Modulation of T-cell CD3-zeta chain expression during normal pregnancy

NF-κB regulation in maternal immunity during normal and IUGR pregnancies

Intrauterine Growth Restriction (IUGR) is a leading cause of perinatal death with no effective cure, affecting 5-10% pregnancies globally. Suppressed pro-inflammatory Th1/Th17 immunity is necessary for pregnancy success. However, in IUGR, the inflammatory response is enhanced and there is a limited understanding of the mechanisms that lead to this abnormality. Regulation of maternal T-cells during pregnancy is driven by Nuclear Factor Kappa B p65 (NF-κB p65), and we have previously shown that p65 degradation in maternal T-cells is induced by Fas activation. Placental exosomes expressing Fas ligand (FasL) have an immunomodulatory function during pregnancy. The aim of this study is to investigate the mechanism and source of NF-κB regulation required for successful pregnancy, and whether this is abrogated in IUGR. Using flow cytometry, we demonstrate that p65⁺ Th1/Th17 cells are reduced during normal pregnancy, but not during IUGR, and this phenotype is enforced when non-pregnant T-cells are cultured with normal maternal plasma. We also show that isolated exosomes from IUGR plasma have decreased FasL expression and are reduced in number compared to exosomes from normal pregnancies. In this study, we highlight a potential role for FasL⁺ exosomes to regulate NF-κB p65 in T-cells during pregnancy, and provide the first evidence that decreased exosome production may contribute to the dysregulation of p65 and inflammation underlying IUGR pathogenesis.

DNA methylation patterns in T lymphocytes are generally stable in human pregnancies but CD3 methylation is associated with perinatal psychiatric symptoms

Objectives

To determine whether DNA methylation patterns in genes coding for selected T-lymphocyte proteins are associated with perinatal psychiatric distress or with complications of pregnancy.

Methods

T lymphocyte DNA was obtained from pregnant women across three time points in pregnancy and the postpartum period and epigenetic patterns were assessed using Illumina 450 ​K Methylation Beadchips. Seven selected genes critical for T cell function were analyzed for methylation changes during pregnancy and for associations of methylation patterns with psychiatric distress or with pregnancy complications, with particular attention paid to spatial aggregations of methyl groups, termed ‘hotspots,’ within the selected genes.

Results

In the candidate gene approach, DNA methylation density within a single cluster of 9 contiguous CpG loci within the CD3 gene was found to be strongly associated with anxiety and depression in mid- and late pregnancy, and weakly associated with the presence of complications of pregnancy. Average DNA methylation density across each of the seven genes examined, and assay-wide, was found to be relatively stable across pregnancy and postpartum, but methylation within the CD3 hotspot was more malleable and changes over time were coordinated across the nine cytosines in the hotspot. CD3 CpGs did not pass array-wide tests for significance, but CpG clusters in two other genes, DTNBP1 and OXSR1, showed array-wide significant associations with anxiety.

Conclusions

Despite the need for tolerating the fetal hemi-allograft, overall DNA methylation patterns in T lymphocytes are generally stable over the mid to late course of human pregnancies and postpartum. However, site-specific changes in DNA methylation density in CD3 appear linked to both symptoms of depression and anxiety in pregnancy and, less strongly, to adverse pregnancy outcomes.

•

Associations exist between DNA methylation density in T cells and measures of stress and mental health in pregnant women.

•

Global DNA methylation density is generally stable over the course of pregnancy.

•

A subregion within the CD3 gene has unusually variable DNA methylation density and is associated with anxiety and depression.

•

Spatial and gene specificity may be important elements of epigenetic regulation of immune function in pregnancy.

Periapical infection may affect birth outcomes via systemic inflammation

OBJECTIVES

Maternal dental periapical infections are associated with preterm birth and intrauterine growth restriction. This study investigates whether the association is mediated through bacterial spread from periapical lesions to placenta (direct pathway) or systemic inflammatory reaction (indirect pathway).

MATERIALS AND METHODS

We compared birth outcomes in Malawian mothers with and without periapical infection. As markers of a direct pathway, we identified placental bacteria using a 16S rDNA approach and assessed histological evidence of inflammation in the placenta and amniotic membranes. We measured C-reactive protein, alpha-1-acid glycoprotein, and salivary cortisol as markers of an indirect pathway. We used regression models to associate the predictor variables with duration of pregnancy and newborn size.

