Global chromatin accessibility of gene locus in CD4+ T cells activated with or without OX40 costimulation

OX40 is a T cell costimulatory molecule in the tumor necrosis factor receptor (TNFR) superfamily. Unlike other costimulatory molecules, OX40 is not expressed by naive T cells, but its expression is rapidly induced following T cell activation, and OX40 costimulation plays a critical role in cell survival, proliferation, and generation of memory cells. We used ATAC-seq to detail the chromatin accessibility of gene locus of activated CD4 T cells with or without OX40 costimulation in the presence of TGF-β1 and IL-2 and identified distinct classes of genes after OX40 costimulation. Naive CD4+ T cells (CD62LhighCD44lowFoxp3−) were sorted from C57/Bl6 Foxp3-eGFP reporter mice, and activated in vitro with soluble anti-CD3 mAb and mitomycin C-treated Wt APCs or OX40L-Tg APCs in the presence of TGF-β1 and IL-2 in 96-well round bottom tissue-culture plates. Forty-eight hours later, living CD4+ T cells were sorted from cultures by flow cytometry. ATAC-seq was performed at Active Motif (Carlsbad, CA).