Regulatory T cells exhibit decreased proliferation but enhanced suppression after pulsing with sirolimus.

Published

Journal Article

Although regulatory T cells (Tregs) suppress allo-immunity, difficulties in their large-scale production and in maintaining their suppressive function after expansion have thus far limited their clinical applicability. Here we have used our nonhuman primate model to demonstrate that significant ex vivo Treg expansion with potent suppressive capacity can be achieved and that Treg suppressive capacity can be further enhanced by their exposure to a short pulse of sirolimus. Both unpulsed and sirolimus-pulsed Tregs (SPTs) are capable of inhibiting proliferation of multiple T cell subpopulations, including CD4(+) and CD8(+) T cells, as well as antigen-experienced CD28(+) CD95(+) memory and CD28(-) CD95(+) effector subpopulations. We further show that Tregs can be combined in vitro with CTLA4-Ig (belatacept) to lead to enhanced inhibition of allo-proliferation. SPTs undergo less proliferation in a mixed lymphocyte reaction (MLR) when compared with unpulsed Tregs, suggesting that Treg-mediated suppression may be inversely related to their proliferative capacity. SPTs also display increased expression of CD25 and CTLA4, implicating signaling through these molecules in their enhanced function. Our results suggest that the creation of SPTs may provide a novel avenue to enhance Treg-based suppression of allo-immunity, in a manner amenable to large-scale ex vivo expansion and combinatorial therapy with novel, costimulation blockade-based immunosuppression strategies.

Full Text

Duke Authors

Cited Authors

  • Singh, K; Kozyr, N; Stempora, L; Kirk, AD; Larsen, CP; Blazar, BR; Kean, LS

Published Date

  • June 2012

Published In

Volume / Issue

  • 12 / 6

Start / End Page

  • 1441 - 1457

PubMed ID

  • 22300641

Pubmed Central ID

  • 22300641

Electronic International Standard Serial Number (EISSN)

  • 1600-6143

International Standard Serial Number (ISSN)

  • 1600-6135

Digital Object Identifier (DOI)

  • 10.1111/j.1600-6143.2011.03963.x

Language

  • eng