Localization of the Th2 cytokines IL-3, IL-4, IL-10 at the fetomaternal interface during human and murine pregnancy and lack of requirement for Fas/Fas ligand interaction for a successful allogeneic pregnancy

MUC16 can Predict the Pregnancy Outcomes in Human and Intraperitoneal Administration of MUC16 can Rescue Pregnancy Losses in Mouse Models

Mucin 16 (MUC16) participates in the process of embryo implantation, but few studies have examined the association between MUC16 and pregnancy loss. To investigate this association, the expression of MUC16 in serum and decidua was compared between women with pregnancy loss and ongoing pregnancies. In vitro experiments and animal models were used to explore the role and underlying mechanisms of MUC16 in pregnancy loss. In human study, the expression of MUC16 in serum and decidua was both consistently lower in the women with pregnancy loss compared with those in women with ongoing pregnancies. In vitro experiments revealed the interaction of MUC16 with peripheral blood natural killer (pNK) cells. MUC16 changed the phenotype and reduced the pro-inflammation ability of pNK cells. MUC16 also inhibited the cytotoxicity of pNK cells through the Src homology region 2 domain-containing phosphatase-1/extracellular signal-regulated kinase (SHP-ERK) pathway. Furthermore, MUC16 promoted the migration, invasion and tube formation of trophoblast cells by co-culturing together with pNK cells. In vivo experiments, the mouse model of abortion was used to further confirm that intraperitoneal administration of MUC16 could rescue the pregnancy loss. This study reveals the still-unknown connection between MUC16 and pNK cells and indicates that MUC16 provides a novel method for future prediction and treatment of unfavorable pregnancy outcomes.

Partner relationship quality and IL-6:IL-10 trajectories from pregnancy to a year after-birth

BACKGROUND

Inflammatory activity during pregnancy and the postpartum period shifts systematically due to pregnancy progression, delivery, and postpartum recovery. Factors that deregulate inflammatory activity increase the risk for adverse pregnancy outcomes and slower postpartum recovery. The IL-6:IL-10 or TNF-α:IL-10 ratio is potentially one way to capture peripheral inflammatory regulation; higher values indicate that anti-inflammatory IL-10 is less effective at regulating pro-inflammatory TNF-α or IL-6, skewing towards maladaptive pro-inflammatory profiles. Associations between partner relationship quality and IL-6:IL-10 or TNF-α:IL-10 trajectories during pregnancy and the postpartum period have not been assessed. The purpose of this study was to test whether partner relationship quality (support, conflict) is associated with attenuated IL-6, IL-10, TNF-α, TNF-α:IL-10 or IL-6:IL-10 trajectories from the third trimester to the postpartum period.

METHODS

A sample of 162 women from the Healthy Babies Before Birth study reported on partner relationship quality (support and conflict) using the Social Support Effectiveness Questionnaire during the third trimester. Plasma samples were collected in the third trimester and at 1-, 6- and 12-months postpartum, and assayed for TNF-α, IL-6 and IL-10. Associations between both indicators of relationship quality (support and conflict) and TNF-α, IL-6, IL-10, IL-6:IL-10, TNF-α:IL-10 trajectories were tested using multi-level modelling, controlling for sociodemographic, pregnancy and health variables.

RESULTS

Partner support interacted with time to predict IL-6:IL-10 trajectories, linear: b = -0.176, SE = 0.067, p =.010, quadratic: b = 0.012, SE = 0.005, p =.009. Lower partner support was associated with steeper increases in IL-6:IL-10 from the third trimester to 6 months postpartum, followed by steeper decreases in IL-6:IL-10 from 6 months postpartum to a year after birth. Partner conflict was not associated with IL-6:IL-10 levels at study entry, b = 0.233, SE = 0.219, p =.290, or over time, p's > 0.782. Neither indicator of partner relationship quality was associated with TNF-α, IL-6, IL-10, or TNF-α:IL-10 trajectories, p's > 0.205.

CONCLUSION

Lower partner support may be associated with reduced moderation of IL-6 by IL-10 between pregnancy and a year postpartum, with possible consequences for maternal health and well-being.

Role of Maternal Infections and Inflammatory Responses on Craniofacial Development

Pregnancy is a tightly regulated immunological state. Mild environmental perturbations can affect the developing fetus significantly. Infections can elicit severe immunological cascades in the mother's body as well as the developing fetus. Maternal infections and resulting inflammatory responses can mediate epigenetic changes in the fetal genome, depending on the developmental stage. The craniofacial development begins at the early stages of embryogenesis. In this review, we will discuss the immunology of pregnancy and its responsive mechanisms on maternal infections. Further, we will also discuss the epigenetic effects of pathogens, their metabolites and resulting inflammatory responses on the fetus with a special focus on craniofacial development. Understanding the pathophysiological mechanisms of infections and dysregulated inflammatory responses during prenatal development could provide better insights into the origins of craniofacial birth defects.

NF-κB and Its Regulators During Pregnancy

The transcriptional factor NF-κB is a nuclear factor involved in both physiological and pathological processes. This factor can control the transcription of more than 400 genes, including cytokines, chemokines, and their modulators, immune and non-immune receptors, proteins involved in antigen presentation and cell adhesion, acute phase and stress response proteins, regulators of apoptosis, growth factors, other transcription factors and their regulators, as well as different enzymes; all these molecules control several biological processes. NF-κB is a tightly regulated molecule that has also been related to apoptosis, cell proliferation, inflammation, and the control of innate and adaptive immune responses during onset of labor, in which it has a crucial role; thus, early activation of this factor may have an adverse effect, by inducing premature termination of pregnancy, with bad outcomes for the mother and the fetus, including product loss. Reviews compiling the different activities of NF-κB have been reported. However, an update regarding NF-κB regulation during pregnancy is lacking. In this work, we aimed to describe the state of the art around NF-κB activity, its regulatory role in pregnancy, and the effect of its dysregulation due to invasion by pathogens like Trichomonas vaginalis and Toxoplasma gondii as examples.

Adoptive transfer of Tregs: A novel strategy for cell-based immunotherapy in spontaneous abortion: Lessons from experimental models

Since half of the genes are inherited from the paternal side, the maternal immune system has to tolerate the presence of foreign paternal antigens. Regulatory T cells facilitate the development and maintenance of peripheral tissue tolerance of the fetus during pregnancy. Reduction in regulatory T cells is associated with complications of pregnancy, including spontaneous abortion. Recent studies in mouse models have shown that the adoptive transfer of Tregs can prevent spontaneous abortion in mouse models through improving maternal tolerance. Thus, adoptive cell therapy using autologous Tregs could potentially be a novel therapeutic approach for cell-based immunotherapy in women with unexplained spontaneous abortion. Besides, strategies for activating and expanding antigen-specific Tregs ex vivo and in vivo based on pharmacological agents can pave the foundation for an approach incorporating immunotherapy and pharmacotherapy. This review aims to elaborate on the current understanding of the therapeutic potential of the adoptive transfer of Tregs in the treatment of spontaneous abortion disease.

Decidual glycodelin-A polarizes human monocytes into a decidual macrophage-like phenotype through Siglec-7

Decidual macrophages constitute 20-30% of the total leukocytes in the uterus of pregnant women, regulating the maternal immune tolerance and placenta development. Abnormal number or activities of decidual macrophages (dMs) are associated with fetal loss and pregnancy complications, such as preeclampsia. Monocytes differentiate into dMs in a decidua-specific microenvironment. Despite their important roles in pregnancy, the exact factors that regulate the differentiation into dMs remain unclear. Glycodelin-A (PAEP, hereafter referred to as GdA) is a glycoprotein that is abundantly present in the decidua, and plays an important role in fetomaternal defense and placental development. It modulates the differentiation and activity of several immune cell types residing in the decidua. In this study, we demonstrated that GdA induces the differentiation of human monocytes into dM-like phenotypes in terms of transcriptome, cell surface marker expression, secretome, and regulation of trophoblast and endothelial cell functions. We found that Sialic acid-binding Ig-like lectin 7 (Siglec-7) mediates the binding and biological actions of GdA in a sialic acid-dependent manner. We, therefore, suggest that GdA, induces the polarization of monocytes into dMs to regulate fetomaternal tolerance and placental development.

