Involvement of decidual Valpha14 NKT cells in abortion

Ovariectomy-induced bone loss through inappropriate inflammatory response: an osteoimmunological perspective on postmenopausal osteoporosis

Postmenopausal osteoporosis (PO) is a prevalent condition that significantly impairs the quality of life in elderly women. While traditionally attributed to estrogen deficiency, emerging evidence suggests that immune dysregulation plays a critical role in its pathogenesis. This study investigates the osteoimmunological mechanisms underlying PO using an ovariectomy (Ovx) mouse model. Our findings indicate that Ovx mice exhibit substantial reductions in bone mineral density and bone volume, accompanied by a marked suppression of interleukin-4 (IL-4) and interferon-gamma (IFN-γ) production, particularly from natural killer T (NKT) cells. Lipidomic analysis of bone marrow further revealed an upregulation of omega-6 fatty acids, contributing to an inflammatory microenvironment that promotes excessive osteoclast activation. Notably, administration of the glycolipid OCH restored cytokine production and mitigated bone loss in Ovx mice, suggesting its therapeutic potential. These findings highlight the complex interplay between immune responses and lipid metabolism in PO and propose novel therapeutic strategies aimed at modulating immune function to prevent bone loss. This study offers valuable insights into the osteoimmunological mechanisms of PO and underscores the potential of immunomodulatory approaches for its management.

IFITM1 aggravates ConA-Induced autoimmune hepatitis by promoting NKT cell activation through increased AMPK-Dependent mitochondrial function

Although interferon-induced transmembrane 1 (IFITM1) is known for its crucial role in antiviral immunity, its involvement in autoimmune hepatitis (AIH) remains largely unexplored. In this study, we observed that IFITM1 expression is markedly upregulated in a Concanavalin A (ConA)-induced AIH model, with particularly high and markedly elevated expression in natural killer T (NKT) cells. To further understand the role of IFITM1, we examined the responses of IFITM1-/- mice in a model of ConA-induced liver injury. In comparison to wild-type mice, IFITM1-/- mice exhibited reduced sensitivity in this model, as evidenced by significantly ameliorated necrosis areas, lower serum aminotransferase levels, a reduced number of intrahepatic NKT cells, and decreased expression of inflammatory factors, such as IL-1β, IL-6, IFN-γ and TNF-α. Notably, by using IFITM1-GFP mice and IFITM1-/- mice, we demonstrated that IFITM1 expression in NKT cells is crucial for their proliferation, proinflammatory cytokine production, and cytotoxic functions. Furthermore, analysis of single-cell RNA sequencingdata revealed that IFITM1 is essential for mitochondrial function, which is mediated by the AMP-activated protein kinase (AMPK) pathway. We also validated the importance of IFITM1 for the AMPK pathway and mitochondrial ATP synthesis in vivo. Together, our findings elucidate that IFITM1 could regulate NKT cell activation and survival by promoting mitochondrial function during AIH.

Immune modulation permits tolerance and engraftment in a murine model of late-gestation transplantation

ABSTRACT

In utero hematopoietic cell transplantation is an experimental nonmyeloablative therapy with potential applications in hematologic disorders, including sickle cell disease (SCD). Its clinical utility has been limited due to the early acquisition of T-cell immunity beginning at ∼14 weeks gestation, posing significant technical challenges and excluding treatment fetuses evaluated after the first trimester. Using murine neonatal transplantation at 20 days postcoitum (DPC) as a model for late-gestation transplantation (LGT) in humans, we investigated whether immune modulation with anti-CD3 monoclonal antibody (mAb) could achieve donor-specific tolerance and sustained allogeneic engraftment comparable with that of the early-gestation fetal recipient at 14 DPC. In allogeneic wild-type strain combinations, administration of anti-CD3 mAb with transplantation resulted in transient T-cell depletion followed by central tolerance induction confirmed by donor-specific clonal deletion and skin graft tolerance. Normal immune responses to third-party major histocompatibility complex and viral pathogens were preserved, and graft-versus-host disease did not occur. We further demonstrated the successful application of this approach in the Townes mouse model of SCD. These findings confirm the developing fetal T-cell response as a barrier to LGT and support transient T-cell depletion as a safe and effective immunomodulatory strategy to overcome it.

Progresses in biomarkers for cancer immunotherapy

Currently, checkpoint inhibitor-based immunotherapy has emerged as prevailing treatment modality for diverse cancers. However, immunotherapy as a first-line therapy has not consistently yielded durable responses. Moreover, the risk of immune-related adverse events increases with combination regimens. Thus, the development of predictive biomarkers is needed to optimize individuals benefit, minimize risk of toxicities, and guide combination approaches. The greatest focus has been on tumor programmed cell death-ligand 1 (PD-L1), microsatellite instability (MSI), and tumor mutational burden (TMB). However, there remains a subject of debate due to thresholds variability and significant heterogeneity. Major unmet challenges in immunotherapy are the discovery and validation of predictive biomarkers. Here, we show the status of tumor PD-L1, MSI, TMB, and emerging data on novel biomarker strategies with oncogenic signaling and epigenetic regulation. Considering the exploration of peripheral and intestinal immunity has served as noninvasive alternative in predicting immunotherapy, this review also summarizes current data in systemic immunity, encompassing solute PD-L1 and TMB, circulating tumor DNA and infiltrating lymphocytes, routine emerging inflammatory markers and cytokines, as well as gut microbiota. This review provides up-to-date information on the evolving field of currently available biomarkers in predicting immunotherapy. Future exploration of novel biomarkers is warranted.

NK and T Cell Subtypes in the Endometrium of Patients with Recurrent Pregnancy Loss and Recurrent Implantation Failure: Implications for Pregnancy Success

BACKGROUND

RPL and RIF are challenges in reproductive medicine. The immune system plays a pivotal role in endometrial receptivity, successful implantation, and pregnancy complications. Immunological changes have been associated with RPL and RIF. Understanding immune dysregulation especially in NK and T cell subtypes may lead to better diagnostic concepts and treatments. From July 2019 to August 2020 patients with RPL and RIF underwent a standardized diagnostic procedure including endometrial biopsies. Immune cell analysis was performed using flow cytometry. Patients were contacted in March 2023 and interviewed concerning their pregnancy outcomes following diagnostics.

RESULTS

Out of 68 patients undergoing endometrial biopsies, 49 patients were finally included. Live birth rates were high with 72% in RPL and 86% in RIF. Immune cell analysis revealed that patients with RPL had more cytotoxic CD56dimCD16high cells, while RIF patients had more CD56+ uNK cells. RPL patients with pregnancy complications showed increased NKT cell percentages.

CONCLUSION

Our findings suggest specific immune changes in RPL and RIF patients, offering potential therapeutic targets. Tailored immunotherapy based on endometrial immunophenotyping might be an option, but further research is needed.

New biomarkers exploration and nomogram construction of prognostic and immune-related adverse events of advanced non-small cell lung cancer patients receiving immune checkpoint inhibitors

BACKGROUND

Immune checkpoint inhibitors (ICIs) are regarded as the most promising treatment for advanced-stage non-small cell lung cancer (aNSCLC). Unfortunately, there has been no unified accuracy biomarkers and systematic model specifically identified for prognostic and severe immune-related adverse events (irAEs). Our goal was to discover new biomarkers and develop a publicly accessible method of identifying patients who may maximize benefit from ICIs.

