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

Clone 2.43 is most commonly used in vivo in mice for the selective depletion of CD8+ T cells due to its high specificity for the CD8α molecule on the surface of these cells.

Key in vivo applications include:

• CD8+ T cell depletion: Clone 2.43 reliably eliminates CD8+ T cells in mice to study their roles in various immune responses, such as tumor rejection, viral clearance, transplant rejection, and autoimmune disease models.
• Functional immunological studies: It is used to dissect the specific contribution of cytotoxic T lymphocytes (CTLs) in disease models, allowing researchers to determine how absence of these cells affects disease progression or resistance.
• Immunological mechanism research: Depletion of CD8+ T cells with 2.43 enables investigation into immune modulation, such as the study of T cell–mediated pathophysiology and the mechanisms underlying immunotherapies or infection outcomes.

Additional technical notes:

• Administration: Typical dosing for effective depletion in mice is 250 μg per mouse, delivered intraperitoneally, with doses often given 2–3 times per week for sustained effects.
• Other applications (ex vivo or adjunct): Clone 2.43 can be used in flow cytometry, Western blotting, immunohistochemistry, and immunofluorescence to detect or assess CD8+ T cell populations, though its primary in vivo use remains depletion.
• Limitations: Although highly specific, 2.43 may still elicit some off-target effects or induce immune responses with repeated use, and researchers may substitute or compare it with alternative clones depending on experimental needs.

In summary, the gold standard in vivo use of clone 2.43 in mice is the targeted depletion of CD8+ T cells to assess their function in immune-related studies.

A number of antibodies and proteins are commonly used together with the rat anti-mouse CD8a (clone 2.43) antibody in immunological research, especially for the characterization or depletion of immune cell subsets.

The most frequently co-used antibodies and proteins with 2.43 in published studies include:

• Anti-CD4 antibodies (commonly clone GK1.5): Used to identify or deplete CD4+ T cells, often as a counterpart to CD8+ T cell investigation with 2.43.
• Fluorescently labeled anti-CD8 antibodies: For example, FITC- or PE-conjugated anti-CD8 (sometimes using other anti-CD8 clones like 53-6.7), used in flow cytometry alongside 2.43 for multi-parametric analysis.
• Isotype controls: Such as rat IgG2b, to ensure specificity of 2.43-mediated staining or depletion.
• Other lineage and activation markers: Such as anti-CD3 (TCR complex), anti-CD19 (B cells), anti-NK1.1 (NK cells), and anti-CD25 (activation/regulatory).
• Conjugates or multicolor panels: PE, FITC, APC, or other fluorochrome-conjugated versions of the above antibodies are used for simultaneous detection in flow cytometry panels.
• Alternative anti-CD8 antibodies: Clones such as 53-6.7 are sometimes co-used in comparative or control experiments, or when different epitopes or mouse strains require distinct specificity.

Typical combinations observed in the literature:

• Flow cytometry panels using anti-CD8 (2.43) with anti-CD4 (GK1.5) and additional markers (e.g., anti-CD3) for subset delineation.
• Depletion protocols where 2.43 is used for CD8+ T cell depletion, often alongside anti-CD4 for CD4+ T cell depletion or as controls.
• ImmunoPET or immunofluorescence studies using labeled 2.43 with other fluorescent antibodies for dual or multiplexed tissue or in vivo imaging.

In summary, anti-CD4 (GK1.5) and lineage/activation markers are especially common, and multicolor panels typically combine 2.43 with a range of surface marker antibodies to profile immune populations.

Clone 2.43 is a monoclonal antibody widely cited in scientific literature for its role in selective depletion of CD8+ T cells in vivo, particularly in mouse models. This has made it an essential tool for studying the immunological functions of CD8+ T cells in health and disease.

Key findings from clone 2.43 citations:

• Critical tool for CD8+ T cell depletion: Clone 2.43 specifically targets the CD8α chain, enabling highly selective removal of CD8+ T cells without significant impact on other immune cell populations.
• High specificity and established efficacy: Numerous preclinical studies have demonstrated its robust ability to deplete CD8+ T cells across a wide range of disease and experimental models, including infectious diseases, autoimmunity, and cancer.
• Versatility: Clone 2.43 works in several animal models (most commonly mice, but also rats).
• Dosing ranges: Effective depletion typically uses 100–500 µg per mouse delivered intraperitoneally or intravenously, with 250 µg/mouse as a commonly used standard dose.
• Immunological insights: Use of clone 2.43 has helped reveal the role of CD8+ T cells in viral clearance, adaptive immunity, autoimmune conditions, and vaccine efficacy.
• Comparative studies: Research comparing clone 2.43 with other CD8-depleting antibodies (e.g., clone 53–6.7, clone 3.56) provides guidance for optimal depletion strategies.
• Off-target and immunogenicity concerns: Despite its specificity, repeated use may induce immune responses or minor off-target effects, potentially impacting long-term studies.

