SDRG Rat

Catalog Number: IR1023

Strain Name: SD-Rag2em1Il2rgem1/Cya

Genetic Background: Sprague-Dawley

 

Strain Description

The IL2RG gene, also known as CD132, encodes the interleukin-2 receptor gamma chain (IL-2Rγ), an essential signaling component in multiple interleukin receptors and a common receptor subunit for various critical immune factors, including IL-2, IL-4, IL-7, IL-9, IL-15, and IL-21. These interleukin receptors are located on the surface of immune cells, and when any of these interleukins binds to its receptor, it triggers a cascade of intracellular reactions that promote cell growth and division. Consequently, IL-2Rγ is also called the common gamma chain (γc). In humans, mutations in IL2RG can lead to X-linked severe combined immunodeficiency (X-SCID), a condition characterized by the absence of T cells and natural killer (NK) cells, along with impaired B cell function, leaving patients highly susceptible to recurrent infections and rarely surviving beyond infancy [1]. Studies have shown that Il2rg knockout rats exhibit a severe immunodeficient phenotype, with markedly reduced T and B cells, absent NK cells, and intact macrophages [2].

The RAG2 gene encodes a protein that, together with RAG1, forms the RAG complex, which is crucial for V(D)J recombination during B and T cell maturation. In V(D)J recombination, the RAG complex binds to the recombination signal sequence (RSS) adjacent to DNA's V, D, or J segments. The complex cleaves DNA between the signal sequence and segments, allowing segments to rearrange to different gene regions. This process occurs repeatedly in B and T cells, rearranging V, D, and J segments into various combinations. The resulting protein diversity enables a broader recognition of foreign invaders and allows the body to defend effectively against infections. RAG2 is involved not only in catalysis but also in regulating the reaction by controlling access to specific loci [3]. Lack of functional RAG2 protein can also cause SCID. In rats, Rag2 gene knockout leads to an absence of V(D)J recombination, blocking T and B cell differentiation, development, and maturation, resulting in severe thymic hypoplasia, a lack of mature T and B cells, and a compensatory increase in NK cells [4-5].

SDRG rats are an immunodeficient model with both Il2rg and Rag2 genes knocked out. Research indicates that compared with rats with a single Il2rg or Rag2 gene knockout, rats with a dual knockout of Il2rg and Rag2 exhibit a more severe SCID phenotype. Compared to Il2rg and Rag2 double-knockout mice, Il2rg and Rag2 double-knockout rats show higher engraftment rates for human tumor cells or xenografts in the construction of CDX and PDX models, retaining better characteristics of primary tumors [6]. Data suggest that SDRG rats, characterized by the complete absence of mature T cells, B cells, and circulating NK cells, can be widely applied in oncology and immunology research.

Strain strategy

To generate SDRG rats, Il2rg knockout rats and Rag2 knockout rats on a Sprague-Dawley background were crossbred. The gene-editing strategies for Il2rg and Rag2 knockout rats are illustrated below.


Figure 1. Il2rg Gene Knockout Strategy. The Il2rg gene, located on the X chromosome in rats, was knocked out by targeting Exons 1-6 using gene-editing techniques.


Figure 2. Rag2 Gene Knockout Strategy. The Rag2 gene, located on chromosome 3 in rats, was knocked out by targeting Exon 3 with gene-editing techniques.

Application

  • Oncology: Suitable for CDX and PDX tumor model construction and evaluation of anti-tumor drug screening.
  • Immunology: Investigating mechanisms of immune cell development and the pathogenesis of immune disorders.
  • Pathogen Microbiology: Studying the infection mechanisms of viral and bacterial infectious diseases.
  • Stem Cell Biology: Researching human stem cell transplantation.

 

Validation Data

1. Detection of T, B, and NK Cell


Figure 3. Comparison of Peripheral Blood T Cells (CD3+), B Cells (CD45R+), and NK Cells (CD161+) in Wild-Type (WT) and SDRG Rats. Flow cytometry analysis was performed to detect immune cell composition in the peripheral blood of WT and SDRG rats. Results demonstrated that T cells, B cells, and NK cells were completely absent in the peripheral blood of SDRG rats compared to WT rats.




References
[1]Spolski R, Li P, Leonard WJ. Biology and regulation of IL-2: from molecular mechanisms to human therapy. Nat Rev Immunol. 2018 Oct;18(10):648-659.
[2]Mashimo T, Takizawa A, Voigt B, Yoshimi K, Hiai H, Kuramoto T, Serikawa T. Generation of knockout rats with X-linked severe combined immunodeficiency (X-SCID) using zinc-finger nucleases. PLoS One. 2010 Jan 25;5(1):e8870.
[3]Schatz DG. V(D)J recombination. Immunol Rev. 2004 Aug;200:5-11.
[4]Noto FK, Adjan-Steffey V, Tong M, Ravichandran K, Zhang W, Arey A, McClain CB, Ostertag E, Mazhar S, Sangodkar J, DiFeo A, Crawford J, Narla G, Jamling TY. Sprague Dawley Rag2-Null Rats Created from Engineered Spermatogonial Stem Cells Are Immunodeficient and Permissive to Human Xenografts. Mol Cancer Ther. 2018 Nov;17(11):2481-2489.