Circulating Cytokines Associated with Poor Pregnancy Outcomes in Beninese Exposed to Infection with Plasmodium falciparum

Malaria during pregnancy is a major cause of maternal morbidity as well as fetal and neonatal mortality. Previous studies, including our own, suggested that placental and peripheral cytokine and chemokine levels measured at delivery can be used as biomarkers for pregnancy outcomes. However, the timing of malaria infection during pregnancy matters, and these studies do not address the effect of different cytokines in peripheral blood plasma samples taken at early and midpregnancy and at delivery. Here, we aimed to investigate whether peripheral plasma cytokine levels were associated with pregnancy outcomes in a cohort of 400 Beninese pregnant women. Using a high-sensitivity cytometry-based method, we quantified the levels of interleukin-4 (IL-4), IL-5, IL-10, IL-12p70, and gamma interferon (IFN-γ) in peripheral plasma samples taken at two time points during pregnancy and at delivery in various groups of pregnant women identified with Plasmodium falciparum infection, with anemia, with preterm births, or giving birth to babies who are small for their gestational age. We found that, consistently at all time points, elevated levels of IL-10 were strongly and significantly associated with P. falciparum infection, while the levels of IFN-γ at inclusion and delivery were weakly but also significantly associated. Low levels of IL-5 at delivery were associated with a greater risk of both preterm births and small-for-gestational-age babies. The immunosuppressive effects of IL-10 likely affect the overall cytokine equilibrium during pregnancy in women harboring P. falciparum infections. Our findings highlight the peripheral signature of pregnancy outcomes and strengthen the idea of using cytokines as diagnostic or prognostic markers.

Intercellular wireless communication network between mother and fetus in rat pregnancy-a study on directed and weighted network

BACKGROUND

The maternal body forms a wireless communication system with the embryo through the blood circulation system. Obviously, direct sampling from early embryos is damaging. Therefore, we detected changes in the concentrations of 30 signaling molecules in serum from the pregnant rats at the 14 time points, then the intercellular wireless communication network was established, to explore the regularity of signal communication between mother and fetus.

METHOD OF STUDY

We used liquid chip scanning technology to detect 30 signal molecules at 14 time points. Statistical analysis of the data yielded significant change signal molecules. According to the secretory cells and effector cells involved in signal molecules, the communication network of different stages were drawn by using Biograph software.

RESULTS

The process could be divided into 4 periods including early, middle, late pregnancy, and postpartum. In early pregnancy, two immune transformations occur: (a) interleukin-10 (IL-10), interleukin-13 (IL-13) increased at day 5, which promoted immunoglobin G (IgG) secretion, provided protection through the neonatal Fc receptor for IgG (FcγRn) crossing the placental barrier to reach the embryo, achieved T helper 1 (Th1) transformation into T helper 2 (Th2), reduced maternal innate and cellular immunity, and prevented fetal abortion; (b) the fetal heart was fully developed at day 7, with circulatory system established, which provided a platform for intercellular information exchange. The second transformation corresponded to the maternal immune system providing signaling molecules for the embryo to promote Th2 transformation into Th1, thus activating embryonic innate immune cells, and enabling antibody-mediated immune recognition, response and protection. Days 9-19 was a stable period. After 21 days of pregnancy, the maternal body prepared for delivery. The characteristic signaling molecules in the process were monocyte chemotactic protein-1 (MCP-1), IL-10, IL-13, IL-1ɑ, interferon-inducible protein-10 (IP-10), regulated upon activation normal T cell expressed and secreted (RANTES), thyroid stimulating hormone (TSH), IL-2, IL-6, IL-12p70 and IL-18.

CONCLUSION

Detection of concentration changes of the factors in maternal serum could provide a tool for monitoring, diagnosis, prediction and treatment of embryo differentiation, development and health.

Novel nucleotide variants in SLA-DOB and CD4 are associated with immune traits in pregnant sows

Reinforcing the immunity of pregnant sows can not only improve their own health condition but also increase the survival rate and healthy status of their piglets. This study aims to find single-nucleotide polymorphism (SNP) and molecular markers that are associated with the immune traits of pregnant sows. SLA-DOB and CD4 were selected as candidate genes, and blood samples were randomly collected from pregnant Landrace sows and used to detect T-lymphocyte subsets, interferon alpha, interleukin 6, Toll-like receptor 3, serum antibody immunoglobulin G, and porcine reproductive and respiratory syndrome virus-specific antibody. Then, association analyses were conducted for the polymorphic sites of candidate genes with immune traits. We found 12 mutations in the two genes and conducted an association study with eight of them. Our results indicated that among the eight mutations, SNP1, SNP2, and SNP3 of the SLA-DOB gene and Ins9, SNP10, and SNP11 in the CD4 gene are newly discovered mutations. Except for SNP1, SNP3, and SNP11, the other five SNPs are associated with at least one immune trait tested. Especially, SNP2 and Ins9 are significantly associated with at least one of the T-lymphocyte subgroups and at least one antibody. These novel mutations have potential important effects on the polymorphic loci of the above immune traits in pregnant sows. The results suggest that the SLA-DOB and CD4 genes and their genetic mutations can be considered as important candidate genes and mutations for the immunity of pregnant sows.

Progesterone-Related Immune Modulation of Pregnancy and Labor

Pregnancy involves a complex interplay between maternal neuroendocrine and immunological systems in order to establish and sustain a growing fetus. It is thought that the uterus at pregnancy transitions from quiescent to laboring state in response to interactions between maternal and fetal systems at least partly via altered neuroendocrine signaling. Progesterone (P4) is a vital hormone in maternal reproductive tissues and immune cells during pregnancy. As such, P4 is widely used in clinical interventions to improve the chance of embryo implantation, as well as reduce the risk of miscarriage and premature labor. Here we review research to date that focus on the pathways through which P4 mediates its actions on both the maternal reproductive and immune system. We will dissect the role of P4 as a modulator of inflammation, both systemic and intrinsic to the uterus, during human pregnancy and labor.

Medroxyprogesterone acetate drives M2 macrophage differentiation toward a phenotype of decidual macrophage

M1 macrophage differentiation plays a crucial role in enhanced inflammation during pregnancy, which may lead to pregnancy complications. Therefore, modulation of macrophage differentiation toward the M2 phenotype is desirable to ensure a successful pregnancy. Medroxyprogesterone acetate (MPA) is a potent progestin with an anti-inflammatory property, but its effect on macrophage differentiation is unknown. This study aimed to examine whether MPA can induce an M2 macrophage differentiation by using the human monocytes cell line THP-1 or primary monocytes. THP-1 cells were primed with phorbol-12-myristate-13 acetate (PMA) to initiate macrophage differentiation. By incubating with MPA, the cells (denoted as MPA-pTHP-1) underwent M2 macrophage differentiation with downregulations of CD11c, IL-1β and TNF-α, and upregulations of CD163 and IL-10; while cells incubated with progesterone (P4) did not show the M2 phenotype. Primary monocytes treated with MPA also had the same M2 phenotype. Moreover, M1 macrophages derived from IFN-γ/LPS-treated THP-1 cells, which had high levels of IL-1b and iNOS, and low levels of IL-10 and IDO, were reversed to the M2 phenotype by the MPA treatment. We also found that the MPA-pTHP-1 promoted the decidualization of endometrial stromal cells and the invasion of trophoblast cells. To mimic conditions of exposure to various pathogens, MPA-pTHP-1 cells were stimulated by different types of TLR ligands. We found they produced lower levels of IL-1β and TNF-α, as well as a higher level of IL-10, compared to untreated cells. Finally, we found the level of phosphorylated ERK in the MPA-pTHP-1 cells was increased, but its IL-10 production was suppressed by either the progesterone/glucocorticoid antagonist (Mifepristone) or MEK inhibitor (U0126). Taken together, MPA could drive monocyte differentiation toward an M2 phenotype that mimics decidual macrophages. This finding holds great potential to combat chronic endometrial inflammation.

