Semi-allogeneic Fetus Research Articles

Upregulation of CD81 in trophoblasts induces an imbalance of Treg/Th17 cells by promoting IL-6 expression in preeclampsia.

The disturbance of maternal immune tolerance to a semiallogeneic fetus is recognized as one of the key pathologies of preeclampsia (PE), in which an imbalance between the inflammation-limiting regulatory T cells (Tregs) and the inflammation-mediating Th17 cells plays an essential role. Previously, we reported that the abnormal upregulation of tetraspannin CD81 in trophoblast cells (fetal component) participated in the pathogenesis of PE. However, as one of the potential immune regulatory molecules, whether CD81 induces PE by interfering with the balance of the maternal immune system has not yet been clarified. Thus, we investigated the relationship between the upregulation of CD81 in trophoblast cells and the imbalance of Treg and Th17 cells in mothers. Here, we demonstrated that upregulation of CD81 in trophoblast cells was accompanied by a decrease in Treg cells and an increase in Th17 cells in both the basal plate (placental maternal side) and peripheral blood of patients with PE. In vitro culture of naïve T cells with medium from the CD81-overexpressing trophoblast cell line HTR-8 resulted in enhanced differentiation of T cells into Th17 cells and decreased the formation of Tregs, which was dependent on the paracrine signaling of IL-6 in trophocytes, induced by CD81. In a CD81-induced PE rat model, we found a significant shift of T cell differentiation towards Th17 cells, and administration of IL-6 antibody mitigated the PE phenotype and the imbalance of the Treg/Th17 cells. These results define a vital regulatory cascade involving trophocyte-derived CD81, IL-6, and maternal Treg/Th17 cells in the pathogenesis of PE and suggests new therapeutic approaches based on CD81 and IL-6 downregulation to prevent human PE.

Uterine natural killer cells: To protect and to nurture.

During the course of pregnancy, the maternal-fetal interface is tightly regulated and undergoes dynamic changes that promote the successful development of the semi-allogeneic fetus. In response to embryo implantation, the uterus remodels with maternal immune cells occupying the maternal-fetal interface and uterine natural killer (uNK) cells becoming the most prominent leukocyte. Recently, uNK cells have been discovered to be heterogeneous, including conventional NK and tissue-resident NK cells. Here, we will review the recent advances in uNK cell biology and discuss their functional mechanisms which protect and nurture the growing fetus.

Maintained thymic output of conventional and regulatory T cells during human pregnancy

Maintained thymic output of conventional and regulatory T cells during human pregnancy

295. The characteristic of PE (preeclampsia) complication at lupus on pregnancy

Background Indonesia had the serious challenge of highly maternal mortality over last ten years reflecting the real national health problem. There was 305 maternal death/100.000 deliveries, where 3 major possible cause of PE, PPH and infection persisted. Recently the new comer of diseases was standing tightly behind them: lupus on pregnancy. Material & Method This was a retrospective study from medical records.. Fifty-two cases of Lupus from 4592 pregnancy during 4 years (1.13%) have been observed in DR. Soetomo Teaching Hospital (tertiary hospital) Surabaya, Indonesia from January 2013 through December 2016. Results Sixteen cases of lupus were complicated by PE (30.7%), and 37.5% cases with Lupus Nephritis (that mostly showing increased serum creatinin level > 1.4 mg%). The maternal age were 25–34 years old (62.5%) and 62.5% were multigravida. Almost half cases (43.75%) got flare, leading to 25% early termination, while the remaining casesed (75%) were conservatively managed until 34 weeks gestation. Fetal outcome reported as 11 cases (68.75%) having birthweight > 2 kg, with 37.5% asphyxia (low apgar score). Discussion Pregnancy was discouraged in women affected by SLE, due to the disease becoming more aggresive during pregnancy and a poor pregnancy outcome was frequently reported. During pregnancy, the maternal immune system adapts to allow the growth of a semi-allogenic fetus. Significant immunological changes occur including suppression of type-2 helper cells (Th2), but the upregulation of Th1 cytokines in pregnancy may increase the risk for Th1-mediated diseases. The aboved concept was reflected at our study where most cases were sucessfully managed conservative until 34 weeks gestation and majority baby born with birthweight > 2 kg. Conclusions Our results suggest that lupus women are much more likely to develop worsening maternal spesifically preeclampsia and fetal outcomes when they become pregnant.

