BRGS mice show efficient engraftment of human HSCs comparable to NOD-RG mice. In the BM, human HSC engraftment was examined by flow cytometric analysis 8 weeks after transplantation. C57BL/6-RG mice (■; n = 5), female BRGS mice (●; n = 17), male BRGS mice (○; n = 12), female NOD-RG mice (▴; n = 13), and male NOD-RG mice (▵; n = 5) mice were analyzed. (A) Both BRGS and NOD-RG female mice showed excellent human CD45⁺ reconstitution. BRGS male mice showed significantly better engraftment compared with NOD-RG male mice. (B) Frequencies of CD19⁺ B cells, CD33⁺ myeloid cells, and CD34⁺CD38⁻ HSCs in BRGS and NOD-RG mice.