Exhausted Tumor-infiltrating CD39+CD103+ CD8+ T Cells Unveil Potential for Increased Survival in Human Pancreatic Cancer.

In pancreatic ductal adenocarcinoma, the infiltration of CD8+ T cells within the tumor microenvironment correlates with a favorable prognosis. However, a significant proportion of tumor-infiltrating T cells become trapped within the desmoplastic stroma and lack tumor reactivity. Here, we explored different T-cell subsets in pancreatic tumors and adjacent tissues. We identified a subset of CD8+ T cells, double positive (DP) for CD39 and CD103 in pancreatic tumors, which has recently been described to display tumor reactivity in other types of solid tumors. Interestingly, DP CD8+ T cells preferentially accumulated in central tumor tissues compared with paired peripheral tumor and adjacent non-tumor tissues. Consistent with an antigen encounter, DP CD8+ T cells demonstrated higher proliferative rates and displayed an exhausted phenotype, characterized by elevated expression of PD-1 and TIM-3, compared with CD39-CD103- CD8+ T cells. In addition, DP CD8+ T cells exhibited higher expression levels of the tissue trafficking receptors CCR5 and CXCR6, while displaying lower levels of CXCR3 and CXCR4. Importantly, a high proportion of DP CD8+ T cells is associated with increased patient survival. These findings suggest that DP CD8+ T cells with a phenotype reminiscent of that of tumor-reactive T cells are present in pancreatic tumors. The abundance of DP CD8+ T cells could potentially aid in selecting patients for pancreatic cancer immunotherapy trials. SIGNIFICANCE: Patients with pancreatic cancer with a high proportion of CD39+CD103+ CD8+ T cells exhibiting a tumor-reactive phenotype have improved survival rates, suggesting their potential utility in selecting candidates for immunotherapy trials.

Labour promotes systemic mobilisation of monocytes, T cell activation and local secretion of chemotactic factors in the intervillous space of the placenta.

During pregnancy, maternal blood circulates through the intervillous space of the placenta and the reciprocal interactions between foetal tissues and maternal immune cells makes the intervillous space a unique immunological niche. Labour is characterised by a proinflammatory response in the myometrium, but the relationship between local and systemic changes during the onset of labour remains elusive. We here aimed to investigate how the systemic and intervillous circulatory systems are affected during labour from an immunological point of view. We report that the proportion of monocytes is dramatically higher in peripheral (PB), intervillous blood (IVB) and decidua in labouring (n = 14) compared to non-labouring women (n = 15), suggesting that labour leads to both a systemic and local mobilisation of monocytes. Labour was associated with a relative increase of effector memory T cells in the intervillous space compared to the periphery, and MAIT cells and T cells showed an elevated expression of activation markers both in PB and IVB. Intervillous monocytes consisted to a higher degree of CD14+CD16+ intermediate monocytes compared to peripheral monocytes, independently of mode of delivery, and displayed an altered phenotypic expression pattern. A proximity extension assay analysis of 168 proteins revealed that several proteins associated to myeloid cell migration and function, including CCL2 and M-CSF, were upregulated in IVB plasma in labouring women. Thus, the intervillous space could be a bridging site for the communication between the placenta and the periphery, which contribute to monocyte mobilisation and generation of inflammatory reactions during spontaneous labour.

Chemokine Receptor Expression on T Cells Is Modulated by CAFs and Chemokines Affect the Spatial Distribution of T Cells in Pancreatic Tumors.

The accumulation of T cells is associated with a better prognosis in pancreatic cancer. However, the immunosuppressive tumor microenvironment, largely composed by cancer-associated fibroblasts (CAFs), can prevent T cells from reaching the tumor nests. We examined how human CAFs modulated chemokine receptors known to be associated with T cell trafficking, CXCR3 and CCR5, and T cell exclusion, CXCR4. CAFs decreased the expression of CXCR3 and CCR5 but increased CXCR4 expression in both 2D and 3D cultures, affecting the migratory capacity of T cells towards CXCL10. An immunohistochemistry analysis showed that very few T cells were found in the tumor nests. Within the stroma, CD8+ T cells were localized more distantly from the malignant cells whereas CD4+ T cells were more equally distributed. Tumor tissues with a high production of chemokines were associated with less T cell infiltration when the whole tissue was analyzed. However, when the spatial localization of CD8+ T cells within the tissue was taken into account, levels of CXCR3 ligands and the CCR5 ligand CCL8 showed a positive association with a high relative T cell infiltration in tumor-rich areas. Thus, CXCR3 ligands could mediate T cell trafficking but CAFs could prevent T cells from reaching the malignant cells.