Identifying immune mechanisms mediating the hypertension during preeclampsia

Preeclampsia (PE) is a pregnancy-associated disorder that affects 5-8% of pregnancies and is a major cause of maternal, fetal, and neonatal morbidity and mortality. Hallmark characteristics of PE are new onset hypertension after 20 wk gestation with or without proteinuria, chronic immune activation, fetal growth restriction, and maternal endothelial dysfunction. However, the pathophysiological mechanisms that lead to the development of PE are poorly understood. Recent data from studies of both clinical and animal models demonstrate an imbalance in the subpopulations of CD4+ T cells and a role for these cells as mediators of inflammation and hypertension during pregnancy. Specifically, it has been proposed that the imbalance between two CD4+ T cell subtypes, regulatory T cells (Tregs) and T-helper 17 cells (Th17s), is involved in the pathophysiology of PE. Studies from our laboratory highlighting how this imbalance contributes to vasoactive factors, endothelial dysfunction, and hypertension during pregnancy will be discussed in this review. Therefore, the purpose of this review is to highlight hypertensive mechanisms stimulated by inflammatory factors in response to placental ischemia, thereby elucidating a role.

The role of inflammation in the pathology of preeclampsia

Preeclampsia (PE) affects 5-7% of all pregnancies in the United States and is the leading cause of maternal and prenatal morbidity. PE is associated with hypertension after week 20 of gestation, decreased renal function and small-for-gestational-age babies. Women with PE exhibit chronic inflammation and production of autoantibodies. It is hypothesized that during PE, placental ischaemia occurs as a result of shallow trophoblast invasion which is associated with an immune imbalance where pro-inflammatory CD4(+) T-cells are increased and T regulatory cells (Tregs) are decreased. This imbalance leads to chronic inflammation characterized by oxidative stress, pro-inflammatory cytokines and autoantibodies. Studies conducted in our laboratory have demonstrated the importance of this immune imbalance in causing hypertension in response to placental ischaemia in pregnant rats. These studies confirm that increased CD4(+) T-cells and decreased Tregs during pregnancy leads to elevated inflammatory cytokines, endothelin (ET-1), reactive oxygen species (ROS) and agonistic autoantibodies to the angiotensin II (Ang II), type 1 receptor (AT1-AA). All of these factors taken together play an important role in increasing the blood pressure during pregnancy. Specifically, this review focuses on the decrease in Tregs, and their associated regulatory cytokine interleukin (IL)-10, which is seen in response to placental ischaemia during pregnancy. This study will also examine the effect of regulatory immune cell repopulation on the pathophysiology of PE. These studies show that restoring the balance of the immune system through increasing Tregs, either by adoptive transfer or by infusing IL-10, reduces the blood pressure and pathophysiology associated with placental ischaemia in pregnant rats.

Placental cytokine and chemokine profiles reflect pregnancy outcomes in women exposed to Plasmodium falciparum infection

Pregnancy-associated malaria (PAM) can lead to severe complications for both mother and baby. Certain placental cytokine/chemokine profiles have been shown to reflect poor pregnancy outcomes, including maternal anemia and low birth weight. In intervillous plasma samples from 400 Beninese women living in an area where Plasmodium falciparum is endemic, we quantified 16 cytokines/chemokines. We assessed their profiles in groups with PAM, with maternal anemia, with preterm births, or with a low birth weight for gestational age. Repeated ultrasound measurements ensured that prematurity and low birth weight were highly accurate. Preliminary analyses revealed trends for lower cytokine/chemokine concentrations in placental plasma associated both with babies with low birth weight for gestational age and with P. falciparum infection during pregnancy, while, as a function of the latter, the concentration of gamma interferon (IFN-γ)-inducible protein 10 (IP-10) was higher. Multivariate analyses showed that (i) higher placental plasma interleukin-10 (IL-10) levels were associated with P. falciparum infections and (ii) independently of P. falciparum infections, lower concentrations of both IFN-γ and IL-5 were associated with low birth weight for gestational age. Our data further strengthen the idea that IL-10 and IP-10 could be useful diagnostic markers of P. falciparum infection during pregnancy. The concentrations of cytokines/chemokines in placental plasma may represent previously unrecognized markers of poor fetal growth.

Regulation of the Anti-Inflammatory Cytokines Interleukin-4 and Interleukin-10 during Pregnancy

Inflammation mediated by both innate and adaptive immune cells is necessary for several important processes during pregnancy. Pro-inflammatory immune cell activation plays a critical role in embryo implantation, placentation, and parturition; however dysregulation of these cells can lead to detrimental pregnancy outcomes including spontaneous abortion, fetal growth restriction, maternal pathology including hypertensive disorders, or fetal and maternal death. The resolution of inflammation plays an important role throughout pregnancy and is largely mediated by immune cells that produce interleukin (IL)-4 and IL-10. The temporal and spatial aspects of reducing inflammation during pregnancy represent a complex process that if not functioning optimally can lead to persistent inflammation and pregnancy complications. In this review, we examine how immune cells that produce IL-4 and IL-10 are regulated throughout pregnancy as well as the effects that reduced IL-4 and IL-10 signaling has on fetal and maternal physiology.

Submicroscopic infections with Plasmodium falciparum during pregnancy and their association with circulating cytokine, chemokine, and cellular profiles

The immunological consequences of pregnancy-associated malaria (PAM) due to Plasmodium falciparum have been extensively investigated in cross-sectional studies conducted at delivery, but there have been very few longitudinal studies of changes due to PAM during pregnancy. We conducted a prospective study in Benin to investigate the changes associated with PAM in groups of 131 and 111 women at inclusion in the second trimester and at delivery, respectively. Infected women were identified by standard microscopic examinations of blood smears and by quantitative PCR (qPCR) assays and were matched to uninfected control women by age, gestational age, and gravidity. We quantified plasma levels of a panel of soluble immunological mediators and other mediators, as well as the frequencies of peripheral blood mononuclear cell types. Comparisons of these variables in infected and uninfected women used multivariate analyses, and we also assessed the predictive value of variables measured at inclusion for pregnancy outcomes at delivery. In multivariate analyses, peripheral plasma interleukin 10 (IL-10) and gamma interferon-inducible protein 10 (IP-10) levels were associated with PAM at inclusion and at delivery, while higher IL-10 levels distinguished qPCR-detectable submicroscopic infections at inclusion but not at delivery. Maternal anemia at delivery was associated with markers of proinflammatory (increased frequency of monocytes) and anti-inflammatory (increased IL-10 levels and increased activation of regulatory T cells) activity measured at inclusion. Elevated concentrations of IL-10 are associated with the majority of P. falciparum infections during pregnancy, but this marker alone does not identify all submicroscopic infections. Reliably identifying such occult infections will require more sensitive and specific methods.

Characterization of the Th profile of the bovine endometrium during the oestrous cycle and early pregnancy

Despite extensive research in the area of cow fertility, the extent to which the maternal immune system is modulated during pregnancy in cattle remains unclear. Therefore, the objective of the current study was to characterize the presence and response profile of B, T-helper (LTh), T- cytotoxic (LTc), gamma delta-T (γδT) and natural killer (NK) lymphocytes in terms of cell number, distribution and cytokine expression in bovine endometrial tissue to pregnancy. Endometrial tissue samples were collected from beef heifers on Days 5, 7, 13 and 16 of the estrous cycle or pregnancy. Samples were analysed by immunofluorescence to identify the presence and abundance of B-B7 (B-cells), CD4 (LTh), CD8 (LTc), γδT cell receptor (TCR) and CD335/NKp46 (NK cells) -positive immune cells. Quantitative real time PCR (QPCR) was carried out to analyse mRNA relative abundance of FOXP3 (a marker of regulatory T (Treg) cells) and a panel of immune factors, including MHC-I, LIF, Interleukins 1, 2, 6, 8, 10, 11,12A, IFNa and IFNG. Results indicate that B-B7+ cells are quite populous in bovine endometrial tissue, CD4+ and CD8+ -cells are present in moderate numbers and γδTCR+ and CD335+ cells are present in low numbers. Pregnancy affected the total number and distribution pattern of the NK cell population, with the most significant variation observed on Day 16 of pregnancy. Neither B lymphocytes nor T lymphocyte subsets were regulated temporally during the oestrous cycle or by pregnancy prior to implantation. mRNA transcript abundance of the immune factors LIF, IL1b, IL8 and IL12A, IFNa and IFNG, expression was regulated temporally during the estrous cycle and LIF, IL1b, IL-10, IL11, IL12A were also temporally regulated during pregnancy. In conclusion, the endometrial immune profile of the oestrous cycle favours a Th2 environment in anticipation of pregnancy and the presence of an embryo acts to fine tune this environment.

