Immunological studies of mouse decidual cells. II. Studies of cells in artificially induced decidua

Active role of the predecidual-like zone in endometrial shedding in a mouse menstrual-like model

Cyclic shedding of the endometrium is unique to menstruating species. The status of the decidua in mouse menstrual-like models seems to differ from that of the predecidua in humans before endometrial breakdown. The aim of this study was to determine how this difference in decidual status is related to endometrial breakdown. A mouse menstruallike model was generated by pharmacological progesterone withdrawal. Histomorphological analysis and reticular fiber staining were used to evaluate endometrial status. In situ zymography was used to determine the localization of active collagenase and gelatinase. The functional endometrial layer containing the mature decidual-like zone (MDZ) and predecidual-like zone (PZ) underwent breakdown. The reticular fibers underwent disruption and fragmentation and became loose or disappeared at 12 h in the PZ, where active collagenase and gelatinase were limited. The reticular fibers were visibly reduced at 24 h in the MDZ, where active collagenase was detected. A few reticular fibers remained; however, the functional layer had sloughed into the lumen of the uterus. The results showed that reticular fibers of the PZ are actively degraded during endometrial shedding.

Leukocyte distribution in the pseudopregnant mouse uterus

Pseudopregnancy, induced by mating females with vasectomized males, is a frequently used model for studying pregnancy-like uterine changes in the absence of an embryo. Leukocytes make a significant contribution to uterine cellularity during pregnancy. The present study was designed to determine whether changes in numbers and distribution of leukocytes in the uterus during pseudopregnancy and following intraluminal injection of a deciduogenic stimulus parallel changes observed during the first eight days of pregnancy. Common leukocyte antigen positive (CLA+) cells, macrophages (F4/80+ cells), and granulocytes were assessed between days 1 and 8 of pseudopregnancy using qualitative and quantitative immunohistochemistry. High numbers of CLA+ leukocytes were present on days 1 and 2. Those were comprised primarily by macrophages, polymorphonuclear leukocytes, and eosinophils. High concentrations of leukocytes were detected in the endometrium, and some granulocytes were observed migrating through the luminal epithelium. Leukocytes, principally macrophages, were reduced in number and were distributed throughout the endometrium on days 3 and 4. Introduction of oil to the uterine lumen on day 4 stimulated primary decidualization. Decidual cells were CLA- and F4/80-, and, as decidualization proceeded, CLA+ and F4/80+ cells decreased in number in the anti-mesometrial uterus and were detected primarily in the deep endometrium. Later, a secondary decidualization zone developed in the mesometrial aspect of the uterus. Unlike the initial decidual reaction, which was relatively free of leukocytes, the secondary decidual zone contained very high numbers of CLA+ and F4/80+ cells. The uninjected uterine horn remained relatively unchanged from days 3 through 8.(ABSTRACT TRUNCATED AT 250 WORDS)

Localization of immunoglobulin-containing cells in human endometrium in the first trimester of pregnancy and throughout the menstrual cycle

The distribution of immunoglobulins in normal human endometrium throughout the menstrual cycle and in early pregnancy has been studied with an immunoperoxidase technique. In first-trimester decidua, IgG was detected within many cells of differing morphology and size. Large IgG-containing cells were often binucleate and were believed to be decidual cells. Examination of serial sections showed no kappa or lambda light-chain restriction, suggesting absorption of the immunoglobulin content. Medium-sized, irregular, IgG-containing cells were macrophages. An additional substantial population of small hyperchromatic IgG-containing cells were prominent around arterioles and adjacent to endometrial glands. From examination of adjacent sections stained with phloxine tartrazine, it was concluded that these represented endometrial granulocytes. Labelling for light chains again suggested absorption of the immunoglobulin content. In contrast, in non-pregnant endometrium immunoglobulin-containing stromal cells were uncommon, although IgG and IgA were detected in gland epithelium and secretions and in the stromal interstitium particularly in the secretory phase. These results support the notion that human endometrium lacks a classical secretory immune system and highlight the requirement for correlation between studies of cell surface markers, morphology and cell surface receptors.

Partial characterization of immunosuppressive factors from short-term cultures of murine decidual tissue

Previous in vitro experiments provided evidence for the immunosuppressive properties of supernatants from short-term cultures of decidual tissue obtained from the uterus of the pregnant mouse. The inhibitory activity of supernatants, previously detected in a mixed lymphocyte reaction (MLR), has now been demonstrated in an in vitro thymocyte proliferation assay. Fractionation of these supernatants on Sephadex G-15 and Sephacryl S-300 revealed that inhibition of the thymocyte proliferation assay was associated only with a low molecular weight fraction (less than 1,500), whilst MLR inhibitory activity was associated with three different molecular weight fractions (less than 1,500, 60,000 and 1,000,000). These results are discussed in relation to the different biological factors previously isolated in decidua or deciduoma of rats and humans.

