Anti-Mouse CD4 (Clone YTS191) – Purified in vivo GOLD™ Functional Grade

Use of YTS191 Clone in In Vivo Mouse Studies

The YTS191 clone is a rat anti-mouse CD4 monoclonal antibody that is widely used in immunology research to specifically target and deplete CD4+ T cells in vivo.

Mechanism and Application

• CD4+ T Cell Depletion: YTS191 recognizes the CD4 antigen expressed on the surface of helper T cells, regulatory T cells, some natural killer T (NKT) cells, and subsets of dendritic cells and macrophages in mice. When administered in vivo, this antibody effectively depletes these CD4+ cell populations, most notably CD4+ T cells, which are critical in adaptive immune responses.
• Functional Grade: The purified YTS191 antibody is considered "functional grade," meaning it is suitable for in vivo administration without causing adverse off-target effects.
• Experimental Uses: Researchers use YTS191 primarily to investigate the role of CD4+ T cells in immune responses, immune tolerance, autoimmune diseases, infections, and cancer. By depleting these cells, it is possible to study their specific contributions to disease progression, immune regulation, and therapeutic outcomes.

Dosing and Administration

• Formulation: The antibody is typically supplied as a sterile, low endotoxin (<2 EU/mg), purified solution in phosphate-buffered saline (PBS), optimized for in vivo use.
• Dilution: It is recommended to use InVivoPure pH 7.0 Dilution Buffer for reconstitution, but specifics may vary depending on the experiment.
• Storage: The antibody should be stored at 4°C in stock concentration and not frozen, to maintain stability.
• Dosage: The optimal working dilution and dosage should be determined by the investigator for each specific application, as conditions may vary.

Precautions and Controls

• Isotype Controls: It is important to use appropriate isotype controls (such as rat IgG2b) to ensure specificity and rule out non-specific effects.
• Purity and Safety: YTS191 is produced to high purity (>95% by SDS-PAGE) and low endotoxin levels to minimize inflammatory side effects in vivo.
• Pathogen Testing: Some suppliers offer additional testing to ensure that the antibody is free from common mouse pathogens, which is critical for in vivo studies.

Summary Table: Key Features of YTS191 for In Vivo Use

Conclusion

In vivo, the YTS191 clone is used to selectively and effectively deplete CD4+ T cells in mice, enabling researchers to dissect the functional roles of these cells in health, disease, and therapeutic interventions. Its high purity, low endotoxin content, and established efficacy make it a standard tool in immunological mouse models.

Commonly used antibodies and proteins paired with YTS191 (anti-mouse CD4) in the literature include antibodies that target mouse immune cell subsets for depletion or characterization. When YTS191 is used to deplete or detect CD4+ T cells, researchers frequently use other antibodies to target the following:

• CD8+ T cells: Antibodies such as clone 53-6.7 (anti-CD8?) are commonly used to deplete or label this subset for experiments studying T cell function in vivo.
• CD25: Anti-CD25 antibodies such as clone PC61 are often used to deplete regulatory T cells (Tregs) alongside CD4 targeting.
• CD45: Pan-leukocyte marker used for gating in flow cytometry or characterization studies.
• CD3: To detect all T cells.
• Gr-1 (Ly6G/Ly6C): Antibodies like RB6-8C5, 1A8, and NIMP-R14 are used to deplete or identify neutrophils and monocytes in studies combining multiple immune cell subset depletions.
• B220 (CD45R): For B cell identification or depletion.
• NK1.1: For labeling or depleting natural killer (NK) cells.
• F4/80 or CD11b: To target macrophages or myeloid cells.

These antibody combinations allow comprehensive immune cell profiling and functional studies in vivo and are commonly used together with YTS191 in experiments involving immune modulation, cell depletion, and immunophenotyping.

In summary, alongside YTS191, antibodies targeting CD8, CD25, Gr-1, NK1.1, and myeloid markers are most frequently used in the literature to distinguish or deplete various immune cell subsets, depending on the experimental goals.

Based on the scientific literature examining clone YTS191, several important findings have emerged regarding this monoclonal antibody and its applications in research.

Antibody Characteristics and Specificity

Clone YTS191.1 is a rat anti-mouse CD4 monoclonal antibody with IgG2b isotype that recognizes murine CD4, a T cell differentiation antigen expressed on thymocytes and helper/inducer T cells in peripheral blood. The antibody exhibits depleting activity when used in vivo, making it a valuable tool for studying CD4+ T cell functions.

Therapeutic Intervention and Protection Studies

A significant finding involves the use of YTS191 in studies examining therapeutic protection mechanisms. Research demonstrated that the bacterial enzyme CU43, formulated as an Fc fusion protein, could protect mice humanized for Fc? receptors from YTS191-mediated cytotoxic depletion of CD4+ T cells. This protection occurs through CU43's ability to defeat monoclonal antibody Fc effector functions by cleaving IgG N-glycans.

The protective mechanism requires both glycan and protein binding components. Mutant variants of CU43 that were incapable of binding the IgG N297-linked glycan, including those targeting the glycan core (CU43^Q260A-Y262A^) and the ?1-3 branch (CU43^E294A-E295A^), completely failed to prevent CD4+ T cell depletion by YTS191. Similarly, variants that abolished protein-protein interactions with the Fc substrate showed no protective effect.

Research Applications in Immunology

YTS191 has been extensively utilized in T cell depletion studies to investigate immune responses and therapeutic interventions. In checkpoint inhibitor research, YTS191 has been employed alongside CD8-specific antibodies to selectively deplete CD4+ T cells, allowing researchers to study the individual contributions of different T cell populations.

Experimental Validation of Mechanisms

The antibody has proven particularly valuable for validating biological mechanisms in vivo. Studies using YTS191 have corroborated in vitro structural and mutagenesis analyses, demonstrating that protective enzymes like CU43 require specific binding domains to effectively deglycosylate IgG antibodies and prevent antibody-mediated cell depletion.

These findings collectively establish YTS191 as both a research tool for studying CD4+ T cell biology and a model system for understanding therapeutic interventions that can modulate antibody effector functions through glycan modification.

Clone YTS191 dosing regimens in mouse models typically vary from 100?µg (low dose) to 1?mg (high dose) per mouse administered intraperitoneally, with depletion measured five days after treatment. These regimens are used for both uninfected and persistently LCMV-infected mice to deplete CD4? T cells.

• Low Dose (LD): 100?µg per mouse IP
• High Dose (HD): 1?mg per mouse IP

These doses have been applied in both immunologically naive mice and those chronically infected with LCMV-Cl13, resulting in robust CD4? T cell depletion measured five days after antibody administration.

Additional context:

• Clone YTS191 is a rat IgG2b monoclonal antibody targeting murine CD4, primarily used for in vivo depletion of CD4? T cells in diverse mouse models.
• The exact dosing schedule (number of injections, interval) is typically one injection followed by assessment at five days, but may be adapted depending on experimental design and desired depletion kinetics.
• Product information confirms preparation as purified IgG at 1?mg/ml in PBS, suitable for in vivo use at stated concentrations.

When substituting or comparing clones in other immunotherapy regimens (e.g., checkpoint blockade), dosing ranges for similar monoclonals often fall between 100–500?µg per mouse per dose, but CD4 depletion using YTS191 generally employs the higher 1?mg dose for complete depletion, or 100?µg for partial depletion.

No direct evidence was found for substantial dose variation based on mouse strain, age, or disease type outside of infection status (uninfected vs. LCMV-infected), though protocols may adapt timing and dosing to optimize depletion relative to the immune baseline of each model.