B7-1 and B7-2 costimulatory molecules activate differentially the Th1/Th2 developmental pathways: application to autoimmune disease therapy

Tumor cells impair immunological synapse formation via central nervous system-enriched metabolite

Tumors employ various strategies to evade immune surveillance. Central nervous system (CNS) has multiple features to restrain immune response. Whether tumors and CNS share similar programs of immunosuppression is elusive. Here, we analyze multi-omics data of tumors from HER2+ breast cancer patients receiving trastuzumab and anti-PD-L1 antibody and find that CNS-enriched N-acetyltransferase 8-like (NAT8L) and its metabolite N-acetylaspartate (NAA) are overexpressed in resistant tumors. In CNS, NAA is released during brain inflammation. NAT8L attenuates brain inflammation and impairs anti-tumor immunity by inhibiting cytotoxicity of natural killer (NK) cells and CD8+ T cells via NAA. NAA disrupts the formation of immunological synapse by promoting PCAF-induced acetylation of lamin A-K542, which inhibits the integration between lamin A and SUN2 and impairs polarization of lytic granules. We uncover that tumor cells mimic the anti-inflammatory mechanism of CNS to evade anti-tumor immunity and NAT8L is a potential target to enhance efficacy of anti-cancer agents.

Arsenic trioxide inhibits the response of primary human B cells to influenza virus A in vitro

Arsenic compounds are common environmental toxicants worldwide and particularly enriched in the Northeast and the Southwestern United States, the Alps, and Bangladesh. Exposure to arsenic is linked with various detrimental health outcomes, including cancer, cognitive decline, and kidney damage. Our group has previously shown that arsenic trioxide alters T cell cytokine production. In the current study, we demonstrate that exposure to arsenic compounds alters B cell function in an in vitro influenza model. Human peripheral blood mononuclear cells (PBMCs) were isolated from blood and cultured with arsenic trioxide (As3O2) and subsequently challenged with Influenza A virus. B cells showed decreased expression of CD267, surface IgG and CD80 when treated with As3O2. Taken together, the data suggest that As3O2 affects the activation and surface antibody expression of human peripheral B cells. Overall, this suggests that As3O2 exposure could cause impaired humoral immunity.

Berberine: A natural modulator of immune cells in multiple sclerosis

Berberine is a benzylisoquinoline alkaloid found in such plants as Berberis vulgaris, Berberis aristata, and others, revealing a variety of pharmacological properties as a result of interacting with different cellular and molecular targets. Recent studies have shown the immunomodulatory effects of Berberine which result from its impacts on immune cells and immune response mediators such as diverse T lymphocyte subsets, dendritic cells (DCs), and different inflammatory cytokines. Multiple sclerosis (MS) is a chronic disabling and neurodegenerative disease of the central nervous system (CNS) characterized by the recruitment of autoreactive T cells into the CNS causing demyelination, axonal damage, and oligodendrocyte loss. There have been considerable changes discovered in MS regards to the function and frequency of T cell subsets such as Th1 cells, Th17 cells, Th2 cells, Treg cells, and DCs. In the current research, we reviewed the outcomes of in vitro, experimental, and clinical investigations concerning the modulatory effects that Berberine provides on the function and numbers of T cell subsets and DCs, as well as important cytokines that are involved in MS.

Advances in immune checkpoint-based immunotherapies for multiple sclerosis: rationale and practice

Beyond the encouraging results and broad clinical applicability of immune checkpoint (ICP) inhibitors in cancer therapy, ICP-based immunotherapies in the context of autoimmune disease, particularly multiple sclerosis (MS), have garnered considerable attention and hold great potential for developing effective therapeutic strategies. Given the well-established immunoregulatory role of ICPs in maintaining a balance between stimulatory and inhibitory signaling pathways to promote immune tolerance to self-antigens, a dysregulated expression pattern of ICPs has been observed in a significant proportion of patients with MS and its animal model called experimental autoimmune encephalomyelitis (EAE), which is associated with autoreactivity towards myelin and neurodegeneration. Consequently, there is a rationale for developing immunotherapeutic strategies to induce inhibitory ICPs while suppressing stimulatory ICPs, including engineering immune cells to overexpress ligands for inhibitory ICP receptors, such as program death-1 (PD-1), or designing fusion proteins, namely abatacept, to bind and inhibit the co-stimulatory pathways involved in overactivated T-cell mediated autoimmunity, and other strategies that will be discussed in-depth in the current review. Video Abstract.

Under the influence: environmental factors as modulators of neuroinflammation through the IL-10/IL-10R axis

The IL-10/IL-10 receptor (IL-10R) axis plays an important role in attenuating neuroinflammation in animal models of Multiple Sclerosis (MS) and increased IL-10 has been associated with a positive response to MS disease modifying therapy. Because environmental factors play an important role in MS susceptibility and disease course, identification of environmental factors that impact the IL-10/IL-10R axis has therapeutic potential. In this review, we provide historical and updated perspectives of how IL-10R signaling impacts neuroinflammation, discuss environmental factors and intestinal microbes with known impacts on the IL-10/IL-10R axis, and provide a hypothetical model for how B cells, via their production of IL-10, may be important in conveying environmental "information" to the inflamed central nervous system.

An advanced in vitro human mucosal immune model to predict food sensitizing allergenicity risk: A proof of concept using ovalbumin as model allergen

Background

The global demand of sustainable food sources leads to introduction of novel foods on the market, which may pose a risk of inducing allergic sensitization. Currently there are no validated in vitro assays mimicking the human mucosal immune system to study sensitizing allergenicity risk of novel food proteins. The aim of this study was to introduce a series of sequential human epithelial and immune cell cocultures mimicking key immune events after exposure to the common food allergen ovalbumin from intestinal epithelial cell (IEC) activation up to mast cell degranulation.

Methods

This in vitro human mucosal food sensitizing allergenicity model combines crosstalk between IEC and monocyte-derived dendritic cells (moDC), followed by coculture of the primed moDCs with allogenic naïve CD4+ T cells. During subsequent coculture of primed CD4+ T cells with naïve B cells, IgE isotype-switching was monitored and supernatants were added to primary human mast cells to investigate degranulation upon IgE crosslinking. Mediator secretion and surface marker expression of immune cells were determined.

Results

Ovalbumin activates IEC and underlying moDCs, both resulting in downstream IgE isotype-switching. However, only direct exposure of moDCs to ovalbumin drives Th2 polarization and a humoral B cell response allowing for IgE mediated mast cell degranulation, IL13 and IL4 release in this sequential DC-T cell-B cell-mast cell model, indicating also an immunomodulatory role for IEC.

Conclusion

This in vitro coculture model combines multiple key events involved in allergic sensitization from epithelial cell to mast cell, which can be applied to study the allergic mechanism and sensitizing capacity of proteins.

Development of Adaptive Immunity and Its Role in Lung Remodeling

Asthma is characterized by airflow limitations resulting from bronchial closure, which can be either reversible or fixed due to changes in airway tissue composition and structure, also known as remodeling. Airway remodeling is defined as increased presence of mucins-producing epithelial cells, increased thickness of airway smooth muscle cells, angiogenesis, increased number and activation state of fibroblasts, and extracellular matrix (ECM) deposition. Airway inflammation is believed to be the main cause of the development of airway remodeling in asthma. In this chapter, we will review the development of the adaptive immune response and the impact of its mediators and cells on the elements defining airway remodeling in asthma.

The Role of Cytotoxic T-Lymphocyte Antigen 4 in the Pathogenesis of Multiple Sclerosis

Multiple sclerosis (MS) is an autoimmune neurodegenerative disorder of the central nervous system that presents heterogeneous clinical manifestations and course. It has been shown that different immune checkpoints, including Cytotoxic T-Lymphocyte Antigen 4 (CTLA-4), can be involved in the pathogenesis of MS. CTLA-4 is a critical regulator of T-cell homeostasis and self-tolerance and represents a key inhibitor of autoimmunity. In this scopingreview, we resume the current preclinical and clinical studies investigating the role of CTLA-4 in MS with different approaches. While some of these studies assessed the expression levels of CTLA-4 on T cells by comparing MS patients with healthy controls, others focused on the evaluation of the effects of common MS therapies on CTLA-4 modulation or on the study of the CTLA-4 blockade or deficiency in experimental autoimmune encephalomyelitis models. Moreover, other studies in this field aimed to discover if the CTLA-4 gene might be involved in the predisposition to MS, whereas others evaluated the effects of treatment with CTLA4-Ig in MS. Although these results are of great interest, they are often conflicting. Therefore, further studies are needed to reveal the exact mechanisms underlying the action of a crucial immune checkpoint such as CTLA-4 in MS to identify novel immunotherapeutic strategies for MS patients.