Ia antigen-bearing decidual cells and macrophages in cultures of mouse decidual tissue

The ontogeny of Ia antigen expression on cells within the decidua basalis of the placenta and on decidual cells differentiating in vitro was investigated in the mouse. The results indicate that Ia antigen expression is temporarily restricted and can be detected in short-term cultures of decidual tissue only during the final third of gestation. The Ia antigen positive cells, which are non-phagocytic, non-specific esterase negative and lack Fc receptors, appear to be true decidual cells on the basis of their fine structural characteristics. In contrast, morphologically identical dendritic decidual cells arising from differentiation in vitro of endometrial cells do not express Ia antigens. A population of small rounded cells was also present in cultures of both decidual tissue and in vitro decidualized endometrial cells. These rounded cells possess the macrophage-like properties of Fc receptors, non-specific esterase and phagocytic activity. The possible function of these cell populations within the decidual tissue is discussed.

Life history of decidual cells: a review

Decidual cells are a distinctive cell population observed in the mammalian endometrium during pregnancy. Their appearance can also be induced with appropriate stimuli in the hormone-primed pseudopregnant uterus. This review deals with their life history, including the dynamic morphological events during the process of decidualization, cytochemical markers for decidual cell reaction, the surface markers and functions of decidual cells, and, finally, the origin and fate of this cell class. The recent discovery of the bone marrow origin of decidual cell precursors adds a new dimension to decidual cell biology. Future studies of steps in the differentiation of the decidual cell lineage await the identification of unique lineage-specific cell--surface of cytoplasmic marker(s); a precise knowledge of decidual cell functions can only be obtained from a discriminating analysis using purified cell populations.

Immunological characterisation of surface receptors on rat metrial gland cells

Cells from metrial glands of pregnant rats were examined for surface receptors. No E, EA mu or EAC receptors were demonstrated. Fc gamma receptors were detected by EA gamma rosette formation, using sheep red blood cells sensitised with the IgG fraction of rabbit or rat antisera. Significantly more of the metrial gland cells, and of the rat peritoneal exudate and spleen cells examined as controls, formed rosettes with red cells sensitised with rabbit IgG than with those sensitised with rat IgG. The proportion of metrial gland cells forming EA gamma rosettes decreased significantly between day 12 and day 15 of pregnancy but increased by day 19. Metrial gland cells from deciduomata formed EA gamma rosettes, and the proportions varied during pseudopregnancy. At day 13 of pregnancy a greater proportion of metrial gland cells displayed Fc gamma receptors in multiparous rats than in primigravid rats. The binding affinity of the Fc gamma receptors was characterised by inhibition studies with homologous and heterologous IgGs. Maximal inhibition occurred when the inhibitory IgG was homologous to the IgG used to sensitise the red cells. EA gamma rosette formation by cells from the metrial gland was inhibited by both monomeric and heat-aggregated IgGs.

Bone marrow origin of decidual cell precursors in the pseudopregnant mouse uterus

Decidual cells are considered to be the endproduct of a hormonally induced transformation of endometrial stromal cells of the uterus. However, the source of these precursors remains unknown. This study of evaluated the possibility of their bone marrow origin by an examination of the H-2 phenotype of decidual cells in pseudopregnant bone marrow chimeras. These chimeras were produced by repopulating lethally irradiated CBA/J female (H-2k) mice with bone marrow from (CBA/J x C57BL/6J) F1 female (H-2kb) mice. Pseudopregnancy was produced with a hormonal regimen followed by an oil-induced decidual stimulus. Chimerism was evaluated radioautographically by an identification of the donor-specific Kb phenotype on cells with an immunolabeling technique with monospecific anti-H-2 serum followed by radioiodinated protein A. The extent of chimerism as indicated by the degree of Kb labeling on decidual cells as well as macrophages contained within the decidual nodules was quantitatively compared with that seen on splenic lymphocytes. Fair to good chimerism, as reflected by labeling for the donor-specific marker (Kb), was seen on splenic lymphocytes and macrophages within the decidual nodules in 6 out of 11 animals. A similar level of chimerism was detected on decidual cells in all but one of these six, in which case this was low. One animal showed low chimerism in the spleen but good chimerism on the decidual cells. The remaining four mice were nonchimeric for all three cell types. These results indicate that decidual cells and macrophages appearing within the decidual nodules of pseudopregnant mice are ultimate descendants of bone marrow cells.