Immunotherapy in pancreatic cancer-an emerging role: a narrative review.

BACKGROUND AND OBJECTIVE: Immunotherapy is the fastest growing branch in oncology that have already revolutionized the treatment of few solid cancers. The number of immunotherapy trials for pancreatic cancer (PC) is growing but the vast number of different agents used make it difficult to comprehend a possible success trait of a certain type of immunotherapy. The aim of this review is to summarize and critically evaluate the outcome of immunotherapy trials for PC intended to aid the comprehensiveness for the treating physicians. METHODS: A PubMed search was performed to identify clinical trials in patients with PC, published in English from year 2000 to June 2021 and using combination of the terms immunotherapy, PC, and cross-checked the bibliography of the revised literature as the dublettes have been removed. Studies were divided into three groups depending on what immune components have been applied: passive products (peptides, antibodies, etc.), antigen-presenting cells, and adoptive cell transfer trials. KEY CONTENT AND FINDINGS: The vast majority of trials, including those from most recent years, used passive products of the immune system-peptide vaccines and antibodies. The administration was often parallel to chemotherapy that was prevalently gemcitabine-based. Although immunological responses have been detected, the clinical efficacy was very limited. Trials with check point inhibitors did not show survival advantage. Dendritic cell (DC) vaccines have been associated with some clinical objective response and prolonged survival in few patients with delayed type hypersensitivity reactions. Trials with adoptive transfer therapy are lacking. The very few trials with lymphokine-activated killer (LAK)/cytokine-induced killer (CIK) cells tested only in Asian population have resulted in some clinical effects with prolonged survival. In none of the trials have the patients been preconditioned before receiving immunotherapy. CONCLUSIONS: Although the clinical effectiveness in the majority of the reported trials has been limited, the immunological effects observed in almost all trials show a proof of concept-that immunotherapy can work. Careful re-evaluation of the clinical premises and focus on combination and cell therapy may be the way to achieve improved survival by immunotherapy in PC.

Interactions between Cancer-Associated Fibroblasts and T Cells in the Pancreatic Tumor Microenvironment and the Role of Chemokines.

Less than 10% of patients diagnosed with pancreatic ductal adenocarcinoma (PDAC) survive 5 years or more, making it one of the most fatal cancers. Accumulation of T cells in pancreatic tumors is associated with better prognosis, but immunotherapies to enhance the anti-tumor activity of infiltrating T cells are failing in this devastating disease. Pancreatic tumors are characterized by a desmoplastic stroma, which mainly consists of activated cancer-associated fibroblasts (CAFs). Pancreatic CAFs have emerged as important regulators of the tumor microenvironment by contributing to immune evasion through the release of chemokines, cytokines, and growth factors, which alters T-cell migration, differentiation and cytotoxic activity. However, recent discoveries have also revealed that subsets of CAFs with diverse functions can either restrain or promote tumor progression. Here, we discuss our current knowledge about the interactions between CAFs and T cells in PDAC and summarize different therapy strategies targeting the CAF-T cell axis with focus on CAF-derived soluble immunosuppressive factors and chemokines. Identifying the functions of different CAF subsets and understanding their roles in T-cell trafficking within the tumor may be fundamental for the development of an effective combinational treatment for PDAC.

Optimisation of the Synthesis and Cell Labelling Conditions for [89Zr]Zr-oxine and [89Zr]Zr-DFO-NCS: a Direct In Vitro Comparison in Cell Types with Distinct Therapeutic Applications.

