Immunological Barrier Research Articles

CD8+ cytotoxic T lymphocytes in cancer immunotherapy: A review

CD8+ cytotoxic T lymphocytes (CTLs) are preferred immune cells for targeting cancer. During cancer progression, CTLs encounter dysfunction and exhaustion due to immunerelated tolerance and immunosuppression within the tumor microenvironment (TME), with all favor adaptive immune-resistance. Cancer-associated fibroblasts (CAFs), macrophage type 2 (M2) cells, and regulatory T cells (Tregs) could make immunologic barriers against CD8 + T cell-mediated antitumor immune responses. Thus, CD8 + T cells are needed to be primed and activated toward effector CTLs in a process called tumor immunity cycle for making durable and efficient antitumor immune responses. The CD8 + T cell priming is directed essentially as a corroboration work between cells of innate immunity including dendritic cells (DCs) and natural killer (NK) cells with CD4 + T cells in adoptive immunity. Upon activation, effector CTLs infiltrate to the core or invading site of the tumor (so-called infiltrated-inflamed [I-I] TME) and take essential roles for killing cancer cells. Exogenous reactivation and/or priming of CD8 + T cells can be possible using rational immunotherapy strategies. The increase of the ratio for costimulatory to coinhibitory mediators using immune checkpoint blockade (ICB) approach. Programmed death-1 receptor (PD-1)-ligand (PD-L1) and CTL-associated antigen 4 (CTLA-4) are checkpoint receptors that can be targeted for relieving exhaustion of CD8 + T cells and renewing their priming, respectively, and thereby eliminating antigen-expressing cancer cells. Due to a diverse relation between CTLs with Tregs, the Treg activity could be dampened for increasing the number and rescuing the functional potential of CTLs to induce immunosensitivity of cancer cells.

Rainbow Trout Maintain Intestinal Transport and Barrier Functions Following Exposure to Polystyrene Microplastics.

Ingestion has been proposed as a prominent exposure route for plastic debris in aquatic organisms, including fish. While the consequences of ingestion of large plastic litter are mostly understood, the impacts resulting from ingestion of microplastics (MPs) are largely unknown. We designed a study that aimed to assess impacts of MPs on fish intestinal physiology and examined integrity of extrinsic, physical and immunological barriers. Rainbow trout were exposed to polystyrene (PS) MPs (100-400 μm) via feed for a period of 4 weeks. Fish were fed four types of diets: control, diets containing virgin PS particles, or particles exposed to two different environmental matrices (sewage or harbor effluent). Extrinsic barrier disturbance in intestinal tissue was evaluated via histology. The paracellular permeability toward ions and molecules was examined using Ussing chambers and mRNA expression analysis of tight junction proteins. Active transport was monitored as transepithelial potential difference, short-circuits current and uptake rate of amino acid 3H-lysine. Immune status parameters were measured through mRNA expression level of cytokines, lysozyme activity, and hematological analysis of immune cells. We could not show that PS MPs induced inflammatory responses or acted as physical or chemical hazards upon ingestion. No measurable effects were exerted on fish intestinal permeability, active transport or electrophysiology.

The epithelial immune microenvironment (EIME) in atopic dermatitis and psoriasis

The skin provides both a physical barrier and an immunologic barrier to external threats. The protective machinery of the skin has evolved to provide situation-specific responses to eliminate pathogens and to provide protection against physical dangers. Dysregulation of this machinery can give rise to the initiation and propagation of inflammatory loops in the epithelial microenvironment that result in inflammatory skin diseases in susceptible people. A defective barrier and microbial dysbiosis drive an interleukin 4 (IL-4) loop that underlies atopic dermatitis, while in psoriasis, disordered keratinocyte signaling and predisposition to type 17 responses drive a pathogenic IL-17 loop. Here we discuss the pathogenesis of atopic dermatitis and psoriasis in terms of the epithelial immune microenvironment-the microbiota, keratinocytes and sensory nerves-and the resulting inflammatory loops.

