Efficient in vivo selection and chemo-protection in non-human primates. (A) Representative gene-marking data in a baboon following chemotherapy treatment with either O6BG (120 mg/m2) and TMZ (600–1400 mg/m2) (solid arrows) or O6BG (120 mg/m2) and BCNU (40 mg/m2) (dashed arrows). The data is plotted as FACS+ MGMT-GFP granulocytes (closed circles) and FACS+ YFP granulocytes (open circles). (B) Absolute neutrophil counts following initial conditioning and subsequent chemotherapy treatment with O6BG/TMZ (solid arrows) or O6BG/BCNU (dashed arrow).