Abstract
Costimulation with the recombinant SA-4-1BBL agonist of 4-1BB receptor on conventional CD4+ T cells (Tconvs) overcomes the suppression mediated by naturally occurring CD4+CD25+FoxP3+ T regulatory cells (Tregs). The mechanistic basis of this observation has remained largely unknown. Herein we show that Tconvs, but not Tregs, are the direct target of SA-4-1BBL-mediated evasion of Treg suppression. IL-2 produced by Tconvs in response to 4-1BB signaling is both necessary and sufficient for overcoming Treg suppression. Supernatant from Tconvs stimulated with SA-4-1BBL contains high levels of IL-2 and overcomes Treg suppression in ex vivo Tconv:Treg cocultures. Removal of IL-2 from such supernatant restores Treg suppression and repletion of Tconv:Treg cocultures with exogenous recombinant IL-2 overcomes suppression. This study establishes 4-1BB signaling as a key circuit that regulates physical and functional equilibrium between Tregs and Tconvs with important implications for immunotherapy for indications where a fine balance between Tregs and Teffs plays a decisive role.
Original language | English (US) |
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Article number | e0153088 |
Journal | PloS one |
Volume | 11 |
Issue number | 4 |
DOIs | |
State | Published - Apr 2016 |
Externally published | Yes |
ASJC Scopus subject areas
- General Biochemistry, Genetics and Molecular Biology
- General Agricultural and Biological Sciences
- General