Treatment of experimental autoimmune encephalomyelitis using AAV gene therapy by blocking T cell costimulatory pathways

Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system (CNS), characterized by inflammation and demyelination. Presently, repeated relapses of MS necessitate long-term immune-regulatory therapy. Blocking the CD28-B7 and CD40-CD40L costimulatory pathways is an effective and synergistic method for the prevention and amelioration of clinical symptoms of experimental autoimmune encephalomyelitis (EAE), a mouse model of MS. In this study, to explore the efficacy and safety of MS gene therapy, we used adeno-associated virus (AAV) as a vector to deliver CTLA4-immunoglobulin (Ig) or CD40-Ig on the EAE induced by myelin oligodendrocyte glycoprotein (MOG). Our results showed that a single administration of AAV8-CTLA4-Ig, either alone or with AAV8-CD40-Ig, protected mice from EAE and reversed disease progression. Decreased CD4⁺ and CD8⁺ T cell infiltration, inhibition of MOG antibody response, and downregulation of neuroinflammation were observed in mice receiving AAV, suggesting that autoimmunity was suppressed in EAE pathology. Moreover, no hematological or hepatic toxicity was observed in AAV-treated mice. Thus, compared with treatment with recombinant CTLA4-Ig (belatacept), AAV gene therapy could effectively control clinical symptoms and suppress autoimmunity in the long term. In summary, our study provides a potential therapeutic method for blocking T cell costimulation for the treatment of MS via gene therapy.

Contribution of the Immune Response in the Ileum to the Development of Diarrhoea caused by Helminth Infection: Studies with the Sheep Model

Gastrointestinal helminths are a global health issue, for humans as well as domestic animals. Most studies focus on the tissues that are infected with the parasite, but here we studied the ileum, a tissue that is rarely infected by helminths. We tested whether inflammation in the ileum contributes to the development and severity of diarrhoea, by comparing sheep that are susceptible (n = 4) or resistant (n = 4) to the disease. We analyzed the ileum transcriptome using RNASeq sequencing approach and various bioinformatics tools including FastQC, STAR, featureCounts, DESeq2, DAVID, clusterProfiler, Cytoscape (ClusterONE) and EnrichR. We identified 243 differentially expressed genes (DEGs), of which 118 were up-regulated and 125 were down-regulated DEGs in the diarrhoea-susceptible animals compared to the diarrhoea-resistant animals. The resulting DEGs were functionally enriched for biological processes, pathways and gene set enrichment analysis. The up-regulated DEGs suggested that an inflammatory immune response was coupled with genes involved in 'Th2 immune response' and 'anti-inflammatory response'. The down-regulated DEGs were related to ion transport, muscle contraction and pathways preventing inflammation. We conclude that i) susceptibility to helminth-induced diarrhoea involves an inflammatory response at a non-infectious site; ii) down-regulation of pathways preventing inflammation can contribute to the severity of diarrhoea; and iii) genes involved in anti-inflammatory responses can reduce the inflammation and diarrhoea.

Parthenolide Suppresses T Helper 17 and Alleviates Experimental Autoimmune Encephalomyelitis

T helper (Th) cells play crucial roles in inflammation and adaptive immune system. Importantly, Th17 cells, a major pathogenic Th cell subset, are involved in the pathogenesis of multiple sclerosis (MS) and its classical animal modal experimental autoimmune encephalomyelitis (EAE). Previous studies have shown that parthenolide (PTL), a sesquiterpene lactone, possesses potent anti-cancer and anti-inflammatory activities. However, the immunosuppressive effect of PTL on the pathogenic Th17 cell and MS is unclear. In this study, we showed that PTL treatment could alleviate clinical symptoms by inhibiting inflammatory cell infiltration, reducing inflammation and demyelination of CNS. In addition, the mRNA expression of cytokines and inflammatory factors in CD4⁺ T cells, especially Th1 and Th17 cells, reduced in both CNS and peripheral immune tissue of EAE mice. Furthermore, PTL could inhibit the reactivation of MOG-specific T cells and the differentiation of naïve CD4⁺ T cells into Th17 cells in vitro. We also found that PTL inhibited nuclear factor kappa B (NF-κB) signaling and retinoid-related orphan receptor-γt (RORγt) in mouse Th17 cell and human Jurkat cell line. Taken together, our data demonstrated a critical immune-suppressive effect of PTL on autoimmune inflammation through regulating Th17 cells and the NF-κB/RORγt pathway.

The PDE4 inhibitor tanimilast shows distinct immunomodulatory properties associated with a type 2 endotype and CD141 upregulation

Background

Tanimilast is a novel and selective inhaled inhibitor of phosphodiesterase-4 in advanced clinical development for chronic obstructive pulmonary disease (COPD). Tanimilast is known to exert prominent anti-inflammatory activity when tested in preclinical experimental models as well as in human clinical studies. Recently, we have demonstrated that it also finely tunes, rather than suppressing, the cytokine network secreted by activated dendritic cells (DCs). This study was designed to characterize the effects of tanimilast on T-cell polarizing properties of DCs and to investigate additional functional and phenotypical features induced by tanimilast.

Methods

DCs at day 6 of culture were stimulated with LPS in the presence or absence of tanimilast or the control drug budesonide. After 24 h, DCs were analyzed for the expression of surface markers of maturation and activation by flow cytometry and cocultured with T cells to investigate cell proliferation and activation/polarization. The regulation of type 2-skewing mediators was investigated by real-time PCR in DCs and compared to results obtained in vivo in a randomized placebo-controlled trial on COPD patients treated with tanimilast.

Results

Our results show that both tanimilast and budesonide reduced the production of the immunostimulatory cytokine IFN-γ by CD4⁺ T cells. However, the two drugs acted at different levels since budesonide mainly blocked T cell proliferation, while tanimilast skewed T cells towards a Th2 phenotype without affecting cell proliferation. In addition, only DCs matured in the presence of tanimilast displayed increased CD86/CD80 ratio and CD141 expression, which correlated with Th2 T cell induction and dead cell uptake respectively. These cells also upregulated cAMP-dependent immunosuppressive molecules such as IDO1, TSP1, VEGF-A and Amphiregulin. Notably, the translational value of these data was confirmed by the finding that these same genes were upregulated also in sputum cells of COPD patients treated with tanimilast as add-on to inhaled glucocorticoids and bronchodilators.

Conclusion

Taken together, these findings demonstrate distinct immunomodulatory properties of tanimilast associated with a type 2 endotype and CD141 upregulation in DCs and provide a mechanistic rationale for the administration of tanimilast on top of inhaled corticosteroids.

Immune Modulation by Antigenic Peptides and Antigenic Peptide Conjugates for Treatment of Multiple Sclerosis

The immune system defends our body by fighting infection from pathogens utilizing both the innate and adaptive immune responses. The innate immune response is generated rapidly as the first line of defense. It is followed by the adaptive immune response that selectively targets infected cells. The adaptive immune response is generated more slowly, but selectively, by targeting a wide range of foreign particles (i.e., viruses or bacteria) or molecules that enter the body, known as antigens. Autoimmune diseases are the results of immune system glitches, where the body's adaptive system recognizes self-antigens as foreign. Thus, the host immune system attacks the self-tissues or organs with a high level of inflammation and causes debilitation in patients. Many current treatments for autoimmune diseases (i.e., multiple sclerosis (MS), rheumatoid arthritis (RA)) have been effective but lead to adverse side effects due to general immune system suppression, which makes patients vulnerable to opportunistic infections. To counter these negative effects, many different avenues of antigen specific treatments are being developed to selectively target the autoreactive immune cells for a specific self-antigen or set of self-antigens while not compromising the general immune system. These approaches include soluble antigenic peptides, bifunctional peptide inhibitors (BPI) including IDAC and Fc-BPI, polymer conjugates, and peptide-drug conjugates. Here, various antigen-specific methods of potential treatments, their efficacy, and limitations will be discussed along with the potential mechanisms of action.

Host-directed antileishmanial interventions: Harvesting unripe fruits to reach fruition

Leishmaniasis is an exemplary paradigm of immune evasion, fraught with the perils of limited clinical assistance, escalating costs of treatment and made worse with the lack of suitable vaccine. While drugs remain central to large-scale disease control, the growing emergence of parasite resistance necessitates the need for combination therapy involving host-directed immunological agents. Also, since prolonged disease progression is associated with strong immune suppression of the host, augmentation of host immunity via restoration of the immunoregulatory circuit involving antigen-presenting cells and T-cells, activation of macrophage function and/or CD4⁺ T helper 1 cell differentiation may serve as an ideal approach to resolve severe cases of leishmaniasis. As such, therapies that embody a synergistic approach that involve direct killing of the parasite in addition to elevating host immunity are likely to pave the way for widespread elimination of leishmaniasis in the future. With this review, we aim to recapitulate the various immunotherapeutic agents found to hold promise in antileishmanial treatment both in vitro and in vivo. These include parasite-specific antigens, dendritic cell-targeted therapy, recombinant inhibitors of various components intrinsic to immune cell signaling and agonists or antagonists to immune cells and cytokines. We also summarize their abilities to direct therapeutic skewing of the host cell-immune response and review their potential to combat the disease either alone, or as adjunct modalities.

