Decidual CD4 Research Articles

Differential decidual CD8+ memory T cell responses in spontaneous labor versus induction of labor at term

Differential decidual CD8+ memory T cell responses in spontaneous labor versus induction of labor at term

CD4+ T cell heterogeneity in gestational age and preeclampsia using single-cell RNA sequencing.

A balance between pro-inflammatory decidual CD4+ T cells and FOXP3+ regulatory T cells (FOXP3+ Tregs) is important for maintaining fetomaternal tolerance. Using single-cell RNA-sequencing and T cell receptor repertoire analysis, we determined that diversity and clonality of decidual CD4+ T cell subsets depend on gestational age. Th1/Th2 intermediate and Th1 subsets of CD4+ T cells were clonally expanded in both early and late gestation, whereas FOXP3+ Tregs were clonally expanded in late gestation. Th1/Th2 intermediate and FOXP3+ Treg subsets showed altered gene expression in preeclampsia (PE) compared to healthy late gestation. The Th1/Th2 intermediate subset exhibited elevated levels of cytotoxicity-related gene expression in PE. Moreover, increased Treg exhaustion was observed in the PE group, and FOXP3+ Treg subcluster analysis revealed that the effector Treg like subset drove the Treg exhaustion signatures in PE. The Th1/Th2 intermediate and effector Treg like subsets are possible inflammation-driving subsets in PE.

Antigen-specific decidual CD8+ T cells include distinct effector memory and tissue-resident memory cells.

Maternal decidual CD8+ T cells must integrate the antithetical demands of providing immunity to infection while maintaining immune tolerance for fetal and placental antigens. Human decidual CD8+ T cells were shown to be highly differentiated memory T cells with mixed signatures of dysfunction, activation, and effector function. However, no information is present on how specificity for microbial or fetal antigens relates to their function or dysfunction. In addition, a key question, whether decidual CD8+ T cells include unique tissue-resident memory T cells (Trm) or also effector memory T cell (Tem) types shared with peripheral blood populations, is unknown. Here, high-dimensional flow cytometry of decidual and blood CD8+ T cells identified 2 Tem populations shared in blood and decidua and 9 functionally distinct Trm clusters uniquely found in decidua. Interestingly, fetus- and virus-specific decidual CD8+ Trm cells had similar features of inhibition and cytotoxicity, with no significant differences in their expression of activation, inhibitory, and cytotoxic molecules, suggesting that not all fetus-specific CD8+ T cell responses are suppressed at the maternal-fetal interface. Understanding how decidual CD8+ T cell specificity relates to their function and tissue residency is crucial in advancing understanding of their contribution to placental inflammation and control of congenital infections.

Tim-3+ decidual Mφs induced Th2 and Treg bias in decidual CD4+T cells and promoted pregnancy maintenance via CD132

Tim-3+ decidual Mφs induced Th2 and Treg bias in decidual CD4+T cells and promoted pregnancy maintenance via CD132

Impaired CD8+ T cells in term pregnancy decidua with chronic hepatitis B virus infection.

Hepatitis B virus (HBV) infection is more likely to develop a state of chronicity in early life, particularly mother-to-child transmission (MTCT) of HBV in the fetus during pregnancy. Till now, little is known about the impact of chronic HBV infection on the immune status of the maternal-fetus interface, and the immune profile of placental lymphocytes in MTCT of HBV is poorly understood. Thirteen term pregnant women with chronic HBV infection (HBV-PW) and thirteen normal pregnant women as healthy control (HC-PW) were enrolled. The profile of placental immune cells and paired peripheral blood were analyzed by flow cytometry and immunohistochemistry. Compared with HC-PW, the frequency of CD8+ T cells from the term placenta of HBV-PW was significantly reduced. These cells showed decreased expression of activation molecules CD69 and HLA-DR; thus, decidual CD8+ T cells from HBV-PW demonstrated hypofunctional signature as evidenced by significantly reduced production of IFN-γ, as well as compromised ability of degranulation and proliferation. These findings supported that hypoactivated decidual CD8+ T cells might possess compromised ability in chronically HBV-infected term pregnant women. Our study provides robust evidence for the necessity and importance of antiviral intervention in HBV-PW to prevent MTCT of HBV.

