Anti-Human CD5 [Clone UCHT-2] — Purified in vivo Functional GOLD™ Functional Grade

Clone UCHT-2 is most commonly used in vivo in humanized mouse models to selectively target human CD5-positive cells, especially for immune cell depletion and immunological studies.

Key in vivo applications in mice include:

• Depletion of Human T Cells: Administration of UCHT-2 to humanized mice can selectively eliminate human CD5+ T cells from circulation and tissues, facilitating studies of T cell function, tolerance, autoimmunity, or disease models such as graft-versus-host disease.
• Modeling Human Immune Responses: UCHT-2 is used in humanized mice to dissect the roles of CD5-expressing T cells in orchestrating human immune responses, including antibody production and cytokine secretion in vivo.
• Experimental Autoimmunity and Graft Studies: By depleting CD5+ T cells in humanized mice, the antibody enables modeling of autoimmune diseases or testing interventions to prevent graft rejection or mitigate graft-versus-host disease.
• Validating Therapeutics: Studies using UCHT-2 provide a platform for testing and validating new immunotherapies targeting CD5+ cells in a physiologically relevant in vivo context.

These applications rely on humanized mice, which are engineered to express human immune cells and are required because clone UCHT-2 is highly specific for human CD5 and does not cross-react robustly with murine CD5. Standard experimental protocols involve antibody administration followed by assessment of human CD5+ cell depletion or immune modulation.

Summary:
In vivo, clone UCHT-2 is primarily used for depletion of human CD5+ T cells, modeling human immune functions, and developing or testing therapies in humanized mice.

In the literature, UCHT-2, an anti-CD5 antibody, is commonly used in conjunction with several other antibodies or proteins to identify and study various cell types, particularly T and B cells. Here are some of the other commonly used antibodies or proteins used with UCHT-2:

• CD3 (e.g., clone UCHT1): This is a pan-T cell marker used to broadly define mature T cells. It is often paired with CD5 to identify T cells in flow cytometric analyses.
• CD4 and CD8: These are markers that distinguish between helper T cells (CD4+) and cytotoxic T cells (CD8+), respectively.
• CD19 and CD20: These are B cell markers. CD19 is a more specific B cell marker, while CD20 is expressed on mature B cells. CD5 can also be used to identify a subset of B cells, particularly CLL cells.
• CD22 or CD79: These are novel or functional markers used in more specialized settings for B cell identification.
• CD45: This is a leukocyte common antigen and is used to identify all nucleated white blood cells.

These combinations help in understanding the distribution and function of different lymphocyte subsets in health and disease.

Key Scientific Findings from Clone UCHT-2

Clone UCHT-2 is a murine monoclonal antibody broadly used in immunology research to specifically target and study the human CD5 antigen, a 67 kDa single-chain, type 1 transmembrane glycoprotein. Below are the main scientific findings and applications associated with this clone, as documented in the literature and product specifications.

Specificity and Antigen Expression

• Target: UCHT-2 specifically recognizes human CD5, a marker expressed on most thymocytes, the vast majority of peripheral T lymphocytes (over 90%), and a distinct subset of normal B lymphocytes, especially those found in B cell chronic lymphocytic leukemia (CLL).
• Negative Cells: The antibody does not react with monocytes, granulocytes, or natural killer (NK) cells, confirming its selectivity for lymphocytes.
• Staining Patterns: Peripheral blood T cells stain strongly, whereas thymic T cells show weaker reactivity, and about 70% of normal peripheral blood lymphocytes are positive.

Applications in Research

• Flow Cytometry: UCHT-2 is extensively used for multiparameter flow cytometric analysis to characterize CD5 expression on human peripheral leukocytes and lymphoid subpopulations, aiding in the identification of T cell and B cell subsets.
• Disease Characterization: The clone is leveraged in studies of leukemias and lymphomas, particularly for phenotyping B-CLL samples where CD5-positive B cells are a hallmark.
• Functional Assays: UCHT-2 has been incorporated into protocols to assess cell surface expression, to enrich or deplete CD5+ cells, and in experiments with humanized mouse models for immunotherapy research.

Technical and Clinical Relevance

• Reagent Development: The monoclonal nature and high specificity of UCHT-2 make it a reliable reagent for both research and potential clinical applications, providing reproducible results in multiple assay formats.
• Natural Ligand: CD72 is identified as the natural ligand for CD5, and CD5+ B cells are noted for producing polyreactive antibodies, predominantly IgM.

Summary Table: Key Properties of UCHT-2 Clone

Conclusion

Clone UCHT-2 is a cornerstone reagent for immunophenotyping, enabling precise identification of CD5+ cell populations in both health and disease. Its specificity, validated across decades of use, supports its continued role in basic, applied, and translational immunology research.

Dosing Regimens of Clone UCHT-2 in Mouse Models

Clone UCHT-2 is a widely used anti-human CD5 monoclonal antibody with applications in both in vitro assays (e.g., flow cytometry, immunohistochemistry) and in vivo research, such as humanized mouse models for immunology and oncology. However, detailed, standardized dosing regimens for clone UCHT-2 in various mouse models are not explicitly described in the available literature. Here is a synthesis of current knowledge and practical considerations:

No Universal Dosing Guideline

• There is no published, universally recommended dose for clone UCHT-2 in mouse models. While product sheets describe the antibody's specificity and applications, they do not specify in vivo dosing protocols.
• Optimal dosing must be determined empirically for each experimental setup, taking into account the mouse strain, degree of human immune system engraftment (in humanized mice), the target cell population, and the desired biological effect (e.g., depletion, modulation, or tracking).
• Similar anti-human antibodies (e.g., anti-CD8) are typically administered at 100–250 µg per mouse via intraperitoneal injection, with dosing frequency usually every 3 days. However, these are only general guidelines and may not directly apply to clone UCHT-2.

Practical Considerations for Humanized Mouse Models

• Humanized mice (e.g., THX mice) are increasingly used to model human immune responses, including antibody-mediated therapies. These models reconstitute human lymphoid and myeloid cells, providing a more relevant system for testing anti-human CD5 antibodies like UCHT-2.
• Dosing in these models may require optimization based on the level of human immune cell engraftment, the kinetics of human CD5+ cell repopulation, and the specific research question (e.g., immunotherapy, autoimmunity, or leukemia modeling).
• Empirical testing is essential: Researchers should perform pilot studies to establish the dose, route (intraperitoneal, intravenous, etc.), and frequency that achieve the desired biological effect without excessive toxicity.

General Recommendations

• Start with doses used for similar anti-human antibodies (e.g., 100–250 µg/mouse) as a reference, but titrate based on experimental readouts such as target cell depletion, pharmacokinetics, and tolerability.
• Monitor human CD5+ cell populations in blood and tissues to assess the efficacy and duration of the antibody effect.
• Adjust for specific models: For highly immunodeficient or heavily humanized mice, lower doses may be sufficient, whereas more robust engraftment might require higher or more frequent dosing.
• Consult literature on similar antibodies and consider contacting the antibody supplier or technical support for unpublished data or recommendations from other users.

Summary Table: Key Points

Conclusion

Dosing regimens for clone UCHT-2 in mouse models are not standardized and must be tailored to the specific experimental context. Researchers should base initial doses on those used for similar anti-human antibodies, then empirically optimize for their particular mouse model and research objectives. Collaboration with suppliers and reference to analogous studies can provide practical starting points, but rigorous pilot testing remains essential.