Cell Type-Specific Regulation of Immunological Synapse Dynamics by B7 Ligand Recognition

Immunomodulatory Compounds from the Sea: From the Origins to a Modern Marine Pharmacopoeia

From sea shores to the abysses of the deep ocean, marine ecosystems have provided humanity with valuable medicinal resources. The use of marine organisms is discussed in ancient pharmacopoeias of different times and geographic regions and is still deeply rooted in traditional medicine. Thanks to present-day, large-scale bioprospecting and rigorous screening for bioactive metabolites, the ocean is coming back as an untapped resource of natural compounds with therapeutic potential. This renewed interest in marine drugs is propelled by a burgeoning research field investigating the molecular mechanisms by which newly identified compounds intervene in the pathophysiology of human diseases. Of great clinical relevance are molecules endowed with anti-inflammatory and immunomodulatory properties with emerging applications in the management of chronic inflammatory disorders, autoimmune diseases, and cancer. Here, we review the historical development of marine pharmacology in the Eastern and Western worlds and describe the status of marine drug discovery. Finally, we discuss the importance of conducting sustainable exploitation of marine resources through biotechnology.

Costimulatory and Coinhibitory Immune Checkpoints in Atherosclerosis: Therapeutic Targets in Atherosclerosis?

The benefits of current state-of-the-art treatments to combat atherosclerotic cardiovascular disease (ASCVD) have stagnated. Treatments are mostly based on controlling cardiovascular risk factors, especially hyperlipidemia. Although the most recent advances with PCSK-9 inhibitors support the hyperlipidemia aspect of ASCVD, several lines of experimental evidence have outlined that atherosclerosis is also driven by inflammation. In the past years, phase 1, 2, and 3 clinical trials targeting inflammation to combat ASCVD have revealed that patients do tolerate such immune therapies, show decreases in inflammatory markers, and/or have reductions in cardiovascular endpoints. However, the search for the optimal anti-inflammatory or immune-modulating strategy and the stratification of patients who would benefit from such treatments and appropriate treatment regimens to combat ASCVD is only just beginning. In this review, we focus on immune checkpoint-based therapeutics (costimulation and coinhibition), many of which are already approved by the U.S. Food and Drug Administration for the treatment of cancer or autoimmune diseases, and discuss their use as a novel immunotherapeutic strategy to treat ASCVD.

Based on scRNA-seq and bulk RNA-seq to establish tumor immune microenvironment-associated signature of skin melanoma and predict immunotherapy response

Skin cutaneous melanoma (SKCM), a form of skin cancer, ranks among the most formidable and lethal malignancies. Exploring tumor microenvironment (TME)-based prognostic indicators would help improve the efficacy of immunotherapy for SKCM patients. This study analyzed SKCM scRNA-seq data to cluster non-malignant cells that could be used to explore the TME into nine immune/stromal cell types, including B cells, CD4 T cells, CD8 T cells, dendritic cells, endothelial cells, Fibroblasts, macrophages, neurons, and natural killer (NK) cells. Using data from The Cancer Genome Atlas (TCGA), we employed SKCM expression profiling to identify differentially expressed immune-associated genes (DEIAGs), which were then incorporated into weighted gene co-expression network analysis (WGCNA) to investigate TME-associated hub genes. Discover candidate small molecule drugs based on pivotal genes. Tumor immune microenvironment-associated genes (TIMAGs) for constructing TIMAS were identified and validated. Finally, the characteristics of TIAMS subgroups and the ability of TIMAS to predict immunotherapy outcomes were analyzed. We identified five TIMAGs (CD86, CD80, SEMA4D, C1QA, and IRF1) and used them to construct TIMAS. In addition, five potential SKCM drugs were identified. The results showed that TIMAS-low patients were associated with immune-related signaling pathways, high MUC16 mutation frequency, high T cell infiltration, and M1 macrophages, and were more favorable for immunotherapy. Collectively, TIMAS constructed by comprehensive analysis of scRNA-seq and bulk RNA-seq data is a promising marker for predicting ICI treatment outcomes and improving individualized therapy for SKCM patients.

A better understanding of the role of the CTLA-CD80/86 axis in the treatment of autoimmune diseases

Autoimmune diseases are diseases in which the regulatory mechanisms of the immune response are disturbed. As a result, the body loses self-tolerance. Since one of the main regulatory mechanisms of the immune response is the CTLA4-CD80/86 axis, this hypothesis suggests that autoimmune diseases potentially share a similar molecular basis of pathogenesis. Hence, investigating the CTLA4-CD80/86 axis may be helpful in finding an appropriate treatment strategy. Therefore, this study aims to investigate the molecular basis of the CTLA4-CD80/86 axis in the regulation of the immune response, and then its role in developing some autoimmune diseases, including systemic lupus erythematosus, rheumatoid arthritis, type 1 diabetes, and multiple sclerosis. As well, the main therapeutic strategies affecting the CTLA4-CD80/86 axis have been summarized to highlight the importance of this axis in management of autoimmune diseases.

Immune checkpoint targeting antibodies hold promise for combinatorial cancer therapeutics

Through improving the immune system's ability to recognize and combat tumor cells as well as its receptivity to changes in the tumor microenvironment, immunotherapy has emerged as a highly successful addition to the treatment of cancer. However, tumor heterogeneity poses a significant challenge in cancer therapy as it can undermine the anti-tumor immune response through the manipulation of the extracellular matrix. To address these challenges and improve targeted therapies and combination treatments, the food and drug administration has approved several immunomodulatory antibodies to suppress immunological checkpoints. Combinatorial therapies necessitate the identification of multiple targets that regulate the intricate communication between immune cells, cytokines, chemokines, and cellular responses within the tumor microenvironment. The purpose of this study is to provide a comprehensive overview of the ongoing clinical trials involving immunomodulatory antibodies in various cancer types. It explores the potential of these antibodies to modulate the immune system and enhance anti-tumor responses. Additionally, it discusses the perspectives and prospects of immunomodulatory therapeutics in cancer treatment. Although immunotherapy shows great promise in cancer treatment, it is not exempt from side effects that can arise due to hyperactivity of the immune system. Therefore, understanding the intricate balance between immune activation and regulation is crucial for minimizing these adverse effects and optimizing treatment outcomes. This study aims to contribute to the growing body of knowledge surrounding immunomodulatory antibodies and their potential as effective therapeutic options in cancer treatment, ultimately paving the way for improved patient outcomes and deepening our perception of the intricate interactivity between the immune system and tumors.

Conserved angio-immune subtypes of the tumor microenvironment predict response to immune checkpoint blockade therapy

Immune checkpoint blockade (ICB) therapy has revolutionized cancer treatment. However, only a fraction of patients respond to ICB therapy. Accurate prediction of patients to likely respond to ICB would maximize the efficacy of ICB therapy. The tumor microenvironment (TME) dictates tumor progression and therapy outcome. Here, we classify the TME by analyzing the transcriptome from 11,069 cancer patients based on angiogenesis and T cell activity. We find three distinct angio-immune TME subtypes conserved across 30 non-hematological cancers. There is a clear inverse relationship between angiogenesis and anti-tumor immunity in TME. Remarkably, patients displaying TME with low angiogenesis with strong anti-tumor immunity show the most significant responses to ICB therapy in four cancer types. Re-evaluation of the renal cell carcinoma clinical trials provides compelling evidence that the baseline angio-immune state is robustly predictive of ICB responses. This study offers a rationale for incorporating baseline angio-immune scores for future ICB treatment strategies.