RESULTS

Of 1,024 women, 23.5% had periapical infection. There was no association of periapical infection with either bacterial DNA or histological inflammation in placenta or membranes. Periapical infection was associated with C-reactive protein, alpha-1-acid glycoprotein, and cortisol concentrations in a dose-dependent manner at 36 weeks. Addition of alpha-1-acid glycoprotein or cortisol concentration into regression models attenuated the association between periapical infection and pregnancy outcomes.

CONCLUSION

There was no evidence of direct spread of periapical bacteria to the placenta. Periapical infections and adverse pregnancy outcomes are in part mediated through systemic inflammation.

Periodontal status during pregnancy and postpartum

Objectives

Different studies have documented an association between periodontal disease and low birth-weight delivery. Hence, knowledge of periodontal status during pregnancy and postpartum is important in order to reduce the risks of both diseases. This study aimed to analyze periodontal status at successive stages of pregnancy and 3–6 weeks postpartum in women with initial periodontal alterations.

Materials and methods

Ninety-six pregnant women were examined at 8–10 weeks (pregnancy diagnosis, baseline), 21–23 weeks and 34–36 weeks of gestation and at 40 days postpartum to record plaque scores, clinically assessed gingival inflammation and probing depth (mean depth and % sites with depth >3 mm). Bivariate and multivariate analyses were performed. Type 1 (α) error was established at 0.05

Results

Plaque Index increased (p = 0.043) throughout pregnancy (baseline, 42%±0.18); 21–23 weeks, 42.6%±0.14; 34–36 weeks, 45.6%±0.13 and decreased postpartum (44.8%±0–13). Gingival Index increased (p<0.001) throughout pregnancy (baseline, 56.7%±0.20; 21–23 weeks, 66.36%±0.17; 34–36 weeks, 74.5%±0.18) and decreased postpartum (59.3%±0.21). Probing Depth increased (p<0.001) throughout pregnancy (baseline, 2.51±0.05; 21–23 weeks, 2.63±0.053; 34–36 weeks 2.81±0.055) and decreased postpartum (2.54±0.049). Percentage of sites with Probing Depth >3 mm increased (p<0.001) throughout pregnancy (baseline, 17.6%±0.16; 21–23 weeks, 23.9%±0.17; 34–36 weeks, 31.1%±0.17) and decreased postpartum (21.2%±0.17) but remained significantly (p<0.02) higher than at baseline.

Conclusion

Periodontal status deteriorates during gestation but improves postpartum.

Effectiveness of seasonal trivalent influenza vaccination against hospital-attended acute respiratory infections in pregnant women: A retrospective cohort study

BACKGROUND

Pregnant women are at risk of serious influenza infection. Although previous studies indicate maternal influenza vaccination can prevent hospitalisation in young infants, there is limited evidence of the effect in mothers.

METHODS

A cohort of 34,701 pregnant women delivering between 1 April 2012 and 31 December 2013 was created using birth records. Principal diagnosis codes from hospital emergency department (ED) and inpatient records were used to identify episodes of acute respiratory illness (ARI) during the 2012 and 2013 southern hemisphere influenza seasons. Cox regression models were used to calculate adjusted hazard ratios (aHRs) by maternal vaccination status, controlling for Indigenous status, socioeconomic level, medical conditions, and week of delivery.

RESULTS

3,007 (8.7%) women received a seasonal influenza vaccine during pregnancy. Vaccinated women were less likely to visit an ED during pregnancy for an ARI (9.7 visits per 10,000 person-days vs. 35.5 visits per 10,000 person-days; aHR: 0.19, 95% CI: 0.05-0.68). Vaccinated women were also less likely to be hospitalised with an ARI compared to unvaccinated women (16.2 hospitalisations per 10,000 person-days vs. 34.0 hospitalisations per 10,000 person-days; aHR: 0.35, 95% CI: 0.13-0.97).

CONCLUSIONS

Influenza vaccination during pregnancy was associated with significantly fewer hospital attendances for ARI in pregnant women.

Circulating survivin levels in healthy and asthmatic pregnancy

BACKGROUND

Asthma is one of the most common conditions which complicate pregnancy. Pro- and anti-apoptotic mechanisms can be modulated by asthma accompanying pregnancy. Survivin, an anti-apoptotic protein has been implicated in the pathomechanism of asthma and also in the development of pathological pregnancies; however survivin has not been studied in pregnant asthmatics.

