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

Common In Vivo Applications of Clone IM7 in Mice

Anti-CD44 monoclonal antibody clone IM7 is widely used in vivo to study the function of the CD44 adhesion molecule, which plays pivotal roles in cell migration, lymphocyte activation, immune response modulation, and tumor biology. IM7 binds to an epitope conserved across all known isoforms of mouse and human CD44, making it a versatile tool in immunology and inflammation research.

Key In Vivo Uses

• Modulation of Immune Responses and Inflammation: Administration of IM7 has been shown to reduce joint swelling in murine models of arthritis, specifically by disrupting leukocyte rolling and adhesion—processes critical for leukocyte extravasation and inflammation. This suggests IM7 can dampen inflammatory responses by interfering with CD44-mediated leukocyte trafficking.
• Inhibition of Delayed-Type Hypersensitivity (DTH): In vivo, IM7 is reported to inhibit delayed-type hypersensitivity responses, an immune reaction relevant to contact dermatitis and certain autoimmune diseases. This application is particularly useful for studying mechanisms of adaptive immunity and evaluating potential therapeutic interventions.
• Functional Blockade and Neutralization: IM7 is documented to neutralize CD44 function in vivo, which has been applied to investigate the role of CD44 in processes such as leukocyte activation, homing, and tumor metastasis. The antibody’s ability to block CD44-ligand interactions makes it a valuable tool for dissecting the biological functions of CD44 in vivo.

Additional Biological Effects Observed

• Induction of Systemic Shock: Notably, intravenous administration of IM7 can induce a systemic shock response in mice, characterized by increased vascular permeability, hematocrit elevation, and hypotension. This effect is mediated by platelet-activating factor (PAF) and highlights a potential risk of antibody-based therapies targeting CD44.
• Application in Cancer and Metastasis Studies: Given CD44’s involvement in tumor behavior, IM7 has also been used to assess the role of this molecule in cancer progression and metastasis, although most of these applications are described in in vitro or ex vivo settings.

Typical Experimental Context

IM7 is generally administered intravenously or intraperitoneally, and its effects are monitored in various disease models, including arthritis, DTH, and acute shock. The antibody’s ability to recognize all CD44 isoforms and its documented in vivo efficacy make it a mainstay in immunology and inflammation research in mice.

Summary Table

In summary, clone IM7 is most commonly used in vivo in mice to modulate immune and inflammatory responses by blocking CD44, with established roles in models of arthritis and DTH, and is occasionally used to study acute systemic reactions and tumor biology. Researchers should be aware of the potential to induce systemic shock in some contexts.

Common Antibodies and Proteins Used with IM7 in the Literature

IM7 refers primarily to two distinct entities in the literature:

1. IM7 as an anti-CD44 monoclonal antibody (commonly clone IM7), widely used in immunology and cancer research.
2. Im7 as the Escherichia coli Colicin E7 immunity protein, a small, stable protein scaffold used in protein engineering and display technologies.

Below, the common co-used antibodies/proteins are summarized for each context.

IM7 (Anti-CD44 Monoclonal Antibody)

The IM7 monoclonal antibody is specific for CD44, a cell adhesion molecule expressed on hematopoietic and non-hematopoietic cells. In experimental settings, IM7 is often used alongside other antibodies targeting cell surface markers, adhesion molecules, or functional reagents, depending on the research focus:

• Gr-1 (Ly-6G/Ly-6C): Used for identifying and depleting myeloid subsets (e.g., neutrophils, monocytes).
• PSGL-1 (P-selectin glycoprotein ligand-1): Involved in leukocyte rolling and adhesion; often co-stained with CD44 in inflammation studies.
• Anti-IgG antibodies: Used in secondary detection or functional assays (e.g., complement-dependent cytotoxicity).
• Heparin: Sometimes used in adhesion or migration assays involving CD44.
• Platelets: IM7 has been implicated in studies of platelet function and vascular responses.
• Reagents for cell depletion or functional assays: Depending on the experiment, IM7 may be paired with other cell-specific markers (e.g., CD3, CD19) for flow cytometry or functional studies.

Key Application Contexts:
These combinations are typical in studies of cell adhesion, inflammation, metastasis, lymphocyte homing, and in vivo models of disease (e.g., cancer, autoimmunity).

Im7 (Colicin E7 Immunity Protein)

Im7 is a bacterial protein that binds tightly to the DNase domain of colicin E7, forming one of the tightest known protein–protein interactions. In protein engineering, Im7 is used as a scaffold for creating novel binding proteins. Common partners include:

• Colicin E7 DNase domain: The natural binding partner of Im7; used in binding assays and as a target in phage display libraries.
• Engineered or grafted protein loops: For example, the CDR3 loop from the IgG1b12 antibody (targeting HIV gp120) has been grafted onto Im7 to create chimeric proteins with new binding specificities.
• Anti-Im7 antibodies: Used to detect Im7-fusion proteins in display systems (e.g., phage display).
• Gene 3 fusion proteins (phage display): Im7 is displayed on the surface of fd bacteriophages as a gene 3 fusion for library screening.