In or out of control: Modulating regulatory T cell homeostasis and function with immune checkpoint pathways

Regulatory T cells (Tregs) are the master regulators of immunity and they have been implicated in different disease states such as infection, autoimmunity and cancer. Since their discovery, many studies have focused on understanding Treg development, differentiation, and function. While there are many players in the generation and function of truly suppressive Tregs, the role of checkpoint pathways in these processes have been studied extensively. In this paper, we systematically review the role of different checkpoint pathways in Treg homeostasis and function. We describe how co-stimulatory and co-inhibitory pathways modulate Treg homeostasis and function and highlight data from mouse and human studies. Multiple checkpoint pathways are being targeted in cancer and autoimmunity; therefore, we share insights from the clinic and discuss the effect of experimental and approved therapeutics on Treg biology.

Overexpression of CD86 enhances the ability of THP-1 macrophages to defend against Talaromyces marneffei

BACKGROUND

Macrophages are the first line of defense against Talaromyces marneffei. CD86 is a surface molecule expressed on antigen-presenting cells, such as macrophages, that provide costimulatory signals necessary for T cell activation and survival. In a prior study, it was shown that as infection progressed, CD86 expression levels in macrophages considerably declined while CD86 concentrations in the supernatant significantly increased. Additionally, M1 macrophage polarization was insufficient and switched to M2 macrophage polarization. Besides costimulation, however, additional roles of CD86 are not known or well-studies. Therefore, we hypothesized that upregulating CD86 on macrophages might promote T. marneffei defense.

METHODS

A lentivirus vector, called Lenti-CD86, was used to infect THP-1 cells to overexpress secretory CD86. Through killing assay, nitric oxide detection, and cytokine detection, the capacity of THP-1 macrophages to phagocytose and kill T. marneffei was examined.

RESULTS

In the current study, Lenti-CD86 transfection of THP-1 cells resulted in a signifant expression of CD86. Additionally, the THP-1 macrophages stably transfected with Lenti-CD86 showed higher nitric oxide and IL-1β production, faster polarization, and stronger phagocytosis and killing capabilities than the non-transfected or control virus transfected cells.

CONCLUSION

Our study shows that lentivirus-mediated CD86 overexpression improves THP-1 macrophages' capacity to phagocytose and eliminate T. marneffei.

An update on the use of cryoablation and immunotherapy for breast cancer

The use of cryoablation, a minimally-invasive image-guided technique to target and kill cancer cells, continues to gain traction within the medical field and with patients. This includes the use of cryoablation for the treatment of small breast cancers and focal sites of metastatic disease. In comparison to open surgical approaches, length of hospital stay and recovery time are decreased with the use of cryoablation. Research studies have also found that cryoablation may actually enhance tumor susceptibility to immunotherapy agents. Immunotherapy enhances a person's own immune system to identify and attack cancer cells. It is proposed that after cryoablation there is increased expression of tumor specific antigens which the body can recognize as foreign invaders and with the combination of immunotherapy, result in an even more robust and efficient attack on the cancer cells. In this review we aim to highlight some of the recent advances in cryoablation which support the potential for cryoablation to induce these tumor-specific immune responses and thus supporting the use of combining cryoablation and immunotherapy for the treatment of breast cancer.

CD28 and chemokine receptors: Signalling amplifiers at the immunological synapse

T cells are master regulators of the immune response tuning, among others, B cells, macrophages and NK cells. To exert their functions requiring high sensibility and specificity, T cells need to integrate different stimuli from the surrounding microenvironment. A finely tuned signalling compartmentalization orchestrated in dynamic platforms is an essential requirement for the proper and efficient response of these cells to distinct triggers. During years, several studies have depicted the pivotal role of the cytoskeleton and lipid microdomains in controlling signalling compartmentalization during T cell activation and functions. Here, we discuss mechanisms responsible for signalling amplification and compartmentalization in T cell activation, focusing on the role of CD28, chemokine receptors and the actin cytoskeleton. We also take into account the detrimental effect of mutations carried by distinct signalling proteins giving rise to syndromes characterized by defects in T cell functionality.

Adverse Events and Tolerability of Combined Durvalumab and Tremelimumab versus Durvalumab Alone in Solid Cancers: A Systematic Review and Meta-Analysis

Background: Recently, the combination of durvalumab and tremelimumab, two immune checkpoint inhibitors, for the treatment of different types of cancers has been considered; however, its overall effects, including its safety, are still unclear and need to be further investigated. Objectives: The aim of the present systematic review and meta-analysis was to investigate the safety and tolerability of this combination of drugs. Methods: A systematic review of the literature, based on the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) statement, was conducted by employing online electronic databases and the American Society of Clinical Oncology (ASCO) Meeting Library. The selection of eligible publications was made following a staged screening and selection process. The software RevMan 5.4 was used to run the quantitative analysis and forest plots, while the Cochrane tool was employed for risk of bias assessment. Results: From the retrieved 157 results, 9 randomized controlled trials involving 3060 patients were included. By comparing the combination of durvalumab and tremelimumab vs. durvalumab monotherapy, it was observed that: adverse events (AEs) ≥ Grade 3 incidence was 32.6% (536/1646) vs. 23.8% (336/1414) (Z = 2.80; p = 0.005; risk ratio (RR) = 1.44), reduced appetite incidence was 10.8% (154/1427) vs. 8.3% (108/1305) (Z = 2.26; p = 0.02; RR = 1.31), diarrhea was reported in 15.6% (229/1473) vs. 8.1% (110/1352) (Z = 5.90; p < 0.00001; RR = 1.91), rash incidence was equal to 11.1% (160/1441) vs. 6.5% (86/1320) (Z = 4.35; p <0.0001; RR = 1.75), pruritis was 13.6% (201/1473) vs. 7.7% (104/1352) (Z = 5.35; p < 0.00001; RR = 1.83), fever was 10.5% (42/399) vs. 6.6% (22/330) (Z = 2.27; p = 0.02; RR = 1.77), discontinuation rate was 18% (91/504) vs. 3% (36/434) (Z = 4.78; p < 0.00001; RR = 2.41), and death rate was 2.6% (13/504) vs. 0.7% (3/434) (Z = 1.90; p = 0.06; RR = 2.77). Conclusions: It was observed that the combined (durvalumab and tremelimumab) vs. monotherapy (durvalumab) is associated with a higher risk of treatment discontinuation, mortality, fever, diarrhea, rash, pruritis, and reduced appetite. This information is relevant and should be disclosed, especially to patients that are currently enrolled in clinical trials considering this combined therapy.

Immunomodulatory Properties of Immune Checkpoint Inhibitors-More than Boosting T-Cell Responses?

