A high-quality severe combined immunodeficiency (SCID) rat bioresource

Area of Science:

• Immunology
• Genetics
• Animal Models

Background:

• Immunodeficient animals are crucial for research, including humanized models, regenerative medicine, and oncology.
• Laboratory rats offer advantages over mice for tissue and organ transplantation due to their larger size.
• A lack of high-quality immunodeficient rat models has limited their research applications.

Purpose of the Study:

• To develop a high-quality, accessible resource of immunodeficient rats for scientific research.
• To utilize CRISPR/Cas9 gene editing to create novel immunodeficient rat strains.
• To establish a valuable bioresource for various biomedical research fields.

Main Methods:

• CRISPR/Cas9 genome editing was employed to knock out the interleukin-2 receptor gamma chain gene (Il2rg) and/or recombination activating gene 2 (Rag2) in F344/Jcl rats.
• Founder rats with specific frame-shift mutations were selected and bred to establish lines of immunodeficient rats.
• Phenotypic characterization included assessment of thymic hypoplasia, peripheral blood cell counts, and lymphocyte population analysis via flow cytometry.

Main Results:

• Severe combined immunodeficiency (SCID) rats were successfully generated with mutations in Il2rg and/or Rag2.
• Immunodeficient rats exhibited severe thymic hypoplasia and significantly decreased white blood cell counts, primarily due to lymphocyte reduction.
• Flow cytometry confirmed marked reductions in B cells and natural killer cells, with significant but varied reductions in T cells between single and double knockout rats.
• The developed SCID rats did not display growth retardation or gametogenesis defects.

Conclusions:

• A high-quality resource of immunodeficient rats (SCID rats) has been established using CRISPR/Cas9 technology.
• These novel SCID rats are suitable for transplantation studies and are valuable for humanized animal models, regenerative medicine, and oncology.
• This bioresource, managed by the National BioResource Project in Japan, is now available for widespread research use.