Induction of embryonic stem cells to hematopoietic cells in vitro

In order to get hematopoietic cells from embryonic stem (ES) cells and to s tudy development mechanisms of hematopoietic cells, the method of inducing embryonic stem cells to hematopoietic cells was explored by differenciating mouse ES cells and human embryonic cells in three stages. The differentiat ed cells were identified by flow cytometry, immunohistochemistry and Wright 's staining. The results showed that embryoid bodies (EBs) could form when ES cells were cultured in the medium with 2-mercaptoethanol (2-ME). However , cytokines, such as stem cell factor (SCF), thrombopoietin (TPO), interleu kin-3 (IL-3), interleukin-6 (IL-6), erythropoietin (EPO) and granular colon y stimulating factor (G-CSF), were not helpful for forming EBs. SCF, TPO an d embryonic cell conditional medium were useful for the differentiation of mouse EBs to hematopoietic progenitors. Eighty-six percent of these cells w ere CD34(+) after 6-d culture. Hematopoietic progenitors differentiated to B lymphocytes when they were cocultured with primary bone marrow stroma cel ls in the DMEM medium with SCF and IL-6. 14 d later, most of the cells were CD34(-)CD38(+). Wright's staining and immunohistochemistry showed that 80% of these cells were plasma-like morphologically and immunoglubolin positiv e. The study of hematopoietic cells from human embryonic cells showed that human embryonic cell differentiation was very similar to that of mouse ES c ells. They could form EBs in the first stage and the CD34 positive cells ac count for about 48.5% in the second stage.