Gene-environment interactions increase the risk of pediatric-onset multiple sclerosis associated with ozone pollution

BACKGROUND

We previously reported a relationship between air pollutants and increased risk of pediatric-onset multiple sclerosis (POMS). Ozone is an air pollutant that may play a role in multiple sclerosis (MS) pathoetiology. CD86 is the only non-HLA gene associated with POMS for which expression on antigen-presenting cells (APCs) is changed in response to ozone exposure.

OBJECTIVES

To examine the association between county-level ozone and POMS, and the interactions between ozone pollution, CD86, and HLA-DRB1*15, the strongest genetic variant associated with POMS.

METHODS

Cases and controls were enrolled in the Environmental and Genetic Risk Factors for Pediatric MS study of the US Network of Pediatric MS Centers. County-level-modeled ozone data were acquired from the CDC's Environmental Tracking Network. Participants were assigned ozone values based on county of residence. Values were categorized into tertiles based on healthy controls. The association between ozone tertiles and having MS was assessed by logistic regression. Interactions between tertiles of ozone level and the GG genotype of the rs928264 (G/A) single nucleotide polymorphism (SNP) within CD86, and the presence of DRB1*15:01 (DRB1*15) on odds of POMS were evaluated. Models were adjusted for age, sex, genetic ancestry, and mother's education. Additive interaction was estimated using relative excess risk due to interaction (RERI) and attributable proportions (APs) of disease were calculated.

RESULTS

A total of 334 POMS cases and 565 controls contributed to the analyses. County-level ozone was associated with increased odds of POMS (odds ratio 2.47, 95% confidence interval (CI): 1.69-3.59 and 1.95, 95% CI: 1.32-2.88 for the upper two tertiles, respectively, compared with the lowest tertile). There was a significant additive interaction between high ozone tertiles and presence of DRB1*15, with a RERI of 2.21 (95% CI: 0.83-3.59) and an AP of 0.56 (95% CI: 0.33-0.79). Additive interaction between high ozone tertiles and the CD86 GG genotype was present, with a RERI of 1.60 (95% CI: 0.14-3.06) and an AP of 0.37 (95% CI: 0.001-0.75) compared to the lowest ozone tertile. AP results indicated that approximately half of the POMS risk in subjects can be attributed to the possible interaction between higher county-level ozone carrying either DRB1*15 or the CD86 GG genotype.

CONCLUSIONS

In addition to the association between high county-level ozone and POMS, we report evidence for additive interactions between higher county-level ozone and DRB1*15 and the CD86 GG genotype. Identifying gene-environment interactions may provide mechanistic insight of biological processes at play in MS susceptibility. Our work suggests a possible role of APCs for county-level ozone-induced POMS risk.

Food Allergies and Intolerances: A Clinical Approach to the Diagnosis and Management of Adverse Reactions to Food

Food allergy is an aberrant immunological response to food antigen, which can result in potentially life-threatening reactions. It is often challenging to differentiate food allergy from other adverse reactions to food because their presentations can be indistinguishable. The purpose of this article is to give an overview of the classification, evaluation, and management of adverse food reactions, key differentiating features of food allergy, roles and limitations of various food allergy testing, and promising areas of emerging research. Case studies are used to highlight some of the clinical pearls in diagnosing and managing food-related diseases.

Costimulation molecules differentially regulate the ERK-Zfp831 axis to shape T follicular helper cell differentiation

T follicular helper (Tfh) cells play essential roles in regulating humoral immunity, especially germinal center reactions. However, how CD4⁺ T cells integrate the antigenic and costimulatory signals in Tfh cell development is still poorly understood. Here, we found that phorbol 12-myristate 13-acetate (PMA) + ionomycin (P+I) stimulation, together with interleukin-6 (IL-6), potently induce Tfh cell-like transcriptomic programs in vitro. The ERK kinase pathway was attenuated under P+I stimulation; ERK2 inhibition enhanced Tfh cell development in vitro and in vivo. We observed that inducible T cell costimulator (ICOS), but not CD28, lacked the ability to activate ERK, which was important in sustaining Tfh cell development. The transcription factor Zfp831, whose expression was repressed by ERK, promoted Tfh cell differentiation by directly upregulating the expression of the transcription factors Bcl6 and Tcf7. We have hence identified an ERK-Zfp831 axis, regulated by costimulation signaling, in critical regulation of Tfh cell development.

T helper cells in depression: central role of Th17 cells

Depression is one of the most common neuropsychiatric disorders in the world. While conventional pharmaceutical therapy targets monoaminergic pathway dysfunction, it has not been totally successful in terms of positive outcomes, remission, and preventing relapses. There is an increasing amount of evidence that neuroinflammation may play a significant part in the pathophysiology of depression. Among the key components of the neuroinflammatory pathways already known to be active are the T helper (Th) cells, especially Th17 cells. While various preclinical and clinical studies have reported increased levels of Th17 cells in both serum and brain tissue of laboratory model animals, contradictory results have argued against a pertinent role of Th17 cells in depression. Recent studies have also revealed a role for more pathogenic and inflammatory subsets of Th17 in depression, as well as IL-17A and Th17 cells in non-responsiveness to conventional antidepressant therapy. Despite recent advances, there is still a significant knowledge gap concerning the exact mechanism by which Th17 cells influence neuroinflammation in depression. This review first provides a short introduction to the major findings that led to the discovery of the role of Th cells in depression. The major subsets of Th cells known to be involved in neuroimmunology of depression, such as Th1, Th17, and T regulatory cells, are subsequently described, with an in-depth discussion on current knowledge about Th17 cells in depression.

Suppression of CD80 expression by ICP22 affect HSV-1 replication and CD8+IFNγ+ infiltrates in the eye of infected mice but not latency-reactivation

Previously, we reported that herpes simplex virus type 1 (HSV-1) ICP22 binds to the CD80 promoter and suppresses its expression in vitro and in vivo. To better understand the impact of ICP22 binding to CD80 on HSV-1 infectivity and pathogenicity, we mapped the region of ICP22 required to bind the CD80 promoter to a 40-amino-acid (aa) region of ICP22. We constructed a recombinant HSV-1 expressing a truncated form of ICP22 that lacks these 40 aa, which does not bind to the CD80 promoter (KOS-ICP22Δ40) and retains the ability to replicate efficiently in rabbit skin cells, in contrast to ICP22-null virus. The replication of this recombinant virus in vitro and in vivo was higher than that of the ICP22-null virus, but virus replication kinetics were lower than those of the wild-type (WT) control virus. Similar to ICP22-null virus, the KOS-ICP22Δ40 mutant virus increased CD80 expression in dendritic cells (DCs) and interferon gamma (IFN-γ) expression in CD8⁺ T cells but not CD4⁺ T cells in infected mouse corneas. In contrast to the significantly reduced virus replication in the eyes of ocularly infected mice, the levels of latency reactivation were similar between KOS-ICP22Δ40 virus and WT virus. Thus, blocking ICP22 binding to the CD80 promoter using a recombinant virus expressing a truncated ICP22 that lacks CD80 promoter binding appears to reduce virus replication and enhance CD8⁺IFN-γ⁺ infiltrates in corneas of infected mice, with no effect on latency reactivation.

IMPORTANCE Direct binding of HSV-1 ICP22 to the CD80 promoter downregulates the expression of the costimulatory molecule CD80 but not CD86. In this study, we fine mapped the region of ICP22 required for binding to the CD80 promoter and constructed a recombinant virus containing a deletion in ICP22 that failed to bind to the CD80 promoter. This recombinant virus replicated less efficiently in vitro and in vivo than did the WT control virus, although CD80-expressing CD11c⁺ cells and IFN-γ-expressing CD8⁺ T cells were increased. Interestingly, the levels of latency and reactivation in the two viruses were similar despite lower virus replication in the eyes of infected mice. Therefore, blocking the interaction of ICP22 with the CD80 promoter could be used to temper the immune response.

Functional Ambivalence of Dendritic Cells: Tolerogenicity and Immunogenicity

Dendritic cells (DCs) are the most potent professional antigen-presenting cells (APCs) and inducers of T cell-mediated immunity. Although DCs play a central role in promoting adaptive immune responses against growing tumors, they also establish and maintain peripheral tolerance. DC activity depends on the method of induction and/or the presence of immunosuppressive agents. Tolerogenic dendritic cells (tDCs) induce immune tolerance by activating CD4⁺CD25⁺Foxp3⁺ regulatory T (Treg) cells and/or by producing cytokines that inhibit T cell activation. These findings suggest that tDCs may be an effective treatment for autoimmune diseases, inflammatory diseases, and infertility.

