Anti-Rat Kappa Light Chain (Clone MAR 18.5) – Purified in vivo GOLD™ Functional Grade

Clone MAR 18.5 is a monoclonal antibody against the rat kappa immunoglobulin light chain, frequently used in mouse in vivo studies to enhance the depletion of rat-derived antibodies or cells within the mouse. Its most common application is as a secondary antibody in combination with other rat monoclonal antibodies (such as anti-mouse CD19 and CD22) for in vivo B cell depletion in mice.

Essential context and usage details:

• MAR 18.5 binds specifically to rat kappa light chains (RI-1a and RI-1b allotypes), making it an ideal reagent for recognizing and targeting rat-derived monoclonal antibodies administered to mice.
• When mouse studies require depletion of specific cell types (such as B cells or neutrophils) using rat monoclonal antibodies, MAR 18.5 is co-administered to bind the rat antibodies’ kappa chain. This facilitates:
  • Cross-linking and enhanced opsonization of the targeted cells, leading to increased efficacy in depletion through mechanisms like antibody-dependent cellular cytotoxicity (ADCC) or phagocytosis.
  • Neutralization or masking of rat antibody epitopes, which can modulate the biological activity or duration of action of primary rat antibodies in mouse tissues.
• Protocols often use MAR 18.5 (mouse IgG2a) at doses such as 50 ?g/mouse, injected intraperitoneally, typically after or alongside administration of a rat monoclonal antibody (e.g., anti-Ly6G for neutrophil depletion or anti-mouse CD19/CD22 for B cell depletion).
• Example applications:
  • In B cell depletion, MAR 18.5 is used together with rat anti-mouse CD19 and CD22 to enhance the clearance of target B cells in vivo by facilitating the removal of rat antibody-coated cells.
  • In neutrophil depletion, MAR 18.5 is combined with rat anti-Ly6G antibody to improve depletion kinetics and effectiveness, and is also used to study the bioavailability and antigen masking effects of the primary rat antibody.

Additional relevant info:

• MAR 18.5’s functional grade preparations are optimized for in vivo use, ensuring minimal endotoxin and maximum specificity.
• The antibody is applied in various research contexts, including immunodepletion, immunophenotyping, and mechanistic immunology studies in mouse models.

In summary, clone MAR 18.5 is a key reagent for facilitating depletion protocols in mouse studies that involve rat monoclonal antibodies, working as a secondary cross-linking or clearing agent to enhance removal of targeted cells or neutralization of rat antibodies in vivo.

The correct storage temperature for a sterile packaged clone like "MAR 18.5" typically depends on the type of biological material and how it is formulated or preserved.

For clonal DNA stored dry or resuspended, the recommended storage temperatures according to Twist Bioscience (a major supplier) are:

• Room temperature (20–25°C): up to 3 months
• Refrigerator (4°C): up to 12 months
• Freezer (-20°C): up to 24 months
• Ultra-low freezer (-80°C): recommended for long-term storage

For general sterile packaged items (not specifically DNA or clones but anything sterilized for lab use), recommended storage is:

• Between 18°C and 23°C with relative humidity between 30% and 60%

Best practices:

• Always store in enclosed dust-free containers.
• Maintain integrity of the sterile packaging—do not use items if packaging appears damaged, wet, or wrinkled.
• Minimize freeze-thaw cycles for biologicals and prepare aliquots as appropriate.

If your clone is a DNA/gene construct in sterile packaging, -20°C or -80°C is optimal for long-term storage. For general sterile-packaged equipment or supplies, 18–23°C is acceptable.

If you provide more details about the specific type and formulation of "MAR 18.5," more tailored guidance could be given, but for most sterile packaged DNA clones, -20°C or colder is correct for extended storage. Use at room temperature only for short-term periods (weeks to months depending on the supplier’s instructions).

Other commonly used antibodies or proteins paired with MAR 18.5 (an anti-rat kappa light chain antibody) in the literature include:

• Anti-CD19 and Anti-CD22: Frequently used for in vivo B cell depletion studies in rats or mice.
• J11d.2 (anti-heat-stable antigen), 2.43 (anti-CD8), M5/114 (anti-class II MHC), and 2.4G2 (anti-Fc?R/FcR): Often combined with MAR 18.5 for T cell subset isolation, complement-mediated lysis, or flow cytometric identification.
• Other antibodies described in related methodologies, such as anti-Ly6G or anti-Gr1, are widely used for neutrophil depletion assays, though not always directly with MAR 18.5. These serve as a reference for multi-color flow cytometry in complex immune cell profiling.

These combinations enable multi-parameter immunophenotyping, cell sorting, or functional depletion and are well-represented in immunological studies employing MAR 18.5 as a kappa chain marker or depleting agent.

Key pairs with MAR 18.5:

• Anti-CD19 (B cell marking/depletion)
• Anti-CD22 (B cell marking/depletion)
• 2.4G2 (Fc gamma receptor, used for blocking or cross-linking immune cells)
• J11d.2 (thymocyte and T cell subset, heat-stable antigen)
• 2.43 (CD8, cytotoxic T cells)
• M5/114 (class II MHC)

These antibodies are used in various combinations for detailed immune cell analysis or depletion experiments, often cited in B and T cell studies.

Typical applications:

• Flow Cytometry
• In vivo depletion (B or T cells)
• Complement-mediated lysis
• Functional assays

References consistently support this set of markers as common companions to MAR 18.5, with anti-CD19 and anti-CD22 especially prominent in depletion protocols.

Clone MAR 18.5 is a monoclonal antibody that targets the rat kappa immunoglobulin light chain and is widely used in immunological research, especially in studies involving antibody-mediated cell depletion in rodents. Key findings from its scientific citations are as follows:

• Antigen Specificity and Use: MAR 18.5 binds specifically to the rat kappa light chain of immunoglobulins, one of the two subtypes that make up the immunoglobulin light chain in rodents. Typical applications include in vivo depletion of cells, particularly when combined with other antibody-based targeting strategies.

• Role in Neutrophil Depletion Protocols: MAR 18.5 is integral to protocols that aim to deplete neutrophils in mice. When used in combination with anti-Ly6G antibodies, MAR 18.5 (administered as an anti-rat IgG secondary antibody) enhances the effectiveness and durability of neutrophil depletion. This "combo" approach has been shown to:

  • Specifically and durably reduce neutrophil numbers in blood and lung tissue, though not significantly in the spleen.
  • Address the issue of antigen masking: when primary depleting antibodies (like anti-Ly6G) are used, surface detection of the same antigen is impeded. MAR 18.5, as an anti-rat IgG, allows for improved depletion and detection by circumventing masking issues.
  • Demonstrate that neutrophil mobilization from bone marrow is enhanced under depletion protocols, shown by increased BrdU+ neutrophil fractions in blood and tissue despite reduced total prevalence.

• Technical Implications: Studies highlight the importance of intracellular staining (as opposed to surface staining) for accurately quantifying neutrophils after depletion treatments, due to the persistence of intracellular antigen even when surface markers are masked or depleted.

• Research Impact: MAR 18.5 has been cited in protocols that investigate immune cell function, inflammation, cancer models, and basic immunology. Its broad reactivity with rat Ig kappa makes it a staple tool for antibody-mediated depletion and tracking of Ig-bearing cells in rats and mice.

• Citations: According to Bio X Cell, MAR 18.5 has been cited at least 23 times in scientific literature, reflecting its established role in rodent immunology research.

In summary, clone MAR 18.5 is critically valuable for effective, specific, and durable antibody-mediated cell depletion protocols in rodent models, especially for studies needing robust neutrophil or B cell depletion or tracking.