Cytokines as key players in the pathophysiology of preeclampsia

Preeclampsia (PE) is an important, common, and dangerous complication of pregnancy; it causes maternal and perinatal illness and is responsible for a high proportion of maternal and infant deaths. PE is associated with increased blood pressure and proteinuria, with a whole host of other potentially serious complications in the mother and fetus. The maternal syndrome in PE is primarily that of generalized dysfunction of the maternal endothelium, and this generalized endothelial dysfunction appears to be part of an exaggerated systemic inflammatory response that involves maternal leukocytes and proinflammatory cytokines. This review examines evidence that points to a significant role for the maternal immune system; inadequate trophoblast invasion of spiral arteries initiates ischemia and hypoxia in the placenta, resulting in an increased release of proinflammatory cytokines in the placenta. Placental ischemia and hypoxia also cause the enhanced release of trophoblast microparticles into the maternal circulation which stimulates increased induction of proinflammatory cytokines and the activation of maternal endothelial cells. This activation results in a systemic, diffuse endothelial cell dysfunction which is the fundamental pathophysiological feature of this syndrome. Recent evidence also supports important roles for proinflammatory cytokines in hypertension, proteinuria, and edema which are characteristic features of PE.

Placental trophoblasts shifted Th1/Th2 balance toward Th2 and inhibited Th17 immunity at fetomaternal interface

The aims were to clarify the effect of placental trophoblasts on T lymphocytes by assessing production of cytokines and expression of transcription factors regulating Th1, Th2, and Th17 immunity in T lymphocytes. Placental trophoblasts were isolated and conditioned medium was made after trophoblast cultivation for 72 h. T lymphocytes were cultured in presence or absence of conditioned medium. ELISA was used to detect concentration of IL-2, TNF-α, IFN-γ, IL-4, IL-10, and IL-17 in supernatants of T cell and real-time PCR was used to detect the status of Th1 (T-bet, STAT-4), Th2 (GATA-3, STAT-6), and Th17 (RORC) immunity in T lymphocyte. We found that the level of IL-2, IFN-γ, TNF-α, and IL-17 was significantly decreased when T lymphocytes were cultured in conditioned medium compared with control, while IL-10 and IL-4 level were not significantly changed. The presence of conditioned medium significantly decreased the ratio of Th1/Th2. The expression of GATA-3 and STAT-6 were significantly increased and STAT-4 was reduced when T lymphocyte was cultured in conditioned medium, while the expression of T-bet and RORC was not significantly different. We concluded that placental trophoblast-induced shift of Th1/Th2 balance toward Th2 and inhibition of Th17 might be among the mechanisms involved in maternal tolerance to fetus.

[Effect of intermittent presumptive treatment with sulfadoxine-pyrimethamine on the acquisition of anti-VAR2CSA antibodies in pregnant women living in a hypoendemic area in Senegal]

The impact of intermittent presumptive treatment (IPT) on the immunity of pregnant women in Senegal is still not very well known. We conducted a prospective study at the Roi-Baudouin maternity of Guediawaye in Senegal to assess IgG antibodies production against MSP1, GLURP and DBL5 in pregnant women under IPT. Blood samples were collected from the participating women at inclusion and delivery. Samples were analyzed after centrifugation for the detection of IgG antibodies in sera by Elisa. Informed consent was given by each study participant prior to their inclusion. A total of 101 eligible women aged from 18 to 44 were included in this study. Multigravidae women represented 70.3% of the study population, whereas primigravidae accounted for 29.7%. The IgG level decreased slightly from inclusion to delivery for the women with regard to anti-MSP1 (83.1at inclusion versus 79.5 at delivery, p = 0.52) as well as anti-GLURP-R2 (84.1 at inclusion versus 75.9 at delivery, p = 0.16). After adjustment for number of pregnancies, there was a significant decrease in the production of anti-VAR2CSA between inclusion and delivery (p < 0.05). By reducing the incidence of malaria during pregnancy, IPT reduced the acquisition of placental parasites antibodies suppressors which could delay the development of protective immunity against malaria. The application of IPT in pregnant women would thus be more appropriate in hypoendemic areas where malaria exposure is lower.

Peripheral blood invariant natural killer T cells throughout pregnancy and in preeclamptic women

Invariant natural killer T (iNKT) cells are implicated in the pathogenesis of several diseases. They influence both innate and adaptive immune responses through their capacity to rapidly produce large quantities of cytokines upon activation. During pregnancy maternal immunity is biased towards type 2 cytokine production to regulate type 1 cytokines that could be harmful for the developing fetus. This shift to type 2 cytokines does not occur in preeclamptic women and there is an exaggerated maternal inflammatory response which is dangerous for both mother and baby. We have therefore investigated the numbers, phenotype and functional activity of iNKT cells throughout pregnancy and in women diagnosed with preeclampsia. We demonstrate that the numbers of iNKT cells in the peripheral blood do not change between the first, second and third trimesters of pregnancy, but the cells become activated and less able to produce the type 1 cytokine IFNγ. However, iNKT cells are unchanged in preeclamptic women, when compared to normal pregnancy, suggesting that these cells are not primary players in the pathogenesis of the disease.

Molecular aspects of Plasmodium falciparum Infection during pregnancy

Cytoadherence of Plasmodium-falciparum-parasitized red blood cells (PRBCs) to host receptors is the key phenomenon in the pathological process of the malaria disease. Some of these interactions can originate poor outcomes responsible for 1 to 3 million annual deaths mostly occurring among children in sub-Saharan Africa. Pregnancy-associated malaria (PAM) represents an important exception of the disease occurring at adulthood in malaria endemic settings. Consequences of this are shared between the mother (maternal anemia) and the baby (low birth weight and infant mortality). Demonstrating that parasites causing PAM express specific variant surface antigens (VSA(PAM)), including the P. falciparum erythrocyte membrane protein 1 (P f EMP1) variant VAR2CSA, that are targets for protective immunity has strengthened the possibility for the development of PAM-specific vaccine. In this paper, we review the molecular basis of malaria pathogenesis attributable to the erythrocyte stages of the parasites, and findings supporting potential anti-PAM vaccine components evidenced in PAM.

Tolerance to the foetal allograft?

In this review, we will detail the concept of tolerance and its history in reproductive immunology. We will then consider whether it applies to the foetal-maternal relationship and discuss the mechanisms involved in non-rejection of the foeto-placental unit.

Pregnancy does not deter the development of a potent maternal protective CD8+ T-cell acquired immune response against Listeria monocytogenes despite preferential placental colonization

PROBLEM

Listeria monocytogenes (LM) preferentially colonizes the placenta and causes fetal loss and systemic disease during pregnancy. As systemic CD8+ T-cell memory is critical in controlling LM infection, we addressed the issue as to whether it is modulated during pregnancy.

METHOD OF STUDY

Pregnant mice were infected with LM and their immune response was quantified relative to the non-pregnant cohort using advanced immunological techniques.