Dendrobium huoshanense polysaccharide regionally regulates intestinal mucosal barrier function and intestinal microbiota in mice

The present study investigated the effects of a homogeneous Dendrobium huoshanense polysaccharide (GXG) on mucosal barrier function and microbiota composition in different intestinal regions of mice. Results exhibited, besides changing the intestinal physiological status, orally administrated GXG could improve the intestinal physical barrier function by modulating mucosal structures and up-regulating the expression of tight junction proteins, reinforce the intestinal biochemical barrier function by elevating the expression and secretion of mucin-2, β-defensins and sIgA, and regulate the intestinal immunological barrier function by stimulating the production of cytokines and the functional development of immune cells. Simultaneously, GXG could differentially impact the composition and metabolism of microbiota along intestinal tract. In addition, the immune response in spleen and peripheral blood were effectively regulated by GXG. These results indicated that GXG might be used as functional agent to improve host health.

Modulation of NKG2D, NKp46, and Ly49C/I facilitates natural killer cell-mediated control of lung cancer

Natural killer (NK) cells play a critical role in controlling malignancies. Susceptibility or resistance to lung cancer, for example, specifically depends on NK cell function. Nevertheless, intrinsic factors that control NK cell-mediated clearance of lung cancer are unknown. Here we report that NK cells exposed to exogenous major histocompatibility class I (MHCI) provide a significant immunologic barrier to the growth and progression of malignancy. Clearance of lung cancer is facilitated by up-regulation of NKG2D, NKp46, and other activating receptors upon exposure to environmental MHCI. Surface expression of the inhibitory receptor Ly49C/I, on the other hand, is down-regulated upon exposure to tumor-bearing tissue. We thus demonstrate that NK cells exhibit dynamic plasticity in surface expression of both activating and inhibitory receptors based on the environmental context. Our data suggest that altering the activation state of NK cells may contribute to immunologic control of lung and possibly other cancers.

Caprylic acid and nonanoic acid upregulate endogenous host defense peptides to enhance intestinal epithelial immunological barrier function via histone deacetylase inhibition

The intestinal epithelial barrier plays a critical role in the etiopathogenesis of ulcerative colitis. This study aims to explore the potential effects and underlying mechanisms of medium chain fatty acids (caprylic acid and nonanoic acid) on intestinal epithelial barrier function. Using the porcine jejunal epithelial cell line IPEC-J2, a well-established model, challenged with Escherichia coli ATCC 43889 (O157:H7), we found that treatment with caprylic acid (C8) and nonanoic acid (C9) significantly reduced bacterial translocation, enhanced antibacterial activity, and remarkably increased the secretion of porcine β-defensins 1 (pBD-1) and pBD-2. Mechanistically, like TSA (a histone deacetylase inhibitor), C8 and C9 attenuated the activity of the classical histone deacetylase pathway to facilitate the acetylation of histone 3 lysine 9 (H3K9) at the promoters pBD-1 and pBD-2, and consequently augmented the gene expression of pBD-1 and pBD-2. In conclusion, with their combined antibacterial and defense peptide-induced roles, the use of C8 and C9 may provide a novel method to protect the intestinal barrier of animals and humans from bacterial infection.

CNS infection and immune privilege.

Classically, the CNS is described as displaying immune privilege, as it shows attenuated responses to challenge by alloantigen. However, the CNS does show local inflammation in response to infection. Although pathogen access to the brain parenchyma and retina is generally restricted by physiological and immunological barriers, certain pathogens may breach these barriers. In the CNS, such pathogens may either cause devastating inflammation or benefit from immune privilege in the CNS, where they are largely protected from the peripheral immune system. Thus, some pathogens can persist as latent infections and later be reactivated. We review the consequences of immune privilege in the context of CNS infections and ask whether immune privilege may provide protection for certain pathogens and promote their latency.

Innovations in the Therapy of Atopic Dermatitis Complicated by a Secondary Infection

Reduced skin barrier properties in patients with atopic dermatitis (AtD) are largely caused by microbiome changes and extensive Staphylococcus aureus colonisation of the skin. In this regard, the integument of patients with AtD requires constant care and the use of various emollients. The inclusion of lysates of non-pathogenic microorganisms and prebiotics in the composition of emollients ensures the normalisation of the microbiome composition and the immunological barrier of the skin. The article presents the results of our own observations on the application of two cosmetic scin-care products for damaged skin with vitamin F in children with AtD complicated by a secondary infection, while the composition of one of the products is additionally enriched with ceramides and prebiotics. The safety and high efficacy of both products have been shown, however, the presence of ceramides and prebiotics in the emollient composition makes it possible to achieve a marked decrease in the degree of S. aureus colonisation of the skin.

