Human T cell development in the liver of humanized NOD/SCID/IL-2R-^null(NSG) mice generated by intrahepatic injection of CD34⁺ human (h) cord blood (CB) cells

In this study, we explore the possibility of human T cell development in the liver of humanized mice generated by intrahepatic injection of CD34⁺ hCB cells into conditioned NOD/SCID/IL-2R-^null(NSG) newborn mice. The intrahepatic injection of CD34⁺ hCB cells led to effective reconstitution of human myeloid and lymphoid lineage cells. In contrast to the previously reported Rag2^-/-γ_c^-/- humanized mice, interestingly, the thymus function of humanized NSG mice was markedly reduced in terms of its size and cell contents, whereas the livers of humanized NSG mice profoundly contained double-positive (DP), hCD4 and hCD8 single positive (SP), hCD34⁺hCD38^lohCD1a^- (TSP), hCD34⁺hCD38^hihCD1a^- (ETP), and hCD34⁺hCD38⁺hCD1a⁺ (pre-T cells) cells. Furthermore, immunostaining of the liver revealed that human T cells were co-localized with hDCs. Taken together, our results demonstrate that the intrahepatic injection of hCD34⁺ hCB cells can facilitate human T cell development in the livers of humanized NSG mice.