PTEN inhibits IL-2 receptor–mediated expansion of CD4+ CD25+ Tregs
Patrick T. Walsh, … , Wayne W. Hancock, Laurence A. Turka
Patrick T. Walsh, … , Wayne W. Hancock, Laurence A. Turka
Published September 1, 2006
Citation Information: J Clin Invest. 2006;116(9):2521-2531. https://doi.org/10.1172/JCI28057.
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Research Article Immunology

PTEN inhibits IL-2 receptor–mediated expansion of CD4+ CD25+ Tregs

Abstract

One of the greatest barriers against harnessing the potential of CD4+CD25+ Tregs as a cellular immunotherapy is their hypoproliferative phenotype. We have previously shown that the hypoproliferative response of Tregs to IL-2 is associated with defective downstream PI3K signaling. Here, we demonstrate that targeted deletion of the lipid phosphatase PTEN (phosphatase and tensin homolog deleted on chromosome 10) regulates the peripheral homeostasis of Tregs in vivo and allows their expansion ex vivo in response to IL-2 alone. PTEN deficiency does not adversely affect either the thymic development or the function of Tregs, which retain their ability to suppress responder T cells in vitro and prevent colitis in vivo. Conversely, reexpression of PTEN in PTEN-deficient Tregs as well as in activated CD4+ T cells inhibits IL-2–dependent proliferation, confirming PTEN as a negative regulator of IL-2 receptor signaling. These data demonstrate that PTEN regulates the “anergic” response of Tregs to IL-2 in vitro and Treg homeostasis in vivo and indicate that inhibition of PTEN activity may facilitate the expansion of these cells for potential use in cellular immunotherapy.

Authors

Patrick T. Walsh, Jodi L. Buckler, Jidong Zhang, Andrew E. Gelman, Nicole M. Dalton, Devon K. Taylor, Steven J. Bensinger, Wayne W. Hancock, Laurence A. Turka

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Figure 2

Isolation and analysis of CD4+ CD25+ CD45RBlo Tregs from PTEN-ΔT mice.

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Isolation and analysis of CD4+ CD25...
(A) Expression of the T cell–activation marker CD69 on CD4+ T cells from PTEN-ΔT mice and wild-type littermates at age 2 weeks, before the onset of disease, and at age 8 weeks. (B) Frequency of CD4+ T cells that are CD25hiCD45RBlo from 2-week-old PTEN-ΔT and wild-type littermate mice. (C) Real-time PCR analysis of Foxp3 expression on FACS-purified CD4+CD25–CD45RBhi and CD4+CD25+CD45RBlo cells from 2-week-old PTEN-ΔT and wild-type littermate mice. (D) Purified CD4+CD25–CD45RBhi cells (1 × 105) from littermate control mice were stimulated with anti-CD3 (0.5 μg/ml) plus irradiated APCs (3 × 106) for 72 hours in the presence of the indicated ratios of CD4+CD25+CD45RBlo Tregs purified from either PTEN-ΔT mice or wild-type mice. Tritiated thymidine was added to cultures for the final 16 hours before harvesting. All data are representative of at least 2 independent experiments. Data shown represent mean ± SD of triplicate samples.