Distribution patterns of immunocompetent cells in the pregnant mouse uteri carrying allogeneic mouse and xenogeneic vole embryos

Abstract

Mouse and vole embryos were allogeneically and xenogeneically transferred into pseudopregnant CD-1 and immunodeficient ( scid ) female mice, and we investigated the distribution of immunocompetent cells, uterine natural killer (uNK) cells, mast cells and macrophages, in the implantation sites on days 6, 7 and 8 of gestation. The survival rate of the vole embryos decreased gradually with increased gestation, but the rate was higher in the scid uteri than in the CD-1 mice. The number of uNK cells increased markedly at the mesometrial triangle and the outer decidual area in the CD-1 uteri containing vole embryos; by contrast, scid uteri having vole embryos showed almost the same number as those having mouse embryos. Mast cells were present in large numbers at the myometrium, but rarely in the decidua in all types of pregnant uteri. Cells at the myometrium were more numerous in xenogeneic than in allogeneic transfer. Many mast cells appeared in the inner decidua where xenogeneically transferred vole embryos were dead and aborted. Macrophages were present in the outer decidua and myometria in all types of pregnant uteri, and their distribution pattern did not change even in aborted uterine sites. These results suggest:(1) the response of macrophages to dead embryos is completely inhibited, (2) uNK cells and mast cells increase near dead and aborted embryos, and (3) the increment in uNK cells responding to xenogeneic embryos is suppressed in scid mice, and the suppression may contribute partly to survival of the embryos.

Embryonic Resorption and Polycyclic Aromatic Hydrocarbons: Putative Immune-mediated Mechanisms

“…These combined data served to underscore the role of uNK cells in murine abortion and develop the theory that these cells are the causative effectors in CBA Â DBA resorption [Chaouat 2003]. A recently published xenogeneic model showed that vole embryos transferred to the uterus of a CD1 mouse were excluded by d11 of gestation, with excessive infiltration of uNK cells at the implantation site and destruction of the trophoblastic barriers [Widayati et al 2004]. Furthermore, while transfer of vole embryos to the uteri of SCID mice yielded longer survival rates, these xenogeneic transfers were still ultimately rejected while allogeneic embryos in SCID uteri survived, suggesting some NK involvement in fetal rejection [Widayati et al 2004].…”

“…Neutrophils and monocytes circulate throughout the maternal placental vasculature and have been shown to infiltrate areas of infection, damage, or resorption [Girardi 2008;Girardi et al 2003;Rogerson et al 2003]. Lastly, mast cells have been reported to exist within the murine myometrium during normal pregnancy [Wordinger et al 1986] and in greater numbers in the decidua during abortion [Widayati et al 2004]. In humans, increased numbers of mast cells in the uterus are associated with failed pregnancies [Arck et al 2001;Marx et al 1999].…”

“…A recently published xenogeneic model showed that vole embryos transferred to the uterus of a CD1 mouse were excluded by d11 of gestation, with excessive infiltration of uNK cells at the implantation site and destruction of the trophoblastic barriers [Widayati et al 2004]. Furthermore, while transfer of vole embryos to the uteri of SCID mice yielded longer survival rates, these xenogeneic transfers were still ultimately rejected while allogeneic embryos in SCID uteri survived, suggesting some NK involvement in fetal rejection [Widayati et al 2004]. Lastly, inflammation-induced fetal loss in IL-10-deficient mice was reported to be mediated by uNK cells [Murphy et al 2005], once again cementing the role of this cell type in murine spontaneous abortion.…”

Cellular Mechanism Underlying Embryo-Maternal Relationship in Intraspecific and Interspecific Pregnancy

“…This immune tolerance prevails not only for the progeny of the mother, but also for the transferred embryo, therefore the transferred embryo can develop to full term. However in the case of xenogeneic transferred embryo the immune tolerance does not appear and maternal rejection do not enable the xenogeniec embryo to develop successfully (Widayati et al, 2004). The trophoblast, which is the only fetal cell type that is exposed to the maternal uterine decidua and blood, has been suggested play an immunological role in protection embryo from the maternal rejection (Pavia and Stites, 1981;Rossant et al, 1983).…”