Within the last few years, regulatory T cells (T(reg) cells) have re-entered the stage of immunology. This astonishing revival is mainly due to recent studies on peripheral tolerance, which demonstrated the existence of T(reg) cells and allowed the isolation and phenotypic and functional characterization of these cells. However, information on the role of T(reg) cells in the control of immune responses against infections is still limited, although host defense represents the prime function of the immune system. In this overview, we summarize current knowledge on T(reg) cells in immunity to infection, discuss potential functions of T(reg) cells during infection, and finally, point to possible implications of T(reg) cell functions for our understanding of fundamental aspects of host-pathogen interactions.