238. The gut microbiome in pregnant mice: Relation to maternal immune responses?

Introduction Pregnancy is associated with maternal immunological adaptations in order to tolerate and support the development of the semi-allogeneic fetus. Hypothesis Since intestinal microbiota are linked to immune modulations, we hypothesized that intestinal microbiota are altered during pregnancy to support maternal immune adaptations. Methods Pregnant (day 18) and non-pregnant C57BL/6 and BALB/c mice were sacrificed and feces and colonic tissue were harvested. Fecal microbiota composition (MITchip) and intestinal gene expression (microarray (Affymetrix)) were evaluated. Results Pregnancy influenced intestinal microbiota diversity and composition in a mouse strain dependent way. Pregnant BALB/c mice had, among others, a higher abundance of various Lactobacillus species (e.g. L. paracasei et rel. and L. plantarum), Allobaculum et rel, Roseburia intestinalis et rel. and Eubacterium hallii et rel., as compared to non-pregnant BALB/c mice. The microbiota composition in C57BL/6 mice hardly changed during pregnancy. Additionally, intestinal immunological pathways were changed during pregnancy, again in a mouse strain dependent way. For example, pathways related to B cell development and CD28 signaling in T helper cells were only affected in C57BL/6 mice, while IL-10 signaling was only affected in BALB/c mice. Using advanced statistics, we combined microarray data with microbiota composition data from BALB/c mice and found many correlations between the presence of various pregnancy affected intestinal bacteria and immunological genes. Various bacteria with a higher abundance in pregnant mice (such as Allobaculum et rel.) correlated with clusters of genes, with many genes involved in immune responses (for instance T cell development). Conclusion Our data support a role for the microbiome in adapting immune responses in pregnancy. However, also other factors are involved, since in C57BL/6 mice many immunological changes take place in the absence of microbiome changes. Follow up studies are needed to study the exact relationship between intestinal bacteria and maternal immune responses in pregnancy.

Development of a core outcome set for immunomodulation in pregnancy (COSIMPREG): a protocol for a systematic review and Delphi study

IntroductionTo establish pregnancy, the maternal immune system must adapt to tolerate the semiallogenic fetus. Less than optimal adaptation of the maternal immune system during (early) pregnancy is implicated in several...

Immune Cells at the Fetomaternal Interface: How the Microenvironment Modulates Immune Cells To Foster Fetal Development.

Immune cells adapt their phenotypic and functional characteristics in response to the tissue microenvironment within which they traffic and reside. The fetomaternal interface, consisting of placental trophoblasts and the maternal decidua, is a highly specialized tissue with a unique and time-limited function: to nourish and support development of the semiallogeneic fetus and protect it from inflammatory or immune-mediated injury. It is therefore important to understand how immune cells within these tissues are educated and adapt to fulfill their biological functions. This review article focuses on the local regulatory mechanisms ensuring that both innate and adaptive immune cells appropriately support the early events of implantation and placental development through direct involvement in promoting immune tolerance of fetal alloantigens, suppressing inflammation, and remodeling of maternal uterine vessels to facilitate optimal placental function and fetal growth.

Expression of immune regulatory genes in early, mid and late stages of pig (Sus scrofa domesticus) gestation

Semi-allogeneic foetus and placenta exploit various mechanisms to avoid immune-mediated maternal rejection. Several factors and cytokines are attributed for production of immune tolerance during gestation and very little information on expression of these immune-regulatory genes is available in pig. Chorioallantoic membrane (CAM) from early, mid and late gestational stages (n=4) were analysed for expression of immune regulatory genes, viz. Fas ligand (FasL), transporter for antigen processing-1 (TAP-1), transforming growth factor β1 (TGF-β1) and macrophage migration inhibitory factor (MIF) whereas Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was employed as housekeeping gene. FasL gene expression was significantly higher in mid (13.46 fold) and late (28.77 fold) gestation than the early (1 fold) stage.TAP-1 mRNA expression was enhanced by 4.95 fold and 2.69 fold during mid and late gestation respectively in comparison to the early (1 fold) stage. TGF-β1 gene expression was up regulated in mid (2.43 fold) and late (2.29 fold) gestation than the early (1 fold) stage. MIF mRNA expression was enhanced in mid (3.04 fold) and late (1.59 fold) gestation in relation to the early (1 fold) stage. Placenta of pig remains entirely epitheliochorial which may minimise immune recognition and is supposed to diminish potent immune-regulatory mechanisms. However, our present study revealed consistent expression for immune regulatory factors which suggests immune modulation does exist in pig and may impart a role in pregnancy success.

