Context-dependent effects of IL-2 rewire immunity into distinct cellular circuits

Abstract:

Interleukin 2 (IL-2) is a key homeostatic cytokine, with potential therapeutic applications in both immunogenic and tolerogenic immune modulation. Clinical application has been hampered by pleiotropic functionality and wide-spread receptor expression, with unexpected adverse events during trials. To characterize the IL-2 homeostatic network, we developed a novel mouse strain allowing IL-2 production to be diverted. Rewiring of IL-2 production to diverse leukocyte sources allowed the identification of contextual influences over IL-2 impact. Network analysis identified a priority access for Tregs, and a competitive fitness cost induced among both Tregs and conventional CD4 T cells for IL-2 production. CD8 T cells and NK cells, by contrast, exhibited a preference for autocrine IL-2 production. IL-2 sourced from dendritic cells amplified the Treg circuit, while IL-2 produced by B cells induced two context-dependent circuits: dramatic expansion of CD8 + Tregs and ILC2 cells. The former was associated with an unexpected concentration of rare CD8 + Tregs in B cell zones, while the latter drove a downstream, IL-5-mediated, eosinophilic circuit. The source-specific effects demonstrate the contextual influence of IL-2 function and potentially explain unexpected adverse effects observed during clinical trials of exogenous IL-2. Targeted IL-2 production therefore has the potential to amplify or quench particular circuits in the IL-2 network, based on clinical desirability. Graphical abstract

Authors:

C Whyte, K Singh, O Burton, M Aloulou, A Moudra, C Roca, F Naranjo, F Lombard-Vadnais, L Kouser, T Hochepied, T Halim, S Schlenner, S Lesage, J Dooley, A Liston

Publication date:

1st Aug 2020

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