| Abstract: | Using terminal deoxynucleotide transferase mediated dUTP digoxigenin nick end labeling (TUNEL) assay and propidium iodide DNA staining flow cytometry assay, the effects of mouse thymic dendritic cells (MTSC4) on the process of programmed cell death of thymocytes in vitro were investigated. It was noticed that thymocytes bound to MTSC4 used in this study. That the percentages of apoptotic nuclei of the bound thymocytes on MTSC4 were much higher than those of medium cultured thymocytes, while the bound thymocytes on mouse thymic epithelial cell (MTEC1) showed much lower percentages of apoptosis. FACS analysis quantitatively confirmed the observation. Phenotype analysis showed that MTSC4 induced the deletion of CD4+CD8+ cells and CD4+CD8 cells in 18 h of coculture. The results suggest that the negative selection of medullary thymocytes may be achieved by thymic dendritic cells through their enhancing effects on apoptosis. |