Vitamin D, autoimmunity and recurrent pregnancy loss: More than an association.

Recurrent pregnancy loss (RPL) affects close to 1% of couples; however, the etiology is known in only about 50% of the cases. Recent studies show that autoimmune dysregulation is a probable cause of RPL, which in some cases may be overlooked. In order for a pregnancy to proceed to term, early modulation of immunologic response is required to induce tolerance to the semi-allogenic fetus. Certain subsets of both the innate and adaptive immune responses play a role in the induction of fetomaternal tolerance. A relatively predominant T-cell helper (Th) 2 and T regulatory (Treg) cell population seem to favor a better pregnancy outcome, whereas Th1 and Th17 cell populations appear to have an opposite effect. Lately, the role of vitamin D in the modulation of immune response was established. Vitamin D has been shown to promote a more favorable environment for pregnancy through various mechanisms, such as enhancement of the shift toward Th2 cells and regulation of immune cell differentiation and cytokine secretion. Therefore, it seems that vitamin D deficiency sways the balance toward a worse outcome and may play a part in recurrent pregnancy loss. This review sheds light on the immunologic changes, which occur in early pregnancy and the regulatory role vitamin D has in the maintenance of this delicate balance.

Soluble inflammatory mediators induce transcriptional re-organization that is independent of dna methylation changes in cultured human chorionic villous trophoblasts

The studies proposed here were undertaken to test the hypothesis that, under specific circumstances (e.g., a strong enough inflammatory stimulus), genes that are repressed at the maternal-fetal interface via DNA methylation might be de-methylated, allowing either a maternal immune response to the semi-allogenic fetus or the onset of early labor. Chorionic trophoblasts (CT) were isolated from fetal membranes, followed by incubation with medium from LPS-activated PBMC or resting PBMC medium for 2 h. RNA and DNA were isolated from the cells for RNA-seq and DNA methylation studies. Two hrs after being exposed to conditioned medium from LPS-activated PBMC, CT showed differential expression of 114 genes, all but 2 of which showed higher expression in the stimulated cells than is the unstimulated cells. We also identified 318 differentially methylated regions (DMRs) that associated with 306 genes (155 protein coding genes) in the two groups, but the observed methylation changes had negligible impact on the observed transcriptional changes in CT.CT display complex patterns of transcription in response to inflammation. DNA methylation does not appear to be an important regulator of the observed transcriptional changes.

Deep Surveying of the Transcriptional and Alternative Splicing Signatures for Decidual CD8+ T Cells at the First Trimester of Human Healthy Pregnancy.

Decidual CD8+ (dCD8) T cells have been proposed to play important roles in immune protection against the invading pathogens and in tolerance toward the growing semi-allogeneic fetus during early pregnancy. However, their phenotypic and functional characteristics remain poorly defined. Here, we performed the first analysis of the transcriptional and alternative splicing (AS) signatures for human first-trimester dCD8 T cells using high-throughput mRNA sequencing. Our data revealed that dCD8 T cells have distinct transcriptional and AS landscapes when compared with their autologous peripheral blood CD8+ (pCD8) T counterparts. Furthermore, human dCD8 T cells were observed to contain CD8-Treg and effector-memory T-cell subsets, and display enhanced functionality in terms of degranulation and cytokine production on a per-cell basis. Additionally, we have identified the novel splice junctions that use a high ratio of the non-canonical splicing motif GC-AG and found that AS is not a major contributor to the gene expression-level changes between paired pCD8 and dCD8 T cells. Together, our findings not only provide a comprehensive framework of the transcriptional and AS landscapes but also reveal the functional feature of human dCD8 T cells, which are of great importance in understanding the biology of these cells and the physiology of human healthy pregnancy.