Standards for Deriving Nonhuman Primate-Induced Pluripotent Stem Cells, Neural Stem Cells and Dopaminergic Lineage.

Humans and nonhuman primates (NHP) are similar in behavior and in physiology, specifically the structure, function, and complexity of the immune system. Thus, NHP models are desirable for pathophysiology and pharmacology/toxicology studies. Furthermore, NHP-derived induced pluripotent stem cells (iPSCs) may enable transformative developmental, translational, or evolutionary studies in a field of inquiry currently hampered by the limited availability of research specimens. NHP-iPSCs may address specific questions that can be studied back and forth between in vitro cellular assays and in vivo experimentations, an investigational process that in most cases cannot be performed on humans because of safety and ethical issues. The use of NHP model systems and cell specific in vitro models is evolving with iPSC-based three-dimensional (3D) cell culture systems and organoids, which may offer reliable in vitro models and reduce the number of animals used in experimental research. IPSCs have the potential to give rise to defined cell types of any organ of the body. However, standards for deriving defined and validated NHP iPSCs are missing. Standards for deriving high-quality iPSC cell lines promote rigorous and replicable scientific research and likewise, validated cell lines reduce variability and discrepancies in results between laboratories. We have derived and validated NHP iPSC lines by confirming their pluripotency and propensity to differentiate into all three germ layers (ectoderm, mesoderm, and endoderm) according to standards and measurable limits for a set of marker genes. The iPSC lines were characterized for their potential to generate neural stem cells and to differentiate into dopaminergic neurons. These iPSC lines are available to the scientific community. NHP-iPSCs fulfill a unique niche in comparative genomics to understand gene regulatory principles underlying emergence of human traits, in infectious disease pathogenesis, in vaccine development, and in immunological barriers in regenerative medicine.

Mucin 2 (MUC2) promoter characterization: an overview.

Transgenic livestock have been studied with a well-known interest in improving quantitative and qualitative traits. In order to direct heterologous gene expression, it is indispensable to identify and characterize a promoter suitable for directing the expression of the gene of interest (GOI) in a tissue-specific way. The gastrointestinal tract is a desirable target for gene expression in several mammalian models. Throughout the surface of the intestinal epithelium, there is an intricate polymer network, formed by gel-forming mucins (especially MUC2 and MUC5AC, of which MUC2 is the major one), which plays a protective role due to the formation of a physical, chemical and immunological barrier between the organism and the environment. The characterization of the gel-forming mucins is difficult because of their large size and repetitive DNA sequences and domains. The main mucin in the small and large intestine, mucin 2 (MUC2), is expressed specifically in goblet cells. MUC2 plays an important role in intestinal homeostasis and its disruption is associated with several diseases and carcinomas. This mucin is also an important marker for elucidating mechanisms that regulate differentiation of the secretory cell lineage. This review presents the state of the art of MUC2 promoter structure and functional characterization.

Characterization of a lung epithelium specific E-cadherin knock-out model: Implications for obstructive lung pathology

The airway epithelium regulates responses to aeroallergens, acting as a physical and immunological barrier. In asthma, epithelial barrier function and the expression of adherens junction protein E-cadherin is compromised, but it is unknown whether this is cause or consequence of the disease. We hypothesized that airway epithelial loss of E-cadherin is a critical step in the development of manifestations of asthma. We generated a transgenic mouse model with conditional loss of E-cadherin in lung epithelial cells at birth and onwards. We observed normal lung development at the time of birth in mice lacking E-cadherin in the lung epithelium. However, E-cadherin deficiency led to progressive epithelial damage in mice growing into adulthood, as evidenced by airway epithelial denudation, decreased zonula occludens (ZO)-1 expression, loss of ciliated cells, and enlarged alveolar spaces. In addition, spontaneous goblet cell metaplasia with mucus production was observed. These epithelial changes were accompanied by elevated levels of the epithelial-derived chemokine CCL17, infiltration of eosinophils and dendritic cells, and mucus production. In conclusion, loss of E-cadherin induces features in the lung reminiscent of those observed in asthma, indicating that the disruption of E-cadherin-mediated cell-cell contacts may play a key role in the development of asthma manifestations.

