Regulatory T cell suppressive potency dictates the balance between bacterial proliferation and clearance during persistent Salmonella infection (137.11)

Abstract

The pathogenesis of persistent infection is dictated by the balance between opposing immune activation and suppression signals. Although regulatory T cells (Tregs) have been widely implicated to control host defense against infection, their role in dictating the natural progression of persistent infection remains incompletely defined. Herein, a sharp dichotomy in infection tempo between early and late time points during persistent Salmonella infection is demonstrated. Early after infection, blunted effector T cell activation and increasing bacterial burden coincide with enhanced Treg suppressive potency. Reciprocally, at later time points, robust effector T cell activation and bacterial clearance occur in parallel with diminished Treg suppression. By enumerating the relative impact of Treg ablation on infection outcome at both early and late time points of persistent infection, the role of Treg suppressive potency in dictating the natural progression of infection was verified. Thus, dynamic control of Treg suppressive potency dictates the tempo of persistent bacterial infection.