Establishment of nude mice with complete loss of lymphocytes and NK cells and application for in vivo bio-imaging.

BACKGROUND Nude mice are used in human xenograft research; however, only 25-35% of human tumors have been successfully transplanted into nude mice and their application is limited due to high natural killer (NK) cell activity. More severely immunodeficient mice with loss of NK activity are needed to overcome this limitation. MATERIALS AND METHODS Balb/c nude Rag-2(-/-)Jak3(-/-) (Nude-RJ) mice were established by crossing Rag-2(-/-)Jak3(-/-) mice and nude mice. The K562 cell line was implanted subcutaneously to compare tumorigenicity between Nude-RJ mice and Nude mice. The cholangiocarcinoma mCherry expressing cell line (KKU-M213) was implanted subcutaneously, and fluorescence intensity and tumor weight were measured. RESULTS Nude R/J mice showed complete loss of lymphocytes and NK cells. Xeno-transplantation of K562 cells showed higher proliferation in Nude R/J mice than nude mice. Subcutaneously-transplanted mCherry-transduced KKU-M213 cells were successfully detected with a fluorescence imager. CONCLUSION Nude-R/J mice are valuable tools for in vivo imaging studies in biomedical research.