Trapianto di rene da donatore vivente in modalità crociata quale nuova strategia per espandere il trapianto di rene da donatore vivente in coppie di difficile trapiantabilità immunologica

Living donor kidney transplantation (LKD) is considered the best type of transplant for end-stage renal disease patients in terms of organ quality and survival. However, ABO incompatibility and positive cross-match remain the most frequent immunological barriers. The novel strategy of kidney paired donation (KPD) has been proposed to facilitate transplantation in patients who have a healthy and willing donor but present this type of barriers. The first experiences of KPD in a single centre were carried out by creating large regional or national registries that increase the choice in difficult-to-match patients. Our experience shows that referring to the National Italian Registry for identifying a correct pair, allows performing KPD with good outcomes of LKD in cases that would otherwise not be feasible.

P136 Successful adeptness of donor exchange program in renal transplantation at King Faisal Specialist Hospital Jeddah

Aim Different methodologies were established to overcome HLA immunological barriers to match the highly increasing number of patients with end-stage renal disease in Saudi Arabia, which is currently ranged between 120 and 150 patients per million per annum. At our hospital, King Faisal Specialist Hospital Jeddah, we therefore successfully established the desensitization and ABOi renal transplantation. Recently we have started to use a donor exchange program. We hereby report about our experience to overcome the immunological incompatibilities by using this program. Methods We used an IT program with high grade on flexibilities by performing different options including simple two-pair exchanges, more complicated domino exchanges and chain donations. All recipients with willing donors and with high titer HLA antibodies and/or strong positive cross match were included in the program. HLA typing was performed by using One Lambda SSOr and SSP. HLA Antibody Identification, Single Antigen Class I/II and C1q test, was performed by One Lambda. T and B cell IgG XM is performed by FACSCanto II flow cytometer, where the cut-off for positive XM is determined based on normal human studies. Results 20 patients were transplanted successfully by using the donor exchange program within a period of 12 months. Considering a total number of 220 transplanted kidneys during this time, which makes our hospital as the largest center for renal transplantation in Saudi Arabia, we were able to increase the number of transplanted organs significantly by 9% and we continue to extend and optimize our histocompatibility services at the hospital. Conclusions Our experience demonstrates the high efficiency of the donor exchange program in overcoming immunological barriers in renal transplantation. This program provides in some cases also an alternative to the invasive and costly desensitization protocols. Further efforts and thoughts are going on to include deseased donors as well in this successful donor exchange program.

Oral Vaccine Delivery for Intestinal Immunity-Biological Basis, Barriers, Delivery System, and M Cell Targeting.

Most currently available commercial vaccines are delivered by systemic injection. However, needle-free oral vaccine delivery is currently of great interest for several reasons, including the ability to elicit mucosal immune responses, ease of administration, and the relatively improved safety. This review summarizes the biological basis, various physiological and immunological barriers, current delivery systems with delivery criteria, and suggestions for strategies to enhance the delivery of oral vaccines. In oral vaccine delivery, basic requirements are the protection of antigens from the GI environment, targeting of M cells and activation of the innate immune response. Approaches to address these requirements aim to provide new vaccines and delivery systems that mimic the pathogen’s properties, which are capable of eliciting a protective mucosal immune response and a systemic immune response and that make an impact on current oral vaccine development.

Novel mechanisms regulating endothelial barrier function in the pulmonary microcirculation

The pulmonary epithelial and vascular endothelial cell layers provide two sequential physical and immunological barriers that together form a semi-permeable interface and prevent alveolar and interstitial oedema formation. In this review, we focus specifically on the continuous endothelium of the pulmonary microvascular bed that warrants strict control of the exchange of gases, fluid, solutes and circulating cells between the plasma and the interstitial space. The present review provides an overview of emerging molecular mechanisms that permit constant transcellular exchange between the vascular and interstitial compartment, and cause, prevent or reverse lung endothelial barrier failure under experimental conditions, yet with a clinical perspective. Based on recent findings and at times seemingly conflicting results we discuss emerging paradigms of permeability regulation by altered ion transport as well as shifts in the homeostasis of sphingolipids, angiopoietins and prostaglandins.

