Localization of the Th2 cytokines IL-3, IL-4, IL-10 at the fetomaternal interface during human and murine pregnancy and lack of requirement for Fas/Fas ligand interaction for a successful allogeneic pregnancy

PROBLEM: Th2 cytokines and Fas/Fas ligand interactions are proposed to be p art of the placental barrier that contribute to the success of allogeneic p regnancy. To fully understand the role regulation of Th2 cytokines, we must isolate and identify the cells that produce them. We also need to assess t he requirement for Fas/Fas ligand interaction in facilitating a successful allogeneic pregnancy. METHOD OF STUDY: To assess the site of production of Th2 cytokines, we used immunohistochemistry sections from placental and decidual tissue obtained at various stages of gestation in mice and humans. We used mice that are ge netically deficient in Fas/Fas ligand interactions and raised specific anti -paternal CTLs by anti-paternal immunization of the mother before mating. RESULTS: The detailed results show that in both species the bulk of Th2 pro duction may come from non-lymphoid tissues in the placenta and decidua, wit h a major role for trophoblasts. This raises questions about the mechanism( s) by which alloimmunization enhances local Th2 cytokine production. This i ssue is discussed. CONCLUSIONS: The success of allopregnancy in mice with circulating anti-pat ernal CTLs and deficient Fas/Fas ligand interactions rules out a mandatory role for such a mechanism in ensuring the success of allogeneic pregnancy.