Anti-Mouse GM-CSF – Purified in vivo PLATINUM™ Functional Grade

Common In Vivo Applications of Clone MP1-22E9 in Mice

Clone MP1-22E9 is a rat monoclonal antibody specific for mouse granulocyte-macrophage colony-stimulating factor (GM-CSF), also known as colony stimulating factor 2 (CSF2). Its primary in vivo application in mice is as a potent neutralizing agent to block the biological activity of GM-CSF, a cytokine involved in the proliferation, differentiation, and activation of granulocytes, monocytes, and macrophages.

Key In Vivo Uses

• GM-CSF Neutralization: The antibody is widely used to neutralize endogenous mouse GM-CSF in vivo, allowing researchers to study the role of GM-CSF in inflammatory, autoimmune, and infectious disease models. By blocking GM-CSF activity, scientists can assess the cytokine’s contribution to disease pathogenesis, immune cell recruitment, and tissue homeostasis.
• Disease Model Studies: MP1-22E9 has been employed in models of experimental autoimmune encephalomyelitis (EAE), arthritis, and other conditions where GM-CSF signaling is implicated. This helps delineate the specific contributions of GM-CSF to disease progression and immune regulation.
• Functional In Vivo Blockade: The antibody is often administered via intraperitoneal or intravenous injection, and its efficacy in vivo is supported by its high purity and low endotoxin content, which is critical for minimizing nonspecific immune activation in animal studies.

Typical Experimental Design

• Dosing: The antibody is usually administered at concentrations sufficient to achieve systemic neutralization of GM-CSF, with protocols depending on the specific experiment and disease model.
• Combination with Other Tools: While primarily used for in vivo neutralization, MP1-22E9 can also be paired with other antibodies (e.g., biotinylated detection antibodies) for ex vivo analysis of GM-CSF levels in biological samples using ELISA or ELISpot.
• Controls: Proper isotype controls (rat IgG2a) are recommended to confirm specificity of effects observed in vivo.

Summary Table

In summary, clone MP1-22E9 is most commonly used in mice for in vivo neutralization of GM-CSF to investigate the cytokine's physiological and pathological roles, particularly in models of inflammation and autoimmunity. Its high specificity and suitability for in vivo administration make it a valuable tool for dissecting GM-CSF biology in the whole organism.

The most commonly used companion antibody with MP1-22E9 is the biotinylated MP1-31G6 antibody, particularly in sandwich ELISA and ELISPOT assays, where MP1-22E9 acts as the capture antibody and MP1-31G6 serves as the detection antibody.

Other proteins and reagents frequently used with MP1-22E9 include:

• Recombinant mouse GM-CSF as the standard protein for ELISA calibration and assay validation.
• Isotype controls such as Rat IgG2a-LE/AF or Rat IgG2a-UNLB for specificity assessment in flow cytometry and other assays.
• Fluorochrome-conjugated versions of MP1-22E9 (e.g., PE, BV421) for intracellular flow cytometry staining of GM-CSF-producing cells.

MP1-22E9 is applied across multiple assay platforms:

• ELISA (sandwich/capture or detection)
• ELISPOT
• Flow cytometry (intracellular staining)
• Immunohistochemistry of frozen sections
• Immunocytochemistry
• Western blotting
• Neutralization and bioassays for GM-CSF activity.

In summary, biotinylated MP1-31G6 for detection and recombinant GM-CSF as a standard are the principal reagents paired with MP1-22E9 in published protocols and commercial literature, with the specific format or conjugate of MP1-22E9 selected based on the application.

The MP1-22E9 antibody clone has been extensively utilized in scientific research to study GM-CSF biology and its role in various disease contexts. This neutralizing antibody against mouse GM-CSF has generated significant findings across multiple areas of investigation.

GM-CSF's Role in Inflammatory Disease

Research using MP1-22E9 has revealed critical insights into GM-CSF-mediated inflammatory pathways. Studies have demonstrated that GM-CSF drives dysregulated hematopoietic stem cell activity and promotes extramedullary myelopoiesis, leading to tissue-toxic neutrophil accumulation in target organs. The antibody has proven valuable both as a prophylactic and therapeutic intervention in these contexts.

In arthritis research, the clone has helped establish that NK cell-derived GM-CSF potentiates inflammatory arthritis. Specifically, synovial NK cells propagate antibody-mediated joint inflammation through GM-CSF production following IL-18 activation, highlighting a previously underappreciated cellular source of this inflammatory cytokine.

Neutralization and Functional Characterization

The MP1-22E9 clone has been instrumental in defining GM-CSF bioactivity thresholds. Functional studies show that at concentrations of 1.25 µg/mL, the antibody inhibits 50% of the biological effects produced by 1 ng/mL mouse GM-CSF in MC/9 cell proliferation assays. This precise neutralization capacity has made it a standard tool for blocking GM-CSF signaling in experimental models.

SARS-CoV-2 and Respiratory Disease

Emerging research has documented elevated GM-CSF levels in SARS-CoV-2 infected patients with acute respiratory distress syndrome. The availability of effective neutralizing antibodies like MP1-22E9 has facilitated experimental studies examining GM-CSF's contribution to COVID-19 pathology. Additionally, studies using GM-CSF knockout mice—validated using this antibody—have revealed that absence of GM-CSF or its receptor leads to pulmonary alveolar proteinosis.

Technical Applications

Beyond disease modeling, MP1-22E9 has established standardized protocols for GM-CSF detection and quantification. The clone serves as the capture antibody in sandwich ELISAs at optimal concentrations of 1-4 µg/mL, typically paired with biotinylated MP1-31G6 for detection. These methodologies have become widely adopted for measuring colony-stimulating factor expression in various experimental contexts.

The extensive citation record demonstrates MP1-22E9's value as both a research tool for mechanistic studies and a therapeutic intervention in preclinical models of inflammatory and hematologic disorders.

Dosing regimens for the clone MP1-22E9, a monoclonal antibody targeting mouse granulocyte-macrophage colony-stimulating factor (GM-CSF), can vary significantly across different mouse models. These variations are necessary due to the specific research goals and requirements of each model. Here are some examples of dosing regimens mentioned in the literature:

1. Intraperitoneal Injection: In one study dealing with SARS-CoV-2 infected models, the MP1-22E9 antibody was administered intraperitoneally (i.p.) at a dose of 250 μg in 100 μL sterile PBS. This dosing is specific to neutralization studies and might not be applicable universally.

2. Autochthonous Intrahepatic Cholangiocarcinoma Mice Models: Here, the dosing regimen involved administering 30 mg/kg of MP1-22E9 intraperitoneally every two days for four weeks. This high dose is used in more aggressive tumor models where significant neutralization of GM-CSF is required.

3. Non-Standardized Regimens: In general, dosing regimens for clone MP1-22E9 are not standardized and must be empirically determined for each specific study. This means researchers often need to conduct preliminary experiments to find the optimal dose for their particular mouse model.

In summary, while specific dosing regimens are mentioned for certain models, the general approach is to tailor the dose based on the experimental goals and the type of mouse model being used. The MP1-22E9 antibody is versatile and can be used in a variety of applications, including GM-CSF neutralization, ELISA capture, flow cytometry, and more.