Defining CD4 T Cell Memory by the Epigenetic Landscape of CpG DNA Methylation [Affymetrix]

Memory T cells are primed for rapid responses to antigen; however, the molecular mechanisms responsible for priming remain incompletely defined. CpG methylation in promoters is an epigenetic modification, which regulates gene transcription. Using targeted bisulfite sequencing, we examined methylation of 2100 genes (56,000 CpG) mapped by deep sequencing to T cell activation in human nave and memory CD4 T cells. 466 CpGs (132 genes) displayed differential methylation between nave and memory cells. 21 genes exhibited both differential methylation and gene expression before activation, linking promoter DNA methylation states to gene regulation; 6 genes encode proteins closely studied in T cells while 15 genes represent novel targets for further study. 39 genes exhibited reduced methylation in memory cells coupled with increased gene expression with activation compared to nave cells, revealing specific genes more rapidly expressed in memory compared to nave cells and potentially regulated by DNA methylation. These findings define a DNA methylation signature unique to memory CD4 T cells and correlated with activation-induced gene expression.

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Komori HK, Hart T, LaMere SA, Chew PV, Salomon DR