Humanizing NOD/SCID/IL-2Rγnull (NSG) mice using busulfan and retro-orbital injection of umbilical cord blood-derived CD34(+) cells.
BACKGROUND
Humanized mouse models are still under development, and various protocols exist to improve human cell engraftment and function.


METHODS
Fourteen NOD/SCID/IL-2Rγnull (NSG) mice (4‒5 wk old) were conditioned with busulfan and injected with human umbilical cord blood (hUCB)-derived CD34(+) hematopoietic stem cells (HSC) via retro-orbital sinuses. The bone marrow (BM), spleen, and peripheral blood (PB) were analyzed 8 and 12 weeks after HSC transplantation.


RESULTS
Most of the NSG mice tolerated the regimen well. The percentage of hCD45(+) and CD19(+) cells rose significantly in a time-dependent manner. The median percentage of hCD45(+)cells in the BM was 55.5% at week 8, and 67.2% at week 12. The median percentage of hCD45(+) cells in the spleen at weeks 8 and 12 was 42% and 51%, respectively. The median percentage of hCD19(+) cells in BM at weeks 8 and 12 was 21.5% and 39%, respectively (P=0.04). Similarly, the median percentage of hCD19(+) cells in the spleen at weeks 8 and 12 was 10% and 24%, respectively (P=0.04). The percentage of hCD19(+) B cells in PB was 23% at week 12. At week 8, hCD3(+) T cells were barely detectable, while hCD7(+) was detected in the BM and spleen. The percentage of hCD3(+) T cells was 2‒3% at week 12 in the BM, spleen, and PB of humanized NSG mice.


CONCLUSIONS
We adopted a simplified protocol for establishing humanized NSG mice. We observed a higher engraftment rate of human CD45(+) cells than earlier studies without any significant toxicity. And human CD45(+) cell engraftment at week 8 was comparable to that of week 12.
Department of Pediatrics, Korea Cancer Center Hospital, Seoul, Korea.
Young Kyung
YK
Kang
Department of Pediatrics, Korea Cancer Center Hospital, Seoul, Korea.
Yunmi
Y
Ko
Department of Pediatrics, Korea Cancer Center Hospital, Seoul, Korea.
Aery
A
Choi
Division of Radiation Effect, Korea Institute of Radiological and Medical Sciences, Seoul, Korea.
Hyeong Jwa
HJ
Choi
Laboratory Animal Facility, Korea Institute of Radiological and Medical Sciences, Seoul, Korea.
Jin-Hee
JH
Seo
Division of Radiation Effect, Korea Institute of Radiological and Medical Sciences, Seoul, Korea.; Laboratory Animal Facility, Korea Institute of Radiological and Medical Sciences, Seoul, Korea.
Minyoung
M
Lee
Department of Pediatrics, Korea Cancer Center Hospital, Seoul, Korea.
Jun Ah
JA
Lee
Busulfan; Hematopoietic stem cell; Humanized mice; Retro-orbital sinus