METHODS

Twenty-eight asthmatic pregnant (AP), 25 asthmatic non-pregnant (ANP), 21 healthy pregnant (HP) and 29 healthy non-pregnant (HNP) women were enrolled in this cross-sectional study. Plasma survivin concentration was determined by ELISA.

RESULTS

Plasma survivin was significantly lower in HP (1.64 /0-74.9/ pg/ml) than in HNP (24.6 /0-333.3/ pg/ml, p = 0.01). However, this difference was not observed between the asthmatic groups (p = 0.64). Similarly, there was no difference either between HNP and ANP (10.5 /0-215.4/ pg/ml, p = 0.23) or between HP and AP (13.9 /0-364.1/ pg/ml, p = 0.30) groups.

CONCLUSIONS

Decreased plasma survivin levels in physiological but not in asthmatic pregnancy may suggest that the normal apoptotic mechanisms are compromised in asthmatic gestation.

Giant granuloma gravidarium of the oral cavity

Oral health is affected by hormonal changes during pregnancy but is usually neglected by both the obstetrician and the patient during follow-up visits. Gingival enlargement is one of the most common oral lesions seen during pregnancy. Rarely, gingival enlargement can be very big, significantly affecting maternal nutrition and impairing haemodynamic status. A giant granuloma gravidarium and appropriate management strategies are discussed. Patients must be encouraged to undergo regular dental check-ups during pregnancy. Simple oral hygiene measures are highly effective in mitigating most oral lesions of pregnancy.

Systemic inflammatory stimulation by microparticles derived from hypoxic trophoblast as a model for inflammatory response in preeclampsia

OBJECTIVE

To determine whether trophoblast-derived microparticles can induce different inflammatory responses of the peripheral blood mononuclear cells depending upon the state of trophoblast when the microparticles are generated.

STUDY DESIGN

A trophoblast-derived cell line (ATCC no. CRL-1584) was cultured under normal or hypoxic conditions. Microparticles were isolated from the cell culture supernatants (microparticles from normal trophoblast; microparticles from hypoxic trophoblast). Peripheral blood mononuclear cells were cultured alone or cocultured with either microparticles from normal trophoblast or microparticles from hypoxic trophoblast.

RESULTS

After 48 hours, the peripheral blood mononuclear cells cocultured with microparticles from normal trophoblast released higher concentrations of interleukin-6 than peripheral blood mononuclear cells cultured alone. The peripheral blood mononuclear cells cocultured with microparticles from hypoxic trophoblast showed higher concentration of interleukin-6 and tumor necrosis factor alpha than peripheral blood mononuclear cells cocultured with microparticles from normal trophoblast, after 24 hours and 48 hours.

CONCLUSION

More intense and rapid inflammatory response of peripheral blood mononuclear cells was observed with microparticles from hypoxic trophoblast than with microparticles from normal trophoblast. This difference might explain the exaggerated systemic inflammatory response as a result of placental hypoxia in preeclampsia.

Heightened pro-inflammatory effect of preeclamptic placental microvesicles on peripheral blood immune cells in humans

Normal pregnancy is associated with the presence of circulating placental microvesicles (MVs). Increased MV shedding and altered immune activation are seen in patients with preeclampsia, suggesting that placental MVs may play a role in the pathophysiology of this disease. Therefore, the aim of this study was to investigate the activation of peripheral blood mononuclear cells (PBMCs) by MVs shed by first-trimester, normal term, and preeclamptic term placenta. First-trimester and preeclamptic term, but not normal term, placental-derived MVs activated PBMCs, as evidenced by elevated IL1B. Significant changes were also seen with several other cytokines and chemokines, and in general when compared to normal term MVs, preeclamptic MVs induced a greater pro-inflammatory response in PBMCs. Pretreatment of PBMCs with first-trimester or normal term placental MVs resulted in a dampened IL1B response to a subsequent lipopolysaccharide (LPS) challenge. In contrast, treatment of PBMCs with preeclamptic term placental MVs exacerbated the LPS response. This was also the case for several other cytokines and chemokines. These studies suggest that placental MVs can modulate basal peripheral immune cell activation and responsiveness to LPS during normal pregnancy, and that in preeclampsia this effect is exacerbated.

Resolution-associated molecular patterns (RAMP): RAMParts defending immunological homeostasis?