The approval of immune checkpoint inhibitors (ICI) that serve to enhance effector T-cell anti-tumor responses has strongly improved success rates in the treatment of metastatic melanoma and other tumor types. The currently approved ICI constitute monoclonal antibodies blocking cytotoxic T-lymphocyte-associated protein (CTLA)-4 and anti-programmed cell death (PD)-1. By this, the T-cell-inhibitory CTLA-4/CD80/86 and PD-1/PD-1L/2L signaling axes are inhibited. This leads to sustained effector T-cell activity and circumvents the immune evasion of tumor cells, which frequently upregulate PD-L1 expression and modulate immune checkpoint molecule expression on leukocytes. As a result, profound clinical responses are observed in 40-60% of metastatic melanoma patients. Despite the pivotal role of T effector cells for triggering anti-tumor immunity, mounting evidence indicates that ICI efficacy may also be attributable to other cell types than T effector cells. In particular, emerging research has shown that ICI also impacts innate immune cells, such as myeloid cells, natural killer cells and innate lymphoid cells, which may amplify tumoricidal functions beyond triggering T effector cells, and thus improves clinical efficacy. Effects of ICI on non-T cells may additionally explain, in part, the character and extent of adverse effects associated with treatment. Deeper knowledge of these effects is required to further develop ICI treatment in terms of responsiveness of patients to treatment, to overcome resistance to ICI and to alleviate adverse effects. In this review we give an overview into the currently known immunomodulatory effects of ICI treatment in immune cell types other than the T cell compartment.

Revisiting the Principles of Designing a Vaccine

Immune principles formulated by Jenner, Pasteur, and early immunologists served as fundamental propositions for vaccine discovery against many dreadful pathogens. However, decisive success in the form of an efficacious vaccine still eludes for diseases such as tuberculosis, leishmaniasis, and trypanosomiasis. Several antileishmanial vaccine trials have been undertaken in past decades incorporating live, attenuated, killed, or subunit vaccination, but the goal remains unmet. In light of the above facts, we have to reassess the principles of vaccination by dissecting factors associated with the hosts' immune response. This chapter discusses the pathogen-associated perturbations at various junctures during the generation of the immune response which inhibits antigenic processing, presentation, or remodels memory T cell repertoire. This can lead to ineffective priming or inappropriate activation of memory T cells during challenge infection. Thus, despite a protective primary response, vaccine failure can occur due to altered immune environments in the presence of pathogens.

Identification and Validation of CYBB, CD86, and C3AR1 as the Key Genes Related to Macrophage Infiltration of Gastric Cancer

Gastric cancer (GC) is rampant around the world. Most of the GC cases are detected in advanced stages with poor prognosis. The identification of marker genes for early diagnosis is of great significance. Studying the tumor environment is helpful to acknowledge the process of tumorigenesis, development, and metastasis. Twenty-two kinds of immune cells were calculated by CIBERSORT from Gene Expression Omnibus (GEO) database. Subsequently, higher infiltration of macrophages M0 was discovered in GC compared with normal tissues. WGCNA was utilized to construct the network and then identify key modules and genes related to macrophages in TCGA. Finally, 18 hub genes were verified. In the PPI bar chart, the top 3 genes were chosen as hub genes involved in most pathways. On the TIMER and THPA websites, it is verified that the expression levels of CYBB, CD86, and C3AR1 genes in tumor tissues were higher than those in normal tissues. These genes may work as biomarkers or targets for accurate diagnosis and treatment of GC in the future. Our findings may be a new strategy for the treatment of GC.

Continuous Modeling of T CD4 Lymphocyte Activation and Function

T CD4+ cells are central to the adaptive immune response against pathogens. Their activation is induced by the engagement of the T-cell receptor by antigens, and of co-stimulatory receptors by molecules also expressed on antigen presenting cells. Then, a complex network of intracellular events reinforce, diversify and regulate the initial signals, including dynamic metabolic processes that strongly influence both the activation state and the differentiation to effector cell phenotypes. The regulation of cell metabolism is controlled by the nutrient sensor adenosine monophosphate-activated protein kinase (AMPK), which drives the balance between oxidative phosphorylation (OXPHOS) and glycolysis. Herein, we put forward a 51-node continuous mathematical model that describes the temporal evolution of the early events of activation, integrating a circuit of metabolic regulation into the main routes of signaling. The model simulates the induction of anergy due to defective co-stimulation, the CTLA-4 checkpoint blockade, and the differentiation to effector phenotypes induced by external cytokines. It also describes the adjustment of the OXPHOS-glycolysis equilibrium by the action of AMPK as the effector function of the T cell develops. The development of a transient phase of increased OXPHOS before induction of a sustained glycolytic phase during differentiation to the Th1, Th2 and Th17 phenotypes is shown. In contrast, during Treg differentiation, glycolysis is subsequently reduced as cell metabolism is predominantly polarized towards OXPHOS. These observations are in agreement with experimental data suggesting that OXPHOS produces an ATP reservoir before glycolysis boosts the production of metabolites needed for protein synthesis, cell function, and growth.

A novel prognostic immunoscore based on The Cancer Genome Atlas to predict overall survival in colorectal cancer patients

Colorectal cancer (CRC) is highly prevalent worldwide. The relationship between the infiltration of immunocytes in CRC and clinical outcome has been investigated in recent years. The present study aims to construct a new prognostic signature using an immunocyte panel. Our novel prognostic immunoscore included 13 types of immunocytes, which were identified by least absolute shrinkage and selection operator (LASSO)-Cox regression. The time-dependent receiver operating characteristic (ROC) curve and Kaplan–Meier survival estimates were applied to evaluate the prognostic ability. Compared with the signature based on a single immune marker (i.e., CD8 mRNA expression and CD8⁺ expressing T cells), the novel prognostic immunoscore possessed better specificity and sensitivity of prognosis (area under the curves (AUCs) are 0.852, 0.856, and 0.774 for 1-, 2-, and 3-year survival times, respectively). Significant differences were identified between the high and low immunoscore groups in overall survival and disease-free survival in training and validation cohorts. Combining the immunoscore with clinical information may provide a more accurate prognosis for CRC. The immunoscore can identify patients with poor outcomes in the high Tumor Mutational Burden (TMB) group, who may benefit the most from immunotherapy. The immunoscore was also closely related to two immune checkpoints (i.e., PD-L1 and PD-1, r = 0.3087 and r = 0.3341, respectively). Collectively, our study demonstrates that the novel prognostic immunoscore reported here may be useful in distinguishing different prognoses and may improve the clinical management of patients with CRC.

