Establishment and characterization of an immortalized renal cell line of the Chinese tree shrew (Tupaia belangeri chinesis).

The Chinese tree shrew holds a great potential as a viable animal model in biomedical research, especially for infectious diseases and neuropsychiatric disorders. A thorough understanding of the innate immunity, which represents the first line that defends the host against viral infection, of the Chinese tree shrew, is needed. However, the progress is hindered by the lack of a proper cell line for research usage. In this study, we established a cell line that is applicable to the study of tree shrew innate immune responses against viral infections. The Chinese tree shrew primary renal cells (TSPRCs) were immortalized by simian virus 40 large T antigen (SV40LT) transduction, and the immortalized cells were termed TSR6 (tree shrew renal cell #6). TSR6 showed a similar morphology to TSPRCs and expressed the epithelial cell-specific marker cytokeratin 18 (KRT18). In addition, TSR6 could be transfected by transfection reagent and was suitable for CRISPR/Cas9-mediated gene editing. Infection of Newcastle disease virus (NDV) or herpes simplex virus 1 (HSV-1) in TSR6 induced the mRNA expression of tree shrew interferon-β (tIFNB1) and myxovirus resistance protein 1 (tMx1) in a dose- and time-dependent manner. Collectively, we successfully established a tree shrew renal cell line and demonstrated that this cell line was suitable for the study of the innate immune response to viral infections.