METHODS

This retrospective study enrolled 138 aNSCLC patients receiving ICIs treatment. Progression-free survival (PFS) and severe irAEs were end-points. Data of demographic features, severe irAEs, and peripheral blood inflammatory-nutritional and immune indices before and after 1 or 2 cycles of ICIs were collected. Independent factors were selected by least absolute shrinkage and selection operator (LASSO) combined with multivariate analysis, and incorporated into nomogram construction. Internal validation was performed by applying area under curve (AUC), calibration plots, and decision curve.

RESULTS

Three nomograms with great predictive accuracy and discriminatory power were constructed in this study. Among them, two nomograms based on combined inflammatory-nutritional biomarkers were constructed for PFS (1 year-PFS and 2 year-PFS) and severe irAEs respectively, and one nomogram was constructed for 1 year-PFS based on immune indices. ESCLL nomogram (based on ECOG PS, preSII, changeCAR, changeLYM and postLDH) was constructed to assess PFS (1-, 2-year-AUC = 0.893 [95% CI 0.837-0.950], 0.828 [95% CI 0.721-0.935]). AdNLA nomogram (based on age, change-dNLR, changeLMR and postALI) was constructed to predict the risk of severe irAEs (AUC = 0.762 [95% CI 0.670-0.854]). NKT-B nomogram (based on change-CD3+CD56+CD16+NKT-like cells and change-B cells) was constructed to assess PFS (1-year-AUC = 0.872 [95% CI 0.764-0.965]). Although immune indices could not be modeled for severe irAEs prediction due to limited data, we were the first to find CD3+CD56+CD16+NKT-like cells were not only correlated with PFS but also associated with severe irAEs, which have not been reported in the study of aNSCLC-ICIs. Furthermore, our study also discovered higher change-CD4+/CD8+ ratio was significantly associated with severe irAEs.

CONCLUSIONS

These three new nomograms proceeded from non-invasive and straightforward peripheral blood data may be useful for decisions-making. CD3+CD56+CD16+NKT-like cells were first discovered to be an important biomarker for treatment and severe irAEs, and play a vital role in distinguishing the therapy response and serious toxicity of ICIs.

Inflammation in preterm birth: Novel mechanism of preterm birth associated with innate and acquired immunity

Preterm birth (PB) is the most-frequent complication occurring during pregnancy, with a significant impact on neonatal morbidity and mortality. Chorioamnionitis (CAM), the neutrophil infiltration into chorioamniotic membranes, is a major cause of PB. However, several cases of PB have also been reported without apparent pathogenic infection or CAM. Such cases are now attributed to "sterile inflammation." The concept of sterile inflammation has already attracted attention in various diseases, like cardiovascular diseases, diabetes, and autoimmune diseases; recently been discussed for obstetric complications such as miscarriage, PB, gestational hypertension, and gestational diabetes. Sterile inflammation is induced by alarmins, such as high-mobility group box 1 (HMGB1), interleukins (IL-33 and IL-1α), and S100 proteins, that are released by cellular damage without apparent pathogenic infection. These antigens are recognized by pattern-recognition receptors, expressed mainly on antigen-presenting cells of decidua, placenta, amnion, and myometrium, which consequently trigger inflammation. In reproduction, these alarmins are associated with the development of various pregnancy complications, including PB. In this review, we have summarized the development of PB related to acute CAM, chronic CAM, and sterile inflammation as well as proposed a new mechanism for PB that involves innate immunity, acquired immunity, and sterile inflammation.

Functional prominence of natural killer cells and natural killer T cells in pregnancy and infertility: A comprehensive review and update

During pregnancy, complicated connections are formed between a mother and a fetus. In a successful pregnancy, the maternal-fetal interface is affected by dynamic changes, and the fetus is protected against the mother's immune system. Natural killer (NK) cells are one of the immune system cells in the female reproductive system that play an essential role in the physiology of pregnancy. NK cells not only exist in peripheral blood (PB) but also can exist in the decidua. Studies have suggested multiple roles for these cells, including decidualization, control of trophoblast growth and invasion, embryo acceptance and maintenance by the mother, and facilitation of placental development during pregnancy. Natural killer T (NKT) cells are another group of NK cells that play a crucial role in the maintenance of pregnancy and regulation of the immune system during pregnancy. Studies show that NK and NKT cells are not only effective in maintaining pregnancy but also can be involved in infertility-related diseases. This review focuses on NK and NKT cells biology and provides a detailed description of the functions of these cells in implantation, placentation, and immune tolerance during pregnancy and their role in pregnancy complications.

The Role of Type I and Type II NKT Cells in Materno-Fetal Immunity

NKT cells represent a small but significant immune cell population as being a part of and bridging innate and adaptive immunity. Their ability to exert strong immune responses via cytotoxicity and cytokine secretion makes them significant immune effectors. Since pregnancy requires unconventional maternal immunity with a tolerogenic phenotype, investigation of the possible role of NKT cells in materno-fetal immune tolerance mechanisms is of particular importance. This review aims to summarize and organize the findings of previous studies in this field. Data and information about NKT cells from mice and humans will be presented, focusing on NKT cells characteristics during normal pregnancy in the periphery and at the materno-fetal interface and their possible involvement in female reproductive failure and pregnancy complications with an immunological background.

Phenotypic characterization of NKT-like cells and evaluation of specifically related cytokines for the prediction of unexplained recurrent miscarriage

Problem

Immune system dysregulation is a major cause of unexplained recurrent miscarriage (URM). Women with URM need screening for their pregnancy microenvironment and immune regulators, to prevent spontaneous abortion.

Method of study

In this study we evaluated NKT-like cell subsets in peripheral venous blood of women with URM using flow cytometry. The expression levels of specifically related Th1 cytokines (IFN-γ and IL-2), Th2 cytokine (IL-4), and Th17 cytokines (IL-17), were measured using enzyme-linked immunosorbent assay.

Results

The percentage of CD16+CD56+NKT-like (Double Positive NKT-like; DPNKT-like) cell subset, and the levels of IL-2 and IFN-γ were significantly elevated in blood of non-pregnant and pregnant patients with URM compared with the healthy control groups, and these parameters were significantly increased after pregnancy in the same patients with URM. Based on the prevalence of the candidate immunological factors in patients with URM, the prognostic significance of the NKT-like cell subsets, IFN-γ and IL-2 profiles were evaluated as potential predictors of URM. A cut-off point of 2.55% for DPNKT-like cell subset in the blood and cut-off values of 39.5 and 20.5 pg/ml for the levels of IFN-γ and IL-2, respectively could be used for the prediction of the risk of spontaneous abortion. To the best of our knowledge, this is the first study that described the prognostic significance of the aforementioned immunological parameters before and after pregnancy, and highlighted the correlation of NKT-like cells and the candidate Th1 cytokines with pregnancy loss in women with URM.

Conclusions

DPNKT-like cells, IFN-γ and IL-2 patient profiles could be used as markers to predict the risk of miscarriage in patients with URM.

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Disturbance in the immune system's regulators is an essential factor for recurrent miscarriage.