Comparing immunotherapies to other frequently used treatments of gastric cancer

Introduction: Although standard doublet chemotherapy represents the upfront gold standard to increase survival and improve quality of life of gastric cancer patients, overall improvements in long-term outcomes are modest and novel treatments are urgently needed. Among these, immunotherapy is an increasingly attractive option.Areas covered: A number of clinical trials have shown that checkpoint inhibitors may be of value, but many unclear issues remain controversial and should be promptly untangled. In our short review, we offer the current available data regarding immunotherapies in gastric cancers, discuss potential limits of the reported trials, compare outcomes of checkpoints inhibitor to those of standard chemotherapy or other novel treatments, and present basic principles of immune surveillance and immune escape that may be embraced in the near future with novel drug combinations.Expert opinion: Gastric cancer patients may benefit from immunotherapy, both given alone in advanced lines and upfront in combination with chemotherapy. We believe that appropriate patients' and tumor's selection are crucial issues to maximize its potential efficacy. In addition, we think that assay standardization, biomarker agreement, and translational studies will improve the benefit-to-risk ratio of these agents in the clinical practice.

Integrated Analysis Reveals Prognostic Value and Immune Correlates of CD86 Expression in Lower Grade Glioma

Background

CD86 has great potential to be a new target of immunotherapy by regulating cancer immune response. However, it remains unclear whether CD86 is a friend or foe in lower-grade glioma (LGG).

Methods

The prognostic value of CD86 expression in pan-cancer was analyzed using Cox regression and Kaplan-Meier analysis with data from the cancer genome atlas (TCGA). Cancer types where CD86 showed prognostic value in overall survival and disease-specific survival were identified for further analyses. The Chinese Glioma Genome Atlas (CGGA) dataset were utilized for external validation. Quantitative real-time PCR (qRT-PCR), Western blot (WB), and Immunohistochemistry (IHC) were conducted for further validation using surgical samples from Jiangsu Province hospital. The correlations between CD86 expression and tumor immunity were analyzed using the Estimation of Stromal and Immune cells in Malignant Tumours using Expression data (ESTIMATE) algorithm, Tumor IMmune Estimation Resource (TIMER) database, and expressions of immune checkpoint molecules. Gene Set Enrichment Analysis (GSEA) was performed using clusterprofiler r package to reveal potential pathways.

Results

Pan-cancer survival analysis established CD86 expression as an unfavorable prognostic factor in tumor progression and survival for LGG. CD86 expression between Grade-II and Grade-III LGG was validated using qRT-PCR and WB. Additionally, CD86 expression in LGG with unmethylated O(6)-methylguanine-DNA-methyltransferase (MGMT) promoter was significantly higher than those with methylated MGMT (P<0.05), while in LGG with codeletion of 1p/19q it was significantly downregulated as opposed to those with non-codeletion (P<2.2*10-16). IHC staining validated that CD86 expression was correlated with MGMT status and X1p/19q subtypes, which was independent of tumor grade. Multivariate regression validated that CD86 expression acts as an unfavorable prognostic factor independent of clinicopathological factors in overall survival of LGG patients. Analysis of tumor immunity and GSEA revealed pivotal role of CD86 in immune response for LGG.

Conclusions

Integrated analysis shows that CD86 is an unfavorable prognostic biomarker in LGG patients. Targeting CD86 may become a novel approach for immunotherapy of LGG.

Association of the genetic polymorphisms in inhibiting and activating molecules of immune system with rheumatoid arthritis: A systematic review and meta-analysis

Several studies have demonstrated that the genetic polymorphisms in the genes encoding immune regulatory molecules, namely cytotoxic T-lymphocyte-associated protein 4 (CTLA4) and CD28, play a fundamental role in susceptibility to rheumatoid arthritis (RA). Several disperse population studies have resulted in conflicting outcomes regarding the genetic polymorphisms in these genes and RA risk. This systematic review and meta-analysis study was performed to reach a conclusive understanding of the role of single-nucleotide polymorphisms (SNPs) of CTLA4-rs231775, CTLA4-rs5742909, and CD28-rs1980422 in susceptibility to RA. Databases (ISI Web of Science, MEDLINE/PubMed, and Scopus) were searched to find the case–control studies surveying the association of CTLA4 gene rs231775, CTLA4 gene rs5742909, and CD28 gene rs1980422 polymorphisms and RA susceptibility in different population until August 2020. Association comparison between the polymorphisms and RA proneness was assessed using pooled odds ratio (OR) and their corresponding 95% confidence interval. This study was conducted on 16 population studies, comprising 1078 RA patients and 1118 healthy controls for CTLA4-rs231775, 2193 RA patients and 2580 healthy controls for CTLA4-rs5742909, and 807 RA patients and 732 healthy controls for CD28-rs1980422. Analysis indicated that G-allele, GG and GA genotypes, and dominant model for rs231775, recessive model for rs5742909, and C-allele, CC and CT genotypes, and recessive model for rs1980422 were significantly associated with increased RA risk. This meta-analysis showed that genetic polymorphisms of both immune inhibitory and activating genes, including CTLA4-rs231775, CTLA4-rs5742909, and CD28-rs1980422 polymorphisms, may increase susceptibility to RA.

A LAT-Based Signaling Complex in the Immunological Synapse as Determined with Live Cell Imaging Is Less Stable in T Cells with Regulatory Capability

Peripheral immune regulation is critical for the maintenance of self-tolerance. Here we have investigated signaling processes that distinguish T cells with regulatory capability from effector T cells. The murine Tg4 T cell receptor recognizes a peptide derived from the self-antigen myelin basic protein. T cells from Tg4 T cell receptor transgenic mice can be used to generate effector T cells and three types of T cells with regulatory capability, inducible regulatory T cells, T cells tolerized by repeated in vivo antigenic peptide exposure or T cells treated with the tolerogenic drug UCB9608 (a phosphatidylinositol 4 kinase IIIβ inhibitor). We comparatively studied signaling in all of these T cells by activating them with the same antigen presenting cells presenting the same myelin basic protein peptide. Supramolecular signaling structures, as efficiently detected by large-scale live cell imaging, are critical mediators of T cell activation. The formation of a supramolecular signaling complex anchored by the adaptor protein linker for activation of T cells (LAT) was consistently terminated more rapidly in Tg4 T cells with regulatory capability. Such termination could be partially reversed by blocking the inhibitory receptors CTLA-4 and PD-1. Our work suggests that attenuation of proximal signaling may favor regulatory over effector function in T cells.

Regulating the regulators: Is introduction of an antigen-specific approach in regulatory T cells the next step to treat autoimmunity?

In autoimmunity, the important and fragile balance between immunity and tolerance is disturbed, resulting in abnormal immune responses to the body's own tissues and cells. CD4⁺CD25^hiFoxP3⁺ regulatory T cells (Tregs) induce peripheral tolerance in vivo by means of direct cell-cell contact and release of soluble factors, or indirectly through antigen-presenting cells (APC), thereby controlling auto-reactive effector T cells. Based on these unique capacities of Tregs, preclinical studies delivered proof-of-principle for the clinical use of Tregs for the treatment of autoimmune diseases. To date, the first clinical trials using ex vivo expanded polyclonal Tregs have been completed. These pioneering studies demonstrate the feasibility of generating large numbers of polyclonal Tregs in a good manufacturing practices (GMP)-compliant manner, and that infusion of Tregs is well tolerated by patients with no evidence of general immunosuppression. Nonetheless, only modest clinical results were observed, arguing that a more antigen-specific approach might be needed to foster a durable patient-specific clinical cell therapy without the risk for general immunosuppression. In this review, we discuss current knowledge, applications and future goals of adoptive immune-modulatory Treg therapy for the treatment of autoimmune disease and transplant rejection. We describe the key advances and prospects of the potential use of T cell receptor (TCR)- and chimeric antigen receptor (CAR)-engineered Tregs in future clinical applications. These approaches could deliver the long-awaited breakthrough in stopping undesired autoimmune responses and transplant rejections.