Localization, Occurrence, and CSF Changes of SP-G, a New Surface Active Protein with Assumable Immunoregulatory Functions in the CNS.

Conventional surfactant proteins (A, B, C, and D) are important players of the innate immunity in the central nervous system and serve as effective regulators of cerebrospinal fluid rheology, probably being involved in clearance of detrimental metabolites like beta-amyloid and phospho-tau. Recently, a novel surfactant protein, SP-G, was described in kidneys and peripheral endocrine and exocrine glands. So far, its presence and possible functions in the central nervous system are unknown. Therefore, our study aimed to elucidate the presence of SP-G in the brain and its concentration in normal and pathologic samples of cerebrospinal fluid in order to gain first insight into its regulation and possible functions. A total of 121 samples of human cerebrospinal fluid (30 controls, 60 hydrocephalus patients, 7 central nervous system infections, and 24 brain hemorrhage patients) and 21 rat brains were included in our study. CSF samples were quantified using a commercially available ELISA system. Results were analyzed statistically using SPSS 22, performing Spearman Rho correlation and ANOVA with Dunnett's post hoc analysis. Rat brains were investigated via immunofluorescence to determine SP-G presence and colocalization with common markers like aquaporin-4, glial fibrillary acidic protein, platelet endothelial adhesion molecule 1, and neuronal nuclear antigen. SP-G occurs associated with brain vessels, comparable to other conventional SPs, and is present in a set of cortical neurons. SP-G is furthermore actively produced by ependymal and choroid plexus epithelium and secreted into the cerebrospinal fluid. Its concentrations are low in control subjects and patients suffering from aqueductal stenosis, higher in normal pressure hydrocephalus (p < 0.01), and highest in infections of the central nervous system and brain hemorrhage (p < 0.001). Interestingly, SP-G did correlate with total CSF protein in patients with CNS infections and hemorrhage, but not with cell count. Based on the changes in CSF levels of SP-G in hydrocephalus, brain hemorrhage, and CNS infections as well as its abundance at CSF flow-related anatomical structures closely associated with immunological barrier systems, importance for CSF rheology, brain waste clearance, and host defense is assumable. Thus, SP-G is a potential new CSF biomarker, possibly not only reflecting aspects of CNS innate immune responses, but also rheo-dynamically relevant changes of CSF composition, associated with CSF malabsorbtion. However, further studies are warranted to validate our findings and increase insight into the physiological importance of SP-G in the CNS.

Estrogen matters in metastasis

Metastatic cancer cells meet several physical, biochemical and immunological barriers before colonizing a new territory. Cancerous cells turn invasive, mobile and eventually disengage from their native niche. This is followed by their intravasation, extravasation, survival, proliferation, and colonization into distant organs. Unlike well-confined tumors, which respond favorably to anti-cancer therapeutics, metastatic tumors are life-threatening and incurable. More than 90% of cancer-related mortality is caused by metastases, hence the emphasis is now on developing the strategies to block or reverse the process of metastasis. This has ensued intensive research with a focus on the mechanisms underlying metastasis. Substantial work carried out in this direction has led to the identification of specific enzymes, proteins, cytokines, chemokines, growth factors, exosomes, miRNA and lipids, etc. as the facilitators of metastasis. Metastatic cells are exposed to a diverse array of local and systemic signals. Among these, estrogens are of great relevance. Estrogens have been strongly linked to cancers, especially of breast and uterine origin. Recent data hint that estrogens, well recognized for their role in proliferation, may have a role in metastasis also. It is proposed that influence of estrogen on metastasis may be independent of its proliferation-inducing ability. Data are emerging to suggest that estrogens have potential to modulate various events of the metastatic cascade such as local invasion, intravasation, anoikis, immune evasion, extravasation, angiogenesis and metastatic colonization. This review summarizes some of the recent advances in our knowledge on the role of estrogens in the metastatic cascade of cancerous cells.

