Anti-Mouse CD223 (LAG-3) [C9B7W] – Purified in vivo PLATINUM™ Functional Grade

Clone C9B7W is used in in vivo mouse studies to functionally block murine LAG-3 (CD223), thereby modulating immune responses, particularly T cell regulation and activation.

• Purpose: Clone C9B7W targets LAG-3 (CD223), a cell surface molecule expressed on activated T lymphocytes, NK cells, and T regulatory cells in mice. LAG-3 is a negative regulator of T cell activation and promotes T regulatory function, suppressing immune responses.

• Mechanism of Action in vivo: Administration of C9B7W in mouse models is reported to block the function of LAG-3, which can lead to enhanced T cell expansion and activation, making it useful for studying immunoregulatory pathways, tumor immunology, and therapies involving checkpoint blockade.

• Interactions: While C9B7W blocks LAG-3 function, it generally does not block LAG-3's binding to MHC class II molecules, its primary natural ligand. However, at least one study found that C9B7W abolished LAG-3 binding to MHC-II tetramers on certain cells, indicating possible variability depending on context or experimental system.

• Typical Applications:

  • Used in studies involving checkpoint inhibition (e.g., cancer immunotherapy research).
  • Sometimes combined with other inhibitors (like anti-PD-1 antibodies) to investigate synergistic effects on immune activation.
  • Can be administered in vivo to observe effects on T cell populations and immune suppression or activation dynamics.

• Antibody Formulation: Available as a rat IgG1 or chimeric mouse IgG2a for minimizing anti-drug antibody responses in mice, specifically designed for in vivo use.

• Dosing/Protocol Example: While precise dosing depends on experimental design, products are supplied in purified formulations suitable for direct in vivo injection.

• Caveats:

  • Does not block all LAG-3 functions (e.g., may not always block MHC-II binding); experimental context is important.
  • Used purely for research purposes.

In summary, C9B7W is a standard blocking antibody for murine LAG-3 in in vivo mouse studies, essential for dissecting immune checkpoint functions and testing new immunotherapies.

Based on the information available about the C9B7W clone antibody, the correct storage temperature depends on the duration of storage and the specific formulation.

Short-term Storage

For short-term storage (up to one week to one month), the antibody should be stored undiluted at 2-8°C. This temperature range maintains antibody stability and activity for immediate use applications.

Long-term Storage

For long-term storage, the antibody should be stored at -20°C in aliquots without diluting. This prevents degradation over extended periods while avoiding repeated freeze-thaw cycles that can damage the antibody structure.

Important Storage Considerations

The C9B7W clone requires specific handling precautions:

• Avoid repeated freeze-thaw cycles as these can cause protein denaturation and decreased antibody activity
• Store in the dark and protect from prolonged light exposure, particularly for fluorescent conjugates
• Do not freeze certain formulations, especially those with fluorescent labels like APC or Brilliant Violet conjugates
• Use a manual defrost freezer rather than frost-free freezers to avoid temperature fluctuations

Formulation-Specific Requirements

Different conjugates of the C9B7W clone may have varying storage requirements. For example, Ultra-LEAF formulations contain no preservatives and require aseptic handling, while standard formulations may contain sodium azide as a preservative. Always refer to the specific product datasheet as storage conditions may vary between manufacturers and formulations.

The shelf life is typically one year from the date of receipt when stored properly.

C9B7W is a widely used antibody specific for mouse LAG-3 (CD223), a negative regulator of T cell function. In the literature, researchers often use C9B7W in combination with other antibodies or proteins to characterize immune cell populations and investigate immune checkpoint pathways.

Commonly used antibodies and proteins with C9B7W include:

• CD3 antibodies: To identify T cells and study T cell activation.
• CD4 and CD8 antibodies: For discriminating helper and cytotoxic T cell subsets when analyzing LAG-3 expression, as LAG-3 is expressed on both populations.
• PD-1 and CTLA-4 antibodies: These are other major immune checkpoint molecules often investigated alongside LAG-3 to explore combinatorial checkpoint regulation.
• MHC class II (I-A/I-E) proteins: Used to study LAG-3's ligand interactions, since LAG-3 binds MHC class II with high affinity; in functional assays, recombinant MHCII tetramers are sometimes used.
• FGL1 (Fibrinogen-like protein 1): A more recently identified ligand for LAG-3, often included in functional or blockade assays with LAG-3 antibodies.
• NK1.1 antibodies: To identify and study LAG-3 expression on natural killer cell subsets.

These combinations are routinely employed in flow cytometry or functional blockade studies to comprehensively characterize immune inhibitory pathways, often within cancer, autoimmunity, or infection models.

When using C9B7W, published studies frequently incorporate panels that at a minimum include anti-CD3, anti-CD4, anti-CD8, and a second checkpoint marker (anti-PD-1 or anti-CTLA-4), sometimes along with MHCII tetramers or FGL1-Fc fusion proteins for ligand-binding/inhibition assays. The precise combination depends on the experimental context—e.g., T cell subset profiling, checkpoint blockade experiments, or studies of ligand-receptor engagement.

Clone C9B7W is a rat monoclonal antibody widely used in mouse immunology to study the inhibitory receptor LAG-3 (CD223). The key findings from citations referencing clone C9B7W in scientific literature are:

• Epitope Specificity: C9B7W recognizes an epitope within the D2 domain of murine LAG-3.
• Blocking Function: The antibody is reported to block the in vitro function of murine LAG-3, thus interfering with its immunoinhibitory role in T cells.
• Mechanism of Action: Although previously thought to block ligand (MHC II) binding, recent structural and functional studies show C9B7W does not directly block LAG-3’s binding to MHC II. Instead, it induces conformational changes or disrupts LAG-3 dimerization, thereby attenuating LAG-3 function. This disruption is sufficient to block downstream signaling mediated by LAG-3 ligand engagement, as shown in cell-based reporter assays.
• Functional Impact on T Cells: C9B7W administration potently impedes LAG-3’s inhibitory effects on T cell activation, supporting its utility as a functional LAG-3 inhibitor in mouse models.

Additional details:

• C9B7W’s inability to block MHC II binding distinguishes it from other clones (e.g., TKB58) that directly block the LAG-3/pMHC II interaction.
• C9B7W is useful for mapping LAG-3’s domains and dissecting the receptor’s role in regulating immune responses.
• It is commercially available and validated for various applications, including flow cytometry and in vitro functional assays.

In summary, clone C9B7W is a D2 domain-specific anti-LAG-3 antibody that disrupts LAG-3 dimerization, indirectly attenuates LAG-3 function, and does not block LAG-3/MHC II binding directly.