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Updated: May 3, 2026

Tailoring In Vivo Cytotoxicity Assays to Study Immunodominance in Tumor-specific CD8+ T Cell Responses
Published on: May 6, 2019
Immunogenic, but not steady-state, antigen presentation permits regulatory T-cells to control CD8+ T-cell effector
Alice McNally1, Michael McNally1, Ryan Galea1
1UQ Diamantina Institute, University of Queensland, Brisbane, Australia.
Abstract:
Absorption of IL-2 is one proposed mechanism of CD4+CD25+FoxP3+ regulatory T cell (Treg) suppression. Direct in vivo experimental evidence for this has recently been obtained. While modulation of IL-2 bioavailability controls CD8+ T-cell effector differentiation under strongly immunogenic conditions it is not known whether Treg modulate CD8+ T cell responses through this mechanism under steady-state conditions. Here we assess this using a mouse model in which dendritic cells (DC) are manipulated to present cognate antigen to CD8+ T cells either in the steady-state or after activation. Our observations show that Treg exert a check on expansion and effector differentiation of CD8+ T cells under strongly immunogenic conditions associated with TLR ligand activation of DC, and this is mediated by limiting IL-2 availability. In contrast, when DC remain unactivated, depletion of Treg has little apparent effect on effector differentiation or IL-2 homeostasis. We conclude that while modulation of IL-2 homeostasis is an important mechanism through which Treg control CD8+ effector differentiation under immunogenic conditions, this mechanism plays little role in modulating CD8+ T-cell differentiation under steady-state conditions.
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