BRGS mice lack lymphocytes and SIRPA recognizes human CD47-Fc. (A) Frequencies of blood leukocytes, erythrocytes, hemoglobin, and platelets in BRGS mice. Leukocyte counts in BRGS (2.69 ± 1.01 × 103/μL) and NOD-RG mice (2.23 ± 0.7 × 103/μL) are significantly decreased compared with that in C57BL/6 mice (9.6 ± 0.32 × 103/μL). BRGS mice have normal erythrocyte (9.63 ± 0.63 × 106/μL), hemoglobin (14.0 ± 0.6 g/dL), and platelet (8.7 ± 2.0 × 105/μL) counts. (B) Representative FACS plots of blood in C57BL/6 and BRGS mice. BRGS mice lacked T, B, and NK cells. (C) Binding activity of human CD47-Fc to SIRPA expressed in peritoneal macrophages derived from C57BL/6-RG, BRGS, or NOD-RG mice. Macrophages from BRGS and NOD-RG mice, but not those from C57BL/6-RG mice, were stained with human CD47-Fc on FACS. (D) Phagocytosis assay of C57BL/6-RG, BRGS, or NOD-RG macrophages against human CD34+CD38− CB HSCs (n = 3). The phagocytic index was determined as the number of engulfed cells per 100 macrophages. Bars indicate mean ± SD.
