The Chip assay was performed by using Zymo-Spin™ ChIP kit according to manufacturer’s recommendation with modifications based on published protocols (30 (link))(31 (link)). Briefly, 5–6 ×106 cells were fixed in 1% paraformaldehyde for 10min at 37°C. 2.5M glycine was added to stop the fixation, and then nuclei were extracted. Chromatin in isolated nuclei were digested by Atlantis MNase (Zymo Research) and after digestion, isolated nuclei were mildly sonicated to release digested chromatin. Digested chromatin was then incubated with the ChIP grade mouse monoclonal antibody against human TBX21 (4B10 and D39) (Santa Cruz Biotech), or the control mouse IgG antibody (Santa Cruz Biotech) for overnight at 4°C, and after the incubation, the bound chromatin was immune-precipitated by MagnaChIP protein A+G magnetic beads (EMD Millipore). After series of washes, bound DNA was isolated and stored at −80°C until PCR was performed with sets of primers (Table Supplemental II) to identity the promoter region of the target gene. All the forward and reverse ChIP primer pairs except IL-4 pairs were designed by NCBI Primer-BLAST (32 (link)). Sequences of a IL-4 ChIP primer pair were derived from Zhou et.al. (33 (link)).