Mota, CatarinaNunes-Silva, VâniaPires, Ana R.Matoso, PaulaVictorino, Rui M. M.Sousa, Ana E.Caramalho, Íris2015-07-142015-07-142014J Immunol 2014; 193:5854-58620022-1767http://dx.doi.org/ 10.4049/jimmunol.1400198http://www.jimmunol.org/cgi/pmidlookup?view=long&pmid=25367118http://hdl.handle.net/10451/18441© 2014 by The American Association of Immunologists, Inc.FOXP3-expressing regulatory T cells (Treg) are essential for the prevention of autoimmunity and were shown to be reduced and/or dysfunctional in several autoimmune diseases. Although Treg-based adoptive transfer represents a promising therapy, the large cell number required to achieve clinical efficacy constitutes an important limitation. Therefore, novel strategies to generate bona fide in vitro-induced Treg (iTreg) are critical. In this study, we report that human memory CD4 T cells can be efficiently converted into iTreg, and that Delta-like 1 (DL1)-mediated Notch signaling significantly enhances this process. The iTreg generated in the presence of DL1 featured higher levels of Treg function-associated molecules and were efficient suppressors. Importantly, these iTreg displayed a stable phenotype in long-term cultures, even in the presence of proinflammatory cytokines. Additionally, DL1 potentiated FOXP3 acquisition by memory CD4 cells through the modulation of the TGF-β signaling pathway and of Foxp3 transcription. Our data demonstrate that iTreg can be efficiently induced from memory CD4 cells, a subset enriched in relevant specificities for targeting in autoimmune diseases, and that DL1 enhances this process. DL1 also enhanced the proliferation and Treg function-associated marker expression of ex vivo-stimulated human circulating FOXP3(+) cells. Manipulation of the Notch signaling pathway constitutes a promising approach to boost the in vitro generation of iTreg and ex vivo Treg expansion, thus facilitating the establishment of effective Treg-based adoptive therapy in autoimmune diseases.engjournal article