Single-cell RNA sequencing reveals immunological rewiring at the maternal-fetal interface following asymptomatic/mild SARS-CoV-2 infection.

While severe coronavirus 2019 (COVID-19) is associated with immune activation at the maternal-fetal interface, responses to asymptomatic/mild severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during pregnancy remain unknown. Here, we assess immunological adaptations in blood and term decidua in response to asymptomatic/mild disease in pregnant women. We report attenuated antigen presentation and type I interferon (IFN) signaling pathways, loss of tissue-resident decidual macrophages, and upregulated cytokine/chemokine signaling in monocyte-derived decidual macrophages. Furthermore, we describe increased frequencies of activated tissue-resident T cells and decreased abundance of regulatory T cells with infection while frequencies of cytotoxic CD4/CD8 T cells are increased in the blood. In contrast to decidual macrophages, type I IFN signaling is higher in decidual T cells. Finally, infection leads to a narrowing of T cell receptor diversity in both blood and decidua. Collectively, these observations indicate that asymptomatic/mild COVID-19 during pregnancy results in remodeling of the immunological landscape of the maternal-fetal interface, with a potential for long-term adverse outcomes for the offspring.

Tim-3+ decidual Mφs induced Th2 and Treg bias in decidual CD4+T cells and promoted pregnancy maintenance via CD132

T-cell immunoglobulin mucin-3 (Tim-3) plays roles in the functional regulation of both adaptive and innate immune cells and is greatly involved in many diseases. However, the precise roles of Tim-3 on macrophages (Mφs) in pregnancy remain unstated. In the current study, we found the higher frequency of Tim-3+ decidual Mφs (dMφs) in response to trophoblasts. The reduced abundance of Tim-3 on Mφs was accompanied by disordered anti- and pro-inflammatory cytokine profiles in miscarriage. Adoptive transfer of Tim-3+Mφs, but not Tim-3−Mφs, relieved murine embryo absorption induced by Mφ depletion. Our flow cytometry results and the extensive microarray analysis confirmed that Tim-3+ and Tim-3−dMφs were neither precisely pro-inflammatory (M1) nor anti-inflammatory (M2) Mφs. However, with higher CD132 expression, Tim-3+dMφs subset induced Th2 and Treg bias in decidual CD4+T cells and promoted pregnancy maintenance. Blockade of Tim-3 or CD132 pathways leaded to the dysfunction of maternal-fetal tolerance and increased fetal loss. These findings underscored the important roles of Tim-3 in regulating dMφ function and maintaining normal pregnancy, and suggested that Tim-3 on Mφs is a potential biomarker for diagnosis of miscarriage. Our study also emphasized the importance of careful consideration of reproductive safety when choosing immune checkpoint blockade therapies in real world clinical care. Though IL-4 treated Tim-3−Mφs could rescue the fetal resorption induced by Mφ depletion, whether IL-4 represent novel therapeutic strategy to prevent pregnancy loss induced by checkpoint inhibition still needs further research.

S16.3: Heterogeneity, function and specificity of human decidual CD8+ T cells

S16.3: Heterogeneity, function and specificity of human decidual CD8+ T cells

PL5.3 (Gusdon Award Finalist): Human decidual CD4+ T cells have phenotypic and functional heterogeneity

PL5.3 <i>(Gusdon Award Finalist)</i>: Human decidual CD4+ T cells have phenotypic and functional heterogeneity

Decreased Expression of Cytotoxic Proteins in Decidual CD8+ T Cells in Preeclampsia.

