IL-17 producers in γδ T cell subsets have been recently identified to play protective roles against bacterial
infection by inducing neutrophil infiltrations, organizing granulomas and acquired immunity. During ontogeny, γδ T cells
develop, maturate and localize at different tissues depending on Vγ repertoires. Vγ1+, Vγ4+ and Vγ6+ cells are reportedly
able to produce IL-17. Vγ6+ cells, which develop in the thymus at a very early stage of ontogeny, migrate into the uterus
and reproductive organs, whereas Vγ1+ and Vγ4+ cells, which develop at a later stage in the fetal thymus, migrate into the
spleen, lung and liver. Vγ6+ cells functionally differentiate into IL-17 producers within the thymus and can consequently
rapidly exert an ability to produce IL-17 in response to various stimuli. Thus, by finding IL-17-producing γδ T cells will
open a new paradigm to reveal the unique ontogeny and novel molecular mechanisms of γδ T cells.