Anti-Mouse/Human CD44 [Clone IM7] — Purified in vivo GOLD™ Functional Grade

The clone IM7 is widely used in in vivo mouse studies for its ability to target CD44, a cell surface glycoprotein involved in various biological processes, including cell adhesion, migration, and inflammation. Here's how it's used:

Applications in In Vivo Studies

1. Arthritis Models: IM7 has been used to study arthritis by suppressing joint inflammation. In arthritic mice, administration of IM7 significantly reduces joint swelling and impacts leukocyte-endothelium interactions, disrupting leukocyte rolling and adhesion.

2. Immune Response Modulation: The antibody is effective in modulating immune responses. It can inhibit delayed-type hypersensitivity (DTH) reactions, which are a model for studying immune-mediated inflammation.

3. Cancer and Stem Cell Research: IM7's ability to target CD44 makes it useful for studying cancer, where CD44 is often overexpressed, and stem cell biology.

4. Mechanistic Studies: IM7 is used to investigate the role of CD44 in leukocyte-endothelial interactions. It has been shown that IM7 binding to CD44 on leukocytes, but not endothelial cells, disrupts rolling interactions.

Experimental Approaches

• Administration: IM7 is typically administered intravenously in mouse models.
• Dosage: Effective dosages for reducing joint swelling have been reported at 200 ?g per mouse.
• Assessment: The effects of IM7 treatment are often assessed by monitoring changes in leukocyte behavior, inflammation, and disease severity.

Overall, clone IM7 is a valuable tool for studying the role of CD44 in various biological processes and diseases in mouse models.

Anti-CD44 monoclonal antibody IM7 is commonly used alongside other antibodies and proteins in the literature, especially in studies focused on leukocyte biology, cell adhesion, and inflammation. The most frequently co-used antibodies and proteins include:

• Gr-1 antibody: Used to target granulocytes and study leukocyte depletion, similar to the application of IM7 against CD44.
• Anti-PSGL-1 (P-selectin glycoprotein ligand-1): Applied in intervention studies to cross-link cell surface molecules on granulocytes, resulting in removal from circulation.
• Heparin: Frequently used as a comparator or inhibitor in studies involving IM7, highlighting the interaction between the coagulation system and cell adhesion.

Other proteins and conditions in combination studies:

• Platelets: Platelet depletion studies are often conducted together with IM7 treatment to investigate the impact of CD44 cross-linking on platelet accumulation and neutrophil clearance.
• Soluble P-selectin: Used to explore the relationship between selectin shedding and coagulation events in conjunction with IM7.
• Fibrin(ogen): Experiments show interplay with Mac-1 integrin and the downstream effects of IM7-triggered granulocyte removal.

In experimental setups:

• Goat anti–rat IgG: Employed to induce cross-linking following IM7 Fab administration, allowing assessment of Fc-independent effects.
• Anticoagulants (e.g., heparin): Critical for controlling the procoagulant effects of IM7, providing important experimental controls in immunological studies.

For protein engineering and purification systems involving the Im7 protein (distinct from IM7 antibody):

• CL7 tag: A mutated Colicin E7 DNase used with Im7 for ultra-high-affinity protein purification.
• Partner proteins (e.g., RNAP core enzyme): Im7 scaffold is used for binding and pull-down assays in proteomics workflows.

In summary, IM7 is most often paired with antibodies to Gr-1, PSGL-1, and reagents such as heparin, platelets, and anti-IgG, depending on the focus (cell depletion, adhesion, inflammation, or platelet function). For biotechnology applications, engineered proteins such as CL7 are used in tandem with Im7 for purification purposes.

Key findings from scientific literature citing clone IM7 focus on two main contexts: its role as an anti-CD44 monoclonal antibody in immunological research and its use within protein folding and affinity purification studies.

