Growth, differentiation capacity, and function of mesenchymal stem cells expanded in serum-free medium developed via combinatorial screening.

The presence of serum in cell culture medium presents an obstacle to safe and efficient production of hMSCs for therapeutic purposes. Availability of defined medium will be crucial to elucidating the mechanism of action of hMSCs in many indications as well as a prerequisite to consistently produce cells with predictable performance characteristics. Using a bioinformatics driven approach, which we call the BD Discovery Platform, we have developed a novel serum-free medium that supports highly efficient growth while maintaining the surface markers and functional characteristics defining hMSCs.

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 cytomegalovirus persists in myeloid progenitors and is passed to the myeloid progeny in a latent form.

CD34+ progenitor cells can harbour latent human cytomegalovirus (HCMV); however, the mechanisms of HCMV latency remain unclear. We have investigated the effects of the haematopoietic lineage restriction on the establishment and spread of the latent HCMV to progeny cells. In vitro-infected and latently-infected haematopoietic progenitor cells derived from HCMV seropositive donors were studied.

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.