Sustained production of human β-globin protein (β^A) in the peripheral blood of TNS9-transduced bone marrow chimeras.

(A) The percent of hemoglobin tetramers that incorporate β^A, termed Hbb^hu (filled squares), and the percent of peripheral RBCs that stain positive for β^Achain (filled circles) remained stable up to 40 weeks after BMT. (B) Cellulose acetate gel electrophoresis shows Hbb^hu levels in 3 TNS9-transduced bone marrow chimeras (TNS9) 40 weeks after transplantation. Control lanes contain normal C57BL/6 (B6) and transgenic mouse line A85.68 (Tg28) blood samples. The fraction of Hbb^hu relative to total hemoglobin (Hbb^hu/Hbb^hu + Hbb^mu) is indicated below each sample. (C) Peripheral blood erythrocytes from TNS9-transduced bone marrow chimeras were stained for TER-119 (red) and β^A (green, becoming yellow when superimposed on the red signal), then analyzed under an immunofluorescence microscope. Upper left panel shows normal C57BL/6 RBCs; upper right panel shows 50:50 mix of RBCs from normal C57BL/6 and A85.68 mice; lower panel is a representative blood sample from a TNS9-treated bone marrow chimera analyzed 40 weeks after transplantation. Original magnification × 40.