BLIMP-1 and CD39 expression define human effector memory regulatory T cells in blood and recall responses to viruses

Abstract

BLIMP-1, a transcriptional repressor initially identified in plasma B-cell differentiation, also regulates CD8+ T cells and is differentially expressed between naïve and effector/memory CD4+ T cells. However, the functions of BLIMP-1 in human CD4+ regulatory T cells (Tregs) remain unclear. We found BLIMP-1 mRNA levels were low in naïve Tregs from thymus and cord blood, but high in effector/memory Tregs from adult peripheral blood. We confirmed the expression of BLIMP-1 mRNA by microarray of healthy T-cell populations and single-cell RNA-sequencing of SARS-CoV-2 spike-specific CD4+ T cells from convalescent COVID-19 patients. We found activated memory Tregs expressed the highest levels of BLI..