CD28 Genetic Variants Increase Susceptibility to Diabetic Kidney Disease in Chinese Patients with Type 2 Diabetes: A Cross-Sectional Case Control Study

Few studies have illuminated the genetic role of T cell costimulatory molecule CD28/CD80/CTLA4 variants in diabetic kidney disease (DKD) susceptibility. We aimed to investigate the causal role of genetic polymorphisms in CD28/CD80/CTLA4 with DKD susceptibility in patients with T2DM. A total of 3253 patients with T2DM were recruited for genotyping: including 204 DKD patients and 371 controls in stage 1 and 819 DKD patients and 563 controls in stage 2; besides, 1296 T2DM patients were selected for the analysis of association between loci and DKD-related traits. A subset of 227 T2DM patients (118 patients with DKD and 109 patients without DKD) from the total population above were selected to assess serum soluble CD28 (sCD28) levels. Then, we performed a candidate gene association study to identify single-nucleotide polymorphisms (SNPs) associated with DKD susceptibility and further used those SNPs to perform Mendelian randomization analyses of serum sCD28 level and DKD susceptibility. Under additive genetic models, CD28-rs3116494 (OR = 1.29 [95% CI 1.11, 1.51], P = 0.0011) and CD80-rs3850890 (OR = 1.16 [95% CI 1.02, 1.31], P = 0.0283) were associated with DKD susceptibility adjusted for age, gender, body mass index (BMI), duration of diabetes, and HbA1c. CD28-rs3116494 was associated with serum sCD28 level (β = 0.26 [95% CI 0.08, 0.44], P = 0.0043). The Mendelian randomization analysis showed that CD28-rs3116494 played a causal role in DKD by influencing serum sCD28 levels (β = 1.15 [95% CI 0.46, 1.83], P = 0.0010). In conclusion, we identified that two novel SNPs, CD28-rs3116494 and CD80-rs3850890, were associated with DKD susceptibility. Using the Mendelian randomization analysis, our study provided evidence for a causal relationship between serum CD28 levels and DKD with T2DM in the Chinese population.

Different doses of ovalbumin exposure on dendritic cells determine their genetic/epigenetic regulation and T cell differentiation

It has been reported that allergen dosage can impact the differentiation of dendritic cells (DCs)-mediated T cells. However, the mechanisms of such dose-dependent differentiation are poorly understood. In this study, bone marrow-derived immature DCs stimulated with Ovalbumin (OVA) of different concentrations (0, 10, 100, 1000, 10000μg/ml, respectively). DCs were then co-cultured with naïve T cells. RNA-sequencing detection and DNA methylation of DCs were performed. We show that when DCs were stimulated with low-dose (10μg/ml), 77 genes were up-regulated and 87 genes down-regulated. Most activated genes were related to ribosome synthesis and ion channel inhibition. At the medium-dose (100μg/ml), 339 genes were up-regulated and 168 genes down-regulated. Most activated genes involved cytokine synthesis and regulation of immune responses. At high-dose (10000μg/ml), 2497 genes were up-regulated and 1156 genes down-regulated. TNF signaling pathway, NF-kappa B signaling pathway, antigen processing and presentation signaling pathway were mostly up-regulated. The related co-stimulators, co-inhibitory molecules, inhibitory cytokines, negative regulating enzymes were highly expressed. The monocarbate, coenzyme, fatty acid, glucolipid, starch, sucrose and other metabolism-related signaling pathways were down-regulated. The profiles of DNA methylation and RNA synthesis of DCs varied with different doses of OVA, which serves to induce T cells to differentiate in various directions.

IL-12-Induced Immune Suppressive Deficit During CD8+ T-Cell Differentiation

Autoimmune diseases are characterized by regulatory deficit in both the CD4+ and CD8+ T-cell compartments. We have shown that CD8+ T-cells associated with acute relapse of multiple sclerosis are significantly deficient in their immune suppressive ability. We hypothesized that distinct CD8+ cytotoxic T-cell (Tc) lineages, determined by cytokine milieu during naïve T-cell differentiation, may harbor differential ability to suppress effector CD4+ T-cells. We differentiated purified human naïve CD8+ T-cells in vitro toward Tc0 (media control), Tc1 and Tc17 lineages. Using in vitro flow cytometric suppression assays, we observed that Tc0 and Tc17 cells had similar suppressive ability. In contrast, Tc1 cells showed significant loss of suppressive ability against ex vivo CD4+ T-cells and in vitro-differentiated Th0, Th1 and Th17 cells. Of note, Tc1 cells were also suboptimal in suppressing CD4-induced acute xenogeneic graft versus host disease (xGVHD) in vivo. Tc subtypes derived under various cytokine combinations revealed that IL-12-containing conditions resulted in less suppressive cells exhibiting dysregulated cytotoxic degranulation. RNA sequencing transcriptome analyses indicated differential regulation of inflammatory genes and enrichment in GM-CSF-associated pathways. These studies provide insights into the role of T-cell differentiation in CD8 suppressive biology and may reveal therapeutically targetable pathways to reverse suppressive deficit during immune-mediated disease.

Got your mother in a whirl: The role of maternal T cells and myeloid cells in pregnancy

Appropriate development of the placenta is required for healthy pregnancy to occur. After implantation of the fertilized blastocyst, fetal trophoblasts invade the endometrium and myometrium of the mother's uterus to establish placentation. In this process, fetal trophoblasts encounter maternal immune cells. In this review, we focus on the role of maternal T cells and myeloid cells (macrophages, dendritic cells) in pregnancy and their interaction with trophoblasts. To retain immunologic tolerization, trophoblasts evade immune recognition by T cells and produce factors that modulate their phenotype and function. On top of that, the local environment at the maternal-fetal interface favors expansion of regulatory T cells. Macrophages and dendritic cells are essential in maintaining a healthy pregnancy. They produce soluble factors and act as antigen-presenting cells, thereby interacting with T cells. Herein, M2 macrophages, immature dendritic cells, CD4⁺ Th2 cells, and regulatory T cells represent an axis that maintains a local immune tolerant environment. We consider outstanding issues concerning these cell types and their pathways, which need to be addressed in future investigations. Data from recent single-cell sequencing experiments of the placental bed, to study heterogeneity of maternal immune cells and to predict cell-cell interactions, are discussed. Novel ways for long-term culturing of primary trophoblasts allow for cell-cell interaction studies in a functional way. Future directions should include study of the functionality of currently known and newly identified decidual immune cell subsets in healthy and complicated pregnancies, and their interaction with and modulation by trophoblast cells.

Chromosome 2q33genetic polymorphisms in Tunisian endemic pemphigus foliaceus

Background

Several studies have suggested that polymorphisms within genes encoding T‐lymphocyte immune regulating molecules: CD28, CTLA‐4, and ICOS, may alter the signaling process and subsequently could be involved in susceptibility to a broad spectrum of autoimmune diseases.

Methods

This study aimed to replicate associations between common polymorphisms in the 2q33.2 cluster and susceptibility to pemphigus foliaceus (PF) in the Tunisian population. We investigated seven polymorphisms: rs3116496 and rs1879877 (CD28), rs231775, rs3087243, and (AT)_n repeat (CTLA4); rs11889031 and rs10932029 (ICOS) in a case–control study which enrolled 106 Tunisian PF patients and 205 matched healthy controls.

Results

We confirmed the associations with CTLA4((AT)₁₃, p = 0.00137, OR = 3.96 and (AT)₂₀, p = 0.008, OR = 5.22; respectively) and ICOS genes (rs10932029>CT, p = 0.034, OR = 2.12 and rs10932029>TT, p = 0.04 and OR = 0.41).

Conclusion

Our results indicate that susceptibility to PF is located in the proximal and the distal 3′ flanking region of the CTLA4/ICOS promoter. These findings may open avenues to the treatment of patients with biological drugs targeting CTLA4/ICOS molecules, in a personalized manner to achieve more effective treatment.

Ataxin-1 regulates B cell function and the severity of autoimmune experimental encephalomyelitis

Ataxin-1 (ATXN1) is a ubiquitous polyglutamine protein expressed primarily in the nucleus where it binds chromatin and functions as a transcriptional repressor. Mutant forms of ataxin-1 containing expanded glutamine stretches cause the movement disorder spinocerebellar ataxia type 1 (SCA1) through a toxic gain-of-function mechanism in the cerebellum. Conversely, ATXN1 loss-of-function is implicated in cancer development and Alzheimer's disease (AD) pathogenesis. ATXN1 was recently nominated as a susceptibility locus for multiple sclerosis (MS). Here, we show that Atxn1-null mice develop a more severe experimental autoimmune encephalomyelitis (EAE) course compared to wildtype mice. The aggravated phenotype is mediated by increased T helper type 1 (Th1) cell polarization, which in turn results from the dysregulation of B cell activity. Ataxin-1 ablation in B cells leads to aberrant expression of key costimulatory molecules involved in proinflammatory T cell differentiation, including cluster of differentiation (CD)44 and CD80. In addition, comprehensive phosphoflow cytometry and transcriptional profiling link the exaggerated proliferation of ataxin-1 deficient B cells to the activation of extracellular signal-regulated kinase (ERK) and signal transducer and activator of transcription (STAT) pathways. Lastly, selective deletion of the physiological binding partner capicua (CIC) demonstrates the importance of ATXN1 native interactions for correct B cell functioning. Altogether, we report a immunomodulatory role for ataxin-1 and provide a functional description of the ATXN1 locus genetic association with MS risk.