Ectromelia-encoded virulence factor C15 specifically inhibits antigen presentation to CD4+ T cells post peptide loading

Smallpox and monkeypox pose severe threats to human health. Other orthopoxviruses are comparably virulent in their natural hosts, including ectromelia, the cause of mousepox. Disease severity is linked to an array of immunomodulatory proteins including the B22 family, which has homologs in all pathogenic orthopoxviruses but not attenuated vaccine strains. We demonstrate that the ectromelia B22 member, C15, is necessary and sufficient for selective inhibition of CD4+ but not CD8+ T cell activation by immunogenic peptide and superantigen. Inhibition is achieved not by down-regulation of surface MHC- II or co-stimulatory protein surface expression but rather by interference with antigen presentation. The appreciable outcome is interference with CD4+ T cell synapse formation as determined by imaging studies and lipid raft disruption. Consequently, CD4+ T cell activating stimulus shifts to uninfected antigen-presenting cells that have received antigen from infected cells. This work provides insight into the immunomodulatory strategies of orthopoxviruses by elucidating a mechanism for specific targeting of CD4+ T cell activation, reflecting the importance of this cell type in control of the virus.

What did we learn from CTLA-4 insufficiency on the human immune system?

Cytotoxic-T-lymphocyte-antigen-4 (CTLA-4) is a negative immune regulator constitutively expressed on regulatory T (Treg) cells and upregulated on activated T cells. CTLA-4 inhibits T cell activation by various suppressive functions including competition with CD28, regulation of the inhibitory function of Treg cells, such as transendocytosis, and the control of adhesion and motility. Intrinsic CTLA-4 signaling has been controversially discussed, but so far no distinct signaling pathway has been identified. The CTLA-4-mediated Treg suppression plays an important role in the maintenance of peripheral tolerance and the prevention of autoimmune diseases. Human CTLA-4 insufficiency is caused by heterozygous germline mutations in CTLA4 and characterized by a complex immune dysregulation syndrome. Clinical studies on CTLA4 mutation carriers showed a reduced penetrance and variable expressivity, suggesting modifying factor(s). One hundred and forty-eight CTLA4 mutation carriers have been reported; patients showed hypogammaglobulinemia, recurrent infectious diseases, various autoimmune diseases, and lymphocytic infiltration into multiple organs. The CTLA-4 expression level in Treg cells was reduced, while the frequency of Treg cells was increased in CTLA-4-insufficient patients. The transendocytosis assay is a specific functional test for the assessment of newly identified CTLA4 gene variants. Immunoglobulin substitution, corticosteroids, immunosuppressive therapy, and targeted therapy such as with CTLA-4 fusion proteins and mechanistic target of rapamycin (mTOR) inhibitors were applied; patients with life-threatening, treatment-resistant symptoms underwent hematopoietic stem cell transplantation. The fact that in humans CTLA-4 insufficiency causes severe disease taught us that the amount of CTLA-4 molecules present in/on T cells matters for immune homeostasis. However, whether the pathology-causing activated T lymphocytes in CTLA-4-insufficient patients are antigen-specific is an unsolved question. CTLA-4, in addition, has a role in autoimmune diseases and cancer. Anti-CTLA-4 drugs are employed as checkpoint inhibitors to target various forms of cancer. Thus, clinical research on human CTLA-4 insufficiency might provide us a deeper understanding of the mechanism(s) of the CTLA-4 molecule and immune dysregulation disorders.

[Biologics in rheumatology]

BACKGROUND

Monoclonal antibodies and fusion proteins were introduced into clinical rheumatology 20 years ago. Nowadays they are an established component of modern internal medical practice.

OBJECTIVE

This article gives an overview of the breadth of biologics currently in clinical use.

MATERIAL AND METHODS

Evaluation of published approval studies and guideline recommendations, discussion of the immunological principles and targets in the treatment with biologics.

RESULTS

Monoclonal antibodies and fusion proteins for influencing cytokine signals, T‑cell costimulation and B‑cell function are the most important innovations in the treatment of rheumatological diseases. Nowadays they are indispensible for the treatment of moderate and severe disease courses of rheumatoid arthritis, spondylarthropathies and vasculitides.

CONCLUSION

Although a cure or permanent freedom from symptoms in rheumatological autoimmune diseases is still not possible, much more favorable disease courses with less long-term limitations can be achieved by the early administration of biologics.

Gelatinase B/matrix metalloproteinase-9 and other neutrophil proteases switch off interleukin-2 activity

Interleukin 2 (IL-2) is critical for T cell development and homeostasis, being a key regulator of adaptive immune responses in autoimmunity, hypersensitivity reactions and cancer. Therefore, its abundance in serum and peripheral tissues needs tight control. Here, we described a new mechanism contributing to the immunobiology of IL-2. We demonstrated, both in biochemical and cell-based assays, that IL-2 is subject to proteolytic processing by neutrophil matrix metalloproteinase-9 (MMP-9). IL-2 fragments produced after cleavage by MMP-9 remained linked by a disulfide bond and displayed a reduced affinity for all IL-2 receptor subunits and a distinct pattern and timing of signal transduction. Stimulation of IL-2-dependent cells, including murine CTLL-2 and primary human regulatory T cells, with cleaved IL-2 resulted in significantly decreased proliferation. The concerted action of neutrophil proteases destroyed IL-2. Our data suggest that in neutrophil-rich inflammatory conditions in vivo, neutrophil MMP-9 may reduce the abundance of signaling-competent IL-2 and generate a fragment that competes with IL-2 for receptor binding, whereas the combined activity of granulocyte proteases has the potential to degrade and thus eliminate bioavailable IL-2.

The suppressive effect of co-inhibiting PD-1 and CTLA-4 expression on H22 hepatomas in mice

Objective

We investigated the suppressive effect of siRNA-mediated co-inhibition of PD-1 and CTLA-4 expression on H22 hepatomas in mice.

Methods

Murine H22 cells were cultured in vivo in ICR mice. An allograft tumor model was also established in another ICR mouse group. The tumor-bearing mice were randomly divided into four groups: control, single PD-1 siRNA, single CTLA-4 siRNA, and double PD-1 + CTLA-4 siRNAs. The survival time and physiological condition of the mice were observed after the injection of the siRNAs and placebo. The volume and weight of the solid tumor were measured to assess the inhibition of the tumor. To assess the effects of siRNAs on mouse immune function, the protein levels of IFN-γ and IL-10 in the blood and PD-L1 in the tumor and liver were determined using ELISA, and the mRNA levels of IFN-γ, PD-L1, PD-1, CTLA-4, IL-6 and Survivin in the tumor, liver and spleen were determined using quantitative RT-PCR. The ratios of Bax and Bcl-2 protein were determined via western blot to analyze the effect of siRNAs on tumor cell apoptosis.

