Human hematopoiesis in the livers of mice transplanted with fetal cells.

<p>(A) Hematopoietic precursors are present in the liver of a mouse analyzed 130 days after being transplanted with 1×10⁶ hFL cells. Filled arrows identify CD38⁻CD34⁺⁺ and CD133⁺CD34⁺⁺ cells, possible HSCs, whereas open arrows point to committed progenitors. (B) Various committed hematopoietic progenitor populations are evident in the liver including B-cell progenitors and myeloid progenitors shown from among CD19⁻ human cells.The bottom row of data shows immature erythroid cells that express low levels of CD235a and high levels of CD71 as indicated by the arrows. Data are from 4 pooled livers analyzed 148 days after transplantation with 2×10⁵ Lin⁻ hFL cells. (C) HPP-CFC and LPP-CFC responsive to human-specific cytokines were assayed from the light-density livers cells harvested from 5 transplanted and 1 untransplanted NOD-SCID mice. Mice were analyzed 30 days after transplant with 1×10⁷ hFBM cells of 23 weeks' gestation. Lines indicate the total number of CD34^+/++ and CD133⁺CD34⁺⁺ cells (right axis) shown on top of a bar chart of colony numbers (left axis). (D) A photomicrograph of representative myeloid colonies grown from liver cells shows both a large HPP-CFC-derived colony and smaller LPP-CFC-derived colonies. The size of the colonies can be gauged from the 2 mm grid shown in the background.