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Presence of Activated Macrophages in a Murine Model of Early Embryo Loss
Author(s) -
DUCLOS ALAIN J.,
HADDAD ELIAS K.,
BAINES MALCOLM G.
Publication year - 1995
Publication title -
american journal of reproductive immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.071
H-Index - 97
eISSN - 1600-0897
pISSN - 1046-7408
DOI - 10.1111/j.1600-0897.1995.tb00904.x
Subject(s) - embryo , microbiology and biotechnology , biology , immunology , macrophage , andrology , medicine , genetics , in vitro
PROBLEM : Even though our knowledge of the phenomenon at play at the fetoplacental interface has greatly advanced during the past years, a complete understanding of the reasons why the developing embryo is not rejected by maternal immune effector cells remains largely unknown. METHODS : We have used immunohistochemistry with the macrophage‐specific markers F4/80 and MHC II to study the relationship between decidual infiltration and resorption in murine models of embryo loss between days 6 and 10 of gestation. RESULTS : Analysis of day 8 CBA/J × DBA/2 pregnancies has revealed 2 distinct populations of embryos. The majority (69.4%) expressed low levels of F4/80 + cells, but a minority (30.6%) expressed much higher level of the macrophage marker. In CBA/J × BALB/c, most embryos (91.7%) expressed low numbers of F4/80 + cells. As earlier experiments established that products of activated macrophages (TNF‐α and nitric oxide) were implicated in embryo loss in this model, the activation status of the F4/80 + macrophages was assessed through the cell surface expression of MHC II. Again, a similar association was established: 30.6% of the CBA/J × DBA/2 embryos were infiltrated by significantly more MHC II + cells than the control CBA/J × BALB/c mating. Finally, when coordinate expression of F4/80, MHC II and CD11b was assessed, it was found that an embryo significantly infiltrated by cells bearing one of the 3 markers was also heavily infiltrated by cells bearing the 2 other markers. CONCLUSIONS : This study has shown that the augmented infiltration of the deciduum with maternal macrophages is an early event which precedes spontaneous abortion of the early embryo.