The resolution of inflammation is central to the maintenance of good health and immune homeostasis. Recently, several intracellular stress proteins have been described as having extracellular properties that are anti-inflammatory or favour the resolution of inflammation. We propose that these molecules should be defined as resolution-associated molecular patterns (RAMPs). RAMPs are released at times of cellular stress and help to counterbalance the inflammatory effects of pathogen-associated (PAMPs) and damage-associated (DAMPs) molecular patterns. We propose that heat shock protein 10 (HSP10), αB-crystallin (αBC), HSP27 and binding immunoglobulin protein (BiP) should be considered founding members of the RAMP family. A greater understanding of RAMP biology may herald the development of novel immunotherapies.

Trophoblast-derived exosomes mediate monocyte recruitment and differentiation

INTRODUCTION

trophoblast cells have been demonstrated to regulate monocyte migration and differentiation, leading to pro-inflammatory profiles. Because trophoblast cells release exosomes with immunoregulatory properties, trophoblast-derived exosomes are proposed to 'educate' monocytes, creating a pro-inflammatory environment.

METHOD OF STUDY

exosomes were isolated from conditioned media of Swan71 cells by ultrafiltration and ultracentrifugation. Exosome-induced migration was assessed using a two-chamber system. Cytokine profiles were defined using cytokine arrays, and mRNA levels of affected cytokines were examined by qRT-PCR and ELISA.

RESULTS

within 20 min, 8-10% of monocytes took up labeled exosomes isolated from Swan71 cells. Trophoblast-derived exosomes increased monocyte migration in a dose-dependent manner and produced significant increases in production of interleukin (IL)-1β, IL-6, Serpin-E1, granulocyte colony-stimulating factor, granulocyte/monocyte colony-stimulating factor, and tumor necrosis factor-α.

CONCLUSION

this study presents the initial demonstration that trophoblast-derived exosomes are capable of recruiting and 'educating' monocytes to produce pro-inflammatory cytokine/chemokine profiles in a cell-contact-independent manner.

Morphologic and proteomic characterization of exosomes released by cultured extravillous trophoblast cells

Exosomes represent an important intercellular communication vehicle, mediating events essential for the decidual microenvironment. While we have demonstrated exosome induction of pro-inflammatory cytokines, to date, no extensive characterization of trophoblast-derived exosomes has been provided. Our objective was to provide a morphologic and proteomic characterization of these exosomes. Exosomes were isolated from the conditioned media of Swan71 human trophoblast cells by ultrafiltration and ultracentrifugation. These were analyzed for density (sucrose density gradient centrifugation), morphology (electron microscopy), size (dynamic light scattering) and protein composition (Ion Trap mass spectrometry and western immunoblotting). Based on density gradient centrifugation, microvesicles from Sw71 cells exhibit a density between 1.134 and 1.173g/ml. Electron microscopy demonstrated that microvesicles from Sw71 cells exhibit the characteristic cup-shaped morphology of exosomes. Dynamic light scattering showed a bell-shaped curve, indicating a homogeneous population with a mean size of 165nm ± 0.5nm. Ion Trap mass spectrometry demonstrated the presence of exosome marker proteins (including CD81, Alix, cytoskeleton related proteins, and Rab family). The MS results were confirmed by western immunoblotting. Based on morphology, density, size and protein composition, we defined the release of exosomes from extravillous trophoblast cells and provide their first extensive characterization. This characterization is essential in furthering our understanding of "normal" early pregnancy.

NKG2D initiates caspase-mediated CD3zeta degradation and lymphocyte receptor impairments associated with human cancer and autoimmune disease

Deficiencies of the T cell and NK cell CD3ζ signaling adapter protein in patients with cancer and autoimmune diseases are well documented, but mechanistic explanations are fragmentary. The stimulatory NKG2D receptor on T and NK cells mediates tumor immunity but can also promote local and systemic immune suppression in conditions of persistent NKG2D ligand induction that include cancer and certain autoimmune diseases. In this paper, we provide evidence that establishes a causative link between CD3ζ impairment and chronic NKG2D stimulation due to pathological ligand expression. We describe a mechanism whereby NKG2D signaling in human T and NK cells initiates Fas ligand/Fas-mediated caspase-3/-7 activation and resultant CD3ζ degradation. As a consequence, the functional capacities of the TCR, the low-affinity Fc receptor for IgG, and the NKp30 and NKp46 natural cytotoxicity receptors, which all signal through CD3ζ, are impaired. These findings are extended to ex vivo phenotypes of T and NK cells among tumor-infiltrating lymphocytes and in peripheral blood from patients with juvenile-onset lupus. Collectively, these results indicate that pathological NKG2D ligand expression leads to simultaneous impairment of multiple CD3ζ-dependent receptor functions, thus offering an explanation that may be applicable to CD3ζ deficiencies associated with diverse disease conditions.

