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

Clone IM7 is extensively used in in vivo mouse studies as a functional blocking antibody targeting CD44, particularly in research involving inflammation, arthritis, and immune cell trafficking. The antibody serves as both a research tool and therapeutic intervention in various experimental models.

Primary Applications in Mouse Studies

Arthritis ResearchClone IM7 has been prominently used in proteoglycan-induced arthritis (PGIA) models, where it demonstrates robust suppression of joint inflammation. The antibody is typically administered intravenously at doses of 200 ?g per mouse, which effectively reduces joint swelling and inflammatory responses. This application has been particularly valuable for studying the role of CD44 in inflammatory arthritis and testing potential therapeutic approaches.

Leukocyte-Endothelium Interaction StudiesOne of the most significant uses of IM7 in vivo is for investigating how immune cells interact with blood vessel walls during inflammation. When injected intravenously, IM7 causes dramatic changes in leukocyte behavior within minutes. The antibody virtually eliminates rolling interactions between leukocytes and endothelium, with rolling cells disappearing between 5 and 30 minutes after injection. Additionally, adherent leukocytes develop distinctive morphological changes, appearing "hairy" or "disheveled" less than one minute after IM7 administration.

Mechanism of Action in vivo

Target SpecificityThrough bone marrow transplantation studies using CD44 knockout mice, researchers have demonstrated that IM7's effects depend specifically on binding to CD44 expressed on leukocytes rather than endothelial cells. The antibody's binding to leukocyte CD44 is responsible for both the disruption of cell rolling and the morphological changes observed in adherent cells.

Functional RequirementsThe in vivo effects of IM7 require CD44 cross-linking on the leukocyte surface, suggesting that the antibody works by clustering CD44 molecules and disrupting their normal adhesive functions. This mechanism provides insights into how CD44 normally facilitates immune cell migration and positioning during inflammatory responses.

Experimental Considerations

Dosing and AdministrationThe standard dose of 200 ?g per mouse administered intravenously has been established through dose-response studies in arthritis models. This dosing regimen provides rapid onset of effects while maintaining efficacy over extended periods.

Duration of EffectsThe functional blocking effects of IM7 are sustained, with rolling cell frequency still reduced by approximately 60% and firm adhesion decreased by 50% at 24 hours post-injection. Rolling cells begin to reappear slowly 2-4 hours after treatment, indicating that the antibody's effects are reversible but long-lasting.

Control ConsiderationsAppropriate controls in IM7 studies include normal rat IgG at equivalent doses (200 ?g/mouse) and CD44 knockout mice to verify specificity. These controls help distinguish specific CD44-mediated effects from non-specific antibody effects.

Clone IM7 has proven invaluable for dissecting CD44's role in immune cell trafficking and inflammatory diseases in mouse models, making it a standard tool for researchers studying cell adhesion, inflammation, and potential therapeutic interventions targeting the CD44 pathway.

Based on the product information for the sterile packaged clone IM7 CD44 antibody, the correct storage temperatures are:

Primary Storage Recommendations

Short-term storage: Store at 4°C for up to 12 months

Long-term storage: Store at -20°C for extended periods

Initial Handling Instructions

Upon receipt, the antibody is shipped at ambient temperature and should be aliquoted and stored at -20°C. When thawed, you can keep aliquots at 2-8°C for short-term use (up to 4 weeks) and store remaining aliquots at -20°C.

Critical Storage Considerations

Avoid freeze-thaw cycles: Repeated freezing and thawing may denature the antibody and should be avoided. This is particularly important since the preparation contains no preservatives and must be handled under aseptic conditions.

Frost-free freezers: Storage in frost-free freezers is not recommended.

The storage instructions are consistent across multiple suppliers, indicating that 4°C provides adequate preservation for up to 12 months, while -20°C storage extends the shelf life significantly when freeze-thaw cycles are minimized through proper aliquoting practices.

Based on the research literature, several antibodies and proteins are commonly used alongside IM7 in experimental studies. The specific combinations depend on the research context and experimental objectives.

