An enriched population of CD45, CD34 and CD117 stem cells in human umbilical cord blood for potential therapeutic regenerative strategies

Human umbilical cord blood (hUCB) is a primitive source of stem cells and is being banked worldwide for the purpose of future clinical use. Lineage negative (Lin-ve) stem cells are one of the primitive populations in hUCB which are capable of self-renewal and differentiation into multiple lineages. These cells have not been adequately investigated for their stem cell characteristics. We have analyzed the immunophenotypic expression of CD45, CD34 and CD117 markers on three different cell populations in hUCB viz., mononucleated cells (MNCs), Lineage positive (Lin+ve) and Lin-ve cells. The CD34 and CD117 expression was found to be 60 fold more in the Lin-ve population as compared to MNCs and Lin+ve cells. This expression was further enhanced in CD45+Lin-ve fraction. The CD34+ and CD117+ Lin-ve cells showed 99% positivity for CD45. Our data suggest that CD34+ CD117+ Lin-ve cells are reasonably enriched stem cell population in hUCB which can be clinically used for transplantation and other therapeutic purposes.