Simple SummaryCD8+ T cells are prominent decidual cells in the third trimester of healthy human pregnancy. They have a cytotoxic capacity which may control invasion of extravillous trophoblast and therefore affect placentation and play the role in development of preeclampsia. In this study, we examined the expression of CD8+ T cells in decidual tissue and peripheral blood of women with severe and mild preeclampsia in comparison to gestational age-matched healthy pregnancies. Additionally, the expression of cytotoxic proteins in CD8+ T cells was examined in order to specify their subpopulations.In our study, we aimed to establish expression of cytotoxic CD8+ T cells in the decidua basalis and the maternal peripheral blood (mPBL) of severe and mild preeclampsia (PE) and compare to healthy pregnancies. Decidual tissue and mPBL of 10 women with mild PE, 10 women with severe PE, and 20 age-matched healthy pregnancy controls were analyzed by double immunofluorescence and qPCR, respectively. By double immunofluorescence staining, we found a decreased total number of cells/mm2 in decidua basalis of granulysin (GNLY)+ (p ˂ 0.0001), granzyme B (GzB)+(p ˂ 0.0001), GzB+CD8+(p ˂ 0.0001), perforin (PRF1)+ (p ˂ 0.0001), and PRF1+CD8+ (p ˂ 0.01) in the severe PE compared to control group. Additionally, we noticed the trend of lower mRNA expression for GNLY, granzyme A (GZMA), GzB, and PRF1 in CD8+ T cells of mPBL in mild and severe PE, with the latter marker statistically decreased in severe PE (p ˂ 0.001). Forkhead box P3 (FOXP3) mRNA in CD8+ T cells mPBL was increased in mild PE (p ˂ 0.001) compared to controls. In conclusion, severe PE is characterized by altered expression of cytotoxic CD8+ T cells in decidua and mPBL, suggesting their role in pathophysiology of PE and fetal-maternal immune tolerance.

Altered Carcinoembryonic Antigen-Related Cell Adhesion Molecule 1/T-Cell Immunoglobulin Mucin-3 Signaling Causes the Dysregulation of Decidual CD8+T Cells in the Third Trimester during Preeclamptic Pregnancies

Abstract Objective: To investigate the frequency and function of Tim-3+CD8+T cells in the third trimester of normal pregnancies (NPs) and preeclamptic (PE) pregnancies. Methods: T-cell immunoglobulin mucin-3 (Tim-3) expression levels of CD8+T cells in the decidua, peripheral blood, and umbilical cord blood obtained from women showing NPs and PE pregnancies were analyzed using flow cytometry. Decidual CD8+T cells were cultured in the presence of recombinant human carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM1) protein and/or Tim-3-specific neutralizing antibodies for analyzing CD107a and intracellular cytokine expression. The placental CEACAM1 protein expression was analyzed using immunohistochemistry. Results: Tim-3+CD8+T cells were more abundant in the decidua than in the peripheral blood. Tim-3 expression in the decidual CD8+T cells was significantly lower in PE patients. Decidual Tim-3+CD8+T cells from PE patients expressed higher levels of CD107a and the Th1-type cytokine IFN-γ, but lower levels of the Th2-type cytokine IL-4. CEACAM1 altered the CD107a, IFN-γ, and IL-4 levels; this was reversed by anti-Tim-3 antibodies. The CEACAM1 protein levels were lower in the placental tissues of women with PE pregnancies than in those of women with NPs. Conclusions: Abnormal CEACAM1/Tim-3 regulation may participate in the development of PE, accompanied by disturbed Th2 cell predominance and higher cytotoxicity of decidual CD8+T cells.