RESULTS

Pregnant mice exhibited progressive and massive placental LM infection leading to fetal resorptions. In contrast, they harbored significantly lower bacteria in spleen and liver relative to non-pregnant controls, and rapidly cleared systemic infection. Both pregnant and non-pregnant mice exhibited similar activation of systemic innate immunity. Moreover, LM infection in pregnant and non-pregnant hosts evoked strong antigen-specific cytolytic CD8+ T cells that produced IFN-gamma. Consequently, LM infection initiated during pregnancy afforded long-term protective memory to secondary infection.

CONCLUSION

Maternal hosts generate a normal Listeria-specific adaptive immunity in particular CD8+ T-cell memory response suggesting that systemic listeriosis during pregnancy may be an immunopathology associated with placental infection.

Gene expression profiling of human decidual macrophages: evidence for immunosuppressive phenotype

Background

Although uterine macrophages are thought to play an important regulatory role at the maternal-fetal interface, their global gene expression profile is not known.

Methodology/Principal Findings

Using micro-array comprising approximately 14,000 genes, the gene expression pattern of human first trimester decidual CD14+ monocytes/macrophages was characterized and compared with the expression profile of the corresponding cells in blood. Some of the key findings were confirmed by real time PCR or by secreted protein. A unique gene expression pattern intrinsic of first trimester decidual CD14+ cells was demonstrated. A large number of regulated genes were functionally related to immunomodulation and tissue remodelling, corroborating polarization patterns of differentiated macrophages mainly of the alternatively activated M2 phenotype. These include known M2 markers such as CCL-18, CD209, insulin-like growth factor (IGF)-1, mannose receptor c type (MRC)-1 and fibronectin-1. Further, the selective up-regulation of triggering receptor expressed on myeloid cells (TREM)-2, alpha-2-macroglobulin (A2M) and prostaglandin D2 synthase (PGDS) provides new insights into the regulatory function of decidual macrophages in pregnancy that may have implications in pregnancy complications.

Conclusions/Significance

The molecular characterization of decidual macrophages presents a unique transcriptional profile replete with important components for fetal immunoprotection and provides several clues for further studies of these cells.

UNK cells: their role in tissue re-modelling and preeclampsia

In different species of mammal, uterine natural killer (uNK) cells are massively recruited and presented at the fetal maternal interface with a spatio-temporal pattern, and regarded as a constructive element to support reproductive development. Recent insights highlight the uNK cells activation, function and interaction with local compartments, which all contribute to the initiation of vascular structural changes. New trends of uNK cells research will benefit the diagnosis, management and test treatment strategy of preeclampsia. Furthermore, we suggest that more efforts and specific studies are needed to further explore the role of uNK cells at the unique micro-environment.

IL-12 producing monocytes and IFN-γ and TNF-α producing T-lymphocytes are increased in placentas infected by Plasmodium falciparum

Placental Plasmodium falciparum sequestration is associated with dysregulated immune function. Placental inflammatory responses via IFN-gamma and TNF-alpha are implicated in functional damage. However, they are needed during placental infection to control asexual stage parasites. To test the hypothesis that placental immunomodulation associated with malaria disturbs cytokine secretion differently in monocytes and lymphocytes, we have determined the proportion of monocytes and/or lymphocytes secreting IFN-gamma, TNF-alpha, IL-10 and IL-12. Intervillous and peripheral blood monocyte (CD14+) and lymphocyte (CD3/CD4+; CD3/CD8+) cytokine production was compared between 17 P. falciparum-infected and 12 non-infected Senegalese women. After culture with phorbolmyristate acetate/ionomycin (PMA/iono), lipopolysaccharide (LPS) or P. falciparum-infected erythrocytes (IE), the intracellular expression of cytokines in lymphocytes (IFN-gamma, TNF-alpha) and monocytes (IL-10, IL-12, TNF-alpha), was detected. In response to IE, CD4+ and CD8+ T-cells produced IFN-gamma and TNF-alpha at similar rates in both compartments. In response to PMA/iono, the frequencies of CD4+ and CD8+ T-cells producing IFN-gamma and TNF-alpha were similar in both compartments, but increased in P. falciparum-infected placentas. In response to LPS or IE, IL-12 secreting monocytes were increased in infected women, while the frequency of TNF-alpha secreting monocytes was decreased compared to that in non-infected placenta. The monocyte IL-12 response is not impaired in infected women. IL-12 is an important factor for inducing IFN-gamma in T-cells. Thus, IL-12 and IFN-alpha responses may synergistically allow a protective immune response in placental malaria. TNF-alpha production by CD4+ and CD8+ T-cells is up-regulated in P. falciparum-infected placentas, suggesting that T-cells actively participate to inflammatory responses.

Coordinated regulation of human trophoblast invasiveness by macrophages and interleukin 10

Trophoblast invasion and modification of the spiral arterioles are essential for the establishment of adequate uteroplacental blood flow during pregnancy. However, such vascular remodeling is deficient in preeclampsia. This disease is also associated with increased maternal levels of circulating proinflammatory cytokines such as tumor necrosis factor (TNF) and reduced levels of immunoregulatory cytokines such as interleukin 10 (IL10). We have previously shown that activated macrophages inhibit trophoblast invasiveness in vitro. The present study demonstrates that IL10 interferes with the invasion-inhibitory effect that activated macrophages exert on trophoblast cells. Co-culture experiments revealed that human lipopolysaccharide (LPS)-activated macrophages inhibited the ability of immortalized HTR-8/SVneo human trophoblast cells to invade through reconstituted extracellular matrix. This effect of activated macrophages on trophoblast invasiveness was paralleled by decreased expression of urokinase plasminogen activator receptor (PLAUR) on the surface of trophoblast cells, and by increased secretion of plasminogen activator inhibitor type 1 (SERPINE1). Exposure of LPS-treated macrophages to IL10 prior to co-culture prevented their ability to inhibit trophoblast invasion, PLAUR expression, and to stimulate SERPINE1 secretion. Interleukin 10 prevented macrophage activation by LPS as determined by the lack of secretion of TNF in the culture medium, and a neutralizing TNF antibody completely blocked the effect of macrophages on trophoblast invasion. These results indicate that decreased circulating levels of IL10 associated with preeclampsia may contribute to inadequate trophoblast invasion and remodeling of the uterine spiral arterioles.

Early pregnancy decidual lymphocytes beside perforin use Fas ligand (FasL) mediated cytotoxicity

Decidual natural killer (NK) cells are the predominant lymphocytes at the maternal-fetal interface. They are involved in defense against virally infected, parasitized and transformed cells and may contribute to the control of trophoblast invasion. The presence of perforin and other possible cytolytic mediators suggests these functions. Cytolytic mechanisms of unstimulated and Th1 cytokine stimulated decidual lymphocytes (DL), as well as purified decidual CD56(+) cells, were analyzed against NK sensitive and resistant targets. DL were isolated from decidual mononuclear cells (DMC) cultured in the medium only or in the presence of Th1 cytokines: IL-2, IL-12, IL-15, IL-18 and their combinations (IL-12/IL-18 or IL-15/IL-18). Fas ligand (FasL), perforin and granzyme B mRNAs expression and cytotoxicity were analyzed by flow cytometry and/or RT-PCR. DL (containing 72.19+/-7.53% of CD56(+) cells), obtained from 18h-cultured DMC in the medium only, expressed perforin, FasL and granzyme B mRNAs and lysed the NK-sensitive K-562 cell line, and also the NK-resistant P815 and P815-Fas transfected cell lines. Concanamycin A, a blocker of granule exocytosis, decreased significantly K-562 lysis, but not P815 lysis. However, the addition of anti-FasL antibody diminished significantly P815 lysis as well. IL-2 and IL-15, known inducers of perforin and FasL mRNAs and protein expression, could not additionally increase P 815 cell lysis by DL cultured within DMC. These results suggest that DL cultured in DMC for 18h, have the characteristics of lymphokine-activated killer (LAK) cells and are able to use efficiently both the perforin and the FasL cytolytic pathways.

