Key immune cell cytokines have a significant role in the expansion of CD26 population of cord blood mononuclear cells.

BACKGROUND: Umbilical cord blood expresses cluster of differentiation (CD) 26, a fraction of CD34 + cells, negatively regulating in vivo homing and engraftment of hematopoietic stem cells. CD26 is highly expressed in various cells such as HSCs, immune cells, fibroblasts, and epithelial cells. It has been shown that inhibition of the CD26 on CD34 + cells improve the efficiency of transplantation of hematopoietic stem and progenitor cells. This study aimed to investigate the effect of key immune cell cytokines on CD26 expansion. MATERIAL AND METHODS: Cord blood mononuclear cells were cultured for 21 days using the stem cell factor, fetal liver tyrosine kinase 3 (Flt3) ligand (FL), interleukin (IL) 2, IL7, and IL15. Harvested cells were analyzed by flow cytometry at distinct time points. RESULTS: Our results showed that utilization of IL7 significantly improved the expression of total CD26 + cells (8.6-fold higher). When either IL2 or IL15 were added to the culture, the expression also improved 2.5-fold. The IL2 and IL7 showed significant effect on the expansion of both the CD26 + and CD26 fractions of the CD34 + cells. However, the effects of IL15 on CD26 + and CD26 -expansion were similar. CONCLUSION: Taken together, our data suggested that using IL7 causes higher proliferation of CD26 cells in comparison to that seen under other culture conditions.

IL2rg Cytokines Enhance Umbilical Cord Blood CD34+ Cells Differentiation to T Cells.

PURPOSE: Umbilical cord blood (UCB) is an alternative source of hematopoietic stem cell (HSC) transplantation for the treatment of patients with leukemia if matched donor is not available. CD34+ is a pan marker for human hematopoietic stem cells, including umbilical cord blood stem cell. In comparison to other sources, cord blood CD34+ cells proliferate more rapidly and produce large number of progeny cells. For ex vivo expansion of Umbilical Cord Blood- HSCs/HPCs, different combinations of cytokines have been used in many laboratories. IL2rg cytokines, including IL2, IL7 and IL15, are key cytokines in the regulation of differentiation, proliferation and survival of immune cells. IL2 is important cytokine for T cell survival and proliferation, IL7 involve in B cell development and IL15 is a key cytokine for NK cell development. In this study we evaluated the generation of T cells derived from CD34+ and CD34- cord blood mononuclear cells by using combination of cytokines including IL2, IL7 and IL15. METHODS: Cultured cord blood mononuclear cells were evaluated at distinct time points during 21 days by using flow cytometry. RESULTS: Present study showed that differentiation of T cells derived from CD34+ cord blood mononuclear cells increased by using IL2 and IL7 at different time points. In the other hand IL15 did not show any significant role in generation of T cells from CD34+ cord blood mononuclear cells. CONCLUSION: Taken together, our data illustrated that either IL2 or IL7 versus other cytokine combinations, generate more T cell from cord blood CD34 cells, probably this cytokines can be the best condition for ex vivo expansion of UCB HSCs.

CD26+ Cord Blood Mononuclear Cells Significantly Produce B, T, and NK Cells.

BACKGROUND: Umbilical cord blood (UCB) is an alternative source of hematopoietic stem cell transplantation (HSCT), used in Leukemia treatment. CD26+ cells, a fraction of CD34+cells, are a major population of UCB cells which negatively regulate the in vivo homing and engraftment of HSCs. CD26 is highly expressed in various cells such as HSCs, immune cells, fibroblasts, and epithelial cells. It has been shown that the inhibition of the CD26 on CD34+ cells improves the efficiency of Hematopoietic Stem and Progenitor Cell (HPC) transplantation. OBJECTIVE: To evaluate the relationship between the production of B, T, and NK cells from the CD26+ fraction of cord blood mononuclear cells. METHODS: Cord blood mononuclear cells were cultured for 21 days using different combinations of stem cell factors (SCF), Flt3 ligand (FL), IL-2, IL-7, and IL-15. The harvested cells were then analyzed by flowcytometry every week for 21 days. RESULTS: T cell differentiation from CD26 subset of cord blood mononuclear cells increased by using IL-2 and IL-7. Our data showed that IL-2 and IL-7 significantly affected the generation of B cells from CD26 positive cord blood mononuclear cells. On the other hand, NK (NKp46+) derived CD26+ cells increased by IL-15 and IL-2. CONCLUSION: Taking all into account, we conclude that B, T, and NK cells can differentiate from the CD26+ subset of mononuclear cord blood cells by using key regulatory cytokines.