Differentiation of regulatory myeloid and T-cells from adult human hematopoietic stem cells after allogeneic stimulation

Donor hematopoietic stem cell (DHSC) infusions are increasingly being studied in transplant patients for tolerance induction. To analyze the fate of infused DHSCs in patients, we developed an culture system utilizing CD34 DHSCs stimulated with irradiated allogeneic cells in cytokine supplemented medium long-term. Flow cytometric analyses revealed loss of the CD34 marker and an increase in CD33 myeloid and CD3 T-cell proportion by 10.4% and 72.7%, respectively, after 21 days in culture. T-cells primarily expressed TcR-αβ and were of both CD4 and CD8 subsets. Approximately 80% of CD3 T cells lacked expression of the co-stimulatory receptor CD28. The CD4 compartment was predominated by CD4 CD25 CD127-FOXP3 Tregs (>50% CD4 CD127- compartment) with