Murine thymi were treated with enzymes cocktail (Collagenase, Dispase and Dnase) at 37C. Cells were separated by Percoll gradient density centrifugation, filtered, stained with Flow cytometry antibodies and cross linked with Formaldehyde. High troughput ChIP, developed from the iChIP protocol (Lara-Astiaso, Weiner et al. Science 2014)