REGULATORY ROLE OF GAMMA-DELTA T-CELLS IN UTERINE INTRAEPITHELIAL LYMPHOCYTES IN MATERNAL ANTIFETAL IMMUNE-RESPONSE

To elucidate the potential roles of the gamma delta T cells in uterine intraepithelial lymphocytes (IEL) in the regulation of maternal antif etal immune response during pregnancy, we examined the kinetics and fu nction of gamma delta T cells in uterine IEL obtained from (C3H/He x A KR/J) pregnancy. The number of gamma delta T cells increased in the ut erine IEL in (C3H/HexAKR/J) pregnancy more than those in (C3H/HexC3H/H e) pregnancy and much more than in nonpregnant C3H/He mice. The uterin e IEL in (C3H/HexC3H/He) pregnancy significantly proliferated in respo nse to AKR/J stimulator cells. In contrast, the uterine IEL in (C3H/He xAKR/J) pregnancy showed little, if any, proliferation in response to the same stimulator cells. gamma delta T cell depletion from the uteri ne IEL in (C3H/HexAKR/J) pregnancy restored their responsiveness again st AKR/J stimulator cells. Both gamma delta T cell-enriched fraction a nd alpha beta T cell-depleted fraction, but neither gamma delta T cell -depleted fraction nor alpha beta T cell-enriched fraction in the uter ine IEL exhibited suppressive activity against allogeneic responses of nonpregnant C3H/He LN cells. This suppressive activity was shown by t ransferring the supernatant of culture medium in the uterine IEL stimu lated with AKR/J cells that contained a large amount of TGF-beta, and the suppressive activity was significantly blocked by addition of anti -TGF-beta mAb to the culture. Taken together, our results suggest that gamma delta T cells in the uterine IEL suppress the maternal antifeta l immune response at the maternal-fetal interface at least in part thr ough TCF-beta production to prevent a rejection of the fetus.