Type I regulatory T (Tr1) cells are a population of regulatory CD4+ T cells implicated in the suppression of pathological immune responses across multiple diseases, but a unifying transcriptional signature of Tr1 identity across disease contexts has not been characterized. In this issue of the JCI, Edward, Ng, and colleagues identified a conserved transcriptional signature that distinguished Tr1 (IL-10+IFN-γ+) from Th1 (IL-10–IFN-γ+) cells in human and mouse malaria. This signature implicated genes encoding inhibitory receptors — including CTLA-4 and LAG-3 — and transcription factors — including cMAF. The authors identified coinhibitory receptor expression that distinguished Tr1 cells from other CD4+ T cell subsets. Furthermore, cMAF — and, to a lesser extent, BLIMP-1 — promoted IL-10 production in human CD4+ T cells. BLIMP-1 also played a role in supporting the expression of inhibitory receptors. These findings describe a few key features that seem to be conserved by Tr1 cells across multiple species, disease contexts, and marker definitions.
Jason Nideffer, Prasanna Jagannathan
Select features of Tr1 biology are conserved across disease models.