Skip to main content
. Author manuscript; available in PMC: 2013 Sep 19.
Published in final edited form as: Am J Transplant. 2012 Mar 5;12(4):856–866. doi: 10.1111/j.1600-6143.2011.03978.x

Figure 3. ATG-mediated Treg expansion requires initial CD4+ T-cell activation by ATG, but not its immediate presence.

Figure 3

Purified CD4+ and CD14+ T cells were separately treated with ATG or Rbt Ig for 24 h, washed twice to remove ATG or Rbt Ig and cocultured together for another 24 h without any further treatment. No Treg expansion occurred when both cell types were pretreated with rbt Ig, but Tregs expanded significantly when both cell types were separately pretreated with ATG, indicating that no immediate ATG presence is necessary for Treg expansion. To detect whether CD4+ and/or CD14+ cells require activation by ATG to mediate Treg expansion, both cell types were independently treated for 24 h with ATG or Rbt Ig, washed and cocultured with CD14+ or CD4+ cells, respectively, for another 24 h in the absence of additional treatment. Treg expansion occurred when CD4+ T cells were pretreated with ATG, but not when CD14+ cells were pretreated with ATG. As expected, no Treg expansion occurred in any of the experiments with Rbt Ig. These results indicate that ATG-mediated Treg expansion requires activation of CD4+ T cells by ATG but not its immediate presence in the Treg-generating culture. Data are representative of four independent experiments (n = 3). NS, not significant; *p < 0.05.