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

The most common in vivo application of clone YTS-169 in mice is the selective depletion of CD8⁺ T cells, primarily cytotoxic T lymphocytes, to study immune responses or model immune modulation.

Key in vivo uses include:

• CD8⁺ T cell depletion: YTS-169 is consistently used to remove CD8⁺ cells by systemic injection, allowing researchers to study immune function without cytotoxic T cells or to model conditions (e.g., tumor immunology, autoimmune disease, infectious disease) where CD8⁺ T cells play a critical role.
• Immune function studies: By depleting CD8⁺ T cells, investigators can assess the contribution of these cells to immune responses against infections, tumors, or during immunotherapy.
• Blocking studies: Sometimes used to block CD8 interactions (such as with MHC I) to analyze the mechanistic role of CD8 engagement in T cell activation or signaling.
• Combination with other antibodies: Frequently used alongside anti-CD4 depletion (e.g., clone GK1.5) to dissect the roles of different T cell subsets in vivo.

Additional applications sometimes reported (less common than depletion studies):

• Preclinical models of transplantation, autoimmune disease, and cancer immunotherapy, where selective removal of CD8⁺ T cells is informative about disease mechanisms or therapeutic effects.
• Functional blocking or labeling in flow cytometry or immunohistochemistry, though for strictly in vivo functional manipulation, depletion is predominant.

In summary, CD8⁺ T cell depletion is the principal in vivo application of clone YTS-169 in mouse models. This enables mechanistic studies of immune responses where the absence of cytotoxic T cells is informative.

Commonly used antibodies or proteins paired with YTS-169 (anti-mouse CD8α) in the literature include anti-CD4 antibodies and other CD8 antibodies, especially for distinguishing T cell subsets or for conducting immune cell depletion experiments.

Key details and common use cases:

• Anti-CD4 antibodies (e.g., clone GK1.5): Frequently used in combination with YTS-169 for flow cytometric identification and depletion of CD4⁺ versus CD8⁺ T cell populations. Anti-CD4 antibodies are often conjugated with PE (phycoerythrin), and YTS-169 with FITC, to allow dual labeling of T cell subsets.
• Other anti-CD8 antibodies (e.g., clone 2.43): Sometimes used alongside YTS-169 for differential staining or depletion, especially as 2.43 is specific for the Lyt2.2 allele, while YTS-169 binds both Lyt2.1 and Lyt2.2.
• YTS-156 (anti-mouse CD8β): Occasionally used in depletion protocols in combination with YTS-169 to broadly ablate CD8⁺ T cells.

Additional proteins/antibodies sometimes co-used:

• Recombinant mouse CD8αβ heterodimer proteins: Employed in vitro to confirm specificity and affinity of YTS-169 and related antibodies in biochemical assays.
• Fluorochrome-conjugated versions: YTS-169 and other antibodies are widely available conjugated to various fluorochromes for multicolor flow cytometry, enabling combination with antibodies against CD3, CD4, CD44, CD62L, and other cell surface proteins depending on the panel.

Summary table:

In summary, anti-CD4 antibodies (often clone GK1.5) are the most common co-used reagent with YTS-169, with other anti-CD8 antibodies and recombinant proteins used for more specialized applications.

Clone YTS-169 (also cited as YTS169.4) is a rat monoclonal antibody widely used in scientific literature for identifying, depleting, and analyzing mouse CD8+ T cells in vivo and in vitro. Its use is fundamental in immunology, particularly in studies probing T cell function, immune cell depletion, and the role of CD8+ T cells in disease models.

Key findings from scientific literature citing clone YTS-169 include:

• Reliable CD8+ T cell depletion: YTS-169 is extensively cited for its ability to selectively deplete CD8+ T cells in mice, which is a standard approach to study the function of these cells in immune responses, tumor immunity, and autoimmunity. This clone is considered gold-standard for such depletion studies due to its specificity and efficacy.

• Specificity for mouse CD8α antigen: YTS-169 targets the CD8α chain, which is expressed on cytotoxic T cells and some subsets of other immune cells. It is widely used for flow cytometry, immunohistochemistry on frozen sections, and in vivo cell depletion.

• Functional studies in models of disease: Research using YTS-169 has shown that depletion of CD8+ T cells with this clone abrogates certain forms of acquired immunity and is essential for dissecting the respective contributions of CD8+ versus CD4+ T cells in various disease models, including infections, cancer, and autoimmunity.

• Instrumental in studies of immune memory: Depletion using YTS-169 demonstrated that the absence of CD8+ T cells can abolish memory responses in models of acquired immunity, underscoring the critical role of CD8+ T cells in long-term protection.

• Optimization and limitations in usage: YTS-169 (YTS169.4) is often recommended for use in flow cytometry at less than or equal to 0.2 μg per 10^6 cells, and for immunohistochemistry on frozen tissues but not on paraffin-embedded samples. It is not generally useful for standard western blotting or immunohistochemistry on formalin-fixed, paraffin-embedded tissue.

• Preferred tool in experimental immunology: Literature reviews and product pages note that YTS-169 is cited in over 95 publications, reflecting its status as a reference antibody for murine CD8α studies.

Summary of core uses of YTS-169 citations:

In summary, clone YTS-169 and YTS169.4 are fundamental in CD8+ T cell research, enabling cell depletion, detection, and immuno-functional studies in mice across diverse fields such as oncology, autoimmunity, and virology, with usage and limitations well documented in the literature.

Dosing regimens for clone YTS-169 in mouse models demonstrate considerable variability based on experimental objectives, mouse strain characteristics, disease model complexity, and the desired extent and duration of CD8+ T cell depletion.

Standard Dosing Parameters

The typical dosing protocol for clone YTS-169 involves administering 200–400 µg per mouse every 3–7 days through intraperitoneal (i.p.) or intravenous (i.v.) injection. This protocol closely mirrors established standards for other anti-CD8 clones like 2.43, which commonly use doses ranging from 100 µg to 500 µg per mouse. However, dosing for YTS-169 can extend from the low hundreds of micrograms up to 1 mg per mouse per dose depending on specific experimental requirements.

Frequency and Administration Routes

The dosing schedule typically follows a maintenance pattern where antibody is administered every 3 to 7 days to sustain effective CD8+ T cell depletion. Some protocols employ an initial higher loading dose followed by lower maintenance doses to balance depletion efficiency with safety considerations. The preferred routes of administration are intraperitoneal or intravenous injection, with each route potentially affecting the kinetics and efficiency of depletion.

Model-Specific Variations

One documented example demonstrates the flexibility of dosing schedules: in autoimmunity studies using sOVA/OT-I mice, researchers administered three doses of YTS169.4 on days 5, 7, and 9 after birth to delay disease onset. In tumor immunology studies, mice received 200 µg of anti-CD8α (clone YTS169.4) for investigating immune responses to tumor heterogeneity.

Factors Influencing Dosing Decisions

Several critical factors determine the optimal dosing regimen for any particular experiment. Mouse strain characteristics affect antibody pharmacokinetics and immune responsiveness. The specific disease model being studied influences both the timing and magnitude of depletion required. Experimental goals—whether seeking transient depletion for mechanistic studies or sustained depletion for therapeutic modeling—fundamentally shape dosing strategies. Finally, the desired duration of CD8+ T cell absence must be balanced against potential immunogenicity from repeated antibody administration.

The depleting activity of YTS 169.4 makes it highly effective for in vivo applications, but researchers must carefully titrate their specific protocols to achieve optimal results for their particular experimental context.