Time-resolved role of P2X4 and P2X7 during CD8+ T cell activation

Front Immunol. 2024 Feb 15:15:1258119. doi: 10.3389/fimmu.2024.1258119. eCollection 2024.


CD8+ T cells are a crucial part of the adaptive immune system, responsible for combating intracellular pathogens and tumor cells. The initial activation of T cells involves the formation of highly dynamic Ca2+ microdomains. Recently, purinergic signaling was shown to be involved in the formation of the initial Ca2+ microdomains in CD4+ T cells. In this study, the role of purinergic cation channels, particularly P2X4 and P2X7, in CD8+ T cell signaling from initial events to downstream responses was investigated, focusing on various aspects of T cell activation, including Ca2+ microdomains, global Ca2+ responses, NFAT-1 translocation, cytokine expression, and proliferation. While Ca2+ microdomain formation was significantly reduced in the first milliseconds to seconds in CD8+ T cells lacking P2X4 and P2X7 channels, global Ca2+ responses over minutes were comparable between wild-type (WT) and knockout cells. However, the onset velocity was reduced in P2X4-deficient cells, and P2X4, as well as P2X7-deficient cells, exhibited a delayed response to reach a certain level of free cytosolic Ca2+ concentration ([Ca2+]i). NFAT-1 translocation, a crucial transcription factor in T cell activation, was also impaired in CD8+ T cells lacking P2X4 and P2X7. In addition, the expression of IFN-γ, a major pro-inflammatory cytokine produced by activated CD8+ T cells, and Nur77, a negative regulator of T cell activation, was significantly reduced 18h post-stimulation in the knockout cells. In line, the proliferation of T cells after 3 days was also impaired in the absence of P2X4 and P2X7 channels. In summary, the study demonstrates that purinergic signaling through P2X4 and P2X7 enhances initial Ca2+ events during CD8+ T cell activation and plays a crucial role in regulating downstream responses, including NFAT-1 translocation, cytokine expression, and proliferation on multiple timescales. These findings suggest that targeting purinergic signaling pathways may offer potential therapeutic interventions.

Keywords: CD8 + T cells; Ca2+ imaging; Ca2+ microdomains; IFN-γ; NFAT; TCR stimulation; activation; proliferation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • CD8-Positive T-Lymphocytes*
  • Cytokines
  • Signal Transduction*


  • Cytokines

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This work was supported by the Deutsche Forschungsgemeinschaft (DFG) (project number 335447717; SFB1328, project A01 to AG, project A02 to B-PD and RW, project A03 to H-WM, project A10 to JH and project Z02 to FK-N and BR), by the COST Action CA21130-PRESTO, research in the lab was also funded by EU project INTEGRATA DLV-813284 (to AG), and by NCL-Stiftung Hamburg (to AG). We acknowledge financial support from the Open Access Publication Fund of UKE - Universitätsklinikum Hamburg-Eppendorf and DFG – German Research Foundation.