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There is an urgent need for women who have suffered pregnancy loss to identify specific immune regulators that underline recurrent miscarriage, to prevent and control miscarriage.

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CD16+CD56+NKT-like cells, Interferon-γ and Interleukin-2 patient profile could be utilized as biomarkers to predict risk of miscarriage in women who have suffered spontaneous miscarriage.

Tumor necrosis factor inhibitors as therapeutic agents for recurrent spontaneous abortion (Review)

Recurrent spontaneous abortion (RSA) is a troublesome pregnancy disorder that manifests as sequential early pregnancy losses; its causes are diverse and complex. Among the known possible causes of RSA, the development of an immune disorder in response to the embryo appears to be the most pronounced. The imbalance between immune rejection and immune tolerance contributes to pregnancy loss in females with RSA, wherein the abnormal ratio of T helper (Th)1 cell‑related cytokines [predominantly tumor necrosis factor (TNF)‑α] and Th2 cell‑related cytokines is a strong risk factor for RSA. TNF‑α is a pro‑inflammatory cytokine and TNF inhibitors have been effective in the treatment of various autoimmune diseases, such as ankylosing spondylitis, and inflammatory diseases, such as ulcerative colitis. Based on their immunomodulatory properties, TNF inhibitors have been used in the treatment of RSA to reduce the immune rejection rate and improvement in pregnancy outcomes has been observed in females suffering from RSA who were treated with TNF inhibitors. The aim of the present review was to interpret the involvement of TNF‑α in the immunological disorder underlying RSA and summarize the clinical outcomes of TNF inhibitor treatment in patients with RSA.

Transcriptome and Function of Novel Immunosuppressive Autoreactive Invariant Natural Killer T Cells That Are Absent in Progressive Multiple Sclerosis

BACKGROUND AND OBJECTIVE

The aim of this study was to determine whether natural killer T (NKT) cells, including invariant (i) NKT cells, have clinical value in preventing the progression of multiple sclerosis (MS) by examining the mechanisms by which a distinct self-peptide induces a novel, protective invariant natural killer T cell (iNKT cell) subset.

METHODS

We performed a transcriptomic and functional analysis of iNKT cells that were reactive to a human collagen type II self-peptide, hCII707-721, measuring differentially induced genes, cytokines, and suppressive capacity.

RESULTS

We report the first transcriptomic profile of human conventional vs novel hCII707-721-reactive iNKT cells. We determined that hCII707-721 induces protective iNKT cells that are found in the blood of healthy individuals but not progressive patients with MS (PMS). By transcriptomic analysis, we observed that hCII707-721 promotes their development and proliferation, favoring the splicing of full-length AKT serine/threonine kinase 1 (AKT1) and effector function of this unique lineage by upregulating tumor necrosis factor (TNF)-related genes. Furthermore, hCII707-721-reactive iNKT cells did not upregulate interferon (IFN)-γ, interleukin (IL)-4, IL-10, IL-13, or IL-17 by RNA-seq or at the protein level, unlike the response to the glycolipid alpha-galactosylceramide. hCII707-721-reactive iNKT cells increased TNFα only at the protein level and suppressed autologous-activated T cells through FAS-FAS ligand (FAS-FASL) and TNFα-TNF receptor I signaling but not TNF receptor II.

DISCUSSION

Based on their immunomodulatory properties, NKT cells have a potential value in the treatment of autoimmune diseases, such as MS. These significant findings suggest that endogenous peptide ligands can be used to expand iNKT cells, without causing a cytokine storm, constituting a potential immunotherapy for autoimmune conditions, including PMS.

Changes of dendritic cell and natural killer cell on the cord blood with idiopathic fetal growth restriction

OBJECTIVE

To investigate the characteristics of dendritic cells (DC) and natural killer cells (NK) in umbilical cord blood of pregnant patients diagnosed with idiopathic fetal growth restriction (IFGR).

METHODS

A prospective study cohort of IFGR patients was established who were in the third trimester (28-36 weeks), with a healthy, pregnant woman cohort selected as controls. Umbilical cord blood was collected.

RESULTS

The study included 50 pregnant women in the IFGR group and 50 pregnant women in the healthy, control group. The incidence of SGA in the IFGR group was 52.0%, and the incidence of preterm birth was 18.0%. The incidence of neonatal complications in neonates with live birth in the IFGR group was 12.0%. The birth weight, body length and placental weight of the newborns in the IFGR group were significantly lower than those in the control group (p < .05). Flow cytometry revealed no significant difference in the proportion or maturity of DC in umbilical cord blood between IFGR group and control group (p > .05). The proportion of NK cells in umbilical cord blood of IFGR group was significantly higher than that of normal control group. The proportion of CD56dimCD16+ NK cells was also significantly higher than that of the normal control group (p < .05), but the expression of NK cell surface killing activator receptor NKG2D and inhibitory receptor NKG2A was not statistically significant (p > .05).

CONCLUSION

The number and proportion of DC cells in cord blood may not be the key factors affecting the outcomes observed during FGR pregnancies. However, we found the proportion of NK cells in cord blood to be significantly increased, as well as the ratio of CD56dimCD16 + NK to CD56highCD16-NK to be imbalanced, which may be one of the pathogenesis of the pathological pregnancy leading to IFGR.

The interaction between iNKT cells and B cells

Invariant natural killer T cells (iNKTs) bridge the innate immunity with the adaptive immunity and their interaction with B cells has been extensively studied. Here, we give a complete overview of these two cells, from their mechanism of interaction to clinical prospects and existing problems. In our introduction, we describe the relationship between iNKTs and B cells and explore the current research hotspots and future directions. We begin with how B cells interact and benefit from the innate and adaptive help of iNKTs. Next, we describe the multiple roles of these cells in infections, autoimmunity, and cancers. Lastly, we look into the potential immunotherapies that can be based on iNKTs and the possible treatments for infectious, autoimmune, and other diseases.

Gestational Diabetes Mellitus and Maternal Immune Dysregulation: What We Know So Far

Gestational diabetes mellitus (GDM) is an obstetric complication that affects approximately 5-10% of all pregnancies worldwide. GDM is defined as any degree of glucose intolerance with onset or first recognition during pregnancy, and is characterized by exaggerated insulin resistance, a condition which is already pronounced in healthy pregnancies. Maternal hyperglycaemia ensues, instigating a 'glucose stress' response and concurrent systemic inflammation. Previous findings have proposed that both placental and visceral adipose tissue play a part in instigating and mediating this low-grade inflammatory response which involves altered infiltration, differentiation and activation of maternal innate and adaptive immune cells. The resulting maternal immune dysregulation is responsible for exacerbation of the condition and a further reduction in maternal insulin sensitivity. GDM pathology results in maternal and foetal adverse outcomes such as increased susceptibility to diabetes mellitus development and foetal neurological conditions. A clearer understanding of how these pathways originate and evolve will improve therapeutic targeting. In this review, we will explore the existing findings describing maternal immunological adaption in GDM in an attempt to highlight our current understanding of GDM-mediated immune dysregulation and identify areas where further research is required.

