Billiard, after high dose (10 Gy) abdominal irradiation of mice, found tissue- and time-specific differences in the TGFβ expression in the intestinal mucosa and mesentheric lymph nodes. TGFβ was reduced in the mesentheric lymph nodes at earlier time points after irradiation and returned to normal by day 90, while it remained unchanged early after irradiation in the intestinal mucosa, but showed a persistent decrease at later time points [85]. Cao et al. evaluated the level of membrane-bound latent TGFβ1 through determining the expression of the Latency Activated Protein (LAP) on the cell surface of Tregs irradiated in vitro with 30 Gy and found a decreased LAP expression [84]. GARP, expressed by activated Tregs, binds latent TGFβ and LAP and enhances TGFβ secretion. Thus, GARP together with LAP seems to contribute to Treg suppressor activity. No changes were reported in GARP levels in irradiated Tregs [67].