Involvement of decidual Vα14 NKT cells in abortion

The immunological mechanisms that regulate abortion are largely unknown. Here, we found that a distinct subset of lymphocytes, Vα14 NKT cells expressing an invariant antigen receptor encoded by Vα14/Jα281 and Vβ7 segments, accumulated in the decidua during pregnancy and provoked abortion upon stimulation with α-galactosylceramide (α-GalCer), a specific ligand for Vα14 NKT cells. The α-GalCer-mediated abortion was not observed in Vα14 NKT-, IFN-γ-, tumor necrosis factor α-, or perforin-knock-out mice and appeared to be due to the degeneration of embryonic trophoblasts mediated by the activated Vα14 NKT cells whose perforin-dependent killing and production of IFN-γ and tumor necrosis factor α were essential. The possible role of the decidual Vα14 NKT cells in the pathogenesis of abortion is discussed.