Plasmodium falciparum-infected Red Blood Cells Selected for Binding to Cultured Syncytiotrophoblast Bind to Chondroitin Sulfate A and Induce Tyrosine Phosphorylation in the Syncytiotrophoblast

An important pathogenic complication of malaria during human pregnancy is sequestration of Plasmodium-infected red blood cells (iRBCs) in the placental intervillous spaces. This sequestration is thought to be mediated in part by binding of the iRBCs to receptors expressed on the syncytiotrophoblast (ST) membrane. We report here the use of a dynamic system to study the consequences of this cytoadherence on ST function using human syncytiotrophoblast and the choriocarcinoma cell line, BeWo. Laboratory isolates of Plasmodium falciparum were selected for their ability to bind to ST and used to investigate binding-induced cellular changes in the ST. Treatment of the ST cells with chondroitinase ABC suggested that the selected parasites bind predominantly to chondroitin sulfate A, but other receptors for parasite binding may be involved. Intracellular signaling in the ST induced by iRBCs binding was investigated by assessing tyrosine phosphorylation of ST proteins following iRBC binding. We demonstrate for the first time that iRBC cytoadherence to syncytiotrophoblast enhances tyrosine phosphorylation of a series of proteins in these cells. This approach will be useful in further studies of ST function in the malaria-infected placenta, the dynamics of selection of syncytiotrophoblast-binding parasites, and the identification of new receptors for parasite cytoadherence in the placenta.

Dydrogesterone in the reduction of recurrent spontaneous abortion

One hundred and eighty women with a history of recurrent, unexplained spontaneous abortion (mean 3.5 abortions) were randomised to receive oral dydrogesterone (10 mg b.i.d.), intramuscular human chorionic gonadotrophin (hCG; 5000 IU every 4 days) or no additional treatment (controls). Treatment was started as soon as possible after confirmation of pregnancy and continued until the 12th gestational week. All women received standard supportive care. Abortions were significantly (p < or = 0.05) less common in the dydrogesterone group (13.4%) than in the control group (29%); there were no statistically significant differences between the hCG group and the control group. There were no differences between the groups with respect to pregnancy complications or congenital abnormalities. In conclusion, hormonal support with dydrogesterone can increase the chances of a successful pregnancy in women with a history of recurrent spontaneous abortion.

Maternal tolerance to H-Y is independent of IL-10

It has been suggested that the maternal immune system favors noncytotoxic, "TH-2" immune responses in order to tolerate the developing fetus. In some strains of mice, pregnant females will reject a male skin graft, even as they tolerate their male fetuses. This rejection is based on responsiveness to the male antigen H-Y. In this study we test whether functional maternal tolerance of male fetuses is critically dependent on the TH-2 cytokine Interleukin 10 (IL-10). Normal and IL-10-deficient (10-KO) females were sensitized against H-Y by intraperitoneal injection of male spleen cells before mating with 10-KO males. Litters born to 10-KO females were of comparable size to those born to normal females of the same genetic background. The proportion of males per litter was not adversely affected by IL-10 deficiency. Taken together, our work and others suggest that IL-10 may not be critically important for maternal tolerance of the fetus and extends the evidence against the idea that successful mouse pregnancy depends on TH-2 deviation of the maternal immune system.

Correlation of human decidual and cord blood mononuclear cell cytokine production

Human decidua has been shown to produce a number of cytokines. We hypothesized that decidual cytokine production influences cord blood mononuclear cell (CBMC) cytokine production and that cytokine profiles of decidua from allergic women differ from those of decidua from nonallergic women. Using enzyme-linked immunosorbent assay, we measured unstimulated and concanavalin A/phorbol myristate acetate-stimulated production of interleukin-4 (IL-4), IL-5, IL-10, IL-13 and interferon- gamma (IFN-gamma) by decidual explants from 59 healthy women delivered by unlabored cesarean section and from corresponding CBMCs in 39 of the 59. Except for IL-10, there was little or no unstimulated cytokine production. There was a strong correlation between stimulated decidual and stimulated CBMC IFN-gamma production (p = 0.01). In allergic women the ratio of IL-13 to IL-4 production was increased in stimulated explants (p = 0.03). Stimulated CBMCs from infants of allergic mothers were more likely to produce detectable levels of IL-5 than those from infants of nonallergic mothers (p = 0.04) and had a tendency toward higher IL-13 levels as well (p = 0.07). These results suggest that maternal and fetal IFN-gamma production is closely linked and that maternal allergy appears to influence cytokine production in the neonate for IL-5 and possibly IL-13.

Blockade of CD80 and CD86 at the time of implantation inhibits maternal rejection to the allogeneic fetus in abortion-prone matings

CD28/CTLA-4 interactions with their specific B7-ligands (CD80 and CD86) play a decisive role in antigenic and allogenic responses. Recently, experimental transplant studies demonstrated that donor-specific tolerance was achieved by blocking these interactions. However, the role of blockade of CD28/B7 costimulatory pathway in the maintenance of materno-fetal tolerance has received little attention. In the present study, abortion-prone CBA/J females mated with DBA/2 males were administered with anti-CD80 and anti-CD86 monoclonal antibodies (mAbs) on day 4 of gestation (time of murine implantation). We demonstrated that the combined use of anti-CD80 and anti-CD86 mAbs induced maternal tolerance to the fetus in the abortion-prone CBA/J mice, and displayed expansion of the maternal CD4(+)CD25+ regulatory T cell population and up-regulated expression of CTLA-4, suggesting an active mechanism of regulatory T cells in suppressing maternal rejection to the fetus. In addition, the anti-CD80/86 mAbs treatment enhanced Th2 and reduced Th1 cytokine production in mice, implying that the development of Th2 cells might contribute to maternal tolerance to her fetus. Together, these findings indicated that blocking CD80 and CD86 enhanced maternal tolerance to her fetus in mice by increasing regulatory T cell function and skewing toward a Th2 response. Our data might provide an enhanced understanding of the maternal-fetal immune relationship and be helpful in clinical trials for immunotherapy of recurrent spontaneous abortion.

Placental deficiency of interleukin-10 (IL-10) in preeclampsia and its relationship to an IL10 promoter polymorphism

The placenta is pivotal in the acceptance of the feto-placental unit by the maternal immune system. Imbalance at the maternal-fetal interface of tissue pro- and anti-inflammatory cytokines may be partly involved in disease causation. Previous work has shown conflicting levels of IL-10. IL-10 levels have been shown to increase, decrease, or remain unchanged in women with preeclampsia. This study examines the difference in serum and placental IL-10 expression in women with preeclampsia and investigates if the IL10 (-1082) A promoter polymorphism contributes to lower concentrations. In a prospective case-control study of 12 women with preeclampsia and 31 controls we assessed serum IL-10 by ELISA, placental mRNA by quantitative PCR and protein by immunohistochemistry as well as placental IL10 promoter genotype. Comparisons were made with non-parametric tests where necessary and chi-square. We found a significant reduction in placental IL-10 mRNA and protein expression in women with preeclampsia compared to controls. Women with the AA IL-10 promoter genotype expressed less placental IL-10 mRNA compared to women with AG or GG genotype. There was no difference in serum IL-10 concentrations between different genotypes. Preeclampsia is associated with a deficiency of placental IL-10. Placental AA genotype in the promoter region results in significantly less placental IL-10.

Abnormal T-cell reactivity against paternal antigens in spontaneous abortion: adoptive transfer of pregnancy-induced CD4+CD25+ T regulatory cells prevents fetal rejection in a murine abortion model

Mammalian pregnancy is thought to be a state of immunological tolerance. The mechanisms underlying this phenomenon are still poorly understood. Here, we determined whether an inappropriate function of T regulatory (Treg) cells is involved in the pathogenesis of spontaneous abortion. We evaluated spleen and decidual lymphocytes from CBA/J mice undergoing immunological abortion (DBA/2J-mated) or having normal pregnancy (BALB/c-mated) on day 14 of gestation for ex vivo cytokine production after PMA or paternal antigen (alloantigen) stimulation. Treg activity was characterized by quantifying CD4(+)CD25(+) cells, foxp3 expression, and interleukin-10 secretion. Decidual lymphocytes from abortion CBA/J mice contained a significantly higher frequency of interferon-gamma-producing T cells specific for paternal antigens compared to those from normal pregnancy (7.8% versus 2.7%, P < 0.05). Compared to virgin CBA/J females, normal pregnant mice showed strongly elevated numbers of CD4(+)CD25(+) and interleukin-10(+) Treg cells in the thymus whereas significantly lower frequencies of Treg cells were observed in abortion mice. Very interestingly, CD4(+)CD25(+) Treg cells from normal pregnant and nonpregnant CBA/J mice could inhibit both proliferation and interferon-gamma secretion of lymphocytes from abortion mice in vitro whereas in vivo prevention of fetal rejection could only be achieved after adoptive transfer of Treg cells from normal pregnant mice. Our data suggest that pregnancy-induced Treg cells play a vital role in maternal tolerance to the allogeneic fetus.

