Memory γδ T Cells-Newly Appreciated Protagonists in Infection and Immunity

Despite the potential for diversity in their T cell receptor, gamma delta T cells are primarily considered to be innate immune cells. Recently, memory-like gamma delta T cell responses have been identified in murine models of infection and autoimmunity. Similar memory responses have also been described in human and non-human primate gamma delta T cells. It has thus become clear that subpopulations of gamma delta T cells can develop long-lasting memory akin to conventional alpha beta T cells, with protective and pathogenic consequences. Hence, a re-evaluation of their true capabilities and role in infection and immunity is required. This review discusses recent reports of memory-type responses attributed to gamma delta T cells and assesses this under-appreciated facet of these enigmatic cells.