ABSTRACT
Mice ablated for the gene encoding the transcription factor Nfil3 lack peripheral natural killer (NK) cells but retain tissue-resident NK cells, particularly in mucosal sites, including virgin uterus. We undertook a time course histological study of implantation sites from syngeneically (Nfil3(-/-)) and allogeneically (BALB/c) mated Nfil3(-/-) females. We also examined implantation sites from Rag2(-/-)Il2rg(-/-) females preconditioned by adoptive transfer of Nfil3(-/-) marrow or uterine cell suspensions to identify the Nfil3(-/-) pregnancy aberrations that could be attributed to nonlymphoid cells. Uterine NKs (UNKs) reactive and nonreactive with the lectin Dolichos biflorus agglutinin (DBA) differentiate, localize, and mature within Nfil3(-/-) implantation sites, although at reduced abundance. The DBA nonreactive UNK cells were enriched following Nfil3(-/-) marrow transplantation. Uterine lumen closure, early embryonic development, and differentiation of antimesometrial decidua were delayed in Nfil3(-/-) implantation sites. Major disturbances to the decidual-trophoblast interface that did not lead to fetal death were attributed to NFIL3 deficiency in trophoblast. At midgestation, vessels of the placental labyrinth were enlarged, suggestive of reduced branching morphogenesis. A major term complication in most Nfil3(-/-) × Nfil3(-/-) pregnancies but not Nfil3(-/-) × Nfil3(+/-) pregnancies was dystocia. These studies highlight the differentiation potential and functions of Nfil3(-/-) UNK cell progenitors and illustrate that much of the implantation site histopathology associated with this strain is due to Nfil3 deletion in nonlymphoid cell lineages.
