Magnetically sorted hCD2(+) WT and A384T Treg cells (approx. 1x10e7 cells per reaction, prepared in triplicates) were fixed for 30 min at room temperature with 1% formaldehyde, washed with PBS, and stored at -80 °C. Cells were resuspended in lysis buffers and sonicated for solubilization and shearing of crosslinked DNA. The cell extract was incubated overnight at 4 °C with 4 µg of the anti-FoxP3 antibodies and then with Dynabeads protein G (Dynal). Bound complexes were washed and eluted from the magnetic beads by heating at 65°C with occasional vortexing and crosslinking was reversed by overnight incubation at 65°C. The immunoprecipitated DNA and whole-cell extract input DNA were treated with RNase A and proteinase K, purified using MinElute PCR purification kit (QIAGEN) ChIP-seq libraries were prepared using NEBNext ChIP-Seq Library Prep Reagent Set for Illumina (NEB) according to the manufacturer's instructions.