Lethally irradiated mice harboring HSCs deficient for Rb and E2f8 suffer from severe anemia. (A-D) Peripheral blood RBC numbers (A), hemoglobin (B), hematocrit (C), and spleen weights (D) of mice with the indicated genotypes. (E-J) Flow cytometric analysis of spleens (E-F) and BM (G-H) using lineage-specific cell-surface markers. Data labeled “post” were from mice that received BM donor cells harvested from mice that were injected with poly(I:C), whereas data labeled “+35” were from mice that received BM donor cells harvested from mice that had not been injected with poly(I:C). In the latter case, recipient mice were injected with poly(I:C) 35 days after transplantation.