BACKGROUND: There is a need to better characterise cell-based therapies in preclinical models to help facilitate their translation to humans. Long-term high-resolution tracking of the cells in vivo is often impossible due to unreliable methods. Radiolabelling of cells has the advantage of being able to reveal cellular kinetics in vivo over time. This study aimed to optimise the synthesis of the radiotracers [89Zr]Zr-oxine (8-hydroxyquinoline) and [89Zr]Zr-DFO-NCS (p-SCN-Bn-Deferoxamine) and to perform a direct comparison of the cell labelling efficiency using these radiotracers. PROCEDURES: Several parameters, such as buffers, pH, labelling time and temperature, were investigated to optimise the synthesis of [89Zr]Zr-oxine and [89Zr]Zr-DFO-NCS in order to reach a radiochemical conversion (RCC) of >95 % without purification. Radio-instant thin-layer chromatography (iTLC) and radio high-performance liquid chromatography (radio-HPLC) were used to determine the RCC. Cells were labelled with [89Zr]Zr-oxine or [89Zr]Zr-DFO-NCS. The cellular retention of 89Zr and the labelling impact was determined by analysing the cellular functions, such as viability, proliferation, phagocytotic ability and phenotypic immunostaining. RESULTS: The optimised synthesis of [89Zr]Zr-oxine and [89Zr]Zr-DFO-NCS resulted in straightforward protocols not requiring additional purification. [89Zr]Zr-oxine and [89Zr]Zr-DFO-NCS were synthesised with an average RCC of 98.4 % (n = 16) and 98.0 % (n = 13), respectively. Cell labelling efficiencies were 63.9 % (n = 35) and 70.2 % (n = 30), respectively. 89Zr labelling neither significantly affected the cell viability (cell viability loss was in the range of 1-8 % compared to its corresponding non-labelled cells, P value > 0.05) nor the cells' proliferation rate. The phenotype of human decidual stromal cells (hDSC) and phagocytic function of rat bone-marrow-derived macrophages (rMac) was somewhat affected by radiolabelling. CONCLUSIONS: Our study demonstrates that [89Zr]Zr-oxine and [89Zr]Zr-DFO-NCS are equally effective in cell labelling. However, [89Zr]Zr-oxine was superior to [89Zr]Zr-DFO-NCS with regard to long-term stability, cellular retention, minimal variation between cell types and cell labelling efficiency.

The vitamin D analogue calcipotriol promotes an anti-tumorigenic phenotype of human pancreatic CAFs but reduces T cell mediated immunity.

The pancreatic tumour stroma is composed of phenotypically heterogenous cancer-associated fibroblasts (CAFs) with both pro- and anti-tumorigenic functions. Here, we studied the impact of calcipotriol, a vitamin D3 analogue, on the activation of human pancreatic CAFs and T cells using 2- and 3-dimensional (2D, 3D) cell culture models. We found that calcipotriol decreased CAF proliferation and migration and reduced the release of the pro-tumorigenic factors prostaglandin E2, IL-6, periostin, and leukemia inhibitory factor. However, calcipotriol promoted PD-L1 upregulation, which could influence T cell mediated tumour immune surveillance. Calcipotriol reduced T cell proliferation and production of IFN-γ, granzyme B and IL-17, but increased IL-10 secretion. These effects were even more profound in the presence of CAFs in 2D cultures and in the presence of CAFs and pancreatic tumour cell line (PANC-1) spheroids in 3D cultures. Functional assays on tumour infiltrating lymphocytes also showed a reduction in T cell activation by calcipotriol. This suggests that calcipotriol reduces the tumour supportive activity of CAFs but at the same time reduces T cell effector functions, which could compromise the patients' tumour immune surveillance. Thus, vitamin D3 analogues appear to have dual functions in the context of pancreatic cancer, which could have important clinical implications.

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.

Generation of Retinal Pigment Epithelial Cells Derived from Human Embryonic Stem Cells Lacking Human Leukocyte Antigen Class I and II.

Human embryonic stem cell-derived retinal pigment epithelial (hESC-RPE) cells could serve as a replacement therapy in advanced stages of age-related macular degeneration. However, allogenic hESC-RPE transplants trigger immune rejection, supporting a strategy to evade their immune recognition. We established single-knockout beta-2 microglobulin (SKO-B2M), class II major histocompatibility complex transactivator (SKO-CIITA) and double-knockout (DKO) hESC lines that were further differentiated into corresponding hESC-RPE lines lacking either surface human leukocyte antigen class I (HLA-I) or HLA-II, or both. Activation of CD4+ and CD8+ T-cells was markedly lower by hESC-RPE DKO cells, while natural killer cell cytotoxic response was not increased. After transplantation of SKO-B2M, SKO-CIITA, or DKO hESC-RPEs in a preclinical rabbit model, donor cell rejection was reduced and delayed. In conclusion, we have developed cell lines that lack both HLA-I and -II antigens, which evoke reduced T-cell responses in vitro together with reduced rejection in a large-eyed animal model.

MAIT Cells in Health and Disease.

Mucosal-associated invariant T (MAIT) cells are a newly described subset of T cells that are found in the blood and are enriched in many tissues, particularly in the liver. MAIT cells express a semi-invariant T cell receptor restricted by the MHC class I-related (MR1) molecule. MAIT cells are activated in a MR1-dependent manner in response to microbial-derived riboflavin metabolites which leads to rapid effector functions, but they can also be activated in a MR1-independent manner by cytokines and viruses. The use of mice models and MR1 tetramers, among other recent methodological advances, have provided more insight into the development, mode of activation, characterization in different diseases and tissues of MAIT cells. In this chapter, we provide an overview of MAIT cells and yet remaining questions about their potential therapeutic role.