The influence of sex steroid hormones on gingiva of women

Steroid sex hormones have a significant effect on different organ systems. As far as gingiva are concerned, they can influence the cellular proliferation, differentiation and growth of keratinocytes and fibroblasts. Estrogen is mainly responsible for alterations in blood vessels and progesterone stimulates the production of inflammatory mediators. In addition, some micro-organisms found in the human mouth synthesize enzymes needed for steroid synthesis and catabolism. In women, during puberty, ovulation and pregnancy, there is an increase in the production of sex steroid hormones which results in increased gingival inflammation, characterized by gingival enlargement, increased gingival bleeding and crevicular fluid flow and microbial changes.

Circulating microparticles in normal pregnancy and pre-eclampsia

Cellular particles may be larger shed microparticles (>or=100 nm, MPs) that are the products of cell activation or necrosis. There are also smaller endocytic nanoparticles (<100 nm), called exosomes, which are internal vesicles of late endosomes or multivesicular bodies and are released into the extracellular milieu upon fusion of the multivesicular body with the cell surface. Both MPs and exosomes can be detected in the circulations of non-pregnant and pregnant women. In the former MPs are increased in conditions associated with systemic inflammation such as sepsis or metabolic syndrome. During normal pregnancy MPs are increased and they increase further with pre-eclampsia. They include not only MPs derived from platelets, endothelium and various leukocytes but also syncytiotrophoblast derived MPs (often called STBMs). STBMs interact with both immune and endothelial cells and may contribute to the systemic inflammation of both normal and pre-eclamptic pregnancies. However inhibitory activity has also been ascribed to trophoblast derived exosomes. In vitro, they down-regulate T cell activity, a T cell change that has been repeatedly observed, ex vivo, during normal pregnancy.

Specific Isolation of Placenta-Derived Exosomes from the Circulation of Pregnant Women and Their Immunoregulatory Consequences

PROBLEM

One immunoregulatory pathway receiving little attention is placental exosome release. In normal pregnancy, as factors linked with early immunomodulation decline, placental exosomes become critical in modulating T-cell activation, suppressing effector T cells by enhancing lymphocyte apoptosis and CD3-zeta loss.

METHOD OF STUDY

Placental exosomes were specifically isolated from the maternal peripheral circulation by a chromatographic/immunosorbent procedure. Exosomal suppression of T-cell signaling molecules on unfractionated T cells and T subsets was analyzed by Western immunoblot. The role of Fas ligand (FasL) was defined by use of Fas-blocking antibody.

RESULTS

While exosomes of lymphoid origin could be demonstrated in all women, placenta-derived exosomes were only identified in pregnant patients. Placental exosomes suppressed T-cell expression of CD3-zeta and JAK3, while inducing SOCS-2. This downregulation of CD3-zeta was partially reversed by pre-incubating T cells with ZB4 antibody. Using T subsets, the level of CD3-zeta on CD8+ cells was inhibited 1.43-fold more than in CD4+ cells. On CD4+ CD25+ cells, CD3-zeta was not significantly inhibited.

CONCLUSION

Placental exosomes suppressed T-cell signaling components; however, while exosomal FasL is an important contributor, it does not appear to be the sole mediator. The additional expression of PD-L1 may explain immunoregulatory consequences of exosomes with low or absent FasL.

Patterns of exacerbations of chronic non-infectious uveitis in pregnancy and puerperium

PURPOSE

To determine patterns of exacerbations of recurrent non-infectious uveitis during pregnancy and puerperium.

DESIGN

Retrospective cohort study.

METHODS

The medical records of 32 women with a history of chronic non-infectious uveitis, who were pregnant during their follow-up at the Ocular Immunology and Uveitis Service of the Massachusetts Eye and Ear Infirmary, from 1983 through 2003, were reviewed. The uveitis relapse rate during pregnancy was compared to the relapse rate during pregnancy-free periods in these women and to the relapse rate in a control group of women of childbearing age with recurrent non-infectious uveitis.

