Half depletion of Foxp3+ regulatory T cells by diphtheria toxin for long-term study in vivo

Abstract

Depletion of regulatory T cells (Tregs) is an appropriate approach to study the function of Tregs in vivo, and most previous studies have focused on complete depletion. The purpose of the current study was to determine an appropriate dose and timing for half depletion of Tregs in vivo. DETREG (DEpletion of REGulatory T cells) mice were produced and injected with different doses of diphtheria toxin (DT) for 7 days and 14 days. The mice were then sacrificed to collect the spleen and mesenteric lymph nodes (MLN) for analysis using flow cytometry. Foxp3+eGFP+ cells were significantly reduced by DT injection. A dose of 5 ug/kg DT led to half depletion and no deaths. A DT dose of 25, 50, or 100 ug/kg led to a progressively higher depletion rate but also a higher mortality rate. In conclusion, a low dose of DT is effective for half depletion of Tregs and long-term study. Half depletion of Tregs may become a new method for the future study of Tregs in vivo.