We investigated the regulation of thymic stromal cells on the process of programmed cell death of thymocytes. By using DNA electrophoreses and propidium iodide-DNA staining flow cytometry assay, we investigated the effects of mouse thymic stromal cells (MTSC) on the process of programmed cell death of cultured thymocytes. The progressive DNA fragmentation and higher percentage of apoptotic cells hypodiploid DNA were observed in thymocytes at subsequent time point. When the thymocytes were cocultured with mouse thymic epithelial cell line (MTEC1), a sharp decrease of DNA fragmentation was observed in thymocytes at different culture time, while the mouse thymic dendritic cell line (MTSC4) enhanced the DNA fragmentation of thymocytes at 12 to 18 h-coculture time. FACS assay quantitatively confirmed these observation. MTEC1, but not MTSC4 enhanced the survival rate of thymocytes in vitro. By histochemistry DNA in situ staining method, we observed the presence of apoptotic cells around the two thymic stromal cells. These results suggest that thymic stromal cells may regulate the process of thymocytes during the negative selection in thymus through different mechanisms in which providing survival signals and engulfing apoptotic cells may be included.
|Number of pages
|Chinese Journal of Microbiology and Immunology
|Published - 1996
- Thymic stromal cell
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