N-Glycan Branching Decouples B Cell Innate and Adaptive Immunity to Control Inflammatory Demyelination

B cell depletion potently reduces episodes of inflammatory demyelination in multiple sclerosis (MS), predominantly through loss of innate rather than adaptive immunity. However, molecular mechanisms controlling innate versus adaptive B cell function are poorly understood. N-glycan branching, via interactions with galectins, controls endocytosis and signaling of cell surface receptors to control cell function. Here we report that N-glycan branching in B cells dose dependently reduces pro-inflammatory innate responses by titrating decreases in Toll-like receptor-4 (TLR4) and TLR2 surface expression via endocytosis. In contrast, a minimal level of N-glycan branching maximizes surface retention of the B cell receptor (BCR) and the CD19 co-receptor to promote adaptive immunity. Branched N-glycans inhibit antigen presentation by B cells to reduce T helper cell-17 (TH17)/TH1 differentiation and inflammatory demyelination in mice. Thus, N-glycan branching negatively regulates B cell innate function while promoting/maintaining adaptive immunity via BCR, providing an attractive therapeutic target for MS.

The balance of regulatory and stimulatory B cell subsets in breast cancer draining lymph nodes correlates with tumor prognostic factors

AIMS

B cells can promote or inhibit immune responses against breast cancer. We investigated changes in the frequency of B cells with stimulatory or regulatory capacity in breast tumor draining lymph nodes during cancer progression.

MAIN METHODS

We isolated mononuclear cells from fresh axillary lymph nodes (LNs) of 44 patients with breast cancer and stained lymphocytes with antibodies against CD19, CD80, CD86, CD39 and CD73. To assess programmed death-1 (PD-1) and PD-ligand 1 (PD-L1) expression, lymphocytes were briefly stimulated, stained for CD19, PD-1 and PD-L1, and examined with flow cytometry.

KEY FINDINGS

The frequency of CD80⁺ B cells was higher in nonmetastatic lymph nodes, while the percentage of CD86⁺ B cells showed a positive relationship with higher tumor grade and higher numbers of involved LNs. A small proportion of unstimulated B cells expressed PD-1 or PD-L1 but these molecules were rapidly upregulated on B cells following activation. The frequency of stimulated PD-L1⁺ B cells showed an inverse association with estrogen and progesterone receptor expression and a nonsignificant positive association with tumor grade. In addition, the percentage of unstimulated PD-1⁺ B cells was higher in patients with higher-grade tumors. CD73 expression on B cells was associated with lower numbers of involved LNs, and the frequency of CD39⁺ B cells was higher in patients with larger tumors.

SIGNIFICANCE

CD86⁺, CD39⁺, PD-1⁺ and PD-L1⁺ B cells showed associations with poor prognostic factors, therefore their potential role in the suppression of the immune responses against breast cancer should be evaluated in greater detail.

Novel Toll-Like Receptor 9 Agonist Derived from Cryptococcus neoformans Attenuates Allergic Inflammation Leading to Asthma Onset in Mice

INTRODUCTION

The enhanced type 2 helper (Th2) immune response is responsible for the pathogenesis of allergic asthma. To suppress the enhanced Th2 immune response, activation of the Th1 immune response has been an alternative strategy for anti-asthma therapy. In this context, effective Th1-inducing adjuvants that inhibit the development of allergic asthma but do not flare the side effects of the primary agent are required in clinical treatment and preventive medicine.

OBJECTIVE

In this study, we aimed to determine the regulation of the Th2 type immune response in asthma by a novel immunostimulatory oligodeoxynucleotide (ODN) derived from Cryptococcus neoformans, termed ODN112, which contains a cytosine-guanine (CG) sequence but not canonical CpG motifs.

METHODS

Using an ovalbumin-induced asthma mouse model, we assessed the effect of ODN112 on prototypical asthma-related features in the lung and on the Th1/Th2 profile in the lymph nodes and lung of mice treated with ODN112 during sensitization.

RESULTS AND CONCLUSION

ODN112 treatment attenuated asthma features in mice. In the bronchial lymph nodes of the lungs and in the spleen, ODN112 increased interferon-γ production and attenuated Th2 recall responses. In dendritic cells (DCs) after allergen sensitization, ODN112 enhanced cluster of differentiation (CD) 40 and CD80 expression but did not alter CD86 expression. Interleukin-12p40 production from DCs was also increased in a Th2-polarizing condition. Our results suggest that ODN112 is a potential Th1-inducing adjuvant during Th2 cell differentiation in the sensitization phase.

Genetically engineered mesenchymal stem cells: targeted delivery of immunomodulatory agents for tumor eradication

Cancer immunotherapy emerged as a novel therapeutic option that employs enhanced or amended native immune system to create a robust response against malignant cells. The systemic therapies with immune-stimulating cytokines have resulted in substantial dose-limiting toxicities. Targeted cytokine immunotherapy is being explored to overcome the heterogeneity of malignant cells and tumor cell defense with a remarkable reduction of systemic side effects. Cell-based strategies, such as dendritic cells (DCs), fibroblasts or mesenchymal stem cells (MSCs) seek to minimize the numerous toxic side effects of systemic administration of cytokines for extended periods of time. The usual toxicities comprised of a vascular leak, hypotension, and respiratory insufficiency. Natural and strong tropism of MSCs toward malignant cells made them an ideal systemic delivery vehicle to direct the proposed therapeutic genes to the vicinity of a tumor where their expression could evoke an immune reaction against the tumor. Compared with other methods, the delivery of cytokines via engineered MSCs is safer and renders a more practical, and promising strategy. Large numbers of genes code for cytokines have been utilized to reengineer MSCs as therapeutic cells. This review highlights the recent findings on the cytokine gene therapy for human malignancies by focusing on MSCs application in cancer immunotherapy.

Pathogenetic Mechanisms of T Cell Dysfunction in Chronic HBV Infection and Related Therapeutic Approaches

A great effort of research has been devoted in the last few years to developing new anti-HBV therapies of finite duration that also provide effective sustained control of virus replication and antigen production. Among the potential therapeutic strategies, immune-modulation represents a promising option to cure HBV infection and the adaptive immune response is a rational target for novel therapeutic interventions, in consideration of the key role played by T cells in the control of virus infections. HBV-specific T cells are severely dysfunctional in chronic HBV infection as a result of several inhibitory mechanisms which are simultaneously active within the chronically inflamed liver. Indeed, the liver is a tolerogenic organ harboring different non-parenchymal cell populations which can serve as antigen presenting cells (APC) but are poorly efficient in effector T cell priming, with propensity to induce T cell tolerance rather than T cell activation, because of a poor expression of co-stimulatory molecules, up-regulation of the co-inhibitory ligands PD-L1 and PD-L2 upon IFN stimulation, and production of immune regulatory cytokines, such as IL10 and TGF-β. They include resident dendritic cells (DCs), comprising myeloid and plasmacytoid DCs, liver sinusoidal endothelial cells (LSECs), Kupffer cells (KCs), hepatic stellate cells (HSCs) as well as the hepatocytes themselves. Additional regulatory mechanisms which contribute to T cell attrition in the chronically infected liver are the high levels of soluble mediators, such as arginase, indoleamine 2,3-dioxygenase (IDO) and suppressive cytokines, the up-regulation of inhibitory checkpoint receptor/ligand pairs, the expansion of regulatory cells, such as CD4+FOXp3+ Treg cells, myeloid-derived suppressor cells and NK cells. This review will deal with the interactions between immune cells and liver environment discussing the different mechanisms which contribute to T cell dysfunction in chronic hepatitis B, some of which are specifically activated in HBV infection and others which are instead common to chronic inflammatory liver diseases in general. Therapeutic interventions targeting dysregulated pathways and cellular functions will be also delineated.

Distinguish CIDP with autoantibody from that without autoantibody: pathogenesis, histopathology, and clinical features

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is considered to be an immune-mediated heterogeneous disease involving cellular and humoral immunity. In recent years, autoantibodies against nodal/paranodal protein neurofascin155 (NF155), neurofascin186 (NF186), contactin-1 (CNTN1), and contactin-associated protein 1 (CASPR1) have been identified in a small subset of patients with CIDP, which disrupt axo-glial interactions at nodes/paranodes. Although CIDP electrodiagnosis was made in patients with anti-nodal/paranodal component autoantibodies, macrophage-induced demyelination, the characteristic of typical CIDP, was not observed. Apart from specific histopathology, the pathogenic mechanisms and clinical manifestations of CIDP with autoantibody are also distinct. We herein compared pathogenesis, histopathology, clinical manifestations, and therapeutic response in CIDP with autoantibody vs. CIDP without autoantibody. CIDP with autoantibodies should be considered as an independent disease entity, not a subtype of CIDP due to many differences. They possibly should be classified as CIDP-like chronic nodo-paranodopathy, which can better characterize these disorders, help diagnose and make the most effective therapeutic decisions.

