Volume 60, Issue 1 pp. 123-132
Cell Biology

CTLA-4 (CD152) controls homeostasis and suppressive capacity of regulatory T cells in mice

Paula Kolar

Paula Kolar

Deutsches Rheuma-Forschungszentrum Berlin, and Charité–University Hospital, Berlin, Germany

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Karin Knieke

Karin Knieke

University Hospital Magdeburg, Magdeburg, Germany

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J. Kolja E. Hegel

J. Kolja E. Hegel

University Hospital Magdeburg, Magdeburg, Germany

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Dagmar Quandt

Dagmar Quandt

Deutsches Rheuma-Forschungszentrum Berlin, and Charité–University Hospital, Berlin, Germany

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Gerd-R. Burmester

Gerd-R. Burmester

Deutsches Rheuma-Forschungszentrum Berlin, and Charité–University Hospital, Berlin, Germany

Dr. Burmester has received consulting fees, speaking fees, and/or honoraria (less than $10,000) as well as (together with Dr. Brunner-Weinzierl) an unrestricted research grant from Bristol-Myers Squibb.

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Holger Hoff

Holger Hoff

Deutsches Rheuma-Forschungszentrum Berlin, and Charité–University Hospital, Berlin, Germany

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Monika C. Brunner-Weinzierl

Corresponding Author

Monika C. Brunner-Weinzierl

Deutsches Rheuma-Forschungszentrum, Berlin, Charité–University Hospital, Berlin, and University Hospital Magdeburg, Magdeburg, Germany

Department of Paediatrics, University Hospital Magdeburg, Otto-von-Guericke University, Leipziger Strasse 44, 39120 Magdeburg, GermanySearch for more papers by this author
First published: 30 December 2008
Citations: 81

Abstract

Objective

CD4+CD25+ regulatory T cells (known as Treg cells) suppress unwanted and autoreactive T cell responses. Treg cells express the costimulatory molecule CTLA-4 intracellularly, but the mechanisms by which Treg cells exploit CTLA-4 signaling remain unclear. The present study was undertaken to investigate the role of CTLA-4 in controlling the homeostasis and suppressive function of Treg cells.

Methods

Murine Treg cells were analyzed by flow cytometry for coexpression of CTLA-4 and typical Treg cell–expressed molecules, and the influence of CTLA-4 on T cell proliferation, suppression, and apoptosis was investigated by in vitro assays. To analyze the importance of CTLA-4 in Treg cell–mediated suppression in vivo, wild-type Treg cells were transferred into CTLA-4–deficient mice displaying lymphoproliferation, and survival was monitored over time.

Results

A strong correlation between expression of forkhead box P3 and ex vivo expression of CTLA-4 in Treg cells was observed. Inhibition of CTLA-4 signaling in Treg cells during in vitro stimulation increased cell cycling and led to enhanced activation-induced cell death (AICD), which was mediated by CD95/CD95 ligand–induced activation of caspases. Blockade of CTLA-4 signaling resulted in impairment of the suppressive capacity of Treg cells. Despite these effects, high amounts of Treg cells persisted in CTLA-4–deficient mice. Results of transfer experiments in CTLA-4–deficient mice showed that the mice had a significantly prolonged lifespan when CTLA-4–competent Treg cells were injected.

Conclusion

Expression of CTLA-4 on Treg cells serves to control T cell proliferation, to confer resistance against AICD, and to maintain the suppressive function of Treg cells.

The full text of this article hosted at iucr.org is unavailable due to technical difficulties.

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