Signature cytokine-associated transcriptome analysis of effector γδ T cells identifies subset-specific regulators of peripheral activation

Abstract

γδ T cells producing either interleukin-17A (γδ¹⁷ cells) or interferon-γ (γδ^IFN cells) are generated in the mouse thymus, but the molecular regulators of their peripheral functions are not fully characterized. Here we established an Il17a-GFP:Ifng-YFP double-reporter mouse strain to analyze at unprecedented depth the transcriptomes of pure γδ¹⁷ cell versus γδ^IFN cell populations from peripheral lymph nodes. Within a very high fraction of differentially expressed genes, we identify a panel of 20 new signature genes in steady-state γδ¹⁷ cells versus γδ^IFN cells, which we further validate in models of experimental autoimmune encephalomyelitis and cerebral malaria, respectively. Among the signature genes, we show that the co-receptor CD6 and the signaling protein Themis promote the activation and proliferation of peripheral γδ^IFN cells in response to T cell antigen receptor stimulation in vitro and to Plasmodium infection in vivo. This resource can help to understand the distinct activities of effector γδ T cell subsets in pathophysiology.