1. Clone IM7 as an Anti-CD44 Antibody:

• Epitope Specificity: IM7 recognizes an epitope common to all CD44 isoforms, specifically between amino acids 145 and 186 of CD44.
• Applications: This clone has been used in a variety of applications, including immunocytochemistry, immunohistochemistry (on both acetone-fixed and paraffin-embedded tissue), complement-mediated cytotoxicity, immunoprecipitation, and functional in vivo inhibition studies.
• Functional Studies: IM7’s binding is critical for studies of CD44-mediated cell adhesion and migration. For instance, IM7 binding to leukocyte CD44 disrupts cellular rolling and adhesion in inflammation models, but this effect is specifically dependent on the presence of CD44 on leukocytes, not endothelium. IM7 cross-linking is necessary to inhibit these cell interactions.
• Cross-Reactivity: There is evidence for partial cross-reactivity to ferret CD44, although this has not been universally confirmed.

2. IM7 in Protein Folding and Structural Biology:

• Frustrated Folding Intermediate: The protein IM7 (Immunity protein 7, from the colicin E7 system) has been extensively studied as a model for protein folding. It exhibits an unusual mechanism where folding involves a stable, on-pathway intermediate with nonnative interactions. These intermediate states arise due to clusters of highly frustrated interactions in the native structure, deviating from classical "funnel" folding models.
• Implications for Protein Engineering: Mutational analysis shows that redesigning IM7 to reduce frustration eliminates intermediate states, thus streamlining the folding pathway. Notably, the frustrated interactions that cause the intermediate are relieved when IM7 binds to its natural partner, colicin E7.

3. IM7/CL7 System in Protein Purification:

• Affinity Platform: The interaction between the engineered CL7 tag (derived from colicin E7) and IM7 has been harnessed for high-yield, one-step protein purification. The system offers:
  • High column capacity due to robust IM7 immobilization
  • Exceptional stability over multiple regeneration cycles
  • Improved target protein expression, solubility, and proper folding
  • Efficient on-column proteolytic elution, minimizing excess residues
  • Performance robust to high-salt conditions
• This IM7/CL7 affinity system is recognized for providing high-purity, high-activity protein recovery with broad applicability to challenging, clinically relevant proteins.

Summary Table: Contexts and Key Findings

In summary, clone IM7 is widely cited as both a powerful tool in immunological studies targeting CD44 and a model system in protein folding and purification technologies.

The optimal dosing regimen for clone IM7 (anti-CD44, commonly used in mouse models) typically involves an intraperitoneal injection, but the precise dose and schedule can vary depending on the specific mouse strain, experimental purpose (e.g., cell depletion, blocking, in vivo imaging), and disease model. Direct, detailed dosing regimens for clone IM7 across different mouse models are not included in the provided search results, but general principles from related in vivo antibody dosing can be extrapolated.

Key insights from antibody dosing guides for mouse models:

• Dose Range: For in vivo depleting and function-blocking antibodies (such as anti-CD4, anti-CD8, and anti-Gr-1), common dosing ranges are between 200–250 ?g per mouse per injection.
• Route: The standard route of administration is intraperitoneal injection.
• Schedule: Dosing is frequently performed 2–3 times per week or every 2–3 days for sustained cell depletion or continuous blockade.

Experimental context and model variation:

• Strain differences: Immunocompromised versus immunocompetent strains may vary in sensitivity and antibody clearance, with highly immunodeficient strains sometimes requiring lower doses due to reduced antibody clearance.
• Model-dependent variation: Tumor models, autoimmunity, and infection studies might all modulate dosing schedules based on the desired immune effect or depletion duration.

While the precise clone IM7 data are not detailed in your provided results, most in vivo functional antibodies targeting cell surface molecules in mouse models are dosed in the 200–250 ?g/mouse intraperitoneally every 2–3 days or 2–3 times a week. Adjustments may be needed according to pilot study outcomes, specific mouse model immunology, and experimental goals.

If precise, model-specific recommendations for clone IM7 are required, consulting the latest peer-reviewed literature or manufacturer recommendations is strongly advised, as these regimens are refined based on the antibody's affinity, isotype, and application.