Inappropriate activation of invariant natural killer T cells and antigen-presenting cells with the elevation of HMGB1 in preterm births without acute chorioamnionitis

PROBLEM

Acute chorioamnionitis (aCAM) associated with microbial infection is a primary cause of preterm birth (PB). However, recent studies have demonstrated that innate immunity and sterile inflammation are causes of PB in the absence of aCAM. Therefore, we analyzed immune cells in the decidua of early to moderate PB without aCAM.

METHOD OF STUDY

Deciduas were obtained from patients with PB at a gestational age of 24⁺⁰ to 33⁺⁶  weeks without aCAM in pathological diagnosis. The patients were divided into two groups as follows: patients with labor and/or rupture of membrane (ROM) (no aCAM with labor and/or ROM: nCAM-w-LR), and patients without labor and/or ROM (no aCAM without labor and/or ROM: nCAM-w/o-LR). The immune cells and high mobility group box 1 (HMGB1) levels in the decidua were analyzed using flow cytometry. Co-culture of CD56⁺ cells with dendritic cells (DCs) and macrophages obtained from the decidua was also performed in the presence of HMGB1.

RESULTS

The nCAM-w-LR group demonstrated an accumulation of iNKT cells, and increased expression of HMGB1, TLR4, receptors for advanced glycation end products, and CD1d on DCs and macrophages. HMGB1 facilitated the proliferation of iNKT cells co-cultured with DCs and macrophages, which was found to be inhibited by heparin.

CONCLUSIONS

Inappropriate activation of innate immune cells and increased HMGB1 expression may represent parturition signs in human pregnancy. Therefore, control of these cells and HMGB1 antigenicity may be represent a potential therapeutic target for the prevention of PB.

Harmful and beneficial effects of inflammatory response on reproduction: sterile and pathogen-associated inflammation

In reproduction, inflammatory processes play important roles in the development of many pregnancy complications such as preterm labor/birth, recurrent pregnancy loss, recurrent implantation failure, and preeclampsia. Inflammation can be initiated by both microbial and non-microbial causes. Bacterial infection in the feto-maternal interface and uterus can provoke preterm labor/birth, miscarriage, and chronic endometritis. By contrast, inflammation without infection, or 'sterile inflammation,' can also lead to many kinds of complications, such as preterm labor/birth, miscarriage, or preeclampsia. Aberrant inflammation is facilitated by immune cells such as macrophages, dendritic cells, natural killer cells, and invariant natural killer T cells. In addition, cytokines, chemokines, and several kinds of inflammatory mediators are involved. On the other hand, appropriate inflammation is required for a successful offspring during the progression of the entire pregnancy. Herein, we discuss the relation between pregnancy and inflammation with immunological alterations. Understanding the role of inflammation in complications during pregnancy may establish new perspectives of the progress of normal pregnancy as well as treatments during pregnancy complications.

MAIT Cells at the Fetal-Maternal Interface During Pregnancy

One of the main functions of the human placenta is to provide a barrier between the fetal and maternal blood circulations, where gas exchange and transfer of nutrients to the developing fetus take place. Despite being a barrier, there is a multitude of crosstalk between maternal immune cells and fetally derived semi-allogeneic trophoblast cells. Therefore, the maternal immune system has a difficult task to both tolerate the fetus but at the same time also defend the mother and the fetus from infections. Mucosal-associated invariant T (MAIT) cells are an increasingly recognized subset of T cells with anti-microbial functions that get activated in the context of non-polymorphic MR1 molecules, but also in response to inflammation. MAIT cells accumulate at term pregnancy in the maternal blood that flows into the intervillous space inside the placenta. Chemotactic factors produced by the placenta may be involved in recruiting and retaining particular immune cell subsets, including MAIT cells. In this Mini-Review, we describe what is known about MAIT cells during pregnancy and discuss the potential biological functions of MAIT cells at the fetal-maternal interface. Since MAIT cells have anti-microbial and tissue-repairing functions, but lack alloantigen reactivity, they could play an important role in protecting the fetus from bacterial infections and maintaining tissue homeostasis without risks of mediating harmful responses toward semi-allogenic fetal tissues.

Functional significance of lymphocytes in pregnancy and lymphocyte immunotherapy in infertility: A comprehensive review and update

During pregnancy, the fetal-maternal interface underlies several dynamic alterations to permit the fetus to be cultivated and developed in the uterus, in spite of being identifies by the maternal immune system. A large variety of decidual leukocyte populations, including natural killer cells, NKT cells, innate lymphoid cells, dendritic cells, B cells, T cells, subpopulations of helper T cells play a vital role in controlling the trophoblast invasion, angiogenesis as well as vascular remodeling. In contrast, several regulatory immunosuppressive mechanisms, including regulatory T cells, regulatory B cells, several cytokines and mediators are involved in maintain the homeostasis of immune system in the fetal-maternal interface. Nonetheless, aberrant alterations in the balance of immune inflammatory or immunosuppressive arms have been associated with various pregnancy losses and infertilities. As a result, numerous strategies have been developed to revers dysregulated balance of immune players to increase the chance of successful pregnancy. Lymphocyte immunotherapy has been developed through utilization of peripheral white blood cells of the husband or others and administered into the mother to confer an immune tolerance for embryo's antigens. However, the results have not always been promising, implying to further investigations to improve the approach. This review attempts to clarify the involvement of lymphocytes in contributing to the pregnancy outcome and the potential of lymphocyte immunotherapy in treatment of infertilities with dysregulated immune system basis.

Th2-Immune Polarizing and Anti-Inflammatory Properties of Insulin Are Not Effective in Type 2 Diabetic Pregnancy

BACKGROUND

The implication of the immune system in the physiopathology of pregnancy complicated by diabetes has been reported. Here, we investigated the effects of insulin treatment on the frequencies of immune cell subpopulations as well as T cell-derived cytokines in type 2 diabetic (T2D) pregnancy compared to gestational diabetes mellitus (GDM).

METHODS

Fifteen (15) women with GDM, twenty (20) insulin-treated T2D pregnant women, and twenty-five (25) pregnant controls were selected. Immune cell subpopulation frequencies were determined in blood using flow cytometry. The proliferative capacity of T cells was performed, and serum and cell culture supernatant cytokine levels were also quantified.

RESULTS

The frequencies of total CD3+ and CD4+ T cells and nonclassical monocytes significantly increased in insulin-treated T2D pregnant women compared to pregnant controls. The proportions of CD4+ T cells as well as B cells were significantly higher in women with GDM than in pregnant controls. GDM was associated with high frequencies of total CD3+ and CD4+ T cells and B cell expansion, suggesting a concomitant activation of cellular and humoral immunity. Concomitantly, Th1/Th2 ratio, determined as IFN-γ/IL-4, was shifted towards Th1 phenotype in women with GDM and insulin-treated T2D pregnant women. Besides, isolated T cells elicited similar proliferative capacity in the three groups of women. Insulin-treated T2D pregnant women and women with GDM exhibited a low serum IL-10 level, without any change in the number of Treg cells.

CONCLUSION

Our study showed that, despite insulin treatment, pregnant women with T2D displayed a proinflammatory status consistent with high proportions of CD3+ and CD4+ T cells, upregulation of Th1 cytokines, and low IL-10 production, suggesting a reduced immune-suppressive activity of regulatory T cells. However, GDM, although associated with proinflammatory status, has shown increased humoral immunity consistent with high proportion of CD19+ B cells. Thus, the lack of response to insulin in diabetes during pregnancy and clinical implications of these immunological parameters deserves further investigations.

