Figure 3. Graft survival after keratoplasty and i.v. Tregs. 3-week-old recipient rats received allogenic keratoplasty and obtained no additional cells (solid line, n=15) or Tregs intravenously (dotted line, n=4). Without cells, grafts were rejected at a median of POD 9, addition of Tregs into the tail vein resulted in a median rejection of day 11 after keratoplasty. Grafts of syngenic recipients (broken line) were not rejected until POD 29 (n=8).