A proinflammatory CD4+ T cell phenotype in gestational diabetes mellitus.

Numerous adaptations of the maternal immune system are necessary during pregnancy to maintain immunological tolerance to the semi-allogeneic fetus. Several complications of pregnancy have been associated with dysregulation of these adaptive mechanisms. While gestational diabetes mellitus (GDM) has been associated with upregulation of circulating inflammatory factors linked to innate immunity, polarisation of the adaptive immune system has not been extensively characterised in this condition. We aimed to characterise pro- and anti-inflammatory CD4+ (T helper [Th]) T cell subsets in women with GDM vs women without GDM (of similar BMI), during and after pregnancy, and examine the relationship between CD4+ subsets and severity of GDM. This is a prospective longitudinal case-control study of 55 women with GDM (cases) and 65 women without GDM (controls) at a tertiary maternity hospital. Quantification of proinflammatory (Th17, Th17.1, Th1) and anti-inflammatory (regulatory T cell [Treg]) CD4+ T cell subsets was performed on peripheral blood at 37weeks gestation and 7weeks postpartum, and correlated with clinical characteristics and measures of blood glucose. Women with GDM had a significantly greater percentage of Th17 (median 2.49% [interquartile range 1.62-4.60] vs 1.85% [1.13-2.98], p = 0.012) and Th17.1 (3.06% [1.30-4.33] vs 1.55% [0.65-3.13], p = 0.006) cells compared with the control group of women without GDM. Women with GDM also had higher proinflammatory cell ratios (Th17:Treg, Th17.1:Treg and Th1:Treg) in pregnancy compared with the control group of women without GDM. In the control group, there was a statistically significant independent association between 1h glucose levels in the GTT and Th17 cell percentages, and also between 2h glucose levels and percentage of Th17 cells. The percentage of Th17 cells and the Th17:Treg ratio declined significantly after delivery in women with GDM, whereas this was not the case with the control group of women. Nevertheless, a milder inflammatory phenotype persisted after delivery (higher Th17:Treg ratio) in women with GDM vs women without. Dysregulation of adaptive immunity supports a novel paradigm of GDM that extends beyond hyperglycaemia and altered innate immunity.

Maternal-fetal cross talk through cell-free fetal DNA, telomere shortening, microchimerism, and inflammation.

There exists a strong correlation between unscheduled inflammation at the maternal-fetal interface and the continuum of pregnancy complications. In normal pregnancy, immunological tolerance is established to protect the semi-allogeneic fetus. There has been extensive research on how the immunity, endovascular trophoblast migration, and hormonal nexus are orchestrated during pregnancy at the maternal-fetal interface to program a normal pregnancy outcome. It is not clear what contributes to the plasticity of uterine immune tolerance, fetal survial, and long-term post-partum health of the mother and the offspring. Old and new concepts have reemerged and emerged that include cell-free fetal DNA (cffDNA), telomere shortening, microchimerism involving bidirectional migration of maternal and fetal cells, and pregnancy as a stress factor. The question is how these pathways converge in a gestational age-dependent manner to contribute to the health of the mother and the offspring later in life and respond to an array of inflammatory challenges. In this Review, we provide pertinent discussion on maternal-fetal cross talk through cffDNA, telomere shortening, and microchimerism in the context of inflammatory and anti-inflammatory settings, particularly how these pathways lead to normal and adverse pregnancy outcomes.

Genome-wide gene expression analysis of 45 days pregnant fetal cotyledons vis-a-vis non-pregnant caruncles in buffalo (Bubalus bubalis)

