Suppressor cell activity in uterine decidua correlates with success or failure of murine pregnancies.

Abstract

We recently developed a system in which fetal death consistently occurs and is associated with maternal immune reactivity against the fetus. When embryos from Mus caroli, an Asian species of mouse, are transferred to the uteri of Mus musculus, they appear normal until 9.5 days of pregnancy but are resorbed by 15 days. Death is preceded by infiltration with maternal lymphoid cells, and the dying fetuses contain Thy-1.2+, Lyt-1+2+lymphoblasts that lyse Mus caroli target cells in a short-term51Cr-release assay in vitro. In this paper we demonstrate that the decidual suppressor cells present during normal allogeneic intraspecies pregnancy in one uterine horn are not detectable in the decidua associated with xenogeneic Mus caroli conceptuses that have implanted in the opposite uterine horn. This evidence suggests an important role for these suppressor cells in promoting survival of the mammalian fetus.