RESULTS

Among the 32 women who were pregnant during follow-up (40 pregnancies), the rate of flare-ups during pregnancy (1.0 recurrence per year) was lower than that observed during non-pregnant periods (2.4 per year; p<0.001) and lower than that observed in the non-pregnant control group (3.1 per year; p<0.001). Flare-ups were most frequent in the first trimester of pregnancy and decreased markedly in the second and third trimesters (2.3, 0.5, and 0.4 recurrences per year, respectively; p<0.001).

CONCLUSIONS

Pregnancy is associated with lower numbers of flare-ups of non-infectious uveitis compared to the non-pregnant state. If flare-ups do occur during pregnancy, they happen predominantly in the first trimester.

Pregnancy-associated exosomes and their modulation of T cell signaling

Exosome release by viable cells is a feature of activated cell types, including tumors, fetal cells, and cells of the immune system. Exosomes critically regulate immune activation, by mediating activation-induced cell death. Fetal cells may mimic these events to selectively delete reactive lymphocytes. In this study the presence and composition of placenta-derived exosomes are demonstrated in the maternal circulation along with their consequences on T cell activation markers. For all pregnant patients, exosomes were isolated from sera obtained between 28 and 30 wk gestation. For pregnant women, subsequently delivering at term, circulating levels of placental exosomes were 1.8 times greater than those delivering preterm (p < 0.0001). Exosomes isolated from pregnancies subsequently delivering at term expressed significantly higher levels of biologically active components, including Fas ligand (FasL) and HLA-DR, than those from pregnancies delivering preterm. Standardizing for protein concentrations, exosomes from term-delivering pregnancies exhibited greater suppression of CD3-zeta and JAK3 than those delivering preterm. The suppression of CD3-zeta and JAK3 correlated with exosome expression levels of FasL (r2= 0.92 and r2= 0.938, respectively). Fractionation of exosomes from term-delivering pregnancies by continuously eluting electrophoresis indicated that intact 42 kD FasL and an unidentified 24-kDa protein were associated with CD3-zeta suppression. Our results demonstrated that exosomes from pregnancies ultimately delivering at term are present at significantly greater concentrations than those from pregnancies delivering preterm; however, exosomes from term-delivering pregnancies also exhibit significantly greater suppression of CD3-zeta and JAK3.

Current concepts of tumor-infiltrating lymphocytes in human malignancies

Tumor-infiltrating lymphocytes (TILs) develop as manifestations of the recognition and defense against malignant cells by the host immune system. TILs were literally defined as "tumor-infiltrating lymphocytes", which a posteriori locate within the tumor tissues. Although such cells can be found, they fail to control the growth of tumor. Many have proposed diverse mechanisms for dysfunction of TILs with regard to the roles of immunosurveillance against cancer. However, only a few cancer types, e.g. melanoma, have seen the benefits brought by activating these cells for immunotherapy. Functional defects of TILs have been linked to abnormalities of signaling molecules; however, there is conflicting data. The death of TILs was attributed to expression of cancer-derived FasL, PD-1 and RCAS1, and cancer-induced activation-induced cell death (AICD). Confirmed by studies using TILs and animal models, the compromise of tumor-specific immune responses was thought to result from not only mechanisms of clonal anergy but also exhaustion and/or deletion. Furthermore, functional cytotoxic CD8(+) TILs might be rendered incompetent by cancer-induced up-regulation of inhibitory NK receptors or proximal signaling abnormalities. Additionally, immune privilege was partly attributed to recruitment of regulatory T cells to the tumor sites. The failure of IL-2 signaling, which stands at the center of T cell functionalities, had been linked to the enzymatic activity of cancer-derived matrix metalloproteinases (MMPs). Finally, the exploitation of IDO expression, an important enzyme in pregnancy-related immunosuppression, by cancer cells might play a role in tumor immunity. The disparity of cancer types, origin, developmental stages and individual genetic backgrounds likely account for differences, or even contradictions, which might be the reason why immunotherapy works only on a few cancer types. Delineating the mechanisms behind functional defects of TILs can help not only boost chances of the development of a successful cure but understand the not fully identified roles played by immune system in the face of malignancies.

Dialogue materno-fœtal et implantation embryonnaire humaine : des concepts qui évoluent

Multiple immunogical mechanisms allow fetal allograft tolerance. In this review, we first describe the maternal and embryological side in order to expose the dangers for the embryo enabling the development of materno-fetal strategies that will allow fetal survival and growth.

