Generation of functional natural killer and dendritic cells in a human stromal-based serum-free culture system designed for cord blood expansion.

Objective: We have previously reported on the ability of a mesenchymal stem cell-based serum-free culture system to expand human cord blood (CB) hematopoietic stem cells along the myeloid pathway and simultaneously generate a CD7(+)CD34(-) population. In this study, we investigated the ability of the CD7(+)CD34(-) population to differentiate into natural killer and dendritic cells (DCs).

Materials And Methods: CB CD34(+) cells were expanded over a mesenchymal stem cell layer in serum-free medium supplemented with stem cell factor, basic fibroblast growth factor, leukemia inhibitor factor, and Flt-3 ligand for 2 weeks.

A human stromal-based serum-free culture system supports the ex vivo expansion/maintenance of bone marrow and cord blood hematopoietic stem/progenitor cells.

Objective: We investigated the role of human stromal layers (hu-ST) on the ex vivo expansion/maintenance of human hematopoietic stem/progenitor cells (HSC) from adult bone marrow (BM) and umbilical cord blood (CB).

Materials And Methods: BM and CB CD34(+)-enriched cells were cultured in serum-free medium supplemented with SCF, bFGF, LIF, and Flt-3, in the presence or absence of stroma, and analyzed for proliferation, phenotype, and clonogenic potential.

Results: Significant expansion of BM and CB CD34(+) and CD34(+)CD38(-) cells were achieved in the presence of hu-ST.

Human haematopoietic stem cells that mediate long-term in vivo engraftment are not susceptible to infection by human cytomegalovirus.

A human/sheep xenograft model was used to evaluate whether long-term engrafting haematopoietic stem cells (HSC) are susceptible to human cytomegalovirus (HCMV) infection. CD34+ Lin- HSC were isolated by fluorescence-activated cell sorting (FACS) from the bone marrow (BM) of HCMV-positive and HCMV-negative normal donors. Cells from the latter group were infected in vitro with HCMV.