BALB/c-hCD3 Mice

Catalog Number: C001326

Strain Name: BALB/cAnCya-Cd3^tm1(hCD3)/Cya

Genetic Background: BALB/cAnCya

Reproduction: Homozygote x Homozygote

Strain Description

Cluster of differentiation 3 (CD3) is a multimeric protein complex that is essential for T cell activation and antigen recognition. It consists of five different polypeptide chains (γ, δ, ε, ζ, and η) that are noncovalently associated with the T cell receptor (TCR). The TCR is responsible for recognizing antigens presented by antigen-presenting cells (APCs), while CD3 transduces the activation signal into the T cell and activates helper T-cells and cytotoxic T-cells ^[1-2]. The CD3-TCR complex is expressed on the surface of all mature T cells, and its assembly is required for T cell development and function. CD3 plays a crucial role in stabilizing the TCR and facilitating its interaction with antigens. It also recruits signaling molecules to the TCR, which initiates a cascade of events that leads to T cell activation. CD3 is a highly specific T cell marker, and its expression is increased upon T cell activation. This makes it a valuable tool for identifying and characterizing T cells in tissues and blood samples. CD3 staining is also used to diagnose T-cell lymphomas and leukemias. Due to its essential role in T cell activation, CD3 is a promising target for immunosuppressive therapy. Several anti-CD3 monoclonal antibodies have been developed and are being tested in clinical trials for the treatment of autoimmune diseases, such as type 1 diabetes and rheumatoid arthritis ^[3].

This strain was generated using embryonic stem cell (ES cell) targeting technology, where the mouse CD3 coding gene was replaced in situ with the human CD3 gene. This model is valuable for studying T cell activation, antigen recognition mechanisms, and the development of CD3-targeted drugs for autoimmune diseases.

Strain Strategy

The mouse Cd3e, Cd3d, and Cd3g genes which encode the three components of the CD3 complex, Cd3ε, Cd3δ, and Cd3γ, were replaced by the corresponding human homologous genes.

Application

• Research on the immune system;
• T cell activation and antigen recognition studies;
• Research on immunosuppressive therapy for autoimmune diseases;
• Development and evaluation of CD3-targeted drugs.
  
  

Validation Data

1. Detection of human and murine CD3 expression in CD45+ cells

Figure 1. Flow cytometry analysis of the expression of human CD3 (hCD3) and mouse CD3 (mCD3). Human CD3E+ cells were detected in the peripheral blood, thymus, and spleen of homozygous BALB/c-hCD3 mice, while mouse CD3E expression was almost absent. In wild-type mice (WT), only mouse CD3E expression was observed.

2. Assessment of cell subset composition in CD45+CD3+ T cells

Figure 2. Proportion of T cells and their subsets (CD4+ cells and CD8+ cells). The proportions of CD3+ T cells and their subsets, CD4+ and CD8+ T cells, in the peripheral blood (PB) and spleen of homozygous BALB/c-hCD3 and wild-type mice were indistinguishable.

3. Ex Vivo Tumor Killing Effect of PBMCs

Figure 3. In vitro cytotoxicity comparison between peripheral blood mononuclear cells (PBMCs) from wild-type mice (BALB/c), PBMCs from BALB/c-hCD3 mice (BALB/c-hCD3), and human PBMCs (hPBMCs). Isolated PBMCs from mice were incubated with human multiple myeloma cells (MM1R) for 48 hours to assess their tumor-killing efficacy. The results indicate that BALB/c-hCD3 mouse-derived PBMCs exhibit similar cytotoxic effects against human tumor cells as hPBMCs, while PBMCs from wild-type mice show weaker tumor-killing activity. Additionally, internal data suggests that BALB/c-hCD3 mouse PBMCs outperform similar models in the market (data not shown).

Effector cells (E): PBMC; Target cells (T): MM1R; E:T=1 : 1=2*10⁴ : 2*10⁴; Time: 48h; Antibody: 1nM BiTE.

Summary

BALB/c-hCD3 mice successfully express human CD3, and homozygous BALB/c-hCD3 mice no longer express mouse CD3, only human CD3. The proportions of T cells and their subsets (CD4+ T cells and CD8+ T cells) in homozygous BALB/c-hCD3 mice are similar to those in wild-type mice, indicating that the expression of human CD3 does not significantly affect the composition of T cells in mice. Additionally, in vitro cytotoxicity experiments using PBMCs from BALB/c-hCD3 mice demonstrate that they exhibit similar tumor-killing effects as human PBMCs, suggesting functional similarity between BALB/c-hCD3 mouse PBMCs and human PBMCs.

References

[1]Dong D, Zheng L, Lin J, Zhang B, Zhu Y, Li N, Xie S, Wang Y, Gao N, Huang Z. Structural basis of assembly of the human T cell receptor-CD3 complex. Nature. 2019 Sep;573(7775):546-552.
[2]Dykhuizen M, Ceman J, Mitchen J, Zayas M, MacDougall A, Helgeland J, Rakasz E, Pauza CD. Importance of the CD3 marker for evaluating changes in rhesus macaque CD4/CD8 T-cell ratios. Cytometry. 2000 May 1;40(1):69-75.
[3]Bolt S, Routledge E, Lloyd I, Chatenoud L, Pope H, Gorman SD, Clark M, Waldmann H. The generation of a humanized, non-mitogenic CD3 monoclonal antibody which retains in vitro immunosuppressive properties. Eur J Immunol. 1993 Feb;23(2):403-11.