Dendritic Cells as Arbiters of Peritoneal Immune Responses

During the past few years, there has been a substantial increase in the understanding of innate immunity. Dendritic cells are emerging as key players in the orchestration of this early phase of immune responses, with a role that will translate into the subsequent type of adaptive immune response against infection. Here we provide an overview of dendritic cell differentiation and function, with particular emphasis on those features unique to the immune defense of the peritoneal cavity and in the context of peritoneal dialysis-associated immune responses. The reader is referred to the primary references included in the accompanying list for specific details in this fascinating field.

Genetic Adjuvants in Replicating Single-Cycle Adenovirus Vectors Amplify Systemic and Mucosal Immune Responses against HIV-1 Envelope

Most infections occur at mucosal surfaces. Providing a barrier of protection at these surfaces may be a useful strategy to combat the earliest events in infection when there are relatively few pathogens to address. The majority of vaccines are delivered systemically by the intramuscular (IM) route. While IM vaccination can drive mucosal immune responses, mucosal immunization at intranasal (IN) or oral sites can lead to better immune responses at mucosal sites of viral entry. In macaques, IN immunization with replicating single-cycle adenovirus (SC-Ads) and protein boosts generated favorable mucosal immune responses. However, there was an apparent “distance effect” in generating mucosal immune responses. IN immunization generated antibodies against HIV envelope (env) nearby in the saliva, but weaker responses in samples collected from the distant vaginal samples. To improve on this, we tested here if SC-Ads expressing genetic adjuvants could be used to amplify antibody responses in distant vaginal samples when they are codelivered with SC-Ads expressing clade C HIV env immunogen. SC-Ads env 1157 was coadministered with SC-Ads expressing 4-1BBL, granulocyte macrophage colony-stimulating factor (GMCSF), IL-21, or Clostridoides difficile (C. diff.) toxin fragments by IN or IM routes. These data show that vaginal antibody responses were markedly amplified after a single immunization by the IN or IM routes, with SC-Ad expressing HIV env if this vaccine is complemented with SC-Ads expressing genetic adjuvants. Furthermore, the site and combination of adjuvants appear to “tune” these antibody responses towards an IgA or IgG isotype bias. Boosting these priming SC-Ad responses with another SC-Ad or with SOSIP native-like env proteins markedly amplifies env antibody levels in vaginal washes. Together, this data may be useful in informing the choice of route of delivery adenovirus and peptide vaccines against HIV-1.

Costimulation Blockade in Transplantation

T cells play a pivotal role in orchestrating immune responses directed against a foreign (allogeneic) graft. For T cells to become fully activated, the T-cell receptor (TCR) must interact with the major histocompatibility complex (MHC) plus peptide complex on antigen-presenting cells (APCs), followed by a second "positive" costimulatory signal. In the absence of this second signal, T cells become anergic or undergo deletion. By blocking positive costimulatory signaling, T-cell allo-responses can be aborted, thus preventing graft rejection and promoting long-term allograft survival and possibly tolerance (Alegre ML, Najafian N, Curr Mol Med 6:843-857, 2006; Li XC, Rothstein DM, Sayegh MH, Immunol Rev 229:271-293, 2009). In addition, costimulatory molecules can provide negative "coinhibitory" signals that inhibit T-cell activation and terminate immune responses; strategies to promote these pathways can also lead to graft tolerance (Boenisch O, Sayegh MH, Najafian N, Curr Opin Organ Transplant 13:373-378, 2008). However, T-cell costimulation involves an incredibly complex array of interactions that may act simultaneously or at different times in the immune response and whose relative importance varies depending on the different T-cell subsets and activation status. In transplantation, the presence of foreign alloantigen incites not only destructive T effector cells but also protective regulatory T cells, the balance of which ultimately determines the fate of the allograft (Lechler RI, Garden OA, Turka LA, Nat Rev Immunol 3:147-158, 2003). Since the processes of alloantigen-specific rejection and regulation both require activation of T cells, costimulatory interactions may have opposing or synergistic roles depending on the cell being targeted. Such complexities present both challenges and opportunities in targeting T-cell costimulatory pathways for therapeutic purposes. In this chapter, we summarize our current knowledge of the various costimulatory pathways in transplantation and review the current state and challenges of harnessing these pathways to promote graft tolerance (summarized in Table 10.1).

Role of CCR7 on dendritic cell‑mediated immune tolerance in the airways of allergy‑induced asthmatic rats

Dendritic cells (DCs) have an important role in initiating and maintaining the immune inflammatory response in allergic asthma, and CC chemokine receptor 7 (CCR7) is directly involved in the pathogenesis of DC- and T cell-mediated allergic asthma. The present study aimed to investigate the effects of CCR7 on DC-mediated immune tolerance in allergic asthma. In the present study, bone marrow-derived DCs were transfected with an adenovirus encoding the rat CCR7 gene or a short hairpin RNA targeting CCR7 (sh-CCR7). Rats injected with DCs overexpressing CCR7 or presenting CCR7 knockdown were examined. After the rats were injected with DCs via the tail vein, bronchoalveolar lavage fluid was collected to assess its cellular composition. The protein expression levels of CCR7 in DCs were determined using immunohistochemistry and western blot analysis. The protein expression levels of interferon-γ (IFN-γ), interleukin-4 (IL-4), IL-10, IL-12, transforming growth factor-β (TGF-β) and immunoglobulin E (IgE) were determined by ELISA. Compared with the control group, the protein expression level of CCR7 was significantly higher in the CCR7 overexpression group and significantly lower in sh-CCR7 group. Similarly, the number of DCs was higher in the CCR7 overexpression group and lower in the sh-CCR7 group. The protein expression levels of IL-10 and TGF-β were significantly lower in the CCR7 overexpression group and higher in the sh-CCR7 group. In addition, the expression levels of IL-4, IL-12, IFN-γ and IgE were higher in the CCR7 overexpression group and lower in the sh-CCR7 group. The present results suggested that the role of cytokines and IgE in immune inflammation and immune tolerance in allergic asthma may be associated with the expression level of CCR7 in DCs, suggesting that CCR7 may serve a role in DC-mediated immune tolerance in allergic asthma.

Silencing of CD86 in dendritic cells by small interfering RNA regulates cytokine production in T cells from patients with allergic rhinitis in vitro

The aim of the present study was to investigate the expression and role of the co‑stimulatory molecule T‑lymphocyte activation antigen CD86 (CD86) in dendritic cells (DCs) from the peripheral blood of patients with allergic rhinitis (AR) compared with those from healthy individuals. It was observed that mature DCs from the peripheral blood of patients with AR expressed high levels of the co‑stimulatory molecule CD86, but not CD80, compared with healthy control subjects. CD86 expression levels in DCs decreased significantly following transfection with siRNA in a lentiviral vector. Furthermore, the level of transforming growth factor‑β1 produced by T cells co‑cultured with DCs was significantly increased in the siRNA group, while interleukin (IL)‑4 and IL‑5 production was significantly decreased. The findings of the present study indicated that CD86 may play a pivotal role in the regulatory T cell/type 2 helper T cell imbalance in allergic inflammation.

Mesoporous Silica as a Versatile Platform for Cancer Immunotherapy

Immunotherapy has been recognized for decades as a promising therapeutic method for cancer treatment. To enhance host immune responses against cancer, antigen-presenting cells (APCs; e.g., dendritic cells) or T cells are educated using immunomodulatory agents including tumor-associated antigens and adjuvants, and manipulated to induce a cascading adaptive immune response targeting tumor cells. Mesoporous silica materials are promising candidates to improve cancer immunotherapy based on their attractive properties that include high porosity, high biocompatibility, facile surface modification, and self-adjuvanticity. Here, the recent progress on mesoporous-silica-based immunotherapies based on two material forms is summarized: 1) mesoporous silica nanoparticles (MSNs), which can be internalized into APCs, and 2) micrometer-sized mesoporous silica rods (MSRs) that can form a 3D space to recruit APCs. Subcutaneously injected MSN-based cancer vaccines can be taken up by peripheral APCs or by APCs in lymphoid organs to educate the immune system against cancer cells. MSR cancer vaccines can recruit immune cells into the MSR scaffold to induce cancer-specific immunity. Both vaccine systems successfully stimulate the adaptive immune response to eradicate cancer in vivo. Thus, mesoporous silica has potential value as a material platform for the treatment of cancer or infectious diseases.

Immunomodulatory effects of Rhipicephalus haemaphysaloides serpin RHS2 on host immune responses

Background

Rhipicephalus haemaphysaloides is a widespread tick species in China and other South East Asian countries, where it is the vector of many pathogens. The objective of this study was to study the role of serpin (serine protease inhibitor) during the tick-host interaction.