Immunological Similarities between Implantation and Pre-eclampsia

PROBLEM

Cytokines are involved in implantation success and failure. We envisage that they could be similarly involved in pre-eclampsia (PE).

MATERIALS AND METHODS

First, we review the primipaternity and primiparity concepts and then why natural killer (NK) cells are involved in implantation. We stress that the common event in all PE is vascular remodelling.

RESULTS AND CONCLUSION

We conclude that PE could involve cytokine and/or NK dysfunctions, and propose a working hypothesis.

Binding of pregnancy-specific glycoprotein 17 to CD9 on macrophages induces secretion of IL-10, IL-6, PGE2, and TGF-beta1

Pregnancy-specific glycoproteins (PSGs) are a family of secreted proteins produced by the placenta, which are believed to have a critical role in pregnancy success. Treatment of monocytes with three members of the human PSGs induces interleukin (IL)-10, IL-6, and transforming growth factor-beta(1) (TGF-beta(1)) secretion. To determine whether human and murine PSGs have similar functions and use the same receptor, we treated wild-type and CD9-deficient macrophages with murine PSG17N and human PSG1 and -11. Our data show that murine PSG17N induced secretion of IL-10, IL-6, prostaglandin E(2), and TGF-beta(1) and that CD9 expression is required for the observed induction of cytokines. Therefore, the ability of PSG17 to induce anti-inflammatory cytokines parallels that of members of the human PSG family, albeit human and murine PSGs use different receptors, as CD9-deficient and wild-type macrophages responded equally to human PSGs. We then proceeded to examine the signaling mechanisms responsible for the CD9-mediated response to PSG17. Inhibition of cyclooxygenase 2 significantly reduced the PSG17N-mediated increase in IL-10 and IL-6. Further characterization of the response to PSG17 indicated that cyclic adenosine monophosphate-dependent protein kinase A (PKA) is involved in the up-regulation of IL-10 and IL-6, and it is not required for the induction of TGF-beta(1). Conversely, treatment of macrophages with a PKC inhibitor reduced the PSG17-mediated induction of TGF-beta(1), IL-6, and IL-10 significantly. The induction of anti-inflammatory cytokines by various PSGs supports the hypothesis that these glycoproteins have an essential role in the regulation of the maternal immune response in species with hemochorial placentation.

The presence of functional mannose receptor on macrophages at the maternal-fetal interface

BACKGROUND

The mannose receptor (MR) is involved in the initiation of the immune response and regulation of homeostasis during inflammation and tissue remodeling.

METHODS

Distribution, endocytosis and possible natural ligand tumor associated glycoprotein-72 (TAG-72) for the MR have been examined by immunohistology, immunocytochemistry and flow cytometry at the maternal-fetal interface, characterized by extensive tissue remodeling.

RESULTS

Contrary to disseminated distribution of the MR positive (MR+) cells in term placenta, the MR+ cells of early pregnancy decidua intimately surrounded glands and followed tissue distribution of CD14 positive cells. The mannose receptor was present on freshly isolated first trimester decidual mononuclear cells and distributed mostly on macrophages (77.08 +/- 10.55%, mean +/- SD). The expression of the MR on CD14 positive cells decreased following 18 h culture (P < 0.01) and was accompanied by the reduction of fluorescein isothiocyanate (FITC)-dextran uptake. PAM-1 anti-MR antibody, mannan and TAG-72 reduced FITC-dextran uptake by decidual macrophages.

CONCLUSIONS

These data indicate that the MR+ macrophages, surrounding early decidual glands, are able to internalize ligands for carbohydrate recognition domain of the receptor, including decidual secretory phase mucin TAG-72.

No evidence for apoptosis of decidual leucocytes in normal and molar pregnancy: implications for immune privilege

Complete hydatidiform moles are totally paternally derived and represent complete allografts that might be expected to provoke maternal immune rejection. Our previous and other studies have shown expression of Fas by increased numbers of activated decidual CD4(+) T cells in both complete and partial molar pregnancy as well as increased FasL(+) expression by molar trophoblasts compared with trophoblasts in normal pregnancies. As the Fas/FasL system represents a major apoptotic pathway that can play a role in immune privilege, the aim of this study was to investigate whether apoptosis of decidual immune cells, particularly T cells, could be responsible for maternal immune tolerance in molar pregnancy. Using terminal deoxynucleotidyl transferase (TdT)-mediated nick end-labelling (TUNEL), a significant increase in TUNEL(+) cells was demonstrated in decidua associated with partial (P = 0.0052) and complete (P = 0.0096) hydatidiform mole compared with normal early pregnancy. Co-labelling immunoperoxidase studies showed that the TUNEL(+) cells in both normal and molar pregnancies were not activated CD45RO(+) immune cells, CD3(+) T cells, CD56(+) uterine natural killer (NK) cells or CD14(+) CD68(+) macrophages. Double immunohistochemical labelling with antiactive caspase-3 and leucocyte markers confirmed the lack of leucocyte apoptosis. Double immunostaining with anticytokeratin to detect trophoblast and M30 CytoDeath, which detects a neoepitope of cytokeratin 18 revealed after caspase-mediated cleavage, revealed apoptotic extravillous trophoblast cells within decidual tissue. We conclude that there is no evidence that apoptosis of decidual leucocytes plays a role in maintaining maternal tolerance in either normal or molar pregnancy.

Activated peripheral blood mononuclear cells induce p44/42 mitogen-activated protein kinase phosphorylation in trophoblast-like JAR cells

Mammalian pregnancy bears many similarities to transplantation, since the fetus is semi-allogenic to mother. Thus, mammals have developed numerous mechanisms to protect the developing fetus from maternal immunologic recognition and attack. We have previously shown that human choriocarcinoma JAR cells, which resemble first trimester trophoblasts, regulate several important mRNAs in activated peripheral blood mononuclear cells (PBMC). We now provide further evidence that communication between maternal and fetal tissues is bi-directional, and that activation of PBMC leads to activation of specific signaling pathways in JAR cells. Activated PBMC were co-cultured with JAR cells for specific time intervals, after which JAR cells were lysed and subjected to western blotting for activated forms of the JNK, Erk 1-2, and p38 mitogen-activated protein kinases (MAPK). Phosphorylation of Erk 1-2, but not JNK or p38, was induced in co-cultures of PBMC and JAR cells. These results were also obtained when JAR cells were incubated with conditioned medium from activated, but not resting, PBMC. Results were confirmed using specific MAPK reporter constructs, using luciferase activity as a measure of Elk-1 phosphorylation. Erk 1-2 phosphorylation was not required for JAR cells to inhibit IL-2 production in activated PBMC. Addition of the specific MAPK inhibitor UO126 to JAR cells prior to the addition of activated PBMC to the cultures did not abolish the capacity of JAR cells to inhibit IL-2 mRNA expression in PBMC. We conclude that there is likely to be significant bi-directional signaling between leukocytes and trophoblasts at the maternal-fetal interface. We propose the existence of a delicate maternal-fetal immunologic homeostasis based on these experimental results.

Cultured human endometrial epithelial cells produce thymus and activation-regulated chemokine with stimulation of interleukin-4 and interleukin-13

OBJECTIVE

To evaluate the effects of T-helper (Th)1 and Th2 cytokines on the production of thymus and activation-regulated chemokine (TARC) and macrophage-derived chemokine (MDC) by cultured endometrial epithelial cells (EEC) and endometrial stromal cells (ESC).

