FIG. 1.
Human cell reconstitution in mice myeloablated by different protocols and treated with GM-CSF. (A) Determination of optimal doses of irradiation. A significant level of engraftment was achieved at an irradiation dose of between 500 and 650 cGy. A dose of 400 cGy was not effective (not shown). (B) Effect of GM-CSF administration. Newborn pups were irradiated at 650 cGy and injected subcutaneously with GM-CSF every day for 3 weeks (0.1 or 1 μg/dose/mouse) starting at 1 or 2 weeks of age. The number of human cells in the circulation was analyzed 4 weeks after last injection. (C) Effects of intrapartum busulfan administration. Pregnant dams were injected subcutaneously with 15 mg/kg of busulfan solution once, at day 18 postcoitus, and pups were irradiated after birth with 500 cGy or 400 cGy. In the last group busulfan was injected at days 15 and 18 and pups were not irradiated (B × 2). The animals were segregated by litter; each litter received the same CD34+ cell sample. Individual mouse profiles are presented in panels A, B, and C. Numbers above bars correspond to the mouse number (A) and doses of GM-CSF (B). (D) Statistical analysis of the efficacy of different myeloablative procedures presented in panels B and C. The groups were compared to irradiated mice alone. Results are expressed as means ± SEMs. (E) Statistical analysis of the effects of GM-CSF in irradiated animals. *, P < 0.05 by ANOVA.