Characteristics of TCRαβ~+ CD4~- CD8~- thymocytes in fetal thymic organ culture

摘要

TCRαβ~+CD~-CD8~-(TCR~+ DN) thymocytes at different developmental periods, i.e. after either 9 or 18 days of culture in the fetal thymic organ culture (FTOC) system, were characterized in the properties of phenotype, proliferation, differentiation and apoptosis. The results showed that anti-CD3 mAb significantly promoted proliferation of TCRαβ~+ DN cells generated after 18 days of culture in FTOC, whereas the cells generated after 9 days of culture responded to anti-CD3 mAb by proliferation weakly. IL-7 efficiently induced TCRαβ~+ DN cells at day 9 of FTOC to differentiate into TCRαβ~+ CD4~+/CD8~+ SP cells without detectable transitional stage of TCRαβ~+ CD4~+ CD8~+ (DP) cells. In contrast, fewer TCRαβ~+ DN cells generated after 18 days of FTOC were induced to differentiate into SP cells. The thymic stromal cell line MTEC5 cells synergized with IL-7 to promote the differentiation of TCRαβ~+ DN cells. In addition, TCRαβ~+ DN cells were shown to be less susceptible to apoptosis compared with the other major thymocyte subsets. Taken together, these data have provided insight into the characteristics of TCRαβ~+ DN thymocytes.