Methods

The differentiation of bone marrow-derived dendritic cells (BMDC) was induced in vitro, and the effect of RHS2 on the maturation of DCs was evaluated. The effects of RHS2 on T cell activation and cytotoxic T lymphocytes’ (CTLs) activity were analyzed by flow cytometry. Antibody subtypes after immunization of mice with RHS2 and OVA were determined.

Results

RHS2 can inhibit the differentiation of bone marrow-derived cells into DCs and promote their differentiation into macrophages. RHS2 can inhibit the maturation of DCs and the expression of CD80, CD86 and MHCII. The number of CD3⁺CD4⁺ and CD3⁺CD8⁺ T cells secreting IFN-γ, IL-2 and TNF-α was decreased, and the number of CD3⁺CD4⁺ T cells secreting IL-4 was increased, indicating that RHS2 can inhibit the activation of CD4 T cells and CD8 T cells, leading to inhibition of Th1 immune response. RHS2 inhibits the elimination of target cells by cytotoxic T lymphocytes. After immunization of mice with RHS2 and OVA, serum IgG2b was significantly reduced and IgM was increased.

Conclusions

The results show that RHS2 has an inhibitory effect on the host immune response. Ticks have evolved various ways to circumvent adaptive immunity. Their serpin inhibits BMDC differentiation to reduce immune responses.

A global immune gene expression signature for human cancers

Background

Except for a few, the immune gene signatures for most cancer types are not available. We sought to identify a global immune gene signature that is applicable to all human cancers.

Results

We identified an immune gene signature that was intimately correlated with tumor immune characteristics of human cancers and consisted of 382 genes indicative of different immune cell types. The T helper type 1 and 2 cell activation pathway was most significantly enriched in this global immune gene set, while transcription factors, such as SPI1 and STAT family members, were the top regulators of this gene signature. Skin cutaneous melanoma with higher expression of this immune gene signature had significantly longer survival than those with lower immune gene expression. Breast cancer patients with higher immune gene signature were significantly associated with advanced-stage.

Methods

We analyzed the gene expression profiles of 10,062 tumor samples from 32 cancer types in The Cancer Genome Atlas Pan-Cancer data set. Hierarchical clustering analysis of previously-defined immune genes was performed to identify a pan-cancer immune gene signature. Pathway and upstream regulator analyses were used to identify significantly enriched signaling pathways and transcription factors. Kaplan-Meier analysis was used to evaluate the survival difference between dichotomic groups with different immune gene signatures. Correlation of immune gene signature with tumor stage was also examined.

Conclusions

Our identified immune gene signature is applicable in human cancers and can be used to characterize tumor immunogenicity within and across cancer types. Clinical implication of this immune gene set warrants future investigation.

The Diversity of Encephalitogenic CD4+ T Cells in Multiple Sclerosis and Its Animal Models

Autoreactive CD4+ T cells, which target antigens in central nervous system (CNS) myelin, are widely believed to play a critical role in the pathogenesis of multiple sclerosis (MS) in concert with other immune effectors. This theory is supported by data from animal model experiments, genome-wide association studies, and immune profiles of individuals with MS. Furthermore, disease modifying agents that target lymphocytes significantly reduce the rate of MS clinical exacerbations. However, the properties of myelin-reactive CD4+ T cells that are critical for their pathogenic activities are not understood completely. This article reviews the literature on encephalitogenic CD4+ T cells, with an emphasis on T-helper (Th) lineage and cytokine production. An increased understanding of the spectrum of encephalitogenic T cells and how they differ from protective subsets is necessary for the development of the next generation of more effective and safer immunomodulatory therapies customized for individuals with MS and related disorders.

Herpes Simplex Virus 1 ICP22 Suppresses CD80 Expression by Murine Dendritic Cells

Herpes simplex virus type 1 (HSV-1) has the ability to delay its clearance from the eye during ocular infection. Here, we show that ocular infection of mice with HSV-1 suppressed expression of the costimulatory molecule CD80 but not CD86 in the cornea. The presence of neutralizing anti-HSV-1 antibodies did not alleviate this suppression. At the cellular level, HSV-1 consistently downregulated the expression of CD80 by dendritic cells (DCs) but not by other antigen-presenting cells. Furthermore, flow cytometric analysis of HSV-1-infected corneal cells during a 7-day period reduced CD80 expression in DCs but not in B cells, macrophages, or monocytes. This suppression was associated with the presence of virus. Similar results were obtained using infected or transfected spleen cells or bone marrow-derived DCs. A combination of roscovitine treatment, transfection with immediate early genes (IE), and infection with a recombinant HSV-1 lacking the ICP22 gene shows the importance of ICP22 in downregulation of the CD80 promoter but not the CD86 promoter in vitro and in vivo At the mechanistic level, we show that the HSV-1 immediate early gene ICP22 binds the CD80 promoter and that this interaction is required for HSV-1-mediated suppression of CD80 expression. Conversely, forced expression of CD80 by ocular infection of mice with a recombinant HSV-1 exacerbated corneal scarring in infected mice. Taken together, these studies identify ICP22-mediated suppression of CD80 expression in dendritic cells as central to delayed clearance of the virus and limitation of the cytopathological response to primary infection in the eye.IMPORTANCE HSV-1-induced eye disease is a major public health problem. Eye disease is associated closely with immune responses to the virus and is exacerbated by delayed clearance of the primary infection. The immune system relies on antigen-presenting cells of the innate immune system to activate the T cell response. We found that HSV-1 utilizes a robust and finely targeted mechanism of local immune evasion. It downregulates the expression of the costimulatory molecule CD80 but not CD86 on resident dendritic cells irrespective of the presence of anti-HSV-1 antibodies. The effect is mediated by direct binding of HSV-1 ICP22, the product of an immediate early gene of HSV-1, to the promoter of CD80. This immune evasion mechanism dampens the host immune response and, thus, reduces eye disease in ocularly infected mice. Therefore, ICP22 may be a novel inhibitor of CD80 that could be used to modulate the immune response.

Expression of CD80 and CD86 on B cells during coxsackievirus B3-induced acute myocarditis

Introduction

The pathogenesis of viral myocarditis (VMC) is unclear, but many studies have shown that VMC is associated with an excessive immune response. CD80 and CD86 are important costimulatory molecules that play a critical role in autoimmunity. However, whether CD80+/CD86+ B cells participate in the pathogenesis of acute VMC is unknown.

Material and methods

Male C57BL/6 mice were infected by intraperitoneal injection with coxsackievirus B3 (CVB3) to establish a VMC model. Control mice were administered phosphate-buffered saline intraperitoneally. At one week and two weeks post injection, histopathological changes in heart tissue were assessed with haematoxylin and eosin staining. The frequency of splenic CD80+/CD86+ B cells was measured with flow cytometry.

Results

The frequency of CD80+ B cells was significantly increased in VMC, while the frequency of CD86+ B cells was significantly decreased. Furthermore, the frequency of CD80+ B cells related to the severity of VMC.

Conclusions

These data show that CD80+/CD86+B cells are involved in the pathogenesis of VMC, with CD80+B cells being more important than CD86+B cells.

A Novel Engineered Small Protein for Positron Emission Tomography Imaging of Human Programmed Death Ligand-1: Validation in Mouse Models and Human Cancer Tissues

PURPOSE

To design and evaluate a small engineered protein binder targeting human programmed death-1 ligand (hPD-L1) in vivo for PET imaging in four mouse tumor models, and in situ in human cancer specimens.Experimental Design: The hPD-L1 protein binder, FN3_hPD-L1, was engineered using a 12-kDa human fibronectin type-3 domain (FN3) scaffold. The binder's affinity was assayed in CT26 mouse colon carcinoma cells stably expressing hPD-L1 (CT26/hPD-L1). ⁶⁴Cu-FN3_hPD-L1 was assayed for purity, specific activity, and immunoreactivity. Four groups of NSG mice (n = 3-5/group) were imaged with ⁶⁴Cu-FN3_hPD-L1 PET imaging (1-24 hours postinjection of 3.7 MBq/7 μg of Do-FN3 in 200 μL PBS): Nod SCID Gamma (NSG) mice bearing (i) syngeneic CT26/hPD-L1tumors, (ii) CT26/hPD-L1 tumors blocked (blk) by preinjected nonradioactive FN3_hPD-L1 binder, (iii) hPD-L1-negative Raji xenografts, and (iv) MDA-MB-231 xenografts. The FN3_hPD-L1 binder staining was evaluated against validated hPD-L1 antibodies by immunostaining in human cancer specimens.