The crosstalk between fetus and mother starts with the onset of placental attachment to the uterus. The cotyledons and caruncles are the two anatomically distinct structures that play a crucial role in this physiological communication. Using Agilent Gene Chip Genome microarray, we measured the expression profile of pregnancy cotyledons in comparison to caruncular reminiscence of the uteri in non-pregnant buffalo (Bubalus bubalis) for the detection of the early post-pregnancy rapid changes in cellular expression of mRNA transcripts. We identified a total of 497 up- and 578 down-regulated genes with <0.05 the FDR corrected p-values using 4 replicates in each group (cotyledons and caruncles) and their role in pregnancy. Deep bioinformatics analysis of data revealed the cluster of genes involved at the placentome level for various functions such as fetus attachment, transport of nutrition, and immune response. Importantly, the pathways like Hedgehog/Calcium/Wnt signalling, cell cycle regulation and immune responses regulatory functions were highly enriched by the differentially identified genes. A very highly up-regulated IL-2 specific gene showed the role of interleukin-2 signalling in the attachment of the embryo. It was observed that the genes responsible for immune response were downregulated, suggesting an immune suppressive environment which is required to adopt the semiallogeneic fetus for a successful pregnancy. To further evaluate and validate the data, we have performed qRT-PCR analysis of twenty-one genes. The present study highlights the repertoire of active transcripts in the junction of cotyledons and caruncles, which are essential for a successful onset and completion of pregnancy.

Microglia, the missing link in maternal immune activation and fetal neurodevelopment; and a possible link in preeclampsia and disturbed neurodevelopment?

Disturbances in fetal neurodevelopment have extensively been related to neurodevelopmental disorders in early and later life. Fetal neurodevelopment is dependent on adequate functioning of the fetal immune system. During pregnancy, the maternal immune system is challenged to both tolerate the semi-allogenic fetus and to protect the mother and fetus from microbes. The fetal immune system is influenced by maternal immune disturbances; therefore, perturbations in maternal immunity likely do not only alter pregnancy outcome but also alter fetal neurodevelopment. A possible common pathway could be modulating the functioning of tissue macrophages in the placenta and brain.Maternal immune tolerance towards the fetus involves several complex adaptations. In this active maternal immune state, the fetus develops its own immunity. As cytokines and other players of the immune system -which can pass the placenta- are involved in neurodevelopment, disruptions in immune balance influence fetal neurodevelopment. Several studies reported an association between maternal immune activation, complications of pregnancy as preeclampsia, and altered neonatal neurodevelopment. A possible pathway involves dysfunctioning of microglia cells, the immune cells of the brain. Functionality of microglia cells during normal pregnancy is, however, poorly understood. The recent outbreak of ZIKA virus (ZKV), but also the literature on virus infections in general and its consequences on microglial cell function and fetal neurodevelopment show the devastating effects a virus infection during pregnancy can have.

Immune modulation of i.v. immunoglobulin in women with reproductive failure.

BackgroundThe mechanism of maternal immune tolerance of the semi‐allogenic fetus has been explored extensively. The immune reaction to defend from invasion by pathogenic microorganisms should be maintained during pregnancy. An imbalance between the immune tolerance to the fetus and immune activation to the pathogenic organisms is associated with poor pregnancy outcomes. This emphasizes that the immune mechanism of successful reproduction is not just immune suppression, but adequate immune modulation.MethodsIn this review, the action of i.v. immunoglobulin G (IVIg) on the immune system and its efficacy in reproductive failure (RF) was summarized. Also suggested is the indication of IVIg therapy for women with RF.Main findings (Results)Based on the mechanism of the immune regulation of IVIg and following confirmation of the immune modulation effects of it in various aberrant immune parameters in patients with RF, it is obvious that IVIg is effective in recurrent pregnancy losses and repeated implantation failures with immunologic disturbances.ConclusionThe authors recommend IVIg therapy in patients with RF with aberrant cellular immunologic parameters, including a high natural killer cell proportion and its cytotoxicity or elevated T helper 1 to T helper 2 ratio, based on each clinic's cut‐off values. Further clinical studies about the safety of IVIg in the fetus and its efficacy in other immunologic abnormalities of RF are needed.

Corrigendum to: Paternal priming of maternal tissues to optimise pregnancy success.

