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

Clone 2.43 is a rat anti-mouse CD8? monoclonal antibody used in in vivo mouse studies to selectively deplete CD8+ T cells. Researchers administer clone 2.43 to mice, most commonly via intraperitoneal or intravenous injection, at doses typically ranging from 100??g to 500??g per mouse, with 250??g per mouse frequently used as a standard for effective depletion.

Context and Key Details:

• Target and Specificity: Clone 2.43 binds specifically to the CD8? chain of the mouse CD8 protein, a surface marker found on CD8+ T cells, which are crucial for cell-mediated immune responses.
• Research Purpose: The primary use of clone 2.43 is to create a model in which CD8+ T cells are acutely or chronically ablated, facilitating the study of their role in immunological processes, disease models (such as tumor immunity or infection), and therapeutic interventions.
• Administration: The antibody is supplied in low-endotoxin, in vivo-grade preparations to minimize adverse reactions. It is typically administered at 100–500??g per mouse, with routes and frequency tailored to study design. Single or repeated dosing can be used, but repeated administration may elicit immune responses against the rat antibody.
• Controls: Experiments often include isotype controls or untreated groups to distinguish effects due to CD8+ T-cell depletion from other possible antibody-driven effects.

Advantages:

• High specificity: Efficient and selective depletion of CD8+ T cells with minimal impact on other immune populations.
• Well-established: Widely validated in diverse mouse models and research contexts.

Potential Limitations:

• Off-target or immunomodulatory effects may occur, although these are generally limited due to high specificity.
• Immunogenicity: The rat origin of the antibody can induce anti-rat immune responses on repeated dosing, influencing longer term studies.

Additional Applications:

• Clone 2.43 has served as a source of sequence for engineered derivatives (e.g., minibodies) in imaging and mechanistic studies.

In summary, clone 2.43 is the gold standard antibody for in vivo depletion of CD8+ T cells in mouse models, crucial for dissecting CD8+ T cell contributions in immunological research.

Commonly used antibodies or proteins with 2.43 (anti-mouse CD8?, clone 2.43) in the literature are typically selected to identify and characterize different leukocyte populations or functional states in mouse immunology experiments. The most relevant co-used antibodies/proteins include:

• Anti-CD4 (e.g., clone GK1.5): For distinguishing and depleting CD4+ T cells versus CD8+ T cells in phenotyping or depletion studies.
• Anti-CD3: A pan-T cell marker, commonly used alongside anti-CD8? to identify all T cells.
• Anti-CD8? (e.g., clone 53-5.8 or 53-6.7): For more refined phenotyping of CD8+ T cells specifically expressing the ? chain.
• Anti-B220/CD45R: Marks B cells and some subsets of T cells; often used to exclude non-T cells in flow cytometry.
• Anti-NK1.1 or DX5: Used to distinguish NK cells from T cells, especially in studies of cytotoxic lymphocyte populations.
• Anti-MHC class I and II (e.g., I-A/I-E, H-2K^b/D^b): For context about antigen presentation and to characterize APCs in conjunction with CD8+ T cell studies.

Other reagents frequently employed:

• Isotype controls: Such as rat IgG2b, to control for non-specific binding when using clone 2.43 (which is a rat IgG2b).
• Viability dyes: To gate out dead cells during flow cytometry, critical in multi-color panels with 2.43.

Common applications in which these markers are used together include:

• Flow cytometry (FACS), including multicolor panels
• Cell depletion in vivo or in vitro
• Immunoprecipitation and immunofluorescence

Panel design and antibody choice depend on experimental goals, such as distinguishing T cell subsets, characterizing effector/memory populations, or confirming depletion efficacy.

Summary table: Key antibodies and their use with 2.43

This structure reflects the typical experimental design in mouse immunology where clone 2.43 is used.

Clone 2.43 is a monoclonal antibody widely cited in scientific literature for its ability to deplete CD8+ T cells in vivo, mainly in mouse models. Key findings from studies using clone 2.43 include:

• High specificity for CD8?: Clone 2.43 selectively targets the CD8? chain, resulting in specific depletion of CD8+ T cells without generally affecting other immune cell populations.
• Established efficacy: Numerous studies across diverse research areas—such as immunology, aging, cancer, and infectious disease—have shown that 2.43 administration results in robust depletion of CD8+ T cells.
• Versatility: The antibody is effective in multiple animal models, especially mice, and is frequently used to interrogate the role of CD8+ T cells in different biological contexts.

Representative applications and findings:

• Aging and Immunology: Used in studies characterizing T cell memory populations and clonal expansion in aged versus young mice, demonstrating that clonally expanded CD8+ memory populations accumulate with age.
• Infectious Disease: Clone 2.43-mediated CD8+ depletion allows researchers to test the contribution of CD8+ T cells in viral control; for example, CD8 depletion led to higher SARS-CoV-2 replication in mouse lungs, highlighting a key antiviral role for CD8+ T cells.
• Cancer Models: Widely used to assess the role of CD8+ T cells in anti-tumor immunity, though specific cancer studies with clone 2.43 were not directly cited in the retrieved results.

Caveats and limitations:

• Potential off-target or immunomodulatory effects: Although highly specific, repeated administration may induce immune responses against the antibody, compromising long-term experimental integrity or causing unintended immune effects.
• Dosing variability: Effective depletion depends on dose, mouse strain, study design, and route of administration; common dosing ranges are 100–500 µg per mouse, with 250 µg as a typical standard dose.

In summary, clone 2.43 is a standard tool to dissect the function of CD8+ T cells in diverse in vivo studies, with findings relying on its specificity and effectiveness for targeted T cell depletion.

Dosing regimens of clone 2.43—an anti-CD8? monoclonal antibody—vary by mouse model, experimental goal, and protocol, but the typical dose range is 100–500??g per mouse, usually delivered by intraperitoneal injection.

Supporting Details and Context:

• Standard Dose: Most studies use a single dose of 250??g per mouse for effective depletion of CD8? T cells in standard immunological experiments.
• Dose Range: Experimental conditions may call for lower (100??g) or higher (up to 500??g) doses, particularly for sustained or robust depletion.
• Route of Administration: Both intraperitoneal (i.p.) and intravenous (i.v.) injections are used, though i.p. is most common.
• Frequency: To maintain CD8? T cell depletion, antibody is typically administered every 3–7 days. Some protocols employ a single high dose followed by lower maintenance doses.
• Model-Specific Variation:
  • Different mouse strains, tumor models, or infection studies may adjust the dose within this range to compensate for variations in immune system activity, antibody clearance, or experimental duration.
  • For example, autoimmunity studies (like EAE) may use similar dosing as tumor models, but frequency or duration could differ.
• Combination Regimens: Often, clone 2.43 is administered alongside other depleting antibodies (e.g., GK1.5 for CD4? T cells) when the goal is to eliminate several T cell types.
• Other Species: For rats, dosing increases to 0.5–2?mg per rat (higher than for mice), again given i.p..

Key Application Contexts:

• Tumor Immunology: Used to deplete CD8? T cells and assess their role in immune-mediated tumor rejection or immunotherapy studies.
• Infection Models: Used to study viral clearance and the role of cytotoxic T cells.
• Transplantation and Autoimmune Disease: Applied for depletion in graft rejection or EAE mouse models, often with scheduling adapted to experimental timeline.

Summary Table: Clone 2.43 Dosing Across Common Mouse Models

Dosing may be refined based on mouse strain, experimental goal, and antibody source, but the above ranges reflect broad consensus from peer-reviewed protocols.