Results

The anti-tumor effect appeared in all groups with siRNA-mediated inhibition. The tumor growth suppression was stronger in the group with double inhibition. The weight and volume of the tumors were significantly lower and the survival rate improved in the three siRNA groups. IFN-γ levels increased but IL-10 levels decreased in the blood of the siRNA group mice compared with the results for the control group. In the tumor and spleen tissue, the IFN-γ levels significantly increased, but in the liver tissue they significantly decreased in the three siRNA groups. The results of quantitative RT-PCR showed that the mRNAs for PD-1 and CTLA-4 were downregulated in spleen tissue in the three siRNA groups, while the PD-L1 mRNA and protein levels increased significantly in the tumor, but decreased in the liver. Survivin and IL-6 mRNA levels decreased in the tumor. Western blot results showed that ratio of Bax and Bcl-2 had significantly increased. These results indicated that downregulating PD-1 and CTLA-4 could increase the body’s immune response and promote apoptosis of tumor cells.

Conclusion

Co-inhibiting the expressions of PD-1 and CTLA-4 can effectively suppress the growth of H22 hepatoma and promote the apoptosis of tumor cells in mice. Blocking PD-1 and CTLA-4 can improve the vitality of T cells, and improve the immune environment and response.

Integrating farm and air pollution studies in search for immunoregulatory mechanisms operating in protective and high-risk environments

BACKGROUND

Studies conducted in farm environments suggest that diverse microbial exposure promotes children's lung health. The underlying mechanisms are unclear, and the development of asthma-preventive strategies has been delayed. More comprehensive investigation of the environment-induced immunoregulation is required for better understanding of asthma pathogenesis and prevention. Exposure to air pollution, including particulate matter (PM), is a risk factor for asthma, thus providing an excellent counterpoint for the farm-effect research. Lack of comparable data, however, complicates interpretation of the existing information. We aimed to explore the immunoregulatory effects of cattle farm dust (protective, Finland) and urban air PM (high-risk, China) for the first time using identical research methods.

METHODS

We stimulated PBMCs of 4-year-old children (N = 18) with farm dust and size-segregated PM and assessed the expression of immune receptors CD80 and ILT4 on dendritic cells and monocytes as well as cytokine production of PBMCs. Environmental samples were analysed for their composition.

RESULTS

Farm dust increased the percentage of cells expressing CD80 and the cytokine production of children's immune cells, whereas PM inhibited the expression of important receptors and the production of soluble mediators. Although PM samples induced parallel immune reactions, the size-fraction determined the strength of the effects.

CONCLUSIONS

Our study demonstrates the significance of using the same research framework when disentangling shared and distinctive immune pathways operating in different environments. Observed stimulatory effects of farm dust and inhibitory effects of PM could shape responses towards respiratory pathogens and allergens, and partly explain differences in asthma prevalence between studied environments.

The Effect of CD86 Expression on the Proliferation and the Survival of CLL Cells

Micro-environment plays important role in the pathogenesis of CLL by providing protective niche for CLL cells. Several molecules play important role in communication between CLL cells and immune cells like CD86.Some of the data suggest that CLL patients with high CD86 level need earlier treatments and cells with higher CD86 expression has higher proliferation rate but the role of CD86 in the survival and proliferation of CLL cells is unclear. We investigated the effect of CD86 expression to CLL cells in 50 peripheral blood and 15 lymph node biopsy samples from CLL patients. Our results showed that the expressions of CD86 increased significantly after 7 day culturing in medium, or in the presence of bone marrow stromal cells (BMSCs). We found positive correlation between CD86 and CD23 expression (p < 0.05), but no correlation with other markers. Furthermore, no correlation were found between the CD86 expression and the proliferation of CLL cells. Analysis of clinical data showed that cases with high CD86 expression had lower level of serum lymphocyte count (p < 0.04) at the time of the diagnosis. CD86 shows multiple appearances in the lymph nodes containing pseudofollicules, but no correlation was found between CD86 positivity, and Ki67 positivity. Our results suggest that the use of CD86 molecule as a proliferation marker for CLL is highly questionable. However, the CD86 molecule may interfere with the immune system of patients with CLL by activating and depleting immune functions. That can be the reason why CD86 positivity may mean worse prognosis.

Identification of novel immune-relevant drug target genes for Alzheimer's Disease by combining ontology inference with network analysis

AIMS

Alzheimer's disease (AD) is one of the leading causes of death in elderly people. Its pathogenesis is greatly associated with the abnormality of immune system. However, only a few immune-relevant AD drug target genes have been discovered up to now, and it is speculated that there are still many potential drug target genes of AD (at least immune-relevant genes) to be discovered. Thus, this study was designed to identify novel AD drug target genes and explore their biological properties.

METHODS

A combinatorial approach was adopted for the first time to discover AD drug targets by collectively considering ontology inference and network analysis. Moreover, a novel strategy limiting the distance of reasoning and in turn reducing noise interference was further proposed to improve inference performance. Potential AD drug target genes were discovered by integrating information of multiple popular databases (TTD, DrugBank, PharmGKB, AlzGene, and BioGRID). Then, the enrichment analyses of the identified drug targets genes based on nine well-known pathway-related databases were conducted to explore the function of the identified potential drug target genes.

RESULTS

Eighteen potential drug target genes were finally identified, and 13 of them had been reported to be closely associated with AD. Enrichment analyses of these identified drug target genes, based on nine pathway-related databases, revealed that the enriched terms were primarily focus on immune-relevant biological processes. Four of those identified drug target genes are involved in the classical complement pathway and process of antigen presenting.

CONCLUSION

The well-reproducible results showed the good performance of the combinatorial approach, and the remaining five new targets could be a good starting point for our understanding of the pathogenesis and drug discovery of AD. Moreover, this study supported validity of the combinatorial approach integrating ontology inference with network analysis in the discovery of novel drug target for neurological diseases.

Association of CD28 and CTLA4 haplotypes with susceptibility to primary Sjögren's syndrome in Mexican population

BACKGROUND

Primary Sjögren's syndrome (pSS) is an autoimmune disease characterized by destruction of exocrine glands as a result of T and B cells infiltrated in glandular tissue. CD28 and CTLA-4 play a crucial role in T cell activation and inhibition. The aim of this study was to associate CD28 and CTLA4 haplotypes with susceptibility to pSS in patients from western Mexico.

METHODS

Polymerase chain reaction and restriction fragment length polymorphism were performed to identify CD28 and CTLA4 genotypes in 111 patients with pSS and 138 control subjects (CS). Haplotype analysis was carried out by SHEsis program. Soluble serum levels of CD28 (sCD28) and CTLA-4 (sCTLA-4) were quantified by ELISA kit.

