Hematopoietic reconstitution kinetics of enriched stem cells and their ex vivo expanded progeny.
Lethally irradiated B6.SJL mice were injected with 103 Ly-5 congenic Sca-1+c-kit+Lin+ BM cells (open circles; n = 7 mice from 3 experiments), or their entire expanded progeny (approximately 2 × 106 cells) generated after 7 days of culture in IL-6, IL-11, G-CSF, SCF, FLK, and TPO (closed circles; n = 37 mice from 5 experiments). Shown are the mean ± SEM (standard error of the mean) number of (A) peripheral blood leukocytes, (B) erythrocytes, and (C) platelets counted on the indicated days after transplantation. The ranges of blood counts in normal B6.SJL mice are defined by the upper shaded areas; the upper bounds for leukocytes (9.2 × 103/μL) and erythrocytes (11.4 × 106/μL) are off scale. The radiation-induced decline of circulating cells in controls that did not receive a transplant is denoted, until their deaths, by the hatched lines. The lower shaded areas indicate minimal engraftment thresholds for leukocytes, 2 × 103/μL (20% of normal); erythrocytes, 4.7 × 106/μL (50% of normal); and platelets, 2 × 105/μL (20% of normal). Standard errors not shown are too small for the scale used.