Immunobiology of Acute Chorioamnionitis

Acute chorioamnionitis is characterized by neutrophilic infiltration and inflammation at the maternal fetal interface. It is a relatively common complication of pregnancy and can have devastating consequences including preterm labor, maternal infections, fetal infection/inflammation, fetal lung, brain, and gastrointestinal tract injury. In this review, we will discuss current understanding of the pathogenesis, immunobiology, and mechanisms of this condition. Most commonly, acute chorioamnionitis is a result of ascending infection with relatively low-virulence organisms such as the Ureaplasma species. Furthermore, recent vaginal microbiome studies suggest that there is a link between vaginal dysbiosis, vaginal inflammation, and ascending infection. Although less common, microorganisms invading the maternal-fetal interface via hematogenous route (e.g., Zika virus, Cytomegalovirus, and Listeria) can cause placental villitis and severe fetal inflammation and injury. We will provide an overview of the knowledge gleaned from different animal models of acute chorioamnionitis and the role of different immune cells in different maternal-fetal compartments. Lastly, we will discuss how infectious agents can break the maternal tolerance of fetal allograft during pregnancy and highlight the novel future therapeutic approaches.

Chronic Gestational Inflammation: Transfer of Maternal Adaptation over Two Generations of Progeny

Changes in the in utero environment result in generational transfer of maladapted physiology in the context of conditions such as stress, obesity, and anxiety. Given the significant contribution of noncommunicable diseases-which are characterised by chronic inflammation-to population mortality, the potential for chronic maternal inflammation mediating foetal programming is a growing concern. The extent of generational transfer in terms of immune functionality and leukocyte glucocorticoid sensitivity was investigated over two generations of offspring (F1 and F2) in a model of chronic LPS-induced maternal inflammation in C57/BL/6 mice. Maternal inflammation resulted in glucocorticoid hypersensitivity (increased glucocorticoid receptor expression levels) in the majority of leukocyte subpopulations in both F1 and F2 offspring. Furthermore, splenocytes stimulated with LPS in vitro exhibited exacerbated inflammatory cytokine responses, which were even more prominent in F2 than F1; this effect could be ascribed to NLRP3 inflammasome hyperactivity in F1 but not F2. Current data illustrates that parental chronic inflammation may mediate the inflammatory profile in offspring, potentially propagating a maladapted proinflammatory phenotype in subsequent generations.

Recommendations regarding the genetic and immunological study of reproductive dysfunction

In this article several members of diverse scientific associations and reproduction experts from Spain have updated different genetic and immunological procedure recommendations in couples affected by reproductive dysfunction with the goal of providing a set of useful guidelines for the clinic. The laboratory test has been considered as highly recommendable for making clinical decisions when the result of the diagnostic test is relevant, moderately recommendable when the results are of limited evidence because they are inconsistent, and low when the benefit of the test is uncertain. It is expected that these recommendations will provide some useful guidelines for the diagnosis, prognosis and treatment of couples presenting reproductive dysfunction.

Tokishakuyakusan, a traditional Japanese medicine (Kampo) mitigates iNKT cell-mediated pregnancy loss in mice

OBJECTIVE

Tokishakuyakusan (TSS) is a traditional herbal medicine that has been used empirically to prevent recurrent pregnancy loss. Its mode of action remains unclear. With their potent capacity to produce cytokines, invariant natural killer (iNKT) cells are involved in the control of fetomaternal immunity in early gestation. This study aimed to clarify the effect of TSS on iNKT cell activities in a well-studied murine miscarriage model.

METHODS

Pregnant mice were fed 1% TSS-containing or control diet from the day of vaginal plug formation. Alpha-galactosylceramide (AGC) was administered intraperitoneally to the pregnant mice at day 9.5 postcoitus (pc) to stimulate iNKT cells. Peripheral cytokine levels were evaluated using cytokine arrays. The percentage of iNKT cells among splenocytes was examined by flow cytometric analysis. The incidence of pregnancy loss was assessed at day 12.5 pc.

RESULTS

The ratio of fetal resorptions to total conceptuses was significantly higher in the group exposed to TSS (34%) than in controls (78%). A rapid and robust surge in inflammatory cytokines, including IFN-γ and TNF-α, was detected in the peripheral blood of control animals 2 hours after AGC administration. This peripheral cytokine induction was significantly attenuated in the TSS-fed group compared with the control. The percentage of iNKT cells among total splenocytes was lower in the TSS-fed group than in controls.

CONCLUSION

The findings in this study suggest that the inhibitory effects of TSS on pregnancy loss may involve immune modulation of iNKT cells during early pregnancy.

Immune cell and transcriptomic analysis of the human decidua in term and preterm parturition

STUDY QUESTION

Is labour, both at term and preterm, associated with alterations in decidual lymphocyte densities and widespread changes to the decidual transcriptome?

SUMMARY ANSWER

The onset of parturition, both at term and preterm, is associated with widespread gene expression changes in the decidua, many of which are related to inflammatory signalling, but is not associated with changes in the number of any of the decidual lymphocyte populations examined.

WHAT IS KNOWN ALREADY

Given its location, directly at the maternal–foetal interface, the decidua is likely to play a pivotal role in the onset of parturition, however, the molecular events occurring in the decidua in association with the onset of labour, both at term and preterm, remain relatively poorly defined. Using flow cytometry and microarray analysis, the present study aimed to investigate changes to the immune cell milieu of the decidua in association with the onset of parturition and define the decidual gene signature associated with term and preterm labour (PTL).

STUDY DESIGN, SIZE, DURATION

This study used decidual samples collected from 36 women across four clinical groups: term (38–42 weeks of gestation) not in labour, TNL; term in labour, TL; preterm (<35 weeks of gestation)not in labour, PTNL; and preterm in labour, PTL.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Decidual lymphocytes were isolated from fresh decidual tissue collected from women in each of our four patient groups and stained with a panel of antibodies (CD45, CD3, CD19, CD56, CD4, CD8 and TCRVα24-Jα18) to investigate lymphocyte populations present in the decidua (TNL, n = 8; TL, n = 7; PTNL, n = 5; PTL, n = 5). RNA was extracted from decidual tissue and subjected to Illumina HT-12v4.0 BeadChip expression microarrays (TNL, n = 11; TL, n = 8; PTNL, n = 7; PTL, n = 10). Quantitative real-time PCR (qRT-PCR) was used to validate the microarray results.

MAIN RESULTS AND THE ROLE OF CHANCE

The relative proportions of decidual lymphocytes (T cells, NK cells, B cells and invariant natural killer (iNKT) cells) were unaffected by either gestation or labour status. However, we found elevated expression of the non-classical MHC-protein, CD1D, in PTL decidua samples (P < 0.05), suggesting the potential for increased activation of decidual invariant NKT (iNKT) cells in PTL. Both term and PTL were associated with widespread gene expression changes, particularly related to inflammatory signalling. Up-regulation of candidate genes in TL (IL-6, PTGS2, ATF3, IER3 and TNFAIP3) and PTL (CXCL8, MARCO, LILRA3 and PLAU) were confirmed by qRT-PCR analysis.

