The aim of this study was to obtain single cell-derived clones from human umbilical cord blood (hUCB) derived mesenchymal stem cell (MSC) population, to compare the gene expression patterns and differentiation characteristics among the hUCB derived MSC population and its monoclonal cell populations, and to determine if the MSC population is homogenous.

The single cells were isolated from a hUCB derived MSC population and cultured on each well of a culture plate. The gene expression pattern of each monoclonal cell population expanded from the single cells was detected by RT-PCR for osteogenic, chondrogenic, and adipogenic specific genes. The monoclonal cell populations were differentiated into osteogenic, chondrogenic, and adipogenic lineages and were confirmed by specific staining.

Fifteen monoclonal cell populations were obtained from the total seeding of 864 single cells. The cell morphology and gene expression patterns among the hUCB derived MSCs and its monoclonal cell population were different. Tri-lineage differentiation potency was different among the monoclonal cell populations.

The difference in the cell morphology, gene expression patterns, and differentiation characteristics among the monoclonal cell populations suggest heterogeneity of the MSC population isolated using the currently available method.