The differentiation and plasticity of Tc17 cells are regulated by CTLA-4-mediated effects on STATs

Autor: Aditya Arra, Holger Lingel, Benno Kuropka, Jonas Pick, Tina Schnoeder, Thomas Fischer, Christian Freund, Mandy Pierau, Monika C. Brunner-Weinzierl
Jazyk: angličtina
Rok vydání: 2017
Předmět:
Zdroj: OncoImmunology, Vol 6, Iss 2 (2017)
Druh dokumentu: article
ISSN: 2162-402X
2162402X
DOI: 10.1080/2162402X.2016.1273300
Popis: As the blockade of inhibitory surface-molecules such as CTLA-4 on T cells has led to recent advances in antitumor immune therapy, there is great interest in identifying novel mechanisms of action of CD8+ T cells to evoke effective cytotoxic antitumor responses. Using in vitro and in vivo models, we investigated the molecular pathways underlying the CTLA-4-mediated differentiation of IL-17-producing CD8+ T cells (Tc17 cells) that strongly impairs cytotoxicity. Our studies demonstrate that Tc17 cells lacking CTLA-4 signaling have limited production of STAT3-target gene products such as IL-17, IL-21, IL-23R and RORγt. Upon re-stimulation with IL-12, these cells display fast downregulation of Tc17 hallmarks and acquire Tc1 characteristics such as IFNγ and TNF-α co-expression, which is known to correlate with tumor control. Indeed, upon adoptive transfer, these cells were highly efficient in the antigen-specific rejection of established OVA-expressing B16 melanoma in vivo. Mechanistically, in primary and re-stimulated Tc17 cells, STAT3 binding to the IL-17 promoter was strongly augmented by CTLA-4, associated with less binding of STAT5 and reduced relative activation of STAT1 which is known to block STAT3 activity. Inhibiting CTLA-4-induced STAT3 activity reverses enhancement of signature Tc17 gene products, rendering Tc17 cells susceptible to conversion to Tc1-like cells with enhanced cytotoxic potential. Thus, CTLA-4 critically shapes the characteristics of Tc17 cells by regulating relative STAT3 activation, which provides new perspectives to enhance cytotoxicity of antitumor responses.
Databáze: Directory of Open Access Journals