Isolation of Immune Cells from Placental Tissues and Phenotypic and Functional Analysis of MAIT Cells.

The placenta is an immunological paradox since maternal immune cells infiltrating placental tissues need to be tolerant toward the fetus but still retain immunity against potential infections. This makes the placenta an interesting tissue for studying immunological processes. Mucosal-associated invariant T (MAIT) cells are a subset of T cells that respond to bacterially derived metabolites of riboflavin synthesis. Upon activation, MAIT cells respond by secretion of inflammatory cytokines and by directed killing of infected cells by the use of granzymes and perforin. In this protocol, we describe methods for the isolation of immune cells from the placental intervillous space and adjacent tissues such as the umbilical cord, decidua parietalis, and decidua basalis. We further describe how to stimulate MAIT cells in mixed cell suspensions of mononuclear cells with bacteria, and how to analyze the phenotypic and functional responses with flow cytometry.

Recruitment of MAIT Cells to the Intervillous Space of the Placenta by Placenta-Derived Chemokines.

The intervillous space of the placenta is a part of the fetal-maternal interface, where maternal blood enters to provide nutrients and gas exchange. Little is known about the maternal immune cells at this site, which are in direct contact with fetal tissues. We have characterized the T cell composition and chemokine profile in paired intervillous and peripheral blood samples from healthy mothers giving birth following term pregnancies. Mucosal-associated invariant T (MAIT) cells and effector memory (EM) T cells were enriched in the intervillous blood compared to peripheral blood, suggesting that MAIT cells and other EM T cells home to the placenta during pregnancy. Furthermore, pregnant women had lower proportions of peripheral blood MAIT cells compared to non-pregnant women. The levels of several chemokines were significantly higher in intervillous compared to peripheral blood, including macrophage migration inhibitory factor (MIF), CXCL10, and CCL25, whereas CCL21, CCL27 and CXCL12 were lower. Migration assays showed that MAIT cells and EM T cells migrated toward conditioned medium from placental explants. A multivariate factor analysis indicated that high levels of MIF and CCL25 were associated with high proportions of MAIT cells in intervillous blood. Blocking of MIF or a combination of MIF, CCL25, and CCL20 in migration assays inhibited MAIT cell migration toward placenta conditioned medium. Finally, MAIT cells showed migratory capacities toward recombinant MIF. Together, these findings indicate that term placental tissues attract MAIT cells, and that this effect is at least partly mediated by MIF.

Mature naïve B cells are retained in the placental intervillous blood and positively associate with specific chemokines in full-term healthy pregnancy.

PROBLEM: Circulating B-cell numbers are lower during pregnancy compared with non-pregnant women, but the underlying reasons for this are unknown. Pregnancy-related hormones could influence B-cell lymphopoiesis in the bone marrow, but B cells may also be recruited to the placenta. To investigate the latter, we examined whether the proportions of total B cells and B cells at different maturational stages in placental intervillous blood (IVB) differ compared with peripheral blood (PB). METHOD OF STUDY: From 23 paired samples of PB and IVB following full-term healthy pregnancies, total B cells and immature/transitional, mature/naïve, and memory B cells were identified by flow cytometry. Chemokine levels in blood were analyzed using a Luminex assay. Placental explant-derived supernatant was assayed for B-cell chemotactic activity. RESULTS: The proportions of total B cells and mature/naïve B cells were significantly higher in IVB relative to PB, while the fractions of immature/transitional cells and memory B cells were higher in PB. Multivariate factor analysis demonstrated that a specific chemokine profile in IVB, including CCL20, positively associated with higher proportions of mature/naïve B cells in the intervillous space. All B cells expressed CCR6, the corresponding receptor for CCL20, but the intensity of CCR6 expression was significantly higher in mature/naïve B cells relative to immature/transitional B cells. Migration assays showed that placental explant-derived supernatants attract B cells. CONCLUSION: These results indicate that B cells, and mature/naïve B cells in particular, are retained in the intervillous blood in response to certain chemokines produced by the placenta during late healthy pregnancy.

Human Pancreatic Carcinoma-Associated Fibroblasts Promote Expression of Co-inhibitory Markers on CD4+ and CD8+ T-Cells.