Activation of Gonadotropin-releasing Hormone Receptor Impedes the Immunosuppressive Activity of Decidual Regulatory T Cells via Deactivating the Mechanistic Target of Rapamycin Signaling

ABSTRACT Understanding maternal immune tolerance is crucial for the development of therapeutics for immunological pregnancy complications. Decidual regulatory T cells (Tregs) play a pivotal role in the maintenance of maternal immune tolerance. Using a murine allogeneic pregnancy model in the current study, we identified the up-regulation of gonadotropin-releasing hormone receptor (GnRHR) in decidual T cell subsets including CD4+ conventional T cells, CD8+ T cells, and CD4+Foxp3+ Tregs. Using a lentivirus-mediated GnRHR overexpression system and a GnRHR agonist, we found that GnRHR activation decreased the expression of Treg functional molecules such as IL10 (IL-10), IL-35 subunit EBI3 (Ebi3), IL2RA (CD25), TNFRSF18 (GITR), ICOS, and Treg master regulator FOXP3. The functional analysis indicated that GnRHR activation impairs the ability of Tregs to inhibit conventional T cell proliferation. We also revealed that GnRHR activation suppressed the mechanistic target of rapamycin (mTOR) signaling in GnRHR-overexpressing splenic Tregs (Wild type C57BL/6 J background) and decidual Tregs. MHY1485, a potent mTOR activator, effectively abolished the effect of the GnRHR agonist and promoted the immunosuppressive capability of Tregs. Furthermore, in an adoptive transfer model, Treg-specific GnRHR knockdown increased Foxp3 expression in decidual Tregs while decreasing the production of IFN-γ and IL-17 in decidual effector CD4+ T cells and reducing the production of IFN-γ in decidual effector CD8+ T cells. Taken together, the present study unveils a novel mechanism by which the immunosuppressive function of decidual Tregs is modulated, and deepens our understanding of maternal immune tolerance.

Decidual NR2F2-Expressing CD4+ T Cells Promote TH2 Transcriptional Program During Early Pregnancy.

A unique immunotolerant microenvironment with Th2 bias in the decidua provides an essential security for successful pregnancy. The disorganized maternal-fetal immune tolerance contributes to more than 50% of unexplained recurrent spontaneous abortion (RSA). How the Th2 bias is developed at the maternal-fetal interface remains undefined. NR2F2, a member of steroid/thyroid nuclear receptor superfamily, is endowed with diverse importance in cell-fate specification, organogenesis, angiogenesis, and metabolism. Here, we showed that NR2F2 was absolutely highly expressed in decidual CD4+T(dCD4+T) cells, but not in peripheral circulating CD4+T cells during early pregnancy. Decidual NR2F2-expressing CD4+T cells dominantly produced Th2 cytokines. In unexplained RSA patients, NR2F2 expression in dCD4+T cells was significantly decreased, accompanied with disordered phenotype of dCD4+T cells. Furthermore, overexpression of NR2F2 promoted the Th2 differentiation of naive CD4+T cells. Immunoprecipitation experiment confirmed the binding relationship between GATA-3 and NR2F2, which implied GATA-3 may be an important interactive element involved in the immunoregulatory process of NR2F2. This study is the first to reveal a previously unappreciated role for NR2F2-mediated dCD4+T cells in maternal-fetal immune tolerance and maintenance of normal pregnancy, in the hope of providing a potential biomarker for prediction and prevention of clinical unexplained RSA.

P14: Clonally expanded decidual effector memory CD8+ T cells and their PD‐1 expressions differ between miscarriage and preeclampsia

P14: Clonally expanded decidual effector memory CD8⁺ T cells and their PD‐1 expressions differ between miscarriage and preeclampsia

P101: Human decidual CD8+ T cells have phenotypic and functional heterogeneity

P101: Human decidual CD8+ T cells have phenotypic and functional heterogeneity

TIGIT-Fc as a Potential Therapeutic Agent for Fetomaternal Tolerance.

