Transplant tolerance: a new role for IL-34
James I. Kim, Laurence A. Turka
James I. Kim, Laurence A. Turka
Published September 21, 2015
Citation Information: J Clin Invest. 2015;125(10):3751-3753. https://doi.org/10.1172/JCI84010.
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Commentary

Transplant tolerance: a new role for IL-34

Abstract

Immune-suppressive cell populations, including Tregs and suppressor monocytes, have been implicated in long-term survival of allografts in both human transplant recipients and animal models. The factors that drive differentiation and function of these cell populations are not completely understood. In this issue, Bézie and colleagues identify IL-34 as an important mediator of allograft tolerance in a rat model of heart transplantation. Their data support a model in which IL-34 production by Tregs promotes a population of suppressive macrophages that in turn promote Treg differentiation. The results of this study support further exploration of the immunosuppressive properties of IL-34.

Authors

James I. Kim, Laurence A. Turka

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Figure 1

Suppressor monocytes secrete a number of molecules including inducible NOS and arginase I to promote allograft survival and suppress alloreactive T cells.

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Suppressor monocytes secrete a number of molecules including inducible N...
IL-34 is produced by monocytes and cells from a number of organs including the heart and binds to its receptor on monocytes. IL-34 is also expressed by CD45RClo CD4+ and CD8+ Tregs. IL-34 treatment of mixed lymphocyte cultures improves Treg-dependent suppression of effector T cell proliferation. The IL-34 receptor CD115 is not known to be expressed on Tregs; therefore, suppression of the alloresponse and FOXP3 upregulation may be mediated through a suppressor monocyte intermediate. iNOS, inducible NOS; Teff, T effector cell.