RESULTS

FN3_hPD-L1 bound hPD-L1 with 1.4 ± 0.3 nmol/L affinity in CT26/hPD-L1 cells. ⁶⁴Cu-FN3_hPD-L1 radiotracer showed >70% yield and >95% purity. ⁶⁴Cu-FN3_hPD-L1 PET imaging of mice bearing CT26/hPD-L1 tumors showed tumor-to-muscle ratios of 5.6 ± 0.9 and 13.1 ± 2.3 at 1 and 4 hours postinjection, respectively. The FN3_hPD-L1 binder detected hPD-L1 expression in human tissues with known hPD-L1 expression status based on two validated antibodies.

CONCLUSIONS

The ⁶⁴Cu-FN3_hPD-L1 radiotracer represents a novel, small, and high-affinity binder for imaging hPD-L1 in tumors. Our data support further exploration and clinical translation of this binder for noninvasive identification of cancer patients who may respond to immune checkpoint blockade therapies.

Mechanisms underlying immune tolerance caused by recombinant Echinococcus granulosus antigens Eg mMDH and Eg10 in dendritic cells

Mice immunized with recombinant Echinococcus granulosus antigens Eg10 and Eg mMDH do not show elevated resistance to E. granulosus infection but show aggravated infection instead. To gain a deeper insight in the immune tolerance mechanisms in mice immunized with Eg10 and Eg mMDH, this study simulated the immune tolerance process in vitro by culturing bone marrow-derived dendritic cells (BMDCs) in the presence of Eg10 or Eg mMDH. Scanning electron microscopy revealed that Eg10- and Eg mMDH-treated DCs exhibited immature cell morphology, while addition of LPS to the cells induced changes in cell morphology and an increase in the number of cell-surface protrusions. This observation was consistent with the increased expression of the cell-surface molecules MHCII and CD80 in Eg10- and Eg mMDH-treated DCs pretreated with LPS. DCs exposed to the two antigens had a very weak ability to induce T-cell proliferation, but could promote the formation of Treg cells. Introduction of the indoleamine 2,3-dioxygenase (IDO) inhibitor, 1-methyl tryptopha (1-MT) enhanced the ability of the antigens to induce T cells and inhibited the induction of Treg cells. Eg mMDH-treated DCs showed a strong response to 1-MT: the DCs had high mRNA levels of IDO, IL-6, and IL-10, while 1-MT decreased the expression. In contrast, DCs treated with Eg10 did not show significant changes after 1-MT treatment. Eg mMDH inhibited DC maturation and promoted IDO expression, which, on the one hand, decreased the ability of DCs to induce T-cell proliferation, resulting in T-cell anergy, and on the other hand, induced the formation of Tregs, resulting in an immunosuppressive effect. In contrast, the escape mechanisms induced by Eg10 did not primarily depend on the IDO pathway and might involve other mechanisms that need to be further explored.

CD80 Regulates Th17 Cell Differentiation in Coxsackie Virus B3-Induced Acute Myocarditis

The cluster of differentiation protein complex, CD80/CD86, regulates Th1/Th2 differentiation in autoimmune disease. In order to establish the effects of CD80/CD86 on Th17 cell differentiation in acute viral myocarditis (VMC), we infected C57BL/6 mice with Coxsackie virus B3 (CVB3) and examined the effects of the treatment with anti-CD80/CD86 monoclonal antibodies (mAbs) on Th17 cell differentiation in vivo. The effects of anti-CD80/CD86 mAbs on Th17 cell differentiation were further evaluated in vitro. The treatment with anti-CD80 mAb induced marked suppression of Th17 cell differentiation and ROR-γt mRNA expression, whereas anti-CD86 mAb alone had no effect, both in vivo and in vitro. Our finding that CD80 regulates Th17 differentiation supports the potential utility of anti-CD80 mAb as an effective new immunotherapeutic target in acute VMC.

Myeloid-derived suppressor cells exacerbate Sjögren's syndrome by inhibiting Th2 immune responses

Myeloid-derived suppressor cells (MDSCs) can regulate various aspects of immune responses based on their potent immune-suppressive activity. Studies reported that MDSCs participated in many autoimmune diseases. However, the role of MDSCs in Sjögren's syndrome (SS) is unknown. In this study, we determined the frequencies and function of MDSCs in non-obese diabetic (NOD) mice and SS patients. The NOD mice were adoptively transferred with MDSCs or treated with anti-Gr1 antibody. Results showed that peripheral MDSCs increased significantly with the development of SS-like syndrome in NOD mice and the percentage of MDSCs was higher in SS patients than healthy controls. The SS-like syndrome aggravated after transfer of MDSCs in NOD mice. The deletion of MDSCs in NOD mice alleviated SS-like syndrome. Mechanistically, MDSCs down-regulated the percentages of Th2 cells in NOD mice and SS patients. In summary, our findings suggested that MDSCs exacerbated Sjögren's syndrome by inhibiting Th2 cells.

Tobacco Smoke Induces and Alters Immune Responses in the Lung Triggering Inflammation, Allergy, Asthma and Other Lung Diseases: A Mechanistic Review

Many studies have been undertaken to reveal how tobacco smoke skews immune responses contributing to the development of chronic obstructive pulmonary disease (COPD) and other lung diseases. Recently, environmental tobacco smoke (ETS) has been linked with asthma and allergic diseases in children. This review presents the most actual knowledge on exact molecular mechanisms responsible for the skewed inflammatory profile that aggravates inflammation, promotes infections, induces tissue damage, and may promote the development of allergy in individuals exposed to ETS. We demonstrate how the imbalance between oxidants and antioxidants resulting from exposure to tobacco smoke leads to oxidative stress, increased mucosal inflammation, and increased expression of inflammatory cytokines (such as interleukin (IL)-8, IL-6 and tumor necrosis factor α ([TNF]-α). Direct cellular effects of ETS on epithelial cells results in increased permeability, mucus overproduction, impaired mucociliary clearance, increased release of proinflammatory cytokines and chemokines, enhanced recruitment of macrophages and neutrophils and disturbed lymphocyte balance towards Th2. The plethora of presented phenomena fully justifies a restrictive policy aiming at limiting the domestic and public exposure to ETS.

Lipopolysaccharide Exposure Alleviates Asthma in Mice by Regulating Th1/Th2 and Treg/Th17 Balance

Background

It is generally believed that endotoxin exposure exacerbates risk of developing asthmatic symptoms. However, recent studies have indicated that prior bacterial exposure may prevent future symptoms of asthma. Here, we evaluated the influence of pre-exposure to different concentrations of lipopolysaccharide (LPS) to subsequent ovalbumin (OVA) allergen sensitization and challenge.

Material/Methods

Four-week-old Balb/c mice were treated intranasally with varying concentrations of LPS (1 ug, 10 ug, and 100 ug) or sterile PBS for 10 days, then 2 weeks later they were exposed to OVA. Both the molecular and functional airway responses to OVA administration were assessed following prior exposure to different doses of LPS or controls. Additionally, the Th1/Th2 and Treg/Th17 balance was measured.

Results

Airway responsiveness and immune cell recruitment in the bronchoalveolar lavage (BALF) were decreased in animals exposed to a low dose of LPS (1 ug) treatment compared with the asthma group. Moderate-dose (10 ug) and high-dose (100 ug) LPS administration showed no differences from controls. Further, low-dose LPS (1 ug) exposure was associated with increased Th1 cytokines, T-bet, Treg cytokine (IL-10, TGF-β), and Foxp3 expression, but decreased Th2 cytokines (IL-4,5,13), GATA3, Th17, and ROR-γt expression compared with the asthma group. Finally, higher numbers of CD4+CD25+Foxp3+Treg cells, and CD4+INF-γ+T cells, and lower CD4+IL-4+T cells and CD4+IL-17+T cells were observed in the low-dose LPS-treated groups compared to controls.

Conclusions

Our findings suggest that prior exposure to low doses of LPS may protect from OVA-induced airway hyperresponsiveness (AHR) and histopathologic changes through regulation of the Th1/Th2 and Treg/Th17 balance.

Interactions between dendritic cells and T lymphocytes in pathogenesis of nasal polyps

The aim of the present study was to investigate the functional status of dendritic cells (DCs) in nasal polyps (NP) and their interactions with T lymphocytes. The interactions between DC and T lymphocytes in the pathogenesis of NP was also studied. The expression of cluster of differentiation (CD)1a and CD83 in NP was detected using immunohistochemistry and the ratio of CD83 DC/CD1a+DC was counted. The distribution of DCs in NP and normal inferior turbinate mucosa (nITM) was evaluated using double immunostaining (CD1a/CD40) and low illumination fluorescence microscopy. The number of CD1a+ cells, CD83+ cells and CD1a/CD40-dual positive cells in was significantly higher in NP tissues compared with nITM. Furthermore, the density of DCs observed in NP was significantly greater than that observed in nITM. The ratio of CD83 DC/CD1a+DC in NP was significantly higher compared with in nITM tissues. The results of the present study revealed significant infiltration of DCs in NP, with the majority being mature DCs. DCs are able to interact with T cells via the CD40/CD40L costimulatory factor, thus serving an important role in the development and progression of NP.