Generation of hematopoietic stem/progenitor cells with property of strengthened cell mediated immunity from an embryonic stem cell line

AIM:To induce lymphoid stem cells and/or T-cell precursors to differentiate into functional mature T lymphocyte, and to increase the surface marker of T lymphocytes such as CD₃⁺, while embryonic stem(ES) cells differentiated into hematopoietic stem/progenitor cells(HSPCs) in vitro. When they were injected into lethally irradiated mice, these differentiated cells had the advantage in immune reconstitution. METHODS:Embryonic stem cells formed embryoid bodies(EBs) in the medium containing methycellulose, hematopoietic growth factors(HGFs) was added to the culture system on the 6th day, thymopeptide was added at the same time. Flow cytometry were performed to detect the surface marker CD₃₄⁺ and CD₃⁺ of the differentiated cells. Finally the differentiated cells were injected into lethally irradiated mice, 60 days later, the incidence rate of graft versus host disease(GVHD) was taken as the mark of cell mediated immunity, PCR was performed to detect the sex determining region of the Y-chromosome(Sry) in bone marrow cells and spleen cells of the survival host female mice. RESULTS:The percentage of CD₃⁺ T lymphocytes was 10.52% and the incidence rate of GVHD was 0% on the 13th day, but they respectively rose up to 22.93% and 100% if thymopeptide was added in the procedure of inducing ES cells to differentiate into HSPC in vitro. CONCLUSION:The quantity of CD₃⁺ T lymphocytes increased in medium containing thymopeptide when ES cells differentiated into CD₃₄⁺ HSPC.