Anti-Mouse TIGIT [Clone 1G9] — Purified in vivo PLATINUM™ Functional Grade

Clone 1G9 is a mouse monoclonal antibody directed against murine TIGIT (T-cell immunoreceptor with Ig and ITIM domains) and is widely used in in vivo mouse studies to functionally modulate TIGIT signaling, primarily as an agonist to reduce T cell-driven inflammation and disease severity.

Key Details on In Vivo Use:

• Functional Role: 1G9 acts as an agonistic antibody, mimicking the natural ligand (CD155) interaction with TIGIT, leading to inhibitory signaling in T cells. This results in the suppression of T cell responses and reduction of autoimmune pathology in mouse models.
• Experimental Application: In studies such as experimental autoimmune encephalomyelitis (EAE), an established mouse model for multiple sclerosis, administration of 1G9 has been demonstrated to significantly reduce disease severity by decreasing antigen-specific T cell responses and lowering the frequency of pro-inflammatory IL-17^+ Th17 cells in the central nervous system.
• Mechanism: Clone 1G9 blocks CD155 binding to TIGIT, indicating it competes with natural ligand binding and thus affects downstream signaling.
• Usage Formats: The antibody is formulated in a low-endotoxin, carrier-free format, suitable for intravenous or intraperitoneal injection in mouse models.
• Species-Specificity: Clone 1G9 is a mouse IgG1 antibody developed for cross-reactivity specifically with mouse TIGIT, ensuring minimal immunogenicity and compatibility in mouse in vivo experiments.

Additional Relevant Information:

• Typical administration routes include injection (i.p. or i.v.), with dosages dependent on experimental design (refer to individual studies or product datasheets for guidance).
• Besides in vivo use, clone 1G9 is also validated for flow cytometry and in vitro T cell/TIGIT functional assays.
• It does not deplete TIGIT^+ cells in vivo under steady-state conditions, making it suitable for studies focused on functional modulation rather than cell depletion.

In summary, clone 1G9 is primarily used as an agonistic anti-TIGIT antibody to suppress T cell activation and autoimmune disease in mouse models, through blockade of the CD155-TIGIT interaction and subsequent downstream modulation of immune responses.

The correct storage temperature for sterile packaged Clone 1G9 antibody is 2–8°C for up to one month. For longer-term storage, you should aliquot and store it at ? -70°C.

• At 2–8°C, the antibody remains stable for short periods (up to 1 month).
• For extended storage (longer than a month), aseptically aliquot the antibody without diluting and store at -70°C or lower.
• Avoid repeated freeze-thaw cycles, as they can degrade the antibody.

These guidelines are consistent with standard storage recommendations for monoclonal antibodies to maintain activity and sterility.

Commonly used antibodies or proteins in the literature alongside 1G9 depend on the specific 1G9 clone referenced, as several antibodies use this designation in different contexts. The most widely recognized usage in biomedical research refers to the GLP-1 (1G9) monoclonal antibody, which targets glucagon-like peptide-1 (GLP-1).

When studying GLP-1 using the 1G9 antibody, the following antibodies or proteins are commonly used together:

• Insulin antibodies: Since GLP-1 modulates insulin secretion and is involved in glucose metabolism, co-staining with insulin (to label pancreatic beta-cells) is very common in islet and pancreatic studies.
• Glucagon antibodies: Often used to distinguish alpha-cells (which secrete glucagon) from beta-cells in pancreatic tissue, providing spatial context in islet immunohistochemistry.
• Somatostatin antibodies: Used to label delta-cells in the pancreas, helping to define islet architecture alongside GLP-1.
• DAPI or other nuclear counterstains: Not antibodies, but commonly used to visualize nuclei for reference in tissue sections.
• Secondary antibodies: Conjugated to fluorophores or enzymes (e.g., HRP, Alexa Fluor), for the detection of mouse IgG (the isotype for 1G9), as part of indirect immunofluorescence or immunohistochemistry protocols.

Other frequently used proteins or markers in studies involving GLP-1:

• Actin or GAPDH antibodies: Common as internal loading controls for Western blotting experiments.
• Oxyntomodulin and other proglucagon-derived peptides: Used for differentiating peptide processing pathways, since GLP-1, glucagon, and oxyntomodulin are all proglucagon cleavage products.

If referring instead to the RS2-1G9 antibody, used in quorum sensing studies to target bacterial acyl-homoserine lactones (AHLs), researchers might also use:

• Anti-bacterial toxin antibodies: To study interactions between antibodies and various bacterial metabolites and toxins.
• Macrophage surface markers: Such as F4/80 or CD68, when investigating immune responses in conjunction with 1G9 in infection models.

Choice of ancillary antibodies or proteins ultimately depends on the experimental context (e.g., pancreatic biology, infection models).

Technical note: In all immunoassays, appropriate secondary antibodies (matching the host/isotype of 1G9) and internal controls (like actin in Western blot) are standard for validation and quantification purposes.

Key findings from scientific literature on clone 1G9 (an anti-TIGIT antibody) include its ability to modulate T cell responses and reduce autoimmune disease severity by acting as an agonistic antibody in vivo.

• Functional Effects on T Cells:

  • Clone 1G9 blocks the interaction between TIGIT and its ligand CD155 but does not deplete TIGIT+ cells under steady-state conditions.
  • In mouse models, 1G9 reduces antigen-specific T cell proliferation and decreases the secretion of pro-inflammatory cytokines IFN-? and IL-17 after immune challenge, though it is somewhat less potent than clone 4D4.
  • Unlike clone 1B4 (which increases proliferation and cytokine secretion), 1G9 and 4D4 appear to have agonistic effects on TIGIT signaling in vivo.

• Impact on Autoimmunity:

  • In an experimental autoimmune encephalomyelitis (EAE) model (a mouse model of multiple sclerosis), treatment with 1G9 reduces disease severity, similar to clone 4D4.
  • This beneficial effect is associated with reduced frequencies of IL-17+ Th17 cells infiltrating the central nervous system, indicating a dampening of pathogenic immune responses.

• Mechanistic Insights:

  • Despite differences in potency during recall T cell responses, 1G9’s species specificity provides advantages in chronic disease models compared to hamster-derived antibodies such as 4D4.
  • Modulation of T cell magnitude and cytokine profile by clone 1G9 translates into reduced inflammation and tissue damage in autoimmune settings.

• Comparison with Other Clones:

  • Clone 1G9 (agonistic) reduces disease and inflammation.
  • Clone 1B4 (blocking) exacerbates disease and increases Th17 cell infiltration.

These findings highlight 1G9’s potential utility for selectively regulating T cell-driven immune responses and mitigating autoimmune pathology via TIGIT agonism in vivo.