Alterations in T-cell signal transduction molecules associated with recurrent spontaneous pregnancy loss

Clinical evidence suggests that cell-mediated immunity is altered during pregnancy and that failure to suppress the maternal immune response can lead to placentation failure, resulting in partial or total rejection of the fetus. In contrast to women experiencing recurrent spontaneous abortions (RSA), normal uncomplicated pregnancies are associated decreased T-cell proliferation and production of Th1 cytokines and increased T-cell apoptosis. This study addresses a circulating factor in normal pregnancy that may mediate these events. Sera were obtained from three groups: pregnant women who have uncomplicated term deliveries (Group 1, n = 8), pregnant women with a history of RSA, who subsequently abort (Group 2, n = 10), and age-matched non-pregnant female controls (Group 3, n = 8). Pregnancy sera were obtained between 10 and 12 weeks of gestation. Using chromatography, a CD3-zeta inhibitory factor (or analogous fraction) was isolated from each patient within each group and incubated with cultured T-cells, Jurkat and HUT-78 cells. Apoptosis was assayed by a cell-death ELISA and IL-2 production by cytokine-specific ELISA. Apoptosis regulatory proteins and signaling molecules were analyzed by western immunoblotting. Group 1 material induced a significant increase in apoptosis versus Groups 2 and 3. No significant apoptosis was observed between Groups 2 and 3. Material from Group 1 resulted in an increase in the bax expression compared to Groups 2 and 3 (P < 0.001), while no significant differences were observed in the expression of bcl-2. IL-2 secretion was inhibited 2.8-fold by material from Group 1 compared to Groups 2 and 3. Group 1 material decreased the expression of CD3-zeta, JAK3 and STAT5 compared to Groups 2 and 3 (as defined by densitometric units). Circulating materials from normal pregnancies are associated with increased lymphoid apoptosis, possibly through increased bax, and diminished production of the Th1 cytokine, IL-2. Our findings indicate that women experiencing RSA fail to suppress CD3-zeta and JAK3, suggesting a deficiency in this circulating factor that induces their suppression in normal pregnancy.

Differential expression of TcR-CD3 zeta as evidence for altered immunoregulation in preeclamptic versus normotensive women

OBJECTIVE

The study was undertaken to exhibit and quantify the difference in modulation of CD3-zeta protein (an integral component of the T-cell receptor) in preeclamptic and normotensive women.

STUDY DESIGN

Serum was collected from 10 preeclamptic and 10 normotensive women at >or=37 weeks' gestation on admission. Jurkat E-61 cells were incubated with the sera (20% volume to volume) and analyzed with Western immunoblot using mouse monoclonal CD3-zeta antibody. Enhanced chemiluminescence and densitometry were used to qualitatively measure zeta expression of the cells. A de novo flow cytometry assay was developed to quantify the difference in CD3-zeta expression of these cells. Comparisons were performed by t test (P<.05 was significant).

RESULTS

Preeclamptic patient sera produced a 2.4-fold increase in CD3-zeta expression than normotensive patients on Western blot (P<.01). Flow cytometry showed that preeclamptic sera had a 1.4-fold higher expression of CD3-zeta compared with normotensive patients (P<.0003).

CONCLUSION

TcR/CD3-zeta expression is normally suppressed in pregnancy. Loss of this suppression occurs in preeclamptic patients, implying increased T-cell function.

Influence of sex hormones on the periodontium

OBJECTIVES

Sex hormones have long been considered to play an influential role on periodontal tissues, bone turnover rate, wound healing and periodontal disease progression. The objectives of this review article are to (1) address the link between sex hormones and the periodontium, (2) analyse how these hormones influence the periodontium at different life times and (3) discuss the effects of hormone supplements/replacement on the periodontium.

MATERIALS AND METHODS

Two autonomous searches were performed in English language utilizing Medline, Premedline and Pubmed as the online databases. Publications up to 2002 were selected and further reviewed. In addition, a manual search was also performed including specific related journals and books.

RESULTS

It is certain that sexual hormones play a key role in periodontal disease progression and wound healing. More specifically, these effects seem to differentiate by gender as well as lifetime period. In addition, the influence of sex hormones can be minimized with good plaque control and with hormone replacement.

CONCLUSION

Despite profound research linking periodontal condition with sex hormones kinetics, more definitive molecular mechanisms and therapy still remain to be determined.