RESULTS

The CD28 GC haplotype was associated with low risk to pSS (2.5-folds, P < 0.001). CTLA4 CAG and CGA were identified as genetic risk factor (P < 0.001;OR = 3.82[CI95%:2.022-7.296] and P < 0.001; OR = 11.38[CI95%:3.282-37.69] respectively). No difference in sCD28 and sCTLA-4 were found between patients and CS. However, pSS patients carriers of CD28 IVS3 + 17TC genotype showed high sCD28 (P = 0.039 vs TT carriers in CS). In regard to sCTLA-4, patient who carry CTLA4-319C>T, +49 A>G, and +6230 G>A, or their haplotypes did not show any difference.

CONCLUSION

Our findings suggest that CD28 GC, CTLA4 CAG, and CGA haplotypes are associated with susceptibility to pSS in patients from western Mexico. It seems that genetic control of CD28 and CTLA4 as well as local immune response in glandular tissue may regulate the impact of the gene expression in pSS. It is necessary to confirm this hypothesis in an integrative study.

CTLA-4 +49 G/A, a functional T1D risk SNP, affects CTLA-4 level in Treg subsets and IA-2A positivity, but not beta-cell function

To investigate whether CTLA-4 +49 G/A (rs231775), a tagSNP in Asian, is a functional T1D SNP, we genotyped this SNP with 1035 T1D patients and 2575 controls in Chinese Han population. And 1280 controls measured insulin release and sensitivity based on an oral glucose tolerance test; 283 newly diagnosed T1D patients assayed C-peptide level based on a mixed-meal tolerance test. 31 controls were analyzed for different T cell subsets by multi-color flow cytometry. Under additive model, we found that CTLA-4 +49 G/A was significantly associated with T1D (P = 2.82E-04, OR = 1.25, 95% CI: 1.12–1.41), which was further confirmed by meta-analysis (P = 1.19E-08, OR = 1.65, 95% CI: 1.38–1.96) in Chinese Han population. Although we did not find any association between this SNP and beta-cell function in either healthy individuals or newly diagnosed T1D patients, healthy individuals carrying GG/GA genotypes had lower CTLA-4 expression in naïve or activated CD4 Treg subsets (P = 0.0046 and 0.0317 respectively). A higher positive rate of IA-2A was observed among T1D patients with GG genotype compared with AA (OR = 0.51, 95% CI: 0.30–0.84, p = 0.008). Collectively, CTLA-4 +49 G/A reached a GWAS significant association with T1D risk in Chinese Han population, affects CTLA-4 expression in Treg subsets and subsequently humoral immunity in T1D patients.

Homo- and Heterodimerization of Proteins in Cell Signaling: Inhibition and Drug Design

Protein dimerization controls many physiological processes in the body. Proteins form homo-, hetero-, or oligomerization in the cellular environment to regulate the cellular processes. Any deregulation of these processes may result in a disease state. Protein-protein interactions (PPIs) can be inhibited by antibodies, small molecules, or peptides, and inhibition of PPI has therapeutic value. PPI drug discovery research has steadily increased in the last decade, and a few PPI inhibitors have already reached the pharmaceutical market. Several PPI inhibitors are in clinical trials. With advancements in structural and molecular biology methods, several methods are now available to study protein homo- and heterodimerization and their inhibition by drug-like molecules. Recently developed methods to study PPI such as proximity ligation assay and enzyme-fragment complementation assay that detect the PPI in the cellular environment are described with examples. At present, the methods used to design PPI inhibitors can be classified into three major groups: (1) structure-based drug design, (2) high-throughput screening, and (3) fragment-based drug design. In this chapter, we have described some of the experimental methods to study PPIs and their inhibition. Examples of homo- and heterodimers of proteins, their structural and functional aspects, and some of the inhibitors that have clinical importance are discussed. The design of PPI inhibitors of epidermal growth factor receptor heterodimers and CD2-CD58 is discussed in detail.

BANK1 alters B cell responses and influences the interactions between B cells and induced T regulatory cells in mice with collagen-induced arthritis

Background

Functional variants of the B cell gene, B cell scaffold protein with ankyrin repeats 1 (BANK1) contribute to rheumatoid arthritis (RA) susceptibility, but their influences on B cell responses are unclear. Moreover, the function of induced T regulatory cells (iTregs) in the inflammatory milieu in a collagen-induced arthritis (CIA) model is unknown. This study was performed to investigate the roles of BANK1 in CIA and the interaction between B cells and iTregs.

Methods

The changes in BANK1 mRNA and protein levels and their correlation with disease severity in CIA were determined. Next, the antigen-presenting function and autoantibody production in B cells were evaluated by co-culture with effector T cells and iTregs, respectively, both in vitro and in vivo. Then, the mechanisms underlying these interactions were studied by adding neutralizing antibodies or transwell inserts and by adoptive transfer to B-cell-depleted CIA mice.

Results

The BANK1 level decreased in the peripheral blood, spleen and lymph nodes of CIA mice, particularly during the acute stage of arthritis, and exhibited negative correlation with disease severity and autoantibody production. B cell responses were enhanced by this decrease. B cells from CIA mice (CIA-B cells) promoted iTreg differentiation, proliferation and cytotoxic T lymphocyte-associated protein-4 (CTLA-4) expression. Meanwhile, BANK1 expression in CIA-B cells increased after co-culture with iTregs, limiting B cell responses. All these interactions depended on cell contact with CTLA-4-overexpressing iTregs but were independent of CTLA-4 cytokine.

Conclusion

Decreased BANK1 expression promotes B cell responses, resulting in an increased antigen presentation ability and autoantibody production that subsequently influences the communication between B cells and iTregs through a cell-contact-dependent and CTLA-4- cytokine-independent mechanism in CIA mice.

Immunoglobulin superfamily members encoded by viruses and their multiple roles in immune evasion

Pathogens have developed a plethora of strategies to undermine host immune defenses in order to guarantee their survival. For large DNA viruses, these immune evasion mechanisms frequently rely on the expression of genes acquired from host genomes. Horizontally transferred genes include members of the immunoglobulin superfamily, whose products constitute the most diverse group of proteins of vertebrate genomes. Their promiscuous immunoglobulin domains, which comprise the building blocks of these molecules, are involved in a large variety of functions mediated by ligand-binding interactions. The flexible structural nature of the immunoglobulin domains makes them appealing targets for viral capture due to their capacity to generate high functional diversity. Here, we present an up-to-date review of immunoglobulin superfamily gene homologs encoded by herpesviruses, poxviruses, and adenoviruses, that include CD200, CD47, Fc receptors, interleukin-1 receptor 2, interleukin-18 binding protein, CD80, carcinoembryonic antigen-related cell adhesion molecules, and signaling lymphocyte activation molecules. We discuss their distinct structural attributes, binding properties, and functions, shaped by evolutionary pressures to disarm specific immune pathways. We include several novel genes identified from extensive genome database surveys. An understanding of the properties and modes of action of these viral proteins may guide the development of novel immune-modulatory therapeutic tools.

Anti-cancer activity of dose-fractioned mPE +/- bevacizumab regimen is paralleled by immune-modulation in advanced squamous NSLC patients

Background

Results from the BEVA2007 trial, suggest that the metronomic chemotherapy regimen with dose-fractioned cisplatin and oral etoposide (mPE) +/- bevacizumab, a monoclonal antibody to the vascular endothelial growth factor (VEGF), shows anti-angiogenic and immunological effects and is a safe and active treatment for metastatic non-small cell lung cancer (mNSCLC) patients. We carried out a retrospective analysis aimed to evaluate the antitumor effects of this treatment in a subset of patients with squamous histology.