Carcinoma-associated pancreatic fibroblasts (CAFs) are the major type of cells in the stroma of pancreatic ductal adenocarcinomas and besides their pathological release of extracellular matrix proteins, they are also perceived as key contributors to immune evasion. Despite the known relevance of tumor infiltrating lymphocytes in cancers, the interactions between T-cells and CAFs remain largely unexplored. Here, we found that CAFs isolated from tumors of pancreatic cancer patients undergoing surgical resection (n = 15) expressed higher levels of the PD-1 ligands PD-L1 and PD-L2 compared to primary skin fibroblasts from healthy donors. CAFs strongly inhibited T-cell proliferation in a contact-independent fashion. Blocking the activity of prostaglandin E2 (PGE2) by indomethacin partially restored the proliferative capacity of both CD4+ and CD8+ T-cells. After stimulation, the proportion of proliferating T-cells expressing HLA-DR and the proportion of memory T-cells were decreased when CAFs were present compared to T-cells proliferating in the absence of CAFs. Interestingly, CAFs promoted the expression of TIM-3, PD-1, CTLA-4 and LAG-3 in proliferating T-cells. Immunohistochemistry stainings further showed that T-cells residing within the desmoplastic stromal compartment express PD-1, indicating a role for CAFs on co-inhibitory marker expression also in vivo. We further found that PGE2 promoted the expression of PD-1 and TIM-3 on T-cells. Functional assays showed that proliferating T-cells expressing immune checkpoints produced less IFN-γ, TNF-α, and CD107a after restimulation when CAFs had been present. Thus, this indicates that CAFs induce expression of immune checkpoints on CD4+ and CD8+ T-cells, which contribute to a diminished immune function.

MAIT cells accumulate in placental intervillous space and display a highly cytotoxic phenotype upon bacterial stimulation.

During pregnancy, the maternal immune system must tolerate the developing foetus, and yet retain a potent antimicrobial response to prevent infections. Mucosal associated invariant T (MAIT) cells recognize microbial-derived vitamin B metabolites presented on the MR1 molecule, but their presence and function at the foetal-maternal interface is not known. We here isolated mononuclear cells from paired samples of peripheral blood (PB), intervillous blood (IVB), and decidua parietalis (DP) following uncomplicated term pregnancies. Interestingly, MAIT cells were highly enriched in IVB compared to PB and DP. The activation status of IVB MAIT cells was similar to that of PB MAIT cells, except for a lower expression of PD-1. Both IVB MAIT cells and conventional T cells were more dominated by an effector memory phenotype compared to PB MAIT cells and T cells. IVB MAIT cells also responded more vigorously with expression of IFN-γ, granzyme B, and perforin in response to Escherichia coli stimulation compared to PB. MR1 was not expressed in syncytiotrophoblasts, but in placental villous and decidual macrophages. These data indicate that maternal MAIT cells accumulate in the intervillous space of the placenta and that they are highly armed to quickly respond if bacteria are encountered at the foetal-maternal interface.

IFN type I and II induce BAFF secretion from human decidual stromal cells.

B cell activating factor (BAFF) is a critical cytokine for maturation of immature B cells. In murine lymph nodes, BAFF is mainly produced by podoplanin-expressing stromal cells. We have previously shown that circulating BAFF levels are maximal at birth, and that farmers' children exhibit higher BAFF levels in cord blood than non-farmers' children. Here, we sought to investigate whether maternal-derived decidual stromal cells from placenta secrete BAFF and examine what factors could stimulate this production. We found that podoplanin is expressed in decidua basalis and in the underlying villous tissue as well as on isolated maternal-derived decidual stromal cells. Decidual stromal cells produced BAFF when stimulated with IFN-γ and IFN-α, and NK cells and NK-T-like cells competent of IFN-γ production were isolated from the decidua. Finally, B cells at different maturational stages are present in decidua and all expressed BAFF-R, while stromal cells did not. These findings suggest that decidual stromal cells are a cellular source of BAFF for B cells present in decidua during pregnancy.

Mucosal-Associated Invariant T Cells Display a Poor Reconstitution and Altered Phenotype after Allogeneic Hematopoietic Stem Cell Transplantation.

