Anti-Mouse CD8 [Clone YTS-169] — Purified in vivo GOLD™ Functional Grade

Clone YTS-169 (often YTS 169.4) is most commonly used in vivo in mice to deplete CD8⁺ T cells, specifically by targeting the CD8α chain on cytotoxic T lymphocytes. This allows researchers to study the immune function and role of CD8⁺ T cells in various settings by transiently or selectively removing this lymphocyte population.

Key in vivo applications include:

• Depletion of CD8⁺ T cells: YTS-169 is injected into mice to selectively eliminate CD8⁺ cells. This is widely used in immunological studies to determine the contribution of cytotoxic T cells to infection, tumor immunity, autoimmunity, vaccine responses, and transplantation tolerance.
• Functional studies of immune responses: By removing CD8⁺ T cells, researchers can evaluate how the absence of these cells impacts defense against pathogens (viruses, bacteria), tumor growth/regression, and autoimmune processes.
• Preclinical therapeutic models: Used as a tool to create models of immunodeficiency or to test drugs/treatments in CD8-depleted animals.

Additional details:

• YTS-169.4 is a rat IgG2b monoclonal antibody recognizing mouse CD8α, which is the main CD8 subunit on cytotoxic T cells, some dendritic cell subsets, thymocytes, and NK cells.
• It shows potent in vivo depleting activity, meaning treatment leads to a marked reduction in circulating and tissue-resident CD8⁺ T cell populations in mice.
• The antibody is frequently used as a "functional grade" or "in vivo grade" reagent to ensure low endotoxin and high purity, suitable for systemic administration in animal studies.

Summary Table: Common In Vivo Applications of YTS-169 in Mice

The antibody is not generally used for in vivo tracking, staining, or activation—its primary validated role is depletion of CD8⁺ T cells.

Commonly used antibodies or proteins with YTS-169 in the literature include anti-CD4 antibodies (such as YTA1.3.2), other CD8-specific antibodies (including clone 2.43 and YTS 156), and various reagents conjugated for flow cytometry or immune cell depletion.

Key combinations and usage contexts:

• Anti-CD4 antibodies: Frequently used alongside YTS-169 to distinguish CD4+ and CD8+ T cell populations in flow cytometry or in vivo depletion studies. PE-conjugated anti-CD4 antibodies are commonly paired with FITC-conjugated YTS-169 for subset identification.
• Other anti-CD8 antibodies:
  • Clone 2.43: Binds a different epitope (Lyt2.2-specific) on mouse CD8α; used for comparative studies and specific immune subset detection.
  • YTS 156: Another CD8-specific antibody used in depletion protocols, often in combination with YTS-169 for robust CD8+ T cell removal.
• Conjugated antibodies for flow cytometry: YTS-169 is used in various fluorescently labeled formats (such as FITC or PE) for identification and enumeration of T cell subsets.
• Other T cell markers: In some experimental designs, additional antibodies targeting CD3 or CD45 may be included to provide more precise gating or cell identification, although this is not always detailed in primary YTS-169 studies.

Summary table of commonly paired reagents:

These combinations are critical for dissecting T cell responses and for precise immunophenotyping in mouse immunology studies.

Scientific Significance of Clone YTS-169

The clone YTS-169 (also cited as YTS169.4) is a well-established rat monoclonal antibody that specifically recognizes mouse CD8α, a cell surface glycoprotein expressed primarily on cytotoxic T lymphocytes. Since its development, YTS-169 has become a cornerstone tool in immunology for detecting, characterizing, and depleting CD8+ T cells in mice, enabling researchers to dissect the role of these cells in immune responses, disease models, and immunotherapy.

Key Findings and Applications

Depletion of CD8+ T Cells

• In vivo depletion: YTS-169 is widely used for the in vivo depletion of CD8+ T cells in mice. For example, studies have shown that administration of this antibody at 0.5 mg/dose effectively depletes CD8+ cells, a method that has been instrumental in demonstrating the necessity of CD8+ T cells for memory in acquired immunity.
• Functional studies: This depletion approach has been critical in experiments showing that CD8+ T cells are required for the development of type 1 diabetes and that targeting both CD4+ and CD8+ T cells can reverse disease in certain models.

Flow Cytometry and Cell Staining

• Staining protocols: YTS-169 is optimized for flow cytometry, with suggested concentrations of ≤ 0.2 μg per 10⁶ cells in a 100 μl volume. Titration is recommended for each specific application to ensure optimal staining and specificity.
• Limitations: The antibody is effective for staining fresh cells or frozen sections but is not suitable for Western blotting under denaturing conditions or for immunohistochemistry (IHC) on formalin-fixed tissue. It is primarily used for cell surface detection in flow cytometry and immunoprecipitation from cell lysates in mild detergents.

Structural and Molecular Insights

• Specificity: YTS-169 recognizes the CD8α chain, which forms either homodimers (CD8αα) or heterodimers with CD8β (CD8αβ), both of which are part of the immunoglobulin superfamily and act as co-receptors for the T cell receptor (TCR).
• Biological role: CD8α interaction with MHC class I molecules is essential for efficient T cell–antigen-presenting cell interactions, playing a central role in cytotoxic T cell function and immune surveillance.

Broader Impact in Scientific Literature

• Tool validation: YTS-169 has been cited in over 95 publications, reflecting its reliability and widespread adoption in immunological research.
• Model systems: Its use in mouse models has contributed to foundational knowledge in adaptive immunity, autoimmunity, infectious disease, and cancer immunology.
• Experimental flexibility: The antibody is available from multiple vendors in different formats (purified, functional grade, low endotoxin), supporting diverse experimental needs.

Summary Table: Key Features of YTS-169

Conclusion

Clone YTS-169 is a foundational reagent in mouse immunology, enabling precise identification, isolation, and depletion of CD8+ T cells. Its use has been pivotal in elucidating the roles of CD8+ T cells in immune memory, autoimmunity, and disease pathogenesis, and it remains a gold standard for flow cytometric analysis of murine CD8α.

Dosing regimens of clone YTS-169 (YTS169.4) in mouse models typically range from 200–400 µg per mouse every 3–7 days administered intraperitoneally (i.p.) or intravenously (i.v.), but can vary depending on strain, experimental objective, and desired depletion duration.

Key context and variations:

• Common starting regimen: 200–400 µg per mouse per injection, with injections repeated every 3–7 days for sustained CD8+ T cell depletion.
• Dose range: Some protocols use as low as 100 µg, while others go up to 1 mg per mouse, especially for prolonged or deeper depletion.
• Mouse strain and model: Researchers often adjust dose/frequency for different mouse strains or disease models, balancing effective depletion with toxicity risk.
• Route of administration: Both i.p. and i.v. are standard, with similar dosing.
• Experimental variation: For short-term depletion (e.g., neonatal models), specific schedules such as three doses on days 5, 7, and 9 after birth have been used.

Summary table of typical approaches:

Researchers are advised to titrate for their own experimental systems and consult lot-specific datasheets for precise recommendations.

In summary: Most laboratories start at 200–400 µg every 3–7 days i.p. or i.v. per adult mouse, but regimens can be modified for strain, disease context, and experimental endpoints.