Anti-Mouse CD8a (Ly 2.2) [Clone 2.43] — Purified in vivo PLATINUM™ Functional Grade

Clone 2.43 is a rat anti-mouse monoclonal antibody that specifically targets CD8α, making it the gold standard for in vivo depletion of CD8⁺ T cells in mouse models. Its common applications include:

• Depleting CD8⁺ T cells in vivo to study their function in a variety of contexts such as infection, tumor immunity, autoimmunity, transplantation, and immunopathology.
• Dissecting the role of CD8⁺ T cells in disease models, for example, by administering clone 2.43 and assessing disease progression or immune response in the absence of these cells.
• Establishing causality between CD8⁺ T cell activity and observed immunological phenomena by comparing CD8-depleted mice with controls.
• Supporting preclinical studies in experimental immunotherapies or vaccine development, often to validate the contribution of cytotoxic T cells.

Technical context:

• Typical dosage in mice ranges from 100–500 μg per mouse, delivered intraperitoneally or intravenously, with 250 μg being a common standard.
• Depletion is usually sustained by repeated dosing every 3–7 days.
• Clone 2.43 is preferred for its high specificity for CD8α and proven efficacy across multiple mouse strains.

Other research/diagnostic uses (beyond depletion):

• Sometimes applied for flow cytometry, immunohistochemistry, or immuno-PET imaging (rare), though in vivo depletion remains its primary use.
• Its use as a functional blocking antibody to probe CD8-related mechanisms in vivo.

In summary, in vivo depletion of CD8⁺ T cells to study immune cell function and disease mechanisms is the overwhelmingly predominant use of clone 2.43 in mice.

The 2.43 antibody (rat monoclonal, anti-mouse CD8a) is commonly used for depletion, staining, and functional studies of CD8+ T cells. In published literature, it is often used in combination with the following antibodies and proteins:

• Anti-CD4 antibodies (e.g., clone GK1.5): For co-staining, T cell subset identification, or parallel depletion of CD4+ T cells when analyzing immune responses or cell populations.
• Anti-CD3 antibodies: For general T cell identification and stimulation studies, as CD3 is a pan-T cell marker.
• Other anti-CD8 clones (e.g., 53–6.7): Some experiments use 2.43 alongside other clones for comparison, validation, or in multiple staining panels.
• Fluorochrome-conjugated secondary antibodies: Such as FITC- or PE-conjugated anti-CD8a (clone 2.43 or others), often used in flow cytometry together with anti-CD4 highlighters for multi-color analysis.
• Isotype controls (rat IgG2b): To confirm specificity in depletion or staining experiments.
• Functional blocking/activation antibodies: Such as anti-PD-1, anti-CD28, and others, for functional assays involving T cell activation, exhaustion, or inhibition (less common, but found in some immunological studies).

These combinations are especially frequent in:

• Flow cytometry panels for immunophenotyping,
• in vivo depletion studies targeting specific T cell subsets,
• Functional assays to dissect immune responses.

Key pairs used with 2.43 in literature:

References support frequent pairing with anti-CD4 (clone GK1.5), and combining with anti-CD3 and other anti-CD8 clones in flow cytometry or depletion protocols.

In summary, the antibodies most commonly used with 2.43 are anti-CD4 (GK1.5), anti-CD3, and alternative anti-CD8 clones for lineage and functional analysis in mouse immunology.

Key Findings from Clone 2.43 Citations in Scientific Literature

Anti-mouse CD8a (clone 2.43) is a highly cited monoclonal antibody in immunology research, particularly for in vivo CD8+ T cell depletion studies. Its primary uses and findings in the scientific literature include the following:

Function and Applications

• Selective CD8+ T Cell Depletion: Clone 2.43 is recognized for its high specificity in binding to the CD8α co-receptor on mouse T cells, enabling selective depletion of CD8+ T cells in vivo without significant effects on other immune cell populations.
• Preclinical Utility: The antibody is widely used in mouse and rat models to study the role of CD8+ T cells in immunity, autoimmunity, infectious disease, and cancer. Its effectiveness has been validated across a range of experimental conditions and animal species.
• Standardized Protocols: Typical dosing in mice ranges from 100 µg to 500 µg per mouse, usually administered intraperitoneally or intravenously, with 250 µg often used as a standard effective dose.