The perfect synchronization of maternal immune-endocrine mechanisms and those of the fetus is necessary for a successful pregnancy. In this report, decidual immune cells at the maternal-fetal interface were detected that expressed TIGIT (T cell immunoreceptor with Ig and ITIM domains), which is a co-inhibitory receptor that triggers immunological tolerance. We generated recombinant TIGIT-Fc fusion proteins by linking the extracellular domain of TIGIT and silent Fc fragments. The treatment with TIGIT-Fc of human decidual antigen presenting cells (APCs), the decidual dendritic cells (dDCs), and decidual macrophages (dMϕs) increased the production of interleukin 10 and induced the decidua APCs to powerfully polarize the decidual CD4+ T cells toward a classic TH2 phenotype. We further proposed that Notch signaling shows a pivotal effect on the transcriptional regulation in decidual immune cell subsets. Moreover, the administration of TIGIT-Fc to CBA/J pregnant mice at preimplantation induced CD4+ forkhead box P3+ (Foxp3+) regulatory T cells and tolerogenic dendritic cells and increased pregnancy rates in an abortion-prone animal model stress. The results suggested the therapeutic potential of the TIGIT-Fc fusion protein in reinstating immune tolerance in failing pregnancies.

Eomesodermin regulate decidual CD4+T cell function during human early pregnancy

Decidual CD4+T (dCD4+T) cells play pivotal roles in inducing and maintaining maternal-fetal tolerance. Dysfunctional dCD4+T cells are associated with miscarriage. In the present study, we demonstrated that the T-box transcription factor protein eomesodermin (Eomes) was involved in the functional regulation of dCD4+T cells during early pregnancy. We concluded the higher Eomes expression dCD4+T cells during normal pregnancy, and the Eomes+dCD4+T cells displayed an active status and produced more Th2- and Treg type cytokines. Decreased number and altered function of Eomes+dCD4+T cells were observed in miscarriage. Progesterone, the traditional treatment for miscarriage, had no effect on Eomes expression by dCD4+T cells from normal pregnancy, but increased Eomes expression by dCD4+T cells from miscarriage. We also found the higher frequency of Eomes+dCD4+T cells from miscarriage in response to cyclosporine, tacrolimus, Trophoblasts, and HTR8/SVneo cell line, might provide new strategy for therapy to promote maternal-fetal tolerance and prevent pregnancy loss. These results indicated that Eomes might be promising early warming targets of miscarriage, though further studies are required to determine that the altered number and function of Eomes+dCD4+T cells are the cause or consequence of miscarriage.

TCR repertoire and PD-1 expression analysis of decidual and peripheral CD8+T cells in normal and abnormal pregnancies

TCR repertoire and PD-1 expression analysis of decidual and peripheral CD8+T cells in normal and abnormal pregnancies

Newly characterized decidual Tim-3+ Treg cells are abundant during early pregnancy and driven by IL-27 coordinately with Gal-9 from trophoblasts.

