Immune biology of Ag-specific γδ T cells in infections

Accumulating evidence suggests that human gamma delta T cells act as non-classical T cells and contribute to both innate and adaptive immune responses in infections. V gamma 2 V delta 2 T (also termed V gamma 9 V delta 2 T) cells exist only in primates, and in humans represent a dominant circulating gamma delta T-cell subset. Primate V gamma 2 V delta 2 T cells are the only gamma delta T cell subset capable of recognizing microbial phosphoantigen. Since nonhuman primate V gamma 2 V delta 2 T cells resemble their human counterparts, in-depth studies have been undertaken in macaques to understand the biology and function of human V gamma 2 V delta 2 T cells. This article reviews the recent progress for immune biology of V gamma 2 V delta 2 T cells in infections.