Summary

Background: Experimental and clinical protocols are being developed for the cryopreservation of human hematopoietic progenitor cells. However, the effect of these procedures on the potential for HPC[1] to repopulate bone marrow is unknown.

Objectives: To examine the effect of cryopreservation on the ability of fetal human liver HPC, which include CD34+ cells and long-term culture-initiating cells, to repopulate immunodeficient non-obese diabetic/severe combined immunodeficiency mouse bone marrow.

Methods: Groups of sublethally irradiated NOD[2]/SCID[3] mice were injected intravenously with cryopreserved or freshly isolated fetal human liver HPC.

Results: Seven weeks after transplantation, flow cytometric analysis of bone marrow samples showed that mice that received the transplanted cells (either cryopreserved or freshly isolated) demonstrated both lymphoid and myeloid differentiation as well as the retention of a significant fraction of CD34+ cells. Conclusions: Cryopreserved fetal human liver-derived HPC appear to be capable of initiating human cell engraftment in NOD/SCID mouse bone marrow and open the possibility of using cryopreserved fetal human liver HPC for gene manipulation, gene transfusion therapy, and transplantation purposes.
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[1] HPC = hematopoietic progenitor cells
[2] NOD = non-obese diabetic
[3] SCID = severe combined immunodeficiency