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Updated: Aug 17, 2026

Visualization of IL-22-expressing Lymphocytes Using Reporter Mice
Published on: January 25, 2017
IL-21 sustains CD28 expression on IL-15-activated human naive CD8+ T cells
Nuno L Alves1, Fernando A Arosa, René A W van Lier
1Department of Experimental Immunology, Academic Medical Center, Meibergdreef 9, 1105 AZ Amsterdam, The Netherlands. N.M.Lages.Alves@amu.uva.nl
Abstract:
Human naive CD8+ T cells are able to respond in an Ag-independent manner to IL-7 and IL-15. Whereas IL-7 largely maintains CD8+ T cells in a naive phenotype, IL-15 drives these cells to an effector phenotype characterized, among other features, by down-regulation of the costimulatory molecule CD28. We evaluated the influence of the CD4+ Th cell-derived common gamma-chain cytokine IL-21 on cytokine-induced naive CD8+ T cell activation. Stimulation with IL-21 did not induce division and only slightly increased IL-15-induced proliferation of naive CD8+ T cells. Strikingly, however, IL-15-induced down-modulation of CD28 was completely prevented by IL-21 at the protein and transcriptional level. Subsequent stimulation via combined TCR/CD3 and CD28 triggering led to a markedly higher production of IL-2 and IFN-gamma in IL-15/IL-21-stimulated cells compared with IL-15-stimulated T cells. Our data show that IL-21 modulates the phenotype of naive CD8+ T cells that have undergone IL-15 induced homeostatic proliferation and preserves their responsiveness to CD28 ligands.
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