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, V alpha 14 NKT cells expressing an invariant antigen receptor encoded by V alpha 14/J alpha 281 and V beta 7 segments, accumulated in the decidua during pregnancy and provoked abortion upon stimulation with ar-galactosylceramide (alpha-GalCer), a specific ligand for V alpha 14 NKT cells. The alpha-GalCer-mediated abortion was not observed in V alpha 14 NKT-, IFN-gamma-, tumor necrosis factor alpha-, or perforin-knock-out mice and appeared to be due to the degeneration of embryonic trophoblasts mediated by the activated V alpha 14 NKT cells whose perforin-dependent killing and production of lFN-gamma and tumor necrosis factor alpha were essential. The possible role of the decidual V alpha 14 NKT cells in the pathogenesis of abortion is discussed.