Anti-Mouse Galectin-9 (Clone RG9-1) – Purified in vivo PLATINUM™ Functional Grade

Clone RG9-1 is a rat-derived monoclonal antibody targeting mouse galectin-9, widely utilized in preclinical research for studying galectin-9's role in various biological processes. The antibody enables researchers to investigate the functional consequences of neutralizing endogenous galectin-9 activity in living mouse models.

Primary In Vivo Applications

Blockade Studies represent the most common application of RG9-1, where the antibody is administered to neutralize endogenous galectin-9 activity. This approach allows researchers to examine the consequences of galectin-9 inhibition across multiple physiological systems, including immune responses, inflammation, and tumor growth.

Cancer Immunotherapy Research has emerged as a particularly significant application area. The efficacy of galectin-9 blockade using RG9-1 has been investigated in several mouse cancer models. In pancreatic ductal adenocarcinoma models, blockade of galectin-9 slows tumor progression and extends mouse survival. Similarly, in mouse models of colon cancer and triple-negative breast cancer, galectin-9-neutralizing antibody combined with agonist antibodies to T-cell costimulatory receptors synergistically suppresses tumor growth and prolongs survival. These studies demonstrate RG9-1's potential as both a single agent and in combination therapies for cancer treatment.

Immune Response Modulation constitutes another key application, given that galectin-9 is expressed by numerous cell types including T cells, B cells, macrophages, dendritic cells, astrocytes, mast cells, eosinophils, fibroblasts, endothelial cells, and epithelial cells. The antibody has been reported to block some biological activities of galectin-9 when administered in vivo, making it valuable for dissecting immune regulatory mechanisms.

Technical Specifications for In Vivo Use

RG9-1 is manufactured specifically for in vivo applications with rigorous quality controls. The antibody maintains ultra-low endotoxin levels (≤ 0.5 EU/mg), high purity (≥95% by SDS-PAGE and ≥98% monomer by analytical SEC), and is produced in animal-free facilities using in vitro cell culture techniques. These specifications ensure minimal interference with experimental outcomes and protect mouse colonies from pathogen contamination, as the antibody is tested against the IDEXX IMPACT I Mouse Profile.

Commonly used antibodies or proteins co-studied with RG9-1 (an anti-mouse Galectin-9 antibody) include:

• PD-1 (Programmed cell death protein 1)
• TIM-3 (T cell immunoglobulin and mucin-domain containing-3)
• GITR (Glucocorticoid-induced TNFR-related protein)
• PD-L1 (Programmed death-ligand 1)
• Other galectins (such as Galectin-1 and Galectin-8), and various commercial Galectin-9 antibodies as controls or comparators.

These antibodies are often employed in mechanistic and therapeutic immunology studies, particularly to dissect immune checkpoint interactions and to evaluate combinatorial immunotherapies. Studies frequently use RG9-1 in combination with antibodies against PD-1, TIM-3, GITR, and PD-L1 either to evaluate synergistic effects on T cell activity or to benchmark Galectin-9 blockade against other checkpoint inhibitors.

In addition to these immune checkpoint molecules, some studies also analyze Galectin-9 interactions with a wider set of immune glycoprotein receptors, such as:

• VISTA
• 4-1BB
• DR3
• CD40
• CD44
• CD45
• TLR4
• CD206
• Dectin-1
• Protein disulfide isomerase (PDI)
• IgE
• On non-lymphoid cells: CD146, LAMP-2, and GLUT-2.

Alternative anti-Galectin-9 antibodies (e.g., clones Gal-Nab1, Gal-Nab2, 9M1-3, and RG9-35) are also frequently used as controls to compare specificity and blocking characteristics alongside RG9-1.

In summary, the most common proteins/antibodies used with RG9-1 are those targeting immune checkpoints (PD-1, TIM-3, GITR, PD-L1) and other galectin family members, with additional glycoproteins or checkpoint molecules included for broader immune profiling or functional analysis.

Key Findings from Clone RG9-1 in Scientific Literature

Clone RG9-1 is a rat monoclonal antibody specifically targeting mouse galectin-9 (Gal-9), widely used in research to block or detect Gal-9 activity in vivo. The most direct scientific findings related to RG9-1 come from its use as an experimental tool, rather than as a subject of molecular characterization itself—unlike human Gal-9 antibodies, which have been extensively profiled for binding specificity and function.