Key Application Contexts:
Im7 and its engineered variants are used in creating protein scaffolds for molecular recognition, library display, and the development of novel binding molecules.

Summary Table

Key Points

• In immunology/cancer research, IM7 (anti-CD44) is frequently paired with antibodies to Gr-1, PSGL-1, and functional reagents like heparin or anti-IgG, depending on the experimental focus (cell depletion, adhesion, inflammation, or platelet function).
• In protein engineering, Im7 (Colicin immunity protein) is used with its natural partner (Colicin E7 DNase), engineered protein loops, and phage display systems for developing novel binding scaffolds.
• The context (antibody vs. scaffold protein) dictates the choice of co-used molecules; always clarify which "IM7" is referenced in the literature.

Clone IM7 is a monoclonal antibody widely cited in scientific literature for its role in recognizing CD44, a cell surface glycoprotein important in cell adhesion, migration, and signaling. The key findings from studies citing clone IM7 include:

• Epitope Specificity and Versatility: IM7 recognizes an epitope common to all isoforms of CD44, located between amino acids 145 and 186, making it useful for detecting CD44 in a broad range of contexts, including different species and cell types.

• Impact on CD44 Function: IM7 binding can block, modulate, or study CD44-mediated cellular functions such as leukocyte rolling (important in inflammation). Studies show that IM7's inhibition of leukocyte rolling is dependent on CD44 expression on leukocytes rather than endothelium, implying its effects are cell-type specific.

• Applications in Research Methods: IM7 is validated for multiple applications, including immunocytochemistry, flow cytometry, immunohistochemistry (both frozen and paraffin-embedded sections), immunoprecipitation, complement-mediated cytotoxicity, and in vivo functional assays.

• Use in Disease and Therapy Models:

  • Cancer Research: IM7 has been used to target ovarian cancer cells in combination with delivery systems (such as chitosan nanoparticles), demonstrating anti-tumor activity, though toxicity remains an issue.
  • Inflammatory Diseases: Studies using IM7 have provided insights into the role of CD44 in immune cell migration and inflammation, aiding the development of anti-inflammatory therapies.

• Structural and Mechanistic Insights: IM7 studies have enabled exploration of CD44’s role in cell adhesion and migration, with particular emphasis on how antibody binding can perturb cellular interactions relevant to disease processes.

• Validation Across Platforms: IM7 is one of the most used anti-CD44 clones for studying immune cell populations and cellular microenvironments in both murine and human systems due to its broad reactivity and well-characterized properties.

• Limitations and Considerations: While IM7 is widely used, users must consider possible cross-reactivity (e.g., reported but unverified reactivity with ferret CD44) and the functional consequences of antibody binding when interpreting results.

In summary, clone IM7 is a gold-standard reagent for CD44 detection, functional analysis, and therapeutic model studies related to immune modulation, cancer, and inflammation, with broad methodological applications and major contributions to the understanding of CD44 biology.

Dosing regimens for clone IM7 (anti-CD44) in mouse models generally range from 1–10 mg/kg, most commonly as single or repeat intraperitoneal injections, but the precise regimen varies based on the experimental goal, mouse strain, and disease model. The literature and product protocols highlight variability, with most applications specifying dosing empirically or referencing previous studies rather than a universally fixed protocol.

Key details include:

• Typical Dose: 1–10 mg/kg per injection, with many studies using 200–250 μg per mouse for in vivo functional experiments.
• Route: Intraperitoneal (i.p.) injection is most widely used, though intravenous (i.v.) routes have also been reported.
• Frequency: Dosing intervals may range from a single injection to multiple doses given every 3–7 days, depending on the duration of depletion or blockade required.
• Model and Application Variability:
  • In acute depletion/regulation studies, a single 200–250 μg i.p. dose is often sufficient.
  • For tumor and chronic inflammation models or studies requiring sustained blockage, repeated doses (e.g., twice weekly for 2–3 weeks) may be used.
  • Some protocols recommend adjusting regimens based on mouse weight, strain sensitivity, and experimental duration.

Reference Example Regimen:A commonly cited regimen is 200–250 μg of IM7 per mouse (i.p.), administered once or at intervals (every 3–7 days) for chronic experiments. This is consistent across suppliers (Bio X Cell, Leinco) and published experimental protocols.

Considerations Influencing Regimen Choice:

• The mouse strain (e.g., immunocompetent vs. immunodeficient) may influence dose and frequency due to differential CD44 expression or immune responsiveness.
• Disease models (e.g., tumor growth, inflammation, immune activation) might require protocol adjustment to achieve optimal CD44 blockade or modulation.
• Protocols may also recommend monitoring for off-target effects or toxicity with higher/frequent doses.

Flow Cytometry/Profiling Use:For flow cytometry and ex vivo tissue profiling (not in vivo blockade/depletion), clone IM7 is typically used at a much lower concentration, often a 1:100 dilution with 1 × 10⁵–1 × 10⁷ cells/mL in the staining buffer.

Summary Table: Clone IM7 Dosing Regimens in Mouse Models

For best results, adaptation to experimental requirements and mouse strain is advised, and supplier protocols or prior peer-reviewed studies should be consulted for the specific disease or immune system model in use.