Pregnancy is associated with suppression of the nuclear factor kappaB/IkappaB activation pathway in peripheral blood mononuclear cells

Modulations of maternal immune cell function are critical for successful growth and development of an antigenically distinct fetus. It has been proposed that pregnancy is associated both with suppression of the adaptive immune system and a generalised maternal inflammatory response with changes in immune function resembling those associated with septicemia, and these changes are more exaggerated when pregnancies are complicated with pre-eclampsia. The nuclear factor (NF)-kappaB family of transcription factors play a significant role in immune regulation. We hypothesised therefore that if pregnancy is associated with activation of the maternal immune system, this would be supported by the activation of NF-kappaB and degradation of IkappaBalpha and beta in peripheral blood mononuclear cells (PBMCs). We demonstrate the contrary: NF-kappaB activity is suppressed in PBMCs from pregnant females and more in pre-eclampsia. The inhibition of NF-kappaB activation in pregnancy is not attributed to over-expression of IkappaBalpha or beta. In contrast, levels of IkappaBalpha and beta in cytoplasmic extracts from PBMCs in pregnancy are decreased compared with non-pregnant controls, and IkappaBalpha levels are decreased more so in pre-eclampsia. We have shown that activation of NF-kappaB in PBMCs from patients with septicemia follows the classical pathway. This pathway is differentially regulated in pregnancy. Alterations in NF-kappaB nuclear binding and IkappaBalpha levels were reproducible by culturing PBMCs in pooled pregnant serum. Taken together, these data indicate that pregnancy-specific factors exist to regulate expression of NF-kappaB/IkappaB in a pregnancy-specific manner, and may underlie one mechanism by which the fetus avoids maternal rejection throughout pregnancy.

Shed membrane fragment modulation of CD3-zeta during pregnancy: link with induction of apoptosis

Our objective was to identify shed placental plasma membrane fragments in the maternal circulation and determine whether these fragments are capable of down-regulating CD3-zeta chain expression and inducing apoptosis in T lymphocytes. Sera, isolated from the blood of pregnant women at 26-29 weeks gestation that subsequently had uncomplicated term deliveries, were subjected to high exclusion-limit gel chromatography to isolate placental membrane fragments. The placental origin of the fragments was confirmed by the presence of placental-type alkaline phosphates. These shed membrane fragments were further analyzed for the presence of Fas ligand (FasL) and modulation of CD3-zeta expression on cultured T-lymphocytes (Jurkat cells). The ability of the shed membrane fragments to induce apoptosis was assayed using a cell death ELISA. Components associated with Fas-dependent apoptosis (caspase-3, bcl-2 and bax) were characterized using western immunoblot following exposure to serum-derived membrane fragments. Placental membrane fragments were identified in all pregnancy sera, but not in non-pregnant controls. The 41 kDa FasL was identified in membrane fragment isolates and all samples were capable of inducing apoptosis as determined by the ELISA assay. Exposure of T lymphocytes to isolated membrane fragments suppressed the expression of CD3-zeta. The induction of apoptosis correlated with the induction and activation of caspase 3 and the induction of bax. Placenta-derived membrane fragments are detectable in the maternal circulation. These membrane fragment isolates are capable of inducing FasL-mediated apoptosis and down-regulating CD3-zeta expression, which may contribute to the immune tolerance of the fetus.

Modulation of T-cell CD3-zeta chain expression in early pregnancy

PROBLEM

To assess the modulation of T-cell CD3-zeta chain expression by a factor in the sera of women, prior to egg retrieval and 14 days after an in vitro fertilization (IVF) and to delineate the mechanism of this modulation.

METHOD OF STUDY

In this prospective study, blood samples were obtained from 17 patients during an IVF cycle, prior to human chorionic gonadotropin (hCG), and 14 days after embryo return. Serum was incubated with cultured T-lymphocytes (Jurkat cells) for 96 hr and expression of CD3-zeta chain was evaluated.

RESULTS

Eight patients had a positive serum hCG titer 14 days after retrieval, while nine patients had a negative hCG titer. Serum from pregnant patients significantly suppressed CD3-zeta chain expression as compared with their sample prior to retrieval (85.6 +/- 6.2%), while subjects not becoming pregnant failed to suppress zeta expression (99.1 +/- 0.9%, P < 0.0001).

CONCLUSION

A factor capable of suppressing TcR/CD3-zeta expression can be detected in the sera of pregnant women 14 days after embryo retrieval. Loss of zeta chain was associated with the induction of apoptosis.