Regulatory T cells: friend or foe in immunity to infection.

Abstract

Homeostasis in the immune system is dependant on a balance between responses that control infection and tumours and the reciprocal responses that prevent inflammation and autoimmune diseases. It is now recognized that regulatory T (Tr) cells play a critical role in suppressing immune responses to self-antigen and preventing autoimmune diseases. Evidence is also emerging that Tr cells control immune responses to bacteria, viruses, parasites and fungi. This article explores the possibilities that Tr cells can be both beneficial to the host in limiting the immunopathology associated with anti-pathogen immune responses, and to the pathogen through subversion of protective immune responses of the host.