The efficiency of recovery of input for the −1-kb region of Prf1 was 0.97% for the Runx3 ChIP and 0.5% for the Eomes ChIP.We previously reported that Th1 cell differentiation was regulated through a feed-forward loop in which T-bet is up-regulated early and induces Runx3, after which T-bet and Runx3 cooperate to induce IFN-γ and silence IL-4, thus promoting stable differentiation toward the Th1 lineage (15, 22).