Functional and Experimental Use

• In Vivo Blockade of Galectin-9: RG9-1 is employed in mouse studies to neutralize Gal-9, a protein involved in immune regulation. For example, in a study investigating T-cell exhaustion, mice were injected intraperitoneally with 6 mg/kg of anti-galectin-9 (clone RG9-1) to assess the impact of Gal-9 blockade on T-cell function. This highlights its role as an in vivo functional grade reagent for interrogating Gal-9 biology.
• Specificity for Mouse Galectin-9: RG9-1 is explicitly cited as an anti-mouse Gal-9 antibody. It is not reported to cross-react with human Gal-9 or other galectin family members, distinguishing it from some human-specific Gal-9 antibodies which show no cross-reactivity with mouse Gal-9.
• Commercial Availability and Applications: RG9-1 is marketed for both detection and blockade of mouse Gal-9 in various experimental settings, reflecting its established utility in immunology research.

Contextual Findings from Related Literature

While RG9-1 itself is not the focus of molecular characterization in the available literature, studies using human Gal-9 antibodies (which do not cross-react with mouse Gal-9) provide important context about Gal-9’s biological role, which RG9-1 is used to explore:

• Galectin-9 in Immune Regulation: Gal-9 interacts with immune checkpoint receptors such as PD-1 and TIM-3 to regulate T-cell death and exhaustion, making it a target for cancer immunotherapy.
• Antibody-Mediated Inhibition: Neutralizing antibodies against Gal-9 (though not RG9-1 specifically) can protect T-cells from Gal-9-induced death, suggesting that blockade of Gal-9 (as achieved with RG9-1 in mice) could have immunomodulatory effects.

Notable Absences

• Detailed Mechanistic Studies: The available literature does not provide detailed mechanistic studies on RG9-1’s binding epitope, affinity, or in-depth functional assays similar to those performed for human Gal-9 antibodies.
• Clinical or Preclinical Efficacy Data: There are no published reports in the search results detailing therapeutic outcomes or extensive preclinical efficacy studies using RG9-1 in disease models.

Summary Table: Key Attributes of Clone RG9-1

Conclusion

Clone RG9-1 is a critical tool for studying mouse Gal-9 in vivo, enabling researchers to probe the protein’s role in immune regulation, particularly T-cell function. While it is well-established for these purposes, detailed molecular characterization and therapeutic efficacy data are not prominently featured in the currently available scientific literature. Its main value lies in its specificity for mouse Gal-9 and its utility in preclinical immunological research.

Dosing regimens of clone RG9-1 (anti-mouse Galectin-9) in mouse models vary depending on the disease context, experimental design, and desired pharmacodynamic effect, but published information is limited and not as extensive as for some other antibodies.

A published example reported administering RG9-1 at 6 mg/kg intraperitoneally (i.p.), 3 times per week, for 7 weeks in female C57BL/6 mice with leukemia models, which significantly delayed disease progression. This regimen offers a reference point for dosing in oncology-related mouse models.

Most commercial and antibody supplier resources describe product features, isotype, and formulation but state that users must optimize dosing per their specific model, as published, peer-reviewed consensus ranges are lacking specifically for RG9-1. In such cases, suppliers and protocol guides recommend starting with lower doses (for novel or less characterized antibodies like RG9-1), e.g., 100–200 μg per mouse i.p., with subsequent titration based on efficacy and tolerability. This approach aligns with general antibody dosing strategies in murine in vivo studies.

Key practical points:

• Route of administration: Most studies use i.p. injection, but i.v. is also possible depending on the model.
• Frequency and duration: 2–3 times per week is typical for immunomodulatory antibody regimens, with course length adjusted by disease model and study endpoints.
• Model considerations: The optimal dose may vary by mouse strain, age, disease type, tumor burden, and combination with other therapies.

In summary:

• Leukemia model (C57BL/6): 6 mg/kg, i.p., 3×/week, 7 weeks.
• General guidance: Start at low- to mid-range doses (e.g., 100–200 μg/mouse, i.p.) and titrate as needed based on tolerability and response.
• Critical need: Adjust and validate the dosing schedule in each new mouse model due to biological variability and limited cross-study standardization of RG9-1 regimens.

No broad consensus or standardized dosing schedule has been published across a wide range of mouse models for clone RG9-1. Individual studies should justify their regimens based on pilot data and the specifics of their disease context.