The importance of gamma delta T cells in the resolution of pathogen-induced inflammatory immune responses

The aim of our research is to determine the biological function of gamma de lta T lymphocytes and in particular the role they play in microbial immunit y. Although evidence of gamma delta T-cell activation and expansion has bee n obtained from numerous infectious diseases, how they contribute to pathog en-induced immune responses is still not clear Based upon extensive studies of gamma delta T-cell involvement in the immune response to viral and bact erial pathogens in both mice and humans, we have uncovered evidence of thei r direct involvement in terminating host immune responses to infection and preventing chronic disease. We have identified an interaction between perip heral gamma delta T cells and a population of activated, proinflammatory ma crophages elicited by infection that occurs late in the course of infection during or after pathogen clearance. As a result of this interaction, activ ated gamma delta T cells acquire cytotoxic activity and kilt the stimulator y macrophages, leading us to propose a model for gamma delta T-cell-macroph age interactions that contributes to macrophage homeostasis, the resolution of inflammatory immune responses, and prevention of chronic inflammatory d isease.