RESUMO
BACKGROUND: T cells are believed to play an important role in anti-infection, anti-tumor and immune function. However, the mechanism underlying the differentiation and development remains poorly understood. OBJECTIVE: To investigate the distribution of T cells in nude mice that are jointly transplanted human thymus and cord blood and the reconstruction of the immune function. METHODS: Thirty Balb/c nu/nu nude mice were randomly divided into two groups: an experimental group and a control group. In the experimental group, human thymus tissue was transplanted into the renal capsule of nude mice. Two weeks later, freshly isolated human cord blood CD34+ cells suspension was back perfused into the nude mice via the vein. In the control group, CD34+ cells transplantation was performed directly without thymus transplantation. After 60 days of breeding, the immune function of nude mice was detected in two groups. RESULTS AND CONCLUSION: Human thymus tissue in the renal capsule of nude mice survived and expressed CD3 and HLA-DR molecule. In the experimental group, CD3+ cells which distributed in the form of dots were observed in the mouse spleen. The proportion of CD3+, CD4+, CD8+, and CD4+CD25+ cells were significantly higher in the experimental group than in the control group. The nude mice from the experimental group rejected human gastric cancer BGC823 cells, while those from the control group did not. These findings demonstrated that combined human thymus and CD34+ cell transplantation allow nude mice to acquire T cell-mediated cellular immune function and possess the ability of anti-tumor.
RESUMO
BACKGROUND: Further studies are needed to understand the cytobiological character, functional regulation, gene changes and expression difference of CD34~+ and CD133~+ stem cells induced by basic fibroblast growth factor (bFGF) using gene chip. OBJECTIVE: To compare the differences of gene expression and the response to bFGF of human umbilical cord CD34~+ and CD133~+ cells, and to explore gene expression changes of bFGF-induced umbilical cord CD34~+ and CD133~+ hematopotic stem cells/hemapoietic progenitor cells in vitro. METHODS: Human umbilical cord blood CD34~+ and CD133~+ cells were isolated and purified by MiniMACS immunomagnetic beads selection. The CD34~+ and CD133~+cells were cultured for 10 to 15 days in DMEM/F12 medium, supplemented with bFGF and B27. Total RNA from these cells was extracted and the genetic level of these cells was performed using Oligo GEArray(r) chip and GEArray software. Selected rate of CD34~+ and CD133~+ hematopoietic stem cells was detected using flow cytometry. CD34~+ and CD133~+ cell morphological changes were measured before and after bFGF induction. The concentration and purity of RNA were determined by agarose gel electrophoresis degeneration. Gene-chip test results were analyzed.