Ectosomes released by platelets induce differentiation of CD4+T cells into T regulatory cells

Sadallah, Salima and Amicarella, Francesca and Eken, Ceylan and Iezzi, Giandomenica and Schifferli, Jürg A.. (2014) Ectosomes released by platelets induce differentiation of CD4+T cells into T regulatory cells. Thrombosis and Haemostasis, 112 (6). pp. 1219-1229.

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Official URL: https://edoc.unibas.ch/61939/

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Accumulating evidence suggests an immune-modulatory role for platelets (PLT) and PLT-derived microvesicles. In particular, ectosomes, i.e. vesicles budding from PLT surface, have been shown to exert immunosuppressive activities on phagocytes. Here we investigated the effects mediated by PLT-derived ectosomes (PLT-Ecto) on CD4+ T cells. Exposure of activated CD4+ T cells to PLT-Ecto decreased their release of IFNgamma, TNFalpha and IL-6, and increased the production of TGF-beta1. Concomitantly, PLT-Ecto-exposed CD4+ T cells displayed increased frequencies of CD25high Foxp3+ cells. These phenomena were dose-dependent and PLT-Ecto specific, since they were not observed in the presence of polymorphonuclear- and erythrocyte-derived ectosomes. Analysis of specific T cell subsets revealed that PLT-Ecto induced differentiation of naive T cells into Foxp3+ cells, but had no effect on pre-differentiated Foxp3+ regulatory T cells (Tregs). Importantly, PLT-Ecto-induced Foxp3+ cells were as effective as peripheral blood Tregs in suppressing CD8+ T cell proliferation. PLT-Ecto-mediated effects were partly dependent on PLT-derived TGF-beta1, as they were to some extent inhibited by PLT-Ecto pretreatment with TGF-beta1-neutralising antibodies. Interestingly, ectosome-derived TGF-beta1 levels correlated with Foxp3+ T cell frequencies in blood of healthy donors. In conclusion, PLT-Ecto induce differentiation of CD4+ T cells towards functional Tregs. This may represent a mechanism by which PLT-Ecto enhance peripheral tolerance.
Faculties and Departments:03 Faculty of Medicine > Departement Biomedizin > Department of Biomedicine, University Hospital Basel > Cancer Immunotherapy (Iezzi)
UniBasel Contributors:Iezzi, Giandomenica
Item Type:Article, refereed
Article Subtype:Research Article
Note:Publication type according to Uni Basel Research Database: Journal article
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Last Modified:27 Jul 2020 14:32
Deposited On:27 Jul 2020 14:32

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