Ligation of TLR9 induced on human IL-10–secreting Tregs by 1α,25-dihydroxyvitamin D3 abrogates regulatory function
Zoë Urry, … , Zarin Brown, Catherine M. Hawrylowicz
Zoë Urry, … , Zarin Brown, Catherine M. Hawrylowicz
Published January 12, 2009
Citation Information: J Clin Invest. 2009;119(2):387-398. https://doi.org/10.1172/JCI32354.
View: Text | PDF
Research Article Immunology

Ligation of TLR9 induced on human IL-10–secreting Tregs by 1α,25-dihydroxyvitamin D3 abrogates regulatory function

Abstract

Signaling through the TLR family of molecular pattern recognition receptors has been implicated in the induction of innate and adaptive immune responses. A role for TLR signaling in the maintenance and/or regulation of Treg function has been proposed, however its functional relevance remains unclear. Here we have shown that TLR9 is highly expressed by human Treg secreting the antiinflammatory cytokine IL-10 induced following stimulation of blood and tissue CD3+ T cells in the presence of 1α,25-dihydroxyvitamin D3 (1α25VitD3), the active form of Vitamin D, with or without the glucocorticoid dexamethasone. By contrast, TLR9 was not highly expressed by naturally occurring CD4+CD25+ Treg or by Th1 and Th2 effector cells. Induction of TLR9, but not other TLRs, was IL-10 dependent and primarily regulated by 1α25VitD3 in vitro. Furthermore, ingestion of calcitriol (1α25VitD3) by human volunteers led to an increase of both IL-10 and TLR9 expression by CD3+CD4+ T cells analyzed directly ex vivo. Stimulation of 1α25VitD3-induced IL-10–secreting Treg with TLR9 agonists, CpG oligonucleotides, resulted in decreased IL-10 and IFN-γ synthesis and a concurrent loss of regulatory function, but, unexpectedly, increased IL-4 synthesis. We therefore suggest that TLR9 could be used to monitor and potentially modulate the function of 1α25VitD3-induced IL-10–secreting Treg in vivo, and that this has implications in cancer therapy and vaccine design.

Authors

Zoë Urry, Emmanuel Xystrakis, David F. Richards, Joanne McDonald, Zahid Sattar, David J. Cousins, Christopher J. Corrigan, Emma Hickman, Zarin Brown, Catherine M. Hawrylowicz

×

Figure 7

CpG-ODNs abrogate regulatory activity of drug-induced IL-10–Tregs.

Options: View larger image (or click on image) Download as PowerPoint
CpG-ODNs abrogate regulatory activity of drug-induced IL-10–Tregs. CD4+ ...
CD4+ T cells were cultured for two 7-day cycles with anti-CD3, IL-2, IL-4 alone (neutral) or with 1α25VitD3, then harvested, washed, and pretreated for 24 hours with anti-CD3 and IL-2 alone or together with 10 μM CpG-ODN 2006. Autologous CD45RA+ T cells were isolated, CFSE labeled, and cocultured with the cell lines at a ratio of 2:1 responder/cell line for 5 days with suboptimal anti-CD3 (0.1 μg/ml) and CD28 (2 μg/ml). Values within the histograms represent the percentage of proliferating, viable CFSE-labeled responders as assessed by FACS. Data from 1 representative healthy donor of 2 studied are depicted.