Neoadjuvant Chemotherapy Reinforces Antitumour T cell Response in Urothelial Urinary Bladder Cancer

Evidence indicates that neoadjuvant chemotherapy (NAC) may promote antitumour immune responses by activating T cells. The tumour-draining sentinel node (SN) is a key site to study tumour-specific T cell activation, being the primary immunological barrier against the tumour. In this prospective study, we set out to elucidate the effects of NAC on T cell subsets in the SNs of patients with muscle-invasive urothelial bladder cancer. We found that CD8+ effector T (Teff) cell exhaustion was reduced after NAC treatment, while cytotoxicity was increased. Additionally, in complete responders (CR patients), these cells were functionally committed effectors, as displayed by epigenetic analysis. In CD4+ Teffs, NAC treatment was associated with increased clonal expansion of tumour-specific SN-derived cells, as demonstrated by a specific cell reactivity assay. In contrast, we observed an attenuating effect of NAC on regulatory T cells (Tregs) with a dose-dependent decrease in Treg frequency and reduced effector molecule expression in the remaining Tregs. In addition, multicolour flow cytometry analysis revealed that CR patients had higher Teff to activated Treg ratio, promoting antitumoural T cell activation. These results suggest that NAC reinforces the antitumour immune response by activating the effector arm of the T cell compartment and diminishing the influence of suppressive Tregs. Patient summaryIn this report, we analysed the effect of chemotherapy on immune cell subsets of 40 patients with advanced bladder cancer. We found that chemotherapy has a positive effect on immune effector T cells, whereas an opposite, diminishing effect was observed for immune-suppressive regulatory T cells. We conclude that chemotherapy reinforces the antitumour immune response in bladder cancer patients.

Immunological Barriers in ABO-Incompatible Kidney Transplantation

Immunological Barriers in ABO-Incompatible Kidney Transplantation

PO-372 IL-2 and IL-15 cytokine in vitro treatments induce NKG2D, CD158a and CD158b receptor expression on T, NKT- like and NK cell lymphocyte subsets from regional lymph nodes of melanoma patients

IntroductionRegional lymph nodes (LN)s are important immunological barriers in spreading of malignant tumours but also represent the most frequent early metastatic site in melanoma. Considering that cytokine therapy has shown substantial toxicity, there is a growing need for further in vitro testing of these agents to enlighten aspects of their regional application in malignancies. The aim of this study was to investigate the effect interleukin (IL)−2 and IL-15, cytokines with similar immune-enhancing effects, on the expression of activating (NKG2D) and inhibitory (CD158a,CD158b) receptors on CD8+ T, NKT-like and NK cell lymphocyte subsets from regional LNs of melanoma patients.Material and methodsMononuclear cells (MNC)s were purified from regional LNs of 35 melanoma patients (clinical stages II-IV) and in vitro cultured for 7 days in cell culture medium RPMI1640 (CM) alone, CM with 200 IU/ml rhIL-2 and CM with 25 ng/ml IL-15. Expression of NKG2D, CD158a and CD158b receptors on lymphocytes, CD8+ T, NKT-like and NK cells was estimated by flow cytometry. Statistical significance between the values obtained with cytokine compared to control CM treatments was evaluated by Wilcoxon signed rank test. NK cell cytotoxicity was evaluated by standard 51Cr release assay.Results and discussionsOur results show that IL-2 and IL-15 in vitro treatments significantly increase expression of activating NKG2D receptor on lymphocytes and their CD8+ T, NKT-like and NK cell subsets. Regarding investigated inhibitory receptors, the significant increase was obtained for CD158a only after IL-15 treatment on lymphocytes and their CD8+ T and NKT- like subsets. However, the expression of CD158b receptor significantly increased after IL-2 cytokine treatment on lymphocytes, CD8+ T and NK cells, and after IL-15 treatment on all investigated lymphocyte subsets.Both cytokines augmented NK cell antitumor cytotoxicity that positively correlated (p<0.01, Spearman signed rank test) with the expression of NKG2D activating receptor on NK cells from regional LNs of melanoma patients, irrespective of LN involvement. Conversely, the expression of inhibitory receptors did not correlate with NK cell cytotoxicity except for CD158b that after control CM treatment showed negative correlation.ConclusionAntitumor potential of immune cells from regional LNs induced with IL-2 and IL-15 cytokine treatments may indicate the importance of this immune cell population in the development of therapeutic strategies that involve local cytokine application.