LARGE SCALE DATA

Microarray data are available at www.ebi.ac.uk/arrayexpress under accession number E-MTAB-5353.

LIMITATIONS REASONS FOR CAUTION

Whilst no changes in lymphocyte number were observed across our patient samples, we did not investigate the activation state of any of the immune cell sub-populations examined, therefore, it is possible that the function of these cells may be altered in association with labour onset. Additionally, the results of our transcriptomic analyses are descriptive and at this stage, we cannot prove direct causal link with the up-regulation of any of the genes examined and the onset of either term or PTL.

WIDER IMPLICATIONS OF THE FINDINGS

Our findings demonstrate that the onset of parturition is associated with widespread changes to the decidual transcriptome, and there are distinct gene expression changes associated with term and PTL. We confirmed that an inflammatory signature is present within the decidua, and we also report the up-regulation of several genes involved in regulating the inflammatory response. The identification of genes involved in regulating the inflammatory response may provide novel molecular targets for the development of new, more effective therapies for the prevention of preterm birth (PTB). Such targets are urgently required.

STUDY FUNDING AND COMPETING INTEREST(S)

This work was supported by Medical Research Council (grant number MR/L002657/1) and Tommy's, the baby charity. Jane Norman has had research grants from the charity Tommy's and from the National Institute for Health Research on PTB during the lifetime of this project. Jane Norman also sits on a data monitoring committee for GSK for a study on PTB prevention and her institution receives financial recompense for this. The other authors do not have any conflicts of interest to declare.

Activation of Invariant Natural Killer T Cells Redirects the Inflammatory Response in Neonatal Sepsis

Sepsis is the third leading cause of death in the neonatal population, due to susceptibility to infection conferred by immaturity of both the innate and adaptive components of the immune system. Invariant natural killer T (iNKT) cells are specialized adaptive immune cells that possess important innate-like characteristics and have not yet been well-studied in septic neonates. We hypothesized that iNKT cells would play an important role in mediating the neonatal immune response to sepsis. To study this, we subjected 5- to 7-day-old neonatal C57BL/6 mice to sepsis by intraperitoneal (i.p.) cecal slurry (CS) injection. Thirty hours prior to or immediately following sepsis induction, pups received i.p. injection of the iNKT stimulator KRN7000 (KRN, 0.2 µg/g) or vehicle. Ten hours after CS injection, blood and tissues were collected for various analyses. Thirty-hour pretreatment with KRN resulted in better outcomes in inflammation, lung injury, and survival, while immediate treatment with KRN resulted in worse outcomes compared to vehicle treatment. We further analyzed the activation status of neonatal iNKT cells for 30 h after KRN administration, and showed a peak in frequency of CD69 expression on iNKT cells and serum IFN-γ levels at 5 and 10 h, respectively. We then used CD1d knockout neonatal mice to demonstrate that KRN acts through the major histocompatibility complex-like molecule CD1d to improve outcomes in neonatal sepsis. Finally, we identified that KRN pretreatment exerts its protective effect by increasing systemic levels of TGF-β1. These findings support the importance of iNKT cells for prophylactic immunomodulation in neonates susceptible to sepsis.

The Influence of Invariant Natural Killer T Cells on Humoral Immunity to T-Dependent and -Independent Antigens

Vaccination with CD1d-binding glycolipid adjuvants and co-administered protein, lipid, and carbohydrate antigens leads to invariant natural killer T (NKT) cell-dependent enhancement of protective B cell responses. NKT cell activation boosts the establishment of protein antigen-specific B cell memory and long-lived plasma cell (LLPC) compartments. NKT cells may exert a similar effect on some carbohydrate-specific B cells, but not lipid-specific B cells. The mechanisms of action of NKT cells on B cell responsiveness and subsequent differentiation into memory B cells and LLPC is dependent on CD1d expression by dendritic cells and B cells that can co-present glycolipids on CD1d and antigen-derived peptide on MHCII. CD1d/glycolipid-activated NKT cells are able to provide help to B cells in a manner dependent on cognate and non-cognate interactions. More recently, a glycolipid-expanded subset of IL-21-secreting NKT cells known as NKT follicular helper cells has been suggested to be a driver of NKT-enhanced humoral immunity. This review summarizes established and recent findings on how NKT cells impact humoral immunity and suggests possible areas of investigation that may allow the incorporation of NKT-activating agents into vaccine adjuvant platforms.

Impact of Th1/Th2 cytokine polarity induced by invariant NKT cells on the incidence of pregnancy loss in mice

OBJECTIVE

This study aimed to investigate the association of Th1/Th2 polarity induced by CD1d-restricted invariant natural killer T (iNKT) cells with pregnancy outcome.

METHODS

Two types of iNKT cell stimulants with different cytokine induction properties, alpha-galactosylceramide (AGC; Th1-biased inducer), and a sphingosine-truncated derivative of AGC (OCH; Th2-biased inducer) were administered to pregnant mice on day 9.5 post-coitus (pc), and the incidence of pregnancy loss was evaluated. Serum Th1/Th2 cytokine levels after the iNKT cell stimulations were assessed. Cytokine production from cultured splenocytes following iNKT cell activation was analyzed.

RESULTS

No fetal loss was observed after OCH administration, in clear contrast with the high frequency of pregnancy loss after AGC exposure. High serum levels of IL-4 and IL-10 were detected upon OCH administration, whereas a temporary surge of IFN-γ was observed after AGC administration. In splenocyte cultures, increases in IL-4 and IL-10 were noted after OCH administration, whereas IL-12 production was enhanced by AGC. Additionally, AGC-induced pregnancy loss was inhibited by IL-4 administration.

CONCLUSION

The resistance of mouse pregnancy to iNKT cell stimulation by OCH and the prevention of AGC-induced fetal loss by IL-4 were demonstrated. In pregnancy, the regulation of Th1/Th2 polarity by iNKT cells is a key to healthy fetal growth.

Regulatory T cells decrease invariant natural killer T cell-mediated pregnancy loss in mice

Pregnancy loss is the commonest complication of pregnancy. The causes of pregnancy loss are poorly understood. It has been reported that stimulation of invariant natural killer T (iNKT) cells using α-galactosylceramide (αGC) induces pregnancy loss in mice. Here we investigated the mechanisms, especially the role of regulatory T (Treg) cells, in iNKT cell-mediated pregnancy loss. We found that injection of αGC rapidly induced fetal resorption, activated decidual iNKT cells, decreased the percentage of decidual Treg cells and their interleukin (IL)-10 and transforming growth factor (TGF)-β production, and upregulated the levels of interferon (IFN)-γ, tumor necrosis factor-α, IL-4, and IL-10 in serum. Adoptive transfer of iNKT cells from wild-type (WT) and IL-4^-/- mice but not IFN-γ^-/- mice into αGC-treated iNKT cell-deficient Jα18^-/- mice restored αGC-induced pregnancy loss. Adoptive transfer of Treg cells downregulated α-GC-induced pregnancy loss in WT mice. Finally, co-culture with αGC-stimulated decidual iNKT cells decreased the production of IL-10 and TGF-β in decidual Treg cells and inhibited their suppressive activity. These findings suggest that activation of iNKT cells induces pregnancy loss in mice in an IFN-γ-dependent manner. In addition, inhibition of the function of decidual Treg cells has an important role in iNKT cell-mediated pregnancy loss.

