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

Clone 2.43 is a rat anti-mouse CD8? monoclonal antibody that is widely used in in vivo mouse studies to selectively deplete CD8+ T cells. Researchers administer this antibody—typically at a dose of 100–500?µg per mouse, most commonly via intraperitoneal or intravenous injection—to transiently or persistently reduce CD8+ T cell populations and study the resulting effects on immune responses, disease progression, or therapy outcomes.

The principal uses and key features of clone 2.43 in in vivo mouse studies include:

• Selective Depletion: Due to its high specificity for CD8?, clone 2.43 reliably and efficiently depletes CD8+ T cells without significantly affecting other immune cell subsets.
• Experimental Applications:
  • Investigating the role of CD8+ T cells in infection models, such as viral pathogenesis (e.g., COVID-19), where researchers assess disease severity or immune response in their absence.
  • Examining autoimmune disease and tumor immunology by determining how depletion of CD8+ T cells impacts disease development, progression, or therapeutic efficacy.
  • Supporting mechanistic studies by allowing functional interrogation of CD8+ T cells’ roles in tissue homeostasis, inflammation, or response to therapy.
• Dosing Guidelines: Researchers commonly use one dose of 250?µg per mouse as a standard for effective depletion, with dose adjustments based on experimental need. Administration routes include intravenous or intraperitoneal injection for systemic depletion.
• Advantages: Robust, reproducible depletion; broad validation across models; minimal non-specific effects.
• Limitations/Considerations:
  • Possible off-target or immunomodulatory effects, especially with repeated dosing.
  • Immunogenicity in some mice, leading to anti-rat IgG responses if used over prolonged periods.

In summary, clone 2.43 is a standard tool for functional CD8+ T cell ablation in vivo, enabling precise investigation of the contributions these cells make to diverse immune processes and disease states in mouse models.

The correct storage temperature for sterile-packaged clone 2.43 (anti-mouse CD8a monoclonal antibody) is 2 to 8°C for short-term storage (approximately 1 month). For longer-term storage (beyond 1-3 months), it should be stored at -20°C to -70°C.

Key details:

• For short-term use (up to 4 weeks), store at 2–8°C (refrigerator temperature) as supplied, avoiding repeated freeze-thaw cycles.
• For storage up to 3 or more months, -20°C to -70°C is recommended.
• For the longest-term storage (over 12 months), -80°C can be used.
• The solution should be stored undiluted in the dark to prevent degradation.
• Always avoid freeze-thaw cycles, and aliquot if multiple uses are planned.

If the packaging is compromised, sterility can no longer be assured, and the item should not be used.

The 2.43 antibody is a rat monoclonal antibody targeting mouse CD8a, commonly used for depletion, staining, and functional studies of CD8+ T cells. In published work, other commonly used antibodies or proteins alongside 2.43 typically include:

• CD4 antibodies (e.g., clone GK1.5): Used to deplete or label CD4+ T cells when CD8 populations are manipulated, allowing researchers to contrast helper versus cytotoxic T cell responses in the same experiment.
• CD3 antibodies: Marker of all T lymphocytes, often used in flow cytometry panels with CD8 and CD4 to define T cell subsets.
• MHC class I tetramers/antibodies: Detect antigen-specific CD8+ T cells, generally used for functional cytometry panels.
• CD45 and lineage markers: Used for broader immune phenotyping in conjunction with CD8 labeling.
• Isotype controls (e.g., rat IgG2b): Employed as negative controls to ensure specificity of 2.43 staining or depletion.
• Alternative anti-CD8a clones (e.g., 53-6.7): Sometimes used as comparison or when different functional properties or species cross-reactivity are required.
• Activation/functional markers (e.g., CD44, CD62L, PD-1): Used together with CD8a to identify activation status or subpopulations of CD8+ T cells.

In functional studies, the 2.43 clone is also paired with:

• CD8b antibodies: To distinguish between CD8a homodimers and CD8a/8b heterodimers.
• Other immune checkpoint antibodies (e.g., anti-PD-1, anti-CTLA-4): Used to study CD8+ T cell functionality and regulatory mechanisms.

These pairings allow for comprehensive analysis of T cell subsets, function, and depletion/ablation efficacy in immune studies involving the 2.43 antibody.

Key findings from citations on clone 2.43 in scientific literature emphasize its critical role as a monoclonal antibody for CD8+ T cell depletion in vivo, particularly in immunological and disease models.

Main findings from clone 2.43 studies:

• High specificity for CD8?: Clone 2.43 selectively binds to the CD8? molecule, resulting in efficient and targeted depletion of CD8+ T cells without significantly affecting other immune cell types.
• Validated efficacy across models: Extensive preclinical work validates its ability to robustly deplete CD8+ T cells in mice and some other species, supporting studies on T cell function, immunopathology, viral clearance, and autoimmunity.
• Research applications:
  • Used to dissect the role of CD8+ T cells in infection, cancer, autoimmune diseases, and aging-related immune changes.
  • Key to protocols examining immune determinants of viral clearance and vaccine responses in mouse models.
  • Applied for investigating T cell clonal expansion in various physiological and pathological contexts, often serving as a critical tool in aging and atherogenesis research.
• Dosing guidance:
  • Typical dosing in mice ranges from 100–500?µg per mouse, often standardized at 250?µg intraperitoneally or intravenously for effective depletion.
• Potential pitfalls:
  • While highly selective, clone 2.43 may have off-target or immunomodulatory effects, and repeated use can induce anti-antibody responses, potentially confounding long-term experiments.

Notable experimental findings:

• Comparative studies show clone 2.43 (versus other anti-CD8 clones like 3.56) as optimal or standard for depleting CD8+ T cells depending on the experimental context.
• Studies using clone 2.43 demonstrate that CD8+ T cell depletion alters the immune landscape and can clarify CD8+ T cell contribution to disease or therapy responses, as in models of viral infection, cancer immunology, and autoimmune disorders.

Clonal expansion research (context of citation):

• In studies using CD8 depletion (often via clone 2.43), patterns of clonal expansion and memory differentiation of CD8+ T cells are described, especially in aging and chronic disease states.
• Clone 2.43 is described explicitly as the antibody used for in vivo depletion of CD8+ T cells, validating its central methodological role in studies that analyze T cell receptor repertoire and immune memory.

In summary, clone 2.43 is the gold-standard tool for depleting CD8+ T cells in murine models, underpins fundamental discoveries in immunology, and is routinely cited for its specificity, reproducibility, and research utility, with important notes on careful dosing and potential immunogenicity.