Differential IL-2 expression defines developmental fates of follicular versus nonfollicular helper T cells

Academic Article

Abstract

  • ©2018 The American Society for Biochemistry and Molecular Biology,Inc. RNA sequencing of naïve T cells sorted on the basis of IL-2 reporter expression identified cosegregation of transcripts encoding IL-2 and Bcl6-the signature transcription factor of TFH cells. Conversely, IL-2-negative (IL-2-) cells preferentially expressed the gene Prdm1, which encodes the transcriptional repressor Blimp1. Blimp1, in turn, antagonizes Bcl6 and the TFH developmental program. This suggested that IL-2 producers give rise to TFH cells, whereas IL-2 nonproducers give rise to non-TFH effector cells. Moreover, the fact that IL-2 receptor signaling induces expression of Prdm1 via Stat5 suggested that IL-2 producers resisted IL-2 signaling and activated IL-2 signaling in nonproducers in trans. Indeed, in vivo studies established that IL-2 signaling was mostly paracrine and that depletion of IL-2- producing cells selectively impaired TFH cell development. Finally, IL-2 expression was limited to a subset of naïve T cells that received the strongest T cell receptor (TCR) signals, establishing a link between TCR signal strength, IL-2 production, and TFH versus non-TFH differentiation. This study provides newinsights into themechanisms that control early bifurcation of CD4+ T cells into TFH and non-TFH effectors. Naïve T cells that receive differing strengths of TCR signals stratify into those that exceed a threshold predisposing them to IL-2 production and early TFH commitment and those that do not express IL-2 yet receive IL-2 signaling, which reinforces non-TFH effector commitment.
  • Digital Object Identifier (doi)

    Pubmed Id

  • 28105176
  • Author List

  • Ditoro D; Winstead C; Pham D; Witte S; Andargachew R; Singer JR; Wilson CG; Zindl CL; Luther RJ; Silberger DJ
  • Volume

  • 361
  • Issue

  • 6407