Immune regulatory network in successful pregnancy and reproductive failures

Maternal immune system must tolerate semiallogenic fetus to establish and maintain a successful pregnancy. Despite the existence of several strategies of trophoblast to avoid recognition by maternal leukocytes, maternal immune system may react against paternal alloantigenes. Leukocytes are important components in decidua. Not only T helper (Th)1/Th2 balance, but also regulatory T (Treg) cells play an important role in pregnancy. Although the frequency of Tregs is elevated during normal pregnancies, their frequency and function are reduced in reproductive defects such as recurrent miscarriage and preeclampsia. Tregs are not the sole population of suppressive cells in the decidua. It has recently been shown that regulatory B10 (Breg) cells participate in pregnancy through secretion of IL-10 cytokine. Myeloid derived suppressor cells (MDSCs) are immature developing precursors of innate myeloid cells that are increased in pregnant women, implying their possible function in pregnancy. Natural killer T (NKT) cells are also detected in mouse and human decidua. They can also affect the fetomaternal tolerance. In this review, we will discuss on the role of different immune regulatory cells including Treg, γd T cell, Breg, MDSC, and NKT cells in pregnancy outcome.

α-Galactosylceramide-activated murine NK1.1(+) invariant-NKT cells in the myometrium induce miscarriages in mice

Innate immunity, which is unable to discriminate self from allo‐antigens, is thought to be important players in the induction of miscarriages. Here, we show that the administration of IL‐12 to syngeneic‐mated C57BL/6 mice on gestation day 7.5 (Gd 7.5), drives significant miscarriages in pregnant females. Furthermore, the administration on Gd 7.5 of α‐galactosylceramide (α‐GalCer), which is known to activate invariant natural killer T (iNKT) cells, induced miscarriages in both syngeneic‐mated C57BL/6 mice and allogeneic‐mated mice (C57BL/6 (♀) × BALB/c (♂)). Surprisingly, the percentages of both DEC‐205⁺ DCs and CD1d‐restricted NK1.1⁺ iNKT cells were higher in the myometrium of pregnant mice treated i.p. with α‐GalCer than in the decidua. IL‐12 secreted from α‐GalCer‐activated DEC‐205⁺ DCs stimulated the secretion of cytokines, including IL‐2, IL‐4, IFN‐γ, TNF‐α, perforin, and granzyme B, from the NK1.1⁺ iNKT cells in the myometrium, leading to fetal loss in pregnant mice. Finally, the i.p. administration of IL‐12 and/or α‐GalCer in iNKT‐deficient Jα18(‐/‐) (Jα18 KO) mice did not induce miscarriages. This study provides a new perspective on the importance of the myometrium, rather than the decidua, in regulating pregnancy and a mechanism of miscarriage mediated by activated DEC‐205⁺ DCs and NK1.1⁺ iNKT cells in the myometrium of pregnant mice.

Invariant NKT Cell Activation Induces Late Preterm Birth That Is Attenuated by Rosiglitazone

Preterm birth (PTB) is the leading cause of neonatal morbidity and mortality worldwide. Although intra-amniotic infection is a recognized cause of spontaneous preterm labor, the noninfection-related etiologies are poorly understood. In this article, we demonstrated that the expansion of activated CD1d-restricted invariant NKT (iNKT) cells in the third trimester by administration of α-galactosylceramide (α-GalCer) induced late PTB and neonatal mortality. In vivo imaging revealed that fetuses from mice that underwent α-GalCer-induced late PTB had bradycardia and died shortly after delivery. Yet, administration of α-GalCer in the second trimester did not cause pregnancy loss. Peroxisome proliferator-activated receptor (PPAR)γ activation, through rosiglitazone treatment, reduced the rate of α-GalCer-induced late PTB and improved neonatal survival. Administration of α-GalCer in the third trimester suppressed PPARγ activation, as shown by the downregulation of Fabp4 and Fatp4 in myometrial and decidual tissues, respectively; this suppression was rescued by rosiglitazone treatment. Administration of α-GalCer in the third trimester induced an increase in the activation of conventional CD4(+) T cells in myometrial tissues and the infiltration of activated macrophages, neutrophils, and mature dendritic cells to myometrial and/or decidual tissues. All of these effects were blunted after rosiglitazone treatment. Administration of α-GalCer also upregulated the expression of inflammatory genes at the maternal-fetal interface and systemically, and rosiglitazone treatment partially attenuated these responses. Finally, an increased infiltration of activated iNKT-like cells in human decidual tissues is associated with noninfection-related preterm labor/birth. Collectively, these results demonstrate that iNKT cell activation in vivo leads to late PTB by initiating innate and adaptive immune responses and suggest that the PPARγ pathway has potential as a target for prevention of this syndrome.

Activation of decidual invariant natural killer T cells promotes lipopolysaccharide-induced preterm birth

Invariant natural killer T (iNKT) cells are crucial for host defense against a variety of microbial pathogens, but the underlying mechanisms of iNKT cells activation by microbes are not fully explained. In this study, we investigated the molecular mechanisms of iNKT cell activation in lipopolysaccharide (LPS)-stimulated preterm birth using an adoptive transfer system and diverse neutralizing antibodies (Abs) and inhibitors. We found that adoptive transfer of decidual iNKT cells to LPS-stimulated iNKT cell deficient Jα18(-/-) mice that lack invariant Vα14Jα281T cell receptor (TCR) expression significantly decreased the time to delivery and increased the percentage of decidual iNKT cells. Neutralizing Abs against Toll-like receptor 4 (TLR-4), CD1d, interleukin (IL)-12 and IL-18, and inhibitors blocking the activation of nuclear factor κB (NF-κB), mitogen-activated protein kinase (MAPK) p38 and extracellular signal-regulated kinase (ERK) significantly reduced in vivo percentages of decidual iNKT cells, their intracellular interferon (IFN)-γ production and surface CD69 expression. In vitro, in the presence of the same Abs and inhibitors used as in vivo, decidual iNKT cells co-cultured with LPS-pulsed dendritic cells (DCs) showed significantly decreased extracellular and intracellular IFN-γ secretion and surface CD69 expression. Our data demonstrate that the activation of decidual iNKT cells plays an important role in inflammation-induced preterm birth. Activation of decidual iNKT cells also requires TLR4-mediated NF-κB, MAPK p38 and ERK pathways, the proinflammatory cytokines IL-12 and IL-18, and endogenous glycolipid antigens presented by CD1d.