Mucosal-associated invariant T (MAIT) cells are innate-like T cells which are important in the defense against certain bacteria and yeast. The reconstitution of MAIT cells after allogeneic hematopoietic stem cell transplantation (HSCT) is not known. We investigated MAIT cell phenotype and function in 17 patients devoid of relapse and severe graft-versus-host disease (GvHD) in paired samples collected 1-2, 3-6, 12, and 24 months after transplantation. Data were compared to 17 healthy controls (HC), as well as 22 patients with acute GvHD grade 2-3. The frequency of MAIT cells within CD3+ cells was approximately 10-fold lower than in HC and did not increase over the 2 years following HSCT. MAIT cells in HSCT patients displayed an elevated expression of CD69 and intracellular granzyme B and were predominantly composed of CD4/CD8 double-negative cells. The expression of PD-1 on MAIT cells was low and did not change during the observational time, whereas the CD3+CD161dim/negTCRVα7.2dim/neg cells (non-MAIT T cells) displayed a high expression early after HSCT that decreased to normal levels at 24 months. MAIT cells collected 2-6 months post-HSCT showed an impaired IFN-γ and perforin response after bacterial stimulation, but the response was restored at 24 months. Patients with acute GvHD had similar proportions of MAIT cells as patients with grade 0-1, but consisted mainly of CD8+ cells. Finally, MAIT cells were more sensitive to cyclosporine A and sirolimus than non-MAIT T cells. To conclude, MAIT cell reconstitution following HSCT is deficient compared to non-MAIT T cells and GvHD grade ≥2 is not correlated with MAIT cell frequency. MAIT cell functionality was impaired early after HSCT, but restored at 24 months post-HSCT. MAIT cells have an increased sensibility to common immunosuppressive drugs, which maybe could explain their hampered reconstitution after HSCT.

Frontline Science: Placenta-derived decidual stromal cells alter IL-2R expression and signaling in alloantigen-activated T cells.

This study investigated how stromal cells affect the IL-2 pathway in alloantigen-activated T cells. We found that decidual stromal cells (DSCs) from term placentas promoted a high production of IL-2 in cultures with alloantigen-activated T cells. The intensity of expression of cluster of differentiation 25 (CD25; IL-2Rα) on T cells was increased by DSCs, whereas the frequency and intensity of expression of the signaling subunits CD122 (IL-2Rß) and CD132 (IL-2Rγc) were reduced. Consequently, uptake of IL-2 and STAT5 phosphorylation (pSTAT5) was abrogated. DSCs also decreased the proportion of pSTAT5+ T cells in response to IL-15, which also use CD122 for signaling. Addition of DSCs to the allogeneic cultures did not increase the expression of programmed death 1 (PD-1) or CD95, indicating that they did not promote T cell exhaustion. However, exogenous recombinant (r)IL-2 in similar concentrations in the same setting increased the expression of CD95 and down-regulated CD122 in T cells. The antiproliferative effect of sirolimus (SRL) and cyclosporine A (CsA), which target the IL-2 signaling pathway, was diminished by DSCs in vitro. To conclude, DSCs affect IL-2 production and IL-2R expression and signaling, which may contribute to the stromal cell-mediated immune modulation and phenotype shift seen in activated T cells. Altered proliferation in cultures when combining DSCs and SRL or CsA may be of clinical importance, as stromal cells are used in trials for acute inflammation and are often used in combination with conventional immunosuppressive therapies.

Maternal Adaptive Immune Cells in Decidua Parietalis Display a More Activated and Coinhibitory Phenotype Compared to Decidua Basalis.

The maternal part of the placenta, the decidua, consists of maternal immune cells, decidual stromal cells, and extravillous fetal trophoblasts. In a successful pregnancy, these cell compartments interact to provide an intricate balance between fetal tolerance and antimicrobial defense. These processes are still poorly characterized in the two anatomically different decidual tissues, basalis and parietalis. We examined immune cells from decidua basalis and parietalis from term placentas (n = 15) with flow cytometry. By using multivariate discriminant analysis, we found a clear separation between the two decidual compartments based on the 81 investigated parameters. Decidua parietalis lymphocytes displayed a more activated phenotype with a higher expression of coinhibitory markers than those isolated from basalis and contained higher frequencies of T regulatory cells. Decidua basalis contained higher proportions of monocytes, B cells, and mucosal-associated invariant T (MAIT) cells. The basalis B cells were more immature, and parietalis MAIT cells showed a more activated phenotype. Conventional T cells, NK cells, and MAIT cells from both compartments potently responded with the production of interferon-γ and/or cytotoxic molecules in response to stimulation. To conclude, leukocytes in decidua basalis and parietalis displayed remarkable phenotypic disparities, indicating that the corresponding stromal microenvironments provide different immunoregulatory signals.