Characterization of an N-Terminal Non-Core Domain of RAG1 Gene Disrupted Syrian Hamster Model Generated by CRISPR Cas9.

The accumulating evidence demonstrates that Syrian hamsters have advantages as models for various diseases. To develop a Syrian hamster () model of human immunodeficiency caused by gene mutations, we employed the CRISPR/Cas9 system and introduced an 86-nucleotide frameshift deletion in the hamster gene encoding part of the N-terminal non-core domain of RAG1. Histological and immunohistochemical analyses demonstrated that these hamsters (referred herein as hamsters) had atrophic spleen and thymus, and developed significantly less white pulp and were almost completely devoid of splenic lymphoid follicles. The hamsters had barely detectable CD3⁺ and CD4⁺ T cells. The expression of B and T lymphocyte-specific genes (CD3γ and CD4 for T cell-specific) and (CD22 and FCMR for B cell-specific) was dramatically reduced, whereas the expression of macrophage-specific (CD68) and natural killer (NK) cell-specific (CD94 and KLRG1) marker genes was increased in the spleen of hamsters compared to wildtype hamsters. Interestingly, despite the impaired development of B and T lymphocytes, the hamsters still developed neutralizing antibodies against human adenovirus type C6 (HAdV-C6) upon intranasal infection and were capable of clearing the infectious viruses, albeit with slower kinetics. Therefore, the hamster reported herein (similar to the hypomorphic mutations in humans that cause Omenn syndrome), may provide a useful model for studying the pathogenesis of the specific RAG1-mutation-induced human immunodeficiency, the host immune response to adenovirus infection and other pathogens as well as for evaluation of cell and gene therapies for treatment of this subset of RAG1 mutation patients.