德晋贵宾厅

CD5 is a type I transmembrane glycoprotein primarily expressed on T cells and a subset of B cells, where it functions as an important immune regulatory molecule. CD5 modulates T cell receptor signaling thresholds and plays a key role in immune tolerance, autoimmunity, and lymphocyte activation.

The CD5 humanized mice were generated by replacing the extracellular domain of the mouse Cd5 gene with its human counterpart. This strategy preserves physiological expression patterns while enabling human CD5–specific antibody binding and signaling.

This model provides a translational platform for studying human CD5 biology, evaluating CD5-targeting antibodies in vivo, and investigating T cell–mediated autoimmune and inflammatory diseases.

Key Advantages

• Physiological humanized CD5 expression under endogenous regulatory control
• Enables human-specific antibody binding without mouse cross-reactivity
• Preserved immune homeostasis suitable for chronic studies
• High translational relevance for autoimmune and immunotherapy research
• Compatible with multiple disease models, including inflammatory and immune dysregulation models

Validation

• Molecular Validation: Humanized CD5 mRNA is specifically detected in lymphoid tissues of CD5 humanized mice, while mouse Cd5 transcripts are absent.
• Protein Expression Validation: Flow cytometry confirms that humanized CD5 protein is selectively expressed on T cells and CD5-positive immune subsets in CD5 humanized mice, with no detectable mouse CD5 expression.
• Functional Validation: Humanized CD5 maintains normal immune cell development and T cell distribution, while enabling binding and functional assessment of human CD5–specific antibodies in vivo.

Applications

• Autoimmune disease research (e.g., rheumatoid arthritis, multiple sclerosis, systemic lupus erythematosus)
• T cell signaling and immune tolerance studies
• In vivo validation of anti-CD5 antibodies
• Immunotherapy mechanism-of-action studies
• Preclinical pharmacology and safety assessment

Gene targeting strategy for CD5 humanized mice. Exons 2–7 of the mouse Cd5 gene, which encode the extracellular domain, were replaced with human CD5 exons 2–7 in B-hCD5 mice.

Strain-specific analysis of CD5 gene expression was performed in wild-type C57BL/6 mice (+/+) and homozygous CD5 humanized mice (B-hCD5, H/H) by RT-PCR. Thymocytes were collected for RNA isolation. Mouse Cd5 mRNA was detectable in thymocytes of wild-type mice, whereas human CD5 mRNA was detectable only in homozygous CD5 humanized mice and not in wild-type mice.

Strain-specific CD5 protein expression was analyzed by flow cytometry. Splenocytes were collected from wild-type C57BL/6 mice and homozygous CD5 humanized mice (B-hCD5, H/H) and stained with species-specific anti-CD5 antibodies. Mouse CD5 expression was detected in wild-type mice, whereas human CD5 was exclusively detected in homozygous CD5 humanized mice and not in wild-type mice.

Spleen cells were isolated from wild-type C57BL/6 mice (+/+) and homozygous CD5 humanized mice (B-hCD5, H/H) and analyzed by flow cytometry using species-specific anti-CD5 antibodies. Mouse CD5 was detectable in wild-type mice, whereas human CD5 was detectable only in homozygous CD5 humanized mice.

Strain specific CD5 expression analysis in homozygous B-hCD5 mice by flow cytometry. Spleen was collected from wild-type C57BL/6 mice (+/+) and homozygous B-hCD5 mice (H/H), and analyzed by flow cytometry with species-specific anti-CD5 antibody. mCD5 was detectable in wild-type, hCD5 was only detectable in homozygous B-hCD5 mice.

Splenocytes were isolated from wild-type C57BL/6 mice and homozygous CD5 humanized mice (B-hCD5) (n=3, 7-week-old) and analyzed by flow cytometry to determine the frequency of leukocyte subpopulations. (A) Flow cytometry analysis was performed to assess leukocyte composition. (B) Frequencies of immune cell subsets were quantified. The percentages of T cells, B cells, NK cells, dendritic cells, neutrophils, monocytes, macrophages, CD4+ T cells, CD8+ T cells, and Tregs in CD5 humanized mice were comparable to those observed in C57BL/6 mice. These results demonstrate that humanization of CD5 does not alter the frequency, development, or distribution of leukocyte subpopulations in the spleen. In addition, leukocyte subpopulation frequencies in lymph nodes and blood of CD5 humanized mice were also comparable to wild-type C57BL/6 mice (data not shown). Values are expressed as mean ± SEM. Statistical significance was determined using two-way ANOVA. *P < 0.05, **P < 0.01, ***P < 0.001. Homozygous mutation of this gene does not result in a phenotype. (Tarakhovsky A et al., 1994)

Q1: What makes CD5 humanized mice unique?

A1: They express humanized CD5 under physiological control, enabling accurate in vivo testing of human CD5–targeting therapies.

Q2: Can these mice be used for antibody validation?

A2: Yes. They are designed specifically for in vivo validation of anti-human CD5 antibodies.

Q3: Does CD5 humanization affect immune development?

A3: No. Immune cell composition and T cell subsets remain comparable to wild-type mice.

Q4: What disease areas benefit most from this model?

A4: Autoimmune diseases, immune tolerance disorders, and T cell–mediated inflammatory conditions.

Q5: Is this model suitable for long-term studies?

A5: Yes. Normal growth, immune homeostasis, and physiological stability support chronic dosing and longitudinal studies.