Representative applications and findings:

• Viral infection studies: Depletion of CD8+ T cells using clone 2.43 in mouse models has shown the necessity of these cells for clearing acute viral infections and for effective vaccine-induced protection.
• Autoimmune disease models: Targeting CD8+ T cells with clone 2.43 supports investigation of T cell-mediated tissue damage and immunomodulation strategies in autoimmune conditions.
• Memory T cell characterization: In studies of aging, clone 2.43-based depletion helped show that clonally expanded memory CD8+ T cells accumulate in aged mice, contributing to immune landscape changes.
• Flow cytometry and immunohistochemistry: Clone 2.43 is widely used in cell-based assays for identification and quantification of CD8+ T cells.

Summary of advantages and limitations:

• Advantages: High specificity, efficacy in depletion, compatibility with various models, and robust experimental history.
• Limitations: Possible off-target effects, immunogenicity with repeated dosing, and dosage- or protocol-dependent outcomes.

In conclusion, clone 2.43 citations establish it as the gold standard for functional and mechanistic CD8+ T cell depletion studies in experimental immunology.

Dosing regimens of clone 2.43 (anti-mouse CD8α monoclonal antibody) in mice typically range from 100 μg to 500 μg per mouse, with a common standard dose of 250 μg per mouse, administered intraperitoneally or intravenously. The specific dosage, route, and schedule can vary based on the mouse model, experimental objectives, and required duration of CD8⁺ T cell depletion.

Essential context and details:

• Dose Range and Common Protocols:

  • Most studies report using 250 μg per mouse as a standard single dose for effective CD8⁺ T cell depletion.
  • The dose can be as low as 100 μg or as high as 500 μg per mouse, depending on the required extent and duration of depletion, the disease model, and immune status of the animals.
  • Lower doses (100 μg) can be effective in some tumor models or in combination regimens, particularly if repeated at short intervals.
  • Higher doses are sometimes used for robust or longer-lasting depletion, but can increase the risk of adverse effects or immunogenicity.

• Frequency and Scheduling:

  • Initial depletion often uses a single high dose, sometimes followed by maintenance doses every 3–7 days to sustain T cell depletion.
  • 2–3 times per week dosing schedules are common when maintaining depletion for longer experiments.
  • For some acute depletion needs (e.g., around tumor implantation), dosing may be limited to the days immediately preceding and following an intervention.

• Route of Administration:

  • The primary administration route is intraperitoneal (i.p.) injection, with intravenous (i.v.) as an alternative depending on the protocol.

Variability Across Mouse Models:

• Dosing may need adjustment for different strains or disease models, particularly if mice vary in body size, immune status, or the pharmacodynamics of clone 2.43.
• For some specialized transgenic or immunodeficient mouse models, pilot studies or titration may be needed to identify the optimal dose that achieves complete and sustained CD8+ T cell depletion without toxicity.
• Protocols in infectious disease studies, tumor models, and autoimmune disease models all utilize these core regimens but may emphasize different total durations or combination with other depleting antibodies.

Summary Table: Typical Clone 2.43 Dosing in Mouse Models

• References consistently recommend 250 μg/mouse i.p. as the starting point, with upward or downward adjustment as needed for specific experiments.
• Alternative clones (e.g., 53-6.7) may be used in place of 2.43 depending on model requirements, but dosing principles are similar.

Cautions:

• Immunogenicity: Repeated dosing can elicit anti-antibody responses, potentially reducing efficacy in long-term regimens.
• Off-target effects: At higher or more frequent doses, potential for unintended immunomodulation increases, warranting monitoring especially in sensitive disease models.

In summary, clone 2.43 dosing regimens in mice are flexible but typically center on 250 μg/mouse i.p., repeated every 3–7 days or as required by experimental design, with careful adjustment for specific model needs and intended outcomes.