Antibodies Used with IM7

Anti-rat IgG antibodies are frequently employed as secondary antibodies when working with the rat-derived IM7 monoclonal antibody. Goat anti-rat IgG has been specifically used to cross-link IM7 Fab fragments, demonstrating that CD44 cross-linking effects require antibody-mediated bridging of individual CD44 molecules on cell surfaces.

Anti-Gr-1 antibodies have been used in comparative studies with IM7 to examine granulocyte depletion mechanisms. These antibodies target a different surface molecule but produce similar cellular responses, including neutrophil removal from circulation and morphological changes comparable to those induced by IM7 treatment.

Control and Detection Proteins

Anti-Im7 rabbit polyclonal antibodies serve as important detection reagents in research applications. These antibodies are particularly useful for validating Im7 scaffold proteins in phage display systems and protein engineering applications.

P-selectin has been studied alongside IM7 in investigations of cell adhesion pathways and coagulation system interactions. Soluble P-selectin treatments have been shown to produce effects similar to IM7 in certain experimental contexts, particularly regarding fibrin deposition and inflammatory responses.

Associated Binding Partners and Targets

Hyaluronic acid (HA) represents the natural ligand for CD44 and is commonly studied in conjunction with IM7 to understand CD44-mediated cell-matrix interactions. The IM7 antibody recognizes an epitope proximal to the N-terminal HA-binding domain of CD44, making HA a relevant binding partner in functional studies.

Colicin E7 DNase domain serves as the natural binding partner for Im7 protein in studies involving protein scaffolds and purification systems. This 15 kDa protein forms one of the tightest known protein-protein interactions with Im7, with binding affinities reaching 10^-14^ to 10^-17^ M.

The selection of companion antibodies and proteins with IM7 typically depends on whether researchers are investigating CD44 function, developing protein purification methods, or studying inflammatory responses and cell adhesion mechanisms.

Key findings from scientific literature referencing clone IM7 focus on its application as a monoclonal antibody targeting CD44—a cell surface glycoprotein present on many cell types—and its utility in research and functional assays.

Summary of Core Findings:

• Epitope Recognition: Clone IM7 specifically recognizes an epitope shared by all mouse and human CD44 isoforms, located between amino acids 145 and 186 of the protein. This includes both standard (CD44s) and variant isoforms.

• Broad Applications: IM7 is widely used in:

  • Immunocytochemistry (ICC)
  • Immunohistochemistry (IHC) of both frozen and formalin-fixed paraffin-embedded tissue sections
  • Flow cytometry
  • Immunoprecipitation
  • Complement-mediated cytotoxicity
  • In vivo functional studies (for example, inhibition of delayed-type hypersensitivity [DTH])
  • Spatial biology techniques such as IBEX

• CD44 Function Blockade and Mechanistic Insights:

  • IM7 can partially inhibit the binding of hyaluronic acid (HA) to CD44, as it recognizes an epitope near the N-terminal HA-binding domain.
  • IM7’s ability to disrupt leukocyte rolling and adhesion is specific to CD44 on leukocytes (not endothelial CD44), and requires antibody-induced cross-linking of CD44 molecules on these cells.
  • Treatment with IM7 monoclonal antibody versus CD44 genetic deficiency can yield distinct biological outcomes, highlighting the importance of context and mechanism in interpreting experimental results using IM7.

Additional Considerations:

• Isoform and Species Cross-Reactivity: IM7 is validated for use on both mouse and human CD44, with some reports of cross-reactivity to other species (e.g., ferret), though such cross-reactivity is not fully characterized.
• Product Format Recommendations: Endotoxin-free, azide-free IM7 preparations are preferable for functional in vivo experiments due to minimization of antibody-associated toxicity or off-target effects.

References in Practice:
Clone IM7 has been extensively cited in the context of immunological, cancer, and stem cell biology research due to its robust specificity and versatility, serving both as a basic detection reagent and as a tool for functional blockade of CD44-mediated interactions.

If you seek findings related to "IM7" in protein folding (unrelated to the CD44 antibody), note that "IM7" is also the name of a small bacterial immunity protein studied for its folding pathways and energy landscape properties. This is a distinct research area, so please specify if this context is relevant.