A novel hairless highly immunodeficient mice model optimized for in vivo imaging

In vivo imaging is one of the analytical technologies that has been rapidly growing in demand in recent years to non-invasively observe the behavior of molecules such as genes and proteins in vivo and perform quantitative and qualitative analysis. Since the hair blocks and absorbs the fluorescence, Nude and Hairless mice have been used for in vivo imaging. Nude mice have been used for in vivo imaging for a long time; however, more efficient mice are needed for the next generation of imaging. We established a novel Hairless Rag2/Jak3 KO mice (Hairless R/J mice) model that exhibits hairlessness and a lack of T, B, and NK cell phenotypes. Hairless R/J mice exhibit thinner skin than that of Nude R/J mice. These mice also showed superior optical properties compared with Nude R/J mice, as demonstrated by green fluorescent beads and the mCherry-expressing human cholangiocarcinoma cell line M213, following subcutaneous transplantation. Furthermore, we show that Ihara cells, a human malignant melanoma cell line, can be used to facilitate live imaging of the growth of transplanted tumors. This novel mouse model will be a valuable tool for noninvasive tumor monitoring and evaluation of anticancer therapies.