Methods

Retrospective analysis was carried out in a subset of 31 patients with squamous histology enrolled in the study between September 2007 and September 2015. All of the patients received chemotherapy with cisplatin (30 mg/sqm, days 1-3q21) and oral etoposide (50 mg, days 1-15q21) (mPE) and 14 of them also received bevacizumab 5 mg/kg on the day 3q21 (mPEBev regimen).

Results

This treatment showed a disease control rate of 71% with a mean progression free survival (PFS) and overall survival (OS) of 13.6 and 17 months respectively. After 4 treatment courses, 6 patients showing a remarkable tumor shrinkage, underwent to radical surgery, attaining a significant advantage in term of survival (P=0.048). Kaplan-Meier and log-rank test identified the longest survival in patients presenting low baseline levels in neutrophil-to-lymphocyte ratio (NLR) (P=0.05), interleukin (IL) 17A (P=0.036), regulatory-T-cells (T_regs) (P=0.020), and activated CD83+ dendritic cells (DCs) (P=0.03).

Conclusions

These results suggest that the mPE +/- bevacizumab regimen is feasible and should be tested in comparative trials in advanced squamous-NSCLC (sqNSCLC). Moreover, its immune-biological effects strongly suggest the investigation in sequential combinations with immune check-point inhibitors.

Crystal Structure of the Extracellular Domain of the Human Dendritic Cell Surface Marker CD83

CD83 is a type-I membrane protein and an efficient marker for identifying mature dendritic cells. Whereas membrane-bound, full-length CD83 co-stimulates the immune system, a soluble variant (sCD83), consisting of the extracellular domain only, displays strong immune-suppressive activities. Besides a prediction that sCD83 adopts a V-set Ig-like fold, however, little is known about the molecular architecture of CD83 and the mechanism by which CD83 exerts its function on dendritic cells and additional immune cells. Here, we report the crystal structure of human sCD83 up to a resolution of 1.7Å solved in three different crystal forms. Interestingly, β-strands C', C″, and D that are typical for V-set Ig-domains could not be traced in sCD83. Mass spectrometry analyses, limited proteolysis experiments, and bioinformatics studies show that the corresponding segment displays enhanced main-chain accessibility, extraordinary low sequence conservation, and a predicted high disorder propensity. Chimeric proteins with amino acid swaps in this segment show unaltered immune-suppressive activities in a TNF-α assay when compared to wild-type sCD83. This strongly indicates that this segment does not participate in the biological activity of CD83. The crystal structure of CD83 shows the recurrent formation of dimers and trimers in the various crystal forms and reveals strong structural similarities between sCD83 and B7 family members and CD48, a signaling lymphocyte activation molecule family member. This suggests that CD83 exerts its immunological activity by mixed homotypic and heterotypic interactions as typically observed for proteins present in the immunological synapse.

Immunotherapy for colorectal cancer: where are we heading?

INTRODUCTION

In the last few years, significant advances in molecular biology have provided new therapeutic options for colorectal cancer (CRC). The development of new drugs that target the immune response to cancer cells seems very promising and has already been established for other tumor types. In particular, the use of immune checkpoint inhibitors seems to be an encouraging immunotherapeutic strategy. Areas covered: In this review, the authors provide an update of the current evidence related to this topic, though most immunotherapies are still in early-phase clinical trials for CRC. To understand the key role of immunotherapy in CRC, the authors discuss the delicate balance between immune-stimulating and immune-suppressive networks that occur in the tumor microenvironment. Expert opinion: Modulation of the immune system through checkpoint inhibition is an emerging approach in CRC therapy. Nevertheless, selection criteria that could enable the identification of patients who may benefit from these agents are necessary. Furthermore, potential prognostic and predictive immune biomarkers based on immune and molecular classifications have been proposed. As expected, additional studies are required to develop biomarkers, effective therapeutic strategies and novel combinations to overcome immune escape resistance and enhance effector response.

Immunotherapy for gastric cancers: emerging role and future perspectives

INTRODUCTION

The broad use of immunotherapy is revolutionizing the treatment paradigms of many solid tumors. Although chemotherapy remains the treatment backbone for advanced gastric cancer, improvements in its molecular characterization and progresses in understanding its underpinning biology have supported clinical development of novel immunotherapies. However, the results of recent trials testing these new agents raise the question on how to identify the patients that could greatly benefit. Areas covered: This article summarizes the current understanding on the biology and the mechanisms underlying different clinical features of gastric cancers. Particularly, after a comprehensive literature search, we speculate whether specific molecular subsets of patients could derive more benefit from immunotherapy. Expert commentary: Most cancers may evade the immune response, which is normally regulated by a delicate balance between activating and inhibitory signals. For example, both CTLA-4 and PD-1, once linked to PD-L1/2, may inhibit T-cell signaling. The use of agent to harness the power of the immune system appears to be the ultimate frontier in gastric cancer treatment. While anti-CTLA-4 antibodies are minimally active, there is growing evidence for the efficacy of PD1/-L1 inhibitors. The search of predictive factors for immunotherapy will provide key hints towards the optimal use of these agents.

CTLA-4 +49 G/A Polymorphism Confers Autoimmune Disease Risk: An Updated Meta-Analysis

BACKGROUND

Cytotoxic T lymphocyte antigen-4 (CTLA-4) plays a pivotal role in immune homeostasis. Dysregulated expression of CTLA-4 leads to many autoimmune diseases, including rheumatoid arthritis, systemic lupus erythematosus, and type 1 diabetes (T1D). There has been a controversial association between the CTLA-4 +49 G/A SNP (rs231775) and autoimmune diseases. Therefore, this meta-analysis was performed to assess the link between rs231775 and autoimmune disease risk.

MATERIALS AND METHODS

We retrieved the available studies from PUBMED and EMBASE through February, 2016 and then performed meta-analyses that included all populations, as well as by ethnicity.

RESULTS

After evaluating data from 4732 patients and 6270 healthy controls that included both Caucasian and Asian ethnicities, we found that rs231775 is strongly associated with autoimmune disease incidence in a homozygote comparison (GG vs. AA, 95% confidence interval [95% CI] 1.382-2.401), in a heterozygote comparison (AG vs. AA, 95% CI 1.151-1.611), in an allelic model (T allele vs. G allele, 95% CI 1.109-1.441), in a dominant model (GG/AG vs. AA, 95% CI 1.220-1.787), and in a recessive model (GG vs. AA/AG, 95% CI 1.128-1.661). The OR (odds ratio) from all models suggested a very significant association between rs231775 and autoimmune diseases.

CONCLUSION

Our present study indicates that CTLA-4 +49 G/A (rs231775) is associated with the susceptibility of autoimmune disease. Hence, rs231775 might be utilized as a diagnostic biomarker in both Asian and Caucasian populations.