The question of 'how does the allogeneic fetus survive gestation in the face of the maternal immune system?' has yet to be definitively answered. Several acceptable mechanisms exist to facilitate survival of the semi-allogeneic fetus in various species; paramount is the immunological separation of maternal and fetal tissues during gestation. However, keen observation of the maternal immune system during pregnancy has noted maternal immune tolerance to paternal-specific antigens. A mechanism by which the maternal immune system tolerates specific paternal antigens expressed on the fetus would be far more beneficial than the previously proposed immune indolence that would leave the mother susceptible to infection. In species like human or rodent, implantation occurs days after fertilisation and, as such, the mechanisms to establish antigen-specific tolerance must be initiated very early during pregnancy. We and others propose that these mechanisms are initiated at the time of insemination when paternal antigens are first introduced to the maternal immune system. Indeed, a new paradigm demonstrating the importance of paternal-maternal communication at the time of insemination is becoming evident as it relates to maternal tolerance to fetal antigen and ultimately pregnancy success.

Paternal priming of maternal tissues to optimise pregnancy success.

The question of 'how does the allogeneic fetus survive gestation in the face of the maternal immune system?' has yet to be definitively answered. Several acceptable mechanisms exist to facilitate survival of the semi-allogeneic fetus in various species; paramount is the immunological separation of maternal and fetal tissues during gestation. However, keen observation of the maternal immune system during pregnancy has noted maternal immune tolerance to paternal-specific antigens. A mechanism by which the maternal immune system tolerates specific paternal antigens expressed on the fetus would be far more beneficial than the previously proposed immune indolence that would leave the mother susceptible to infection. In species like human or rodent, implantation occurs days after fertilisation and, as such, the mechanisms to establish antigen-specific tolerance must be initiated very early during pregnancy. We and others propose that these mechanisms are initiated at the time of insemination when paternal antigens are first introduced to the maternal immune system. Indeed, a new paradigm demonstrating the importance of paternal-maternal communication at the time of insemination is becoming evident as it relates to maternal tolerance to fetal antigen and ultimately pregnancy success.

P220 A previous miscarriage and a previous successful pregnancy have a different impact on HLA antibody formation during a subsequent successful pregnancy

Aim Inherited paternal HLA antigens from the semi-allogeneic fetus may trigger maternal immune responses during pregnancy, leading to the production of child-specific HLA antibodies. The prevalence of these HLA antibodies increases with the number of successful pregnancies. In the present study we investigated the effect of a single prior miscarriage on HLA antibody formation during a subsequent successful pregnancy. Methods Women with a successful pregnancy with one or more prior miscarriages (n = 58) and women with a successful pregnancy without a prior miscarriage (n = 229) and their children were HLA typed. HLA-antibody analyses were performed in these women to identify whether HLA antibodies were formed against mismatched HLA class-I antigens of the last child. Results The percentage of immunogenic antigens was significantly lower after a single successful pregnancy that was preceded by a single miscarriage (n = 18 women) compared to a successful pregnancy that was preceded by a first successful pregnancy (n = 62 women). Conclusions Our data suggest that a previous miscarriage has a different impact on child-specific HLA antibody formation during a subsequent successful pregnancy than a previous successful pregnancy. The lower immunogenicity in these women cannot be explained by reduced numbers of immunogenic B-cell and T-cell epitopes. Our observations indicate that increasing gravidity is not related to an increased prevalence of HLA antibodies in a single successful pregnancy that was preceded by a single prior miscarriage.

HLA class Ib in pregnancy and pregnancy-related disorders.

The HLA class Ib genes, HLA-E, HLA-F, and HLA-G, were discovered long after the classical HLA class Ia genes. The elucidation of their functions had a modest beginning. However, their basic functions and involvement in pathophysiology and a range of diseases are now emerging. Although results from a range of studies support the functional roles for the HLA class Ib molecules in adult life, especially HLA-G and HLA-F have most intensively been, and were also primarily, studied in relation to reproduction and pregnancy. The expression of HLA class Ib proteins at the feto-maternal interface in the placenta seems to be important for the maternal acceptance of the semi-allogenic fetus. In contrast to the functions of HLA class Ia, HLA-G possesses immune-modulatory and tolerogenic functions. Here, we review an accumulating amount of data describing the functions of HLA class Ib molecules in relation to fertility, reproduction, and pregnancy, and a possible role for these molecules in certain pregnancy complications, such as implantation failure, recurrent spontaneous abortions, and pre-eclampsia. The results from different kinds of studies point toward a role for HLA class Ib, especially HLA-G, throughout the reproductive cycle from conception to the birth weight of the child.