부산대학교 도서관

BACKGROUND:: OBJECTIVE:: METHODS:: RESULTS:: 2,4-Dinitrofluorobenzene immunization induced a population of CD4CD25 Treg cells that controlled CD8 T-cell effector responses in a hapten-specific manner in vivo. High levels of inducible costimulator (ICOS) expression defined a population of CD4CD25FoxP3 (forkhead box protein 3) Treg cells that presented superior suppressive activity. Importantly, ICOS Treg cells were distinguishable from all other FoxP3 Treg cells by the expression of IL-10, IL-17, and IFN-γ. Hapten-specific Treg cells proliferating in response to their cognate antigen in vivo predominantly displayed a CD25FoxP3ICOS phenotype. By using reporter mice, we showed that ICOS Treg cells derived from the expansion of natural CD4FoxP3 Treg cells rather than generation of adaptive Treg cells. Furthermore, the generation of ICOS Treg cells depended on innate cells rather than the effector CD8 T-cell population. CONCLUSION:: Taken together, our data show that a population of CD4CD25FoxP3 T cells upregulates ICOS on in vivo sensitization and specifically suppresses hapten-reactive CD8 T cells both in vivo and in vitro.