Zhang, XiaolongChang Li, XianXiao, XiangSun, RuiTian, ZhigangWei, Haiming2014-03-102013Zhang, Xiaolong, Xian Chang Li, Xiang Xiao, Rui Sun, Zhigang Tian, and Haiming Wei. 2013. “CD4+CD62L+ Central Memory T Cells Can Be Converted to Foxp3+ T Cells.” PLoS ONE 8 (10): e77322. doi:10.1371/journal.pone.0077322. http://dx.doi.org/10.1371/journal.pone.0077322.1932-6203http://nrs.harvard.edu/urn-3:HUL.InstRepos:11878889The peripheral Foxp3+ Treg pool consists of naturally arising Treg (nTreg) and adaptive Treg cells (iTreg). It is well known that naive CD4+ T cells can be readily converted to Foxp3+ iTreg in vitro, and memory CD4+ T cells are resistant to conversion. In this study, we investigated the induction of Foxp3+ T cells from various CD4+ T-cell subsets in human peripheral blood. Though naive CD4+ T cells were readily converted to Foxp3+ T cells with TGF-β and IL-2 treatment in vitro, such Foxp3+ T cells did not express the memory marker CD45RO as do Foxp3+ T cells induced in the peripheral blood of Hepatitis B Virus (HBV) patients. Interestingly, a subset of human memory CD4+ T cells, defined as CD62L+ central memory T cells, could be induced by TGF-β to differentiate into Foxp3+ T cells. It is well known that Foxp3+ T cells derived from human CD4+CD25- T cells in vitro are lack suppressive functions. Our data about the suppressive functions of CD4+CD62L+ central memory T cell-derived Foxp3+ T cells support this conception, and an epigenetic analysis of these cells showed a similar methylation pattern in the FOXP3 Treg-specific demethylated region as the naive CD4+ T cell-derived Foxp3+ T cells. But further research showed that mouse CD4+ central memory T cells also could be induced to differentiate into Foxp3+ T cells, such Foxp3+ T cells could suppress the proliferation of effector T cells. Thus, our study identified CD4+CD62L+ central memory T cells as a novel potential source of iTreg.en-USJournal Article2014-03-1010.1371/journal.pone.0077322