Advantages

• Specificity: Clone 2.43 demonstrates strong binding affinity for CD8α, ensuring targeted depletion and minimal off-target effects in most contexts.
• Versatility: Compatible with multiple animal models, supporting diverse research applications.
• Established Efficacy: Numerous studies confirm its ability to achieve robust and reproducible CD8+ T cell depletion, making it a benchmark tool in immunological research.

Limitations and Considerations

• Potential Off-Target Effects: Despite its specificity, there is a risk of off-target binding or unintended immunomodulatory effects, which may influence experimental outcomes.
• Immunogenicity: Repeated administration can elicit host immune responses against the antibody, potentially compromising long-term studies.
• Comparative Studies: Research comparing clone 2.43 with other CD8-depleting antibodies (e.g., clone 3.56) provides insights into optimal depletion strategies and highlights the nuances of different reagents.

Mechanistic and Translational Insights

• Immune Modulation: Studies utilizing clone 2.43 have elucidated the critical roles of CD8+ T cells in viral clearance, autoimmune pathogenesis, and tumor immunity.
• Disease Models: The antibody has been employed in models of autoimmune disease to investigate targeted immunomodulation and the pathophysiology mediated by CD8+ T cells.
• Cell Phenotyping: In some studies, clone 2.43 is used for depletion, while other CD8 antibodies (e.g., clone 53-6.7) are used for flow cytometry, underscoring the importance of reagent selection based on experimental need.

Representative Experimental Use

Clone 2.43 has been used to deplete CD8+ T cells in vivo to assess the contribution of these cells to adaptive immunity, viral clearance, and immunopathology in various infection and vaccination models. Such studies often pair clone 2.43 with complementary reagents to dissect complex immune interactions.

Summary Table: Clone 2.43 in Scientific Literature

Conclusion

Clone 2.43 is a cornerstone reagent in immunology for in vivo CD8+ T cell depletion, offering high specificity, established efficacy, and broad applicability across preclinical models. Its use has advanced understanding of CD8+ T cell biology in health and disease, though researchers must remain aware of potential limitations related to off-target effects and immunogenicity in long-term studies.

Dosing regimens of clone 2.43 (anti-CD8α monoclonal antibody) typically range from 100 μg to 500 μg per mouse per injection, with most studies using 250 μg administered intraperitoneally or intravenously every 2–7 days, but the exact dose and schedule can be adapted to the mouse strain, disease model, desired depletion kinetics, and experimental length.

Key details on regimen variation:

• Standard Dose: The commonly reported and recommended dose is 250 μg per mouse via intraperitoneal injection, given 2–3 times per week to maintain CD8+ T cell depletion, especially in C57BL/6 and BALB/c strains.

• Dose Range: Published protocols use a range of 100–500 μg per mouse depending on depletion efficiency needs—which can differ by mouse strain, immune baseline, disease context (e.g., infection, tumor, autoimmunity), and antibody pharmacokinetics.

• Single vs. Maintenance Dosing: Some studies administer a single high dose (e.g., 500 μg) for acute depletion, followed by repeated lower maintenance doses (e.g., 100–250 μg every 3–7 days) for ongoing suppression of CD8+ T cells.

• Route of Administration: Intraperitoneal is most common, but intravenous is also used for faster systemic distribution or specific experimental requirements.

• Experimental Context Dependence:

  • In tumor models, 100 μg may be injected 3 days before challenge and then every 3–4 days to sustain depletion through the experiment.
  • For viral infection or autoimmune disease models, doses and intervals are similarly variable, but 250 μg every 2–3 days is typical to match rapid T cell turnover and maintain depletion.
  • Adjustments may be made for mouse strains with distinct pharmacodynamic or immunogenic responses.

• Strain/Model Adjustments: Some strains or experimental setups may require dose escalation or more frequent dosing; larger or older mice may need higher amounts to achieve equivalent depletion, and immune-compromised models sometimes tolerate higher/frequency injections.

• Toxicity and Off-target Effects: Higher dosing regimens (>500 μg per mouse) can increase the risk of off-target immunomodulation or toxicity; standard 250 μg doses show minimal adverse effects but should be monitored.

• Alternatives: For comparison or when unexpected immunogenicity develops, other clones (e.g., YTS 169.4, 53-6.7) may be employed, but 2.43 is generally preferred for robust CD8+ T cell depletion in mouse models.

In summary, dosing regimens for clone 2.43 are not fixed across mouse models but are optimized (100–500 μg, usually 250 μg per mouse, every 2–7 days intraperitoneally) according to the strain, experimental timeline, and the specific biological context, with the standard protocol adaptable for disease, immune kinetics, and individual animal variation.