SignificanceThe CD4⁺T_regresponse following acuteListeriainfection is heterogeneous and deploys two distinct modes of suppression coinciding with initial pathogen exposure and resolution of infection. This bimodal suppression of CD8⁺T cells during priming and contraction is mediated by separate T_reglineages. These findings make a significant contribution to our understanding of the functional plasticity inherent within T_regs, which allows these cells to serve as a sensitive and dynamic cellular rheostat for the immune system to prevent autoimmune pathology in the face of inflammation attendant to acute infection, enable expansion of the pathogen-specific response needed to control the infection, and reestablish immune homeostasis after the threat has been contained.