{gamma}{delta} T cell homeostasis is established in competition with {alpha}{beta} T cells and NK cells.

gammadelta T cells are a diverse population of lymphocytes that play an important role in immune regulation. The size of the gammadelta T cell pool is tightly regulated, comprising only 1-10% of total lymphoid T cells in mice and humans. We examined the homeostatic regulation of gammadelta T cells using a model of lymphopenia-induced homeostatic expansion. We found that IL-15 and, to a lesser extent, IL-7 play an important role in lymphoid gammadelta T cell homeostasis. Moreover, gammadelta T cell homeostatic expansion was limited not only by gammadelta T cells themselves but also by natural killer cells and alphabeta T cells. Our results suggest that CD8(+) alphabeta T cells are the most potent inhibitors of gammadelta T cell homeostasis and exert their effect by competing for IL-15.