DESIGN

The effects of interleukin (IL)-2, IL-4, IL-5, IL-10, IL-12, IL-13, interferon-gamma (IFN-gamma), and tumor necrosis factor-beta (TNF-beta) on the production of TARC and MDC were investigated.

SETTING

Research laboratory at a medical school.

PATIENT(S)

Fifteen endometrial specimens in the mid-late secretory phase were used.

INTERVENTION(S)

The EEC and ESC were incubated for 24 hours with recombinant human IL-2, IL-4, IL-5, IL-10, IL-12, IL-13, IFN-gamma, and TNF-beta.

MAIN OUTCOME MEASURE(S)

The concentrations of TARC and MDC in the culture media were measured using ELISA.

RESULT(S)

Small amounts of TARC were detected in the culture medium of nonstimulated EEC. The increase in levels of TARC in the culture media of EEC paralleled the addition of increasing amounts of IL-4 and IL-13. Other cytokines, however, did not affect the production of TARC by EEC. Production of TARC by ESC was not detected under either nonstimulated or cytokine-stimulated conditions. Production of MDC was not detected in the culture media of EEC and ESC.

CONCLUSION(S)

These results suggest that IL-4 and IL-13 secreted from the embryo during the implantation period may selectively up-regulate the production of TARC by EEC. The controlled production of TARC in the endometrium may contribute to the modulation of the immune reaction by the regulation of Th2 lymphocyte trafficking and functions.

Blockade of CD86 signaling facilitates a Th2 bias at the maternal-fetal interface and expands peripheral CD4+CD25+ regulatory T cells to rescue abortion-prone fetuses

Intervention in B7 (CD80/CD86)/B7-ligand (CD28/CTLA-4) pathways is an effective way of preventing unwanted immune responses, such as allograft rejection. Pregnancy maintenance represents maternal tolerance to the fetal allograft, which is accompanied by a type 2 helper cell (Th2) bias at the maternal-fetal interface. Here, the costimulatory signal of CD86 was selectively blocked, and that of CD80 was kept unimpaired by administration of anti-murine CD86 monoclonal antibody at the early gestational stage in abortion-prone CBA/JxDBA/2 matings and normal pregnant CBA/JxBALB/c matings. It was demonstrated that in vivo blockade of CD86 costimulation could suppress maternal immune attack to the fetus by shifting cytokines from Th1 predominance to Th2 bias at the maternal-fetal interface, and expanding peripheral CD4+CD25+ regulatory T cells, which play an important role in the development and maintenance of maternal-fetal tolerance. Furthermore, the expression of CD28 and its ligands CD80/CD86 on peripheral lymphocytes was down-regulated, whereas that of CTLA-4 was up-regulated, which might facilitate the suppressive effect of CD4+CD25+ regulatory T cells on the alloreactive T cells. The maternal-fetal immunotolerance induced by CD86 blockade decreased fetal resorption in CBA/JxDBA/2 matings, but did not affect normal pregnant CBA/JxBALB/c matings. These results suggest that selective blockade of CD86 costimulation leads to maternal immune tolerance to embryo antigen, and might contribute to a rational immunoregulatory regimen for recurrent spontaneous abortion.

Cytokine secretion patterns of NK cells and macrophages in early human pregnancy decidua and blood: implications for suppressor macrophages in decidua

PROBLEM

Local immune modulation has been shown to be of considerable importance for the maintenance of successful pregnancy. We have previously reported the secretion of interferon-gamma (IFN-gamma), interleukin-4 (IL-4) and IL-10 in human decidua from early normal pregnancy. The aim of this study was to investigate the cellular source of cytokine secretion in the decidua, and compare this to secretion patterns in peripheral blood.

METHOD OF STUDY

Decidual tissue and peripheral blood was collected from 20 women undergoing surgical abortion during first trimester pregnancy. Monocytes/macrophages and NK cells were enriched by immunomagnetic cell separation and cytokine secretion was detected by enzyme-linked immunosorbent spot-forming cell assay.

RESULTS

Decidual and peripheral monocytes/macrophages and NK cells spontaneously secrete IFN-gamma, IL-4 and IL-10. The number of IL-10 secreting cells was significantly higher in decidual macrophages compared with decidual non-monocytic cells as well as compared with blood monocytes/macrophages. These differences were not seen for IFN-gamma or IL-4.

CONCLUSIONS

Our results indicate that decidual macrophages subserve important suppressive functions in the pregnant uterus.

Expression of SLAM as a functional and phenotypic marker in women with recurrent miscarriage

In the present work, we investigated the Th1 and Th2 cytokine patterns secreted by infiltrating endometrial lymphocytes from fertile women and from patients with recurrent spontaneous miscarriage (RSM). Moreover, we also analyzed the expression of cytokines in the whole endometrium from fertile and RSM women. Furthermore, we investigated the expression of the activation marker signaling lymphocytic activation molecule (SLAM) a cell surface glycoprotein expressed on lymphocytes that upon engagement boosts IFN-gamma production. Our results showed a slight increase in IL-10 expression in the endometrium of some fertile women, although no significant differences were found in IFN-gamma and IL-5 expression. In contrast, analysis of IFN-gamma production by polyclonal activated lymphocytes from endometrium and/or peripheral blood from fertile women showed a significant increase compared to RSM. Analysis of SLAM protein expression in luteal phase endometrial samples showed a significant increase in the levels of the receptor in RSM women compared to fertile women. These results correlated with a significant augmentation of SLAM levels in peripheral blood T-lymphocytes from RSM patients. Interestingly, after treatment of RSM patients with paternal mononuclear cells, surface-SLAM-expression in T-cells from RSM patients significantly decreased up to levels comparable to those of fertile women. Taken together, our results suggest that endometrial cells have not a defined pattern-cytokine-production under pre-implatatory conditions, and SLAM might be a potential marker for the diagnosis of RSM and an indicator useful to follow up the patient response to allogeneic immunotherapy.

Extracellular Matrix Protein-dependent Apoptosis of T Cells in Women with a History of Recurrent Spontaneous Abortion

PROBLEM

The purpose of the study was to determine the role of T-cell apoptosis in extracellular matrix (ECM) environment in pregnancy maintenance in women with a history of recurrent spontaneous abortion (RSA).

METHOD OF STUDY

Thirty-nine non-pregnant women with the history of RSA (anatomic, genetic, endocrine and microbiologic causes were excluded) and 22 healthy women with the previous successful pregnancy outcome were studied. In addition, 21 women with the history of RSA were also studied at the beginning of their next pregnancy. We studied apoptosis of peripheral blood T cells after culture with monoclonal antibody (mAb) OKT-3 alone or with mAb OKT-3 following ECM proteins: collagen IV (C-IV) or fibronectin (Fn). We used Cell Death Detection ELISA for studying cell death in cell population. In addition, apoptotic peripheral blood T cells were identified by annexin V-PE staining protocol using flow cytometry. CD29+ and CD95+ T-cell surface receptors were also analyzed by flow cytometry.

RESULTS

The significantly higher values of enrichment factor: mU of the sample (dying/dead cells) per mU of the corresponding control (viable cells) were observed after peripheral blood T-cell culture with C-IV (P = 0.0002) or Fn (P = 0.004) in samples of non-pregnant women with the history of RSA when compared with control women. The significantly higher values of enrichment factor were observed after peripheral blood T-cell culture with C-IV in samples of pregnant women with the history of RSA with successful pregnancy outcome when compared with pregnant women with the history of RSA with failed pregnancy outcome (P = 0.01). However, the percentage of apoptotic T cells stained by annexin V was significantly lower in non-pregnant RSA women compared with control (P = 0.0001). CD95 expression was significantly lower in non-pregnant RSA women compared with control (P = 0.01).

CONCLUSIONS

Apoptosis of T cells might be an interesting possible explanation of successful pregnancy outcome in women with the history of RSA.