FACS analysis of enriched human hematopoietic stem cells (HSCs) and multilineage reconstitution. (A) Pretransplantation umbilical cord blood (UCB) HSC/HPC enrichment as identified by antibodies to CD34 (phycoerythrin [PE]) and CD45 (allophycocyanin [APC]). Positive fraction (right) shows more than 90% purity of CD34⁺CD45⁺ cells. Negative fraction (left) contains no CD34⁺ cells. (B) Multilineage human hematopoietic reconstitution in NOD/scid mouse bone marrow seen 4 weeks after human CD34⁺ cell transplantation. Bone marrow cells stained positive with human specific antibodies against leukocytes (CD45), B cells (CD19), T cells (CD3), and myelomonocytic cells (CD15). All panels shown are gated on live cells. (C) Fluorescence-activated cell sorting (FACS)–sorted control murine EPCs (VEGR-2⁺) from mice undergoing retinal ischemia, stained for DNA content with propidium iodide (left panel); sorted xenograft-derived human EPCs stained for DNA content with propidium iodide (right panel). Both panels exhibit a classic diploid staining profile.