What is the mechanism of Tim-3+ regulatory T (Treg)-cell accumulation in the decidua during early pregnancy and is its disruption associated with recurrent pregnancy loss (RPL)? IL-27 and Gal-9 secreted by trophoblasts activate the Tim-3 signaling pathway in CD4+ T cells and Treg cells and so promote accumulation of Tim-3+ Treg cells, the abnormal expression of IL-27 and Gal-9 is associated with impaired immunologic tolerance in RPL patients. Tim-3+ Treg cells are better suppressors of Teff cell proliferation, and display higher proliferative activity than Tim-3- Treg cells. Tim-3+ Treg cells are tissue-specific promoters of T-cell dysfunction in many tumors. These cells express a unique factor that influences and shapes the tumor microenvironment. The animal study included 80 normal pregnant mice. In human study, decidua tissues in the first trimester for flow cytometry analysis were collected from 32 normal pregnant women and 23 RPL patients. Placenta tissues for immunohistochemistry analysis were collected from 15 normal pregnant women. Placenta tissues for western blot analysis were collected from 5 normal pregnant women, 5 RPL patients and 5 women who have experienced one miscarriage. Blood samples for in vitro experiments were collected from 30 normal pregnant women. This study was performed between January 2017 and March 2019. In this study, we investigated the kinetics of Tim-3+ CD4+ T-cell accumulation, and the proportions of Tim-3+ Treg cells throughout murine pregnancies using flow cytometry. We compared Tim-3 expression on decidual CD4+ T cells and Treg cells during normal pregnancies with expression on the same cell populations in women suffering from RPL. IL-27 and Gal-9 transcription and protein expression in the placenta were determined by RT-PCR and western blot, respectively. An in vitro co-culture model consisting of peripheral CD4+ T cells and primary trophoblasts from early pregnancy was used to mimic the maternal-fetal environment. The percentage of Tim-3+ Treg cells present in mouse uteri fluctuates as gestation proceeds but does not change in the spleen. Levels of Tim3+ Treg cells in uteri peaked at pregnancy Day 6.5 (E 6.5), then progressively diminished, and fell to non-pregnant levels by E18.5. In pregnant mice, Tim-3+ Treg cells constituted 40-70% of Treg cells in uteri but were present at much lower abundance in spleens. About 60% of decidual Treg cells were Tim-3 positive at E6.5. Of these decidual Tim3+ Treg cells, nearly 90% were PD-1 positive. However, only about 16% of Tim3- Treg cells expressed PD-1. Blocking the Tim-3 signaling pathway decreased the proportion of Treg cells and led to embryo resorption. Moreover, much lower Tim-3 expression was observed on CD4+ T cells and Treg cells in women who had suffered from RPL at 6-9 gestational weeks compared with those who had normal pregnancies at matched gestations. In a normal pregnancy, Tim-3 expression on decidual CD4+ T cells is induced initially by IL-27. Then Gal-9-Tim-3 interaction promotes differentiation of decidual Tim-3+ CD4+ T cells into Treg cells. IL-27 and Gal-9 cooperatively induced Tim-3+ Treg cells in vitro. N/A. We did not investigate the kinetics of human decidual Tim-3+ CD4+ T and Tim-3+ Treg cell populations throughout pregnancy due to limited availability of second and third trimester decidua. In addition, functional suppressive data on the decidual Tim-3+ Treg cells are lacking due to limited and low quantities of these cells in decidua. These findings might have therapeutic clinical implications in RPL. This study was supported by research grants from the National Natural Science Foundation of China (No. 81871186) and National Key Research & Developmental Program of China (2018YFC1003900, 2018YFC1003904). The authors declare no conflict of interest.

Distinct changes of in BTLA, ICOS, PD-1, and TIGIT expression on peripheral blood and decidual CD8+ T cells in women with unexplained recurrent spontaneous abortion†.

The two-way communication between the mother and the fetus is accomplished by immune cells. CD8+ T cells of normal pregnant (NP) women express progesterone receptor (PR). Binding of PR to progesterone (P) and the production of progesterone-induced blocking factor (PIBF) can aid immune escape, which is an important factor in the maternal immune response. We detected the proportion of CD8+ T cells and the expression of the surface costimulatory molecules BTLA, TIGIT, ICOS, and PD-1 in peripheral blood and decidual tissues of women with unexplained recurrent spontaneous abortion (URSA) and in NP women. All patients were at 8 -10 weeks of gestation. The results showed that there was no change in the proportions of CD8+ T cells in peripheral blood and decidual tissues of URSA patients compared to those of NP women. In peripheral blood, compared with the NP group, the URSA group showed decreased expression of BTLA + CD8+ T cells and the difference was statistically significant, but there was no difference between the groups in terms of TIGIT + CD8+, PD-1 + CD8+, and ICOS + CD8+ T cells. There was no change in the levels of TIGIT + CD8+, PD-1 + CD8+, ICOS + CD8+, and BTLA + CD8+ T cells in decidual tissue. These data confirm that the number of CD8+ T cells in peripheral blood and decidual tissue is not the main factor leading to the pathogenesis of URSA, and other immune cells may play an important role in URSA, but this hypothesis needs further exploration and research.