gamma delta-T cells: an unpolished sword in human anti-infection immunity

gamma delta-T cells represent a small population of immune cells, but play an indispensable role in host defenses against exogenous pathogens, immune surveillance of endogenous pathogenesis and even homeostasis of the immune system. Activation and expansion of gamma delta-T cells are generally observed in diverse human infectious diseases and correlate with their progression and prognosis. gamma delta-T cells have both 'innate' and 'adaptive' characteristics in the immune response, and their anti-infection activities are mediated by multiple pathways that are under elaborate regulation by other immune components. In this review, we summarize the current state of the literature and the recent advancements in gamma delta-T cell-mediated immune responses against common human infectious pathogens. Although further investigation is needed to improve our understanding of the characteristics of different gamma delta-T cell subpopulations under specific conditions, gamma delta-T cell-based therapy has great potential for the treatment of infectious diseases. Cellular & Molecular Immunology (2013) 10, 50-57; doi:10.1038/cmi.2012.43; published online 15 October 2012