Leukocyte population dynamics and detection of IL-9 as a major cytokine at the mouse fetal-maternal interface

Despite much interest in the mechanisms regulating fetal-maternal interactions, information on leukocyte populations and major cytokines present in uterus and placenta remains fragmentary. This report presents a detailed and quantitative study of leukocyte populations at the mouse fetal-maternal interface, including a comparison between pregnancies from syngeneic and allogeneic crosses. Our results provide evidence for drastic differences not only in the composition of leukocyte populations in the uterus during pregnancy, but also between uterine and placental tissues. Interestingly, we have observed a significant decrease in the number of myeloid Gr1+ cells including monocytes, and myeloid CD11c+ cells including DCs in placenta from an allogeneic pregnancy. In addition, we have compared the expression levels of a panel of cytokines in non-pregnant (NP) or pregnant mouse uterus, in placenta, or in their isolated resident leukocytes. Qualitative and quantitative differences have emerged between NP, pregnant uterus and placenta. Unexpectedly, IL-9 was the major cytokine in NP uterus, and was maintained at high levels during pregnancy both in uterus and placenta. Moreover, we have found that pregnancy is associated with an increase in uterine IL-1a and a significant decrease in uterine G-CSF and GM-CSF. Comparing allogeneic versus syngeneic pregnancy, less allogeneic placental pro-inflammatory cytokines CCL2 (MCP-1), CXCL10 (IP-10) and more IL1-α in whole uterus was reproducibly observed. To our knowledge, this is the first report showing a detailed overview of the leukocyte and cytokine repertoire in the uterus of virgin females and at the fetal-maternal interface, including a comparison between syngeneic and allogeneic pregnancy. This is also the first evidence for the presence of IL-9 in NP uterus and at the maternal-fetal interface, suggesting a major role in the regulation of local inflammatory or immune responses potentially detrimental to the conceptus.

CD1d-restricted NKT cells modulate placental and uterine leukocyte populations during chlamydial infection in mice

Invariant CD1d-restricted natural killer T cells play an important immunoregulatory role and can influence a broad spectrum of immunological responses including against bacterial infections. They are present at the fetal-maternal interface and although it has been reported that experimental systemic iNKT cell activation can induce mouse abortion, their role during pregnancy remain poorly understood. In the present work, using a physiological Chlamydia muridarum infection model, we have shown that, in vaginally infected pregnant mice, C. muridarum is cleared similarly in C57BL/6 wild type (WT) and CD1d(-/-) mice. We have also shown that infected- as well as uninfected-CD1d(-/-) mice have the same litter size as WT counterparts. Thus, CD1d-restricted cells are required neither for the resolution of chlamydial infection of the lower-genital tract, nor for the maintenance of reproductive capacity. However, unexpected differences in T cell populations were observed in uninfected pregnant females, as CD1d(-/-) placentas contained significantly higher percentages of CD4(+) and CD8(+) T cells than WT counterparts. However, infection triggered a significant decrease in the percentages of CD4(+) T cells in CD1d(-/-) mice. In infected WT pregnant mice, the numbers of uterine CD4(+) and CD8(+) T cells, monocytes and granulocytes were greatly increased, changes not observed in infected CD1d(-/-) mice. An increase in the percentage of CD8(+) T cells seems independent of CD1d-restricted cells as it occurred in both WT and CD1d(-/-) mice. Thus, in the steady state, the lack of CD1d-restricted NKT cells affects leukocyte populations only in the placenta. In Chlamydia-infected pregnant mice, the immune response against Chlamydia is dampened in the uterus. Our results suggest that CD1d-restricted NKT cells play a role in the recruitment or homeostasis of leukocyte populations at the maternal-fetal interface in the presence or absence of Chlamydia infection.

Myelin recovery in multiple sclerosis: the challenge of remyelination

Multiple sclerosis (MS) is the most common demyelinating and an autoimmune disease of the central nervous system characterized by immune-mediated myelin and axonal damage, and chronic axonal loss attributable to the absence of myelin sheaths. T cell subsets (Th1, Th2, Th17, CD8⁺, NKT, CD4⁺CD25⁺ T regulatory cells) and B cells are involved in this disorder, thus new MS therapies seek damage prevention by resetting multiple components of the immune system. The currently approved therapies are immunoregulatory and reduce the number and rate of lesion formation but are only partially effective. This review summarizes current understanding of the processes at issue: myelination, demyelination and remyelination—with emphasis upon myelin composition/architecture and oligodendrocyte maturation and differentiation. The translational options target oligodendrocyte protection and myelin repair in animal models and assess their relevance in human. Remyelination may be enhanced by signals that promote myelin formation and repair. The crucial question of why remyelination fails is approached is several ways by examining the role in remyelination of available MS medications and avenues being actively pursued to promote remyelination including: (i) cytokine-based immune-intervention (targeting calpain inhibition), (ii) antigen-based immunomodulation (targeting glycolipid-reactive iNKT cells and sphingoid mediated inflammation) and (iii) recombinant monoclonal antibodies-induced remyelination.

Invariant NKT cells increase lipopolysacchride-induced pregnancy loss by a mechanism involving Th1 and Th17 responses

OBJECTIVE

To determine the role of invariant natural killer T (iNKT) cells in infection-associated pregnancy loss.

METHODS

B6 and iNKT cell-deficient Jα18(-/-) mice were injected i.p. with lipopolysaccharide (LPS) or vehicle, and pregnancy outcomes were examined. Decidual iNKT cell expression of CD69 and intracellular cytokine production were analyzed. Mouse decidual iNKT cells were co-cultured with LPS or PBS-treated dendritic cells (DCs), and iNKT cell CD69 expression and intracellular and extracellular cytokine production were assessed.

RESULTS

The embryo resorption rate was notably lessened for Jα18(-/-) mice treated with LPS on day 6 or day 9 gestation in comparison with B6 mice treated with LPS. Decidual iNKT cell CD69 expression and intracellular IFN-γ and IL-17 production for B6 mice injected with LPS on day 6 or day 9 gestation were significantly up-regulated compared with PBS-treated mice. Levels of IFN-γ and IL-17 in the supernatants of the co-culture of decidual iNKT cells and LPS-sensitized DCs were strikingly increased in comparison with the co-culture of iNKT cells and PBS-treated DCs. CD69 expression and intracellular IFN-γ and IL-17 production of iNKT cells co-cultured with LPS-sensitized DCs were remarkably up-regulated compared with iNKT cells co-cultured with PBS-treated DCs.

CONCLUSIONS

Our results suggest that iNKT cells may play a role in LPS-induced pregnancy loss by Th1 and Th17 cytokine-dependent manner.

Implications of Lymphocyte Anergy to Glycolipids in Multiple Sclerosis (MS): iNKT Cells May Mediate the MS Infectious Trigger

Immunogenic lipids may play key roles in host defenses against infection and in generating autoimmune inflammation and organ-specific damage. In multiple sclerosis (MS) there are unequivocal autoimmune features and vulnerability to aggravation or induction by microbial or viral infection. We have found glycolipid-driven anergy of circulating lymphocytes in MS indicating that this immune response is affected in MS and the robust effects of iNKT activation with potent cellular and cytokine activities emphasizes its potential importance. Diverse glycolipids including the endogenous myelin acetylated-galactosylceramides (AcGalCer) can drive activation that could be critical to the inflammatory demyelination in the central nervous system and clinical consequences. The iNKT cells and their invariant or iTCR (Vα24Jα18Vβ11) receptor an innate defense–a discrete immune arm that is separate from peptide-driven acquired immune responses. This offers new possibilities for insight including a likelihood that the pattern recognition of exogenous microbial and myelin immunogens can overlap and cross-react especially in an inflammatory milieu.