Gestation-related expression of the interferon-gamma receptor gene in mouse uterine and embryonic hematopoietic cells

Abstract

Macrophages and natural killer (NK)-like cells are the major hematopoietic cell populations in the cycling and pregnant mouse uterus and are also found in the embryo. In order to evaluate potential receptivity of these cells to interferon-gamma (IFN-gamma), tissues taken from cycling and pregnant mice were tested for IFN-gamma receptor (IFN-gamma R) mRNA and protein. Macrophages were identified immunohistochemically by using the specific monoclonal antibody F4/80. NK cells were identified by their large size, distinctive intracellular granules, and binding of a monoclonal antibody to the common leukocyte antigen. In cycling uteri, the abundance of IFN-gamma R mRNA relative to an invariant message (glyceraldehyde-3-phosphate dehydrogenase) increased during progression of the hormonally regulated estrous cycle. IFN-gamma R mRNA in situ hybridization signals were slightly higher in macrophage-like than in other types of endometrial stromal cells. In pregnant uteri, the highest proportions of IFN-gamma R mRNA were observed at gestation day (g.d.) 16. Specific message and protein were present in uterine macrophages by g.d. 7 and in NK cells by g.d. 9. IFN-gamma R expression in both lineages remained stable through the balance of pregnancy. In embryos, IFN-gamma R mRNA increased between g.d. 14 and 16. Specific transcripts were present in many cells at g.d. 14, but none were detected in embryonic liver macrophages until g.d. 16. The results of this study suggest relationships between IFN-gamma R expression and ovarian hormones as well as cell maturation and support the postulate that IFN-gamma receptor-ligand interactions may improve the ability of uterine and embryonic hematopoietic cells to perform specific tasks during gestation.