2 demonstrate hyperactivity and transcriptional dysregulation observed in cortical tubers, while neurons with monoallelic mutations show only hypersynchrony .

• Rapamycin response: Compare the response to rapamycin treatment between heterozygous and homozygous mutants to determine therapeutic thresholds

This comprehensive approach helps distinguish between the cellular consequences of losing one versus both TSC2 alleles, which has implications for understanding tuberous sclerosis pathology .

What are common issues when using TS2/16 for integrin activation studies, and how can they be resolved?

When using TS2/16 for integrin activation studies, researchers may encounter several challenges:

• Inconsistent activation:

  • Problem: Variable levels of integrin activation between experiments

  • Solution: Standardize antibody concentration (1-10 μg/ml), incubation time (exactly 10 minutes), and temperature (precisely 37°C). Use fresh antibody preparations and avoid freeze-thaw cycles.

• High background adhesion:

  • Problem: Elevated baseline adhesion making activation effects difficult to detect

  • Solution: Reduce serum concentration during assays, use low-adhesion plates for controls, and include EDTA controls to determine integrin-independent adhesion.

• Cell type-dependent variability:

  • Problem: Different cell types respond differently to TS2/16 stimulation

  • Solution: Optimize antibody concentration for each cell type and consider the expression levels of different α-subunits that pair with β1 integrin.

• Antibody-induced clustering artifacts:

  • Problem: TS2/16 may cause artificial integrin clustering

  • Solution: Use Fab fragments instead of whole IgG molecules when studying native integrin distribution .

How can researchers distinguish between specific and non-specific effects when using TS2 antibodies in functional assays?

To distinguish between specific and non-specific effects when using TS2 antibodies:

• Appropriate controls:

  • Use isotype-matched control antibodies at the same concentration

  • Include F(ab')2 and Fab fragments to control for Fc receptor-mediated effects

  • Perform dose-response experiments to identify concentration-dependent effects

• Validation with multiple approaches:

  • Confirm antibody effects using genetic approaches (siRNA, CRISPR)

  • Use multiple antibodies targeting different epitopes of the same protein

  • Employ blocking peptides specific to the antibody epitope

• Specificity tests:

  • Pre-adsorb the antibody with recombinant target protein

  • Test the antibody on cells lacking the target protein

  • Use flow cytometry to confirm target binding before functional assays

• Statistical analysis:

  • Perform multiple independent experiments (n≥3)

  • Use appropriate statistical tests to determine significance of observed effects

  • Present data showing variability between experiments (standard deviation or standard error) .