Peking University Health Science Center, China
Title: Maturation, migration, and homeostasis of murine CD4+ pre-thymic emigrants
Qing Ge got her M.D. and Ph.D. at Peking University Health Science Center and fi nished postdoctoral training at the Center for Cancer Research, Massachusetts Institute of Technology. She is now a Professor in the Department of Immunology, Peking University Health Science Center. She has published more than 40 papers in reputed journals and is serving as an editorial board member of Antivirus Research. She has done research on T cell homeostasis and differentiation, small interference RNA against infectious viruses. Currently her research focuses on the maturation and migration of pre-RTEs and RTEs, the role of extracellular proteins on the development and differentiation of immune cells, and the tumorigenesis of hematopoietic system.
After a tightly regulated developmental program in the thymus, mature single positive (SP) thymocytes leave the thymus and enter the periphery. These newly arrived recent thymic emigrants (RTEs) are phenotypically and functionally immature, and will complete a dynamic maturation in the peripheral lymphoid organs before being licensed to be resident naive T cells. To study the early events occurring in the RTE maturation process, we identified the phenotype of CD4+ pre-RTEs, a population of CD4+ SP thymocytes that have acquired the thymus egress capability. Compared to peripheral naive T cells, CD4+ pre-RTEs displayed superior survival capability in lymphoreplete mice and faster proliferation under lymphopenic condition. The differences in Bcl2/Bim expression and/or heightened IL-7 signaling pathway may account for the pre-RTEs better responsiveness to homeostatic signals. Qa2, the expression of which indicates the phenotypic maturation of SPs and RTEs, was found to be upregulated in CD4+ pre-RTEs in thymic perivascular space. Migratory dendritic cells surround this region contribute to Qa2 expression.