Homeostasis and self-tolerance in the immune system: turning lymphocytes off

Proteogenomic analysis identifies neoantigens and bacterial peptides as immunotherapy targets in colorectal cancer

Considerable progress has recently been made in cancer immunotherapy, including immune checkpoint blockade, cancer vaccine, and adoptive T cell methods. The lack of effective targets is a major cause of the low immunotherapy response rate in colorectal cancer (CRC). Here, we used a proteogenomic strategy comprising immunopeptidomics, whole exome sequencing, and 16 S ribosomal DNA sequencing analyses of 8 patients with CRC to identify neoantigens and bacterial peptides that can serve as antitumor targets. This study directly identified several personalized neoantigens and bacterial immunopeptides. Immunoassays showed that all neoantigens and 5 of 8 bacterial immunopeptides could be recognized by autologous T cells. Additionally, T cell receptor (TCR) αβ sequencing revealed the TCR repertoire of epitope-reactive CD8+ T cells. Functional studies showed that T cell receptor-T (TCR-T) could be activated by epitope pulsed lymphoblastoid cells. Overall, this study comprehensively profiled the CRC immunopeptidome, revealing several neoantigens and bacterial peptides with potential to serve as immunotherapy targets in CRC.

Hybridizing mechanistic mathematical modeling with deep learning methods to predict individual cancer patient survival after immune checkpoint inhibitor therapy

We present a study where predictive mechanistic modeling is used in combination with deep learning methods to predict individual patient survival probabilities under immune checkpoint inhibitor (ICI) therapy. This hybrid approach enables prediction based on both measures that are calculable from mechanistic models (but may not be directly measurable in the clinic) and easily measurable quantities or characteristics (that are not always readily incorporated into predictive mechanistic models). The mechanistic model we have applied here can predict tumor response from CT or MRI imaging based on key mechanisms underlying checkpoint inhibitor therapy, and in the present work, its parameters were combined with readily-available clinical measures from 93 patients into a hybrid training set for a deep learning time-to-event predictive model. Analysis revealed that training an artificial neural network with both mechanistic modeling-derived and clinical measures achieved higher per-patient predictive accuracy based on event-time concordance, Brier score, and negative binomial log-likelihood-based criteria than when only mechanistic model-derived values or only clinical data were used. Feature importance analysis revealed that both clinical and model-derived parameters play prominent roles in neural network decision making, and in increasing prediction accuracy, further supporting the advantage of our hybrid approach. We anticipate that many existing mechanistic models may be hybridized with deep learning methods in a similar manner to improve predictive accuracy through addition of additional data that may not be readily implemented in mechanistic descriptions.

Immunologic aspects of preeclampsia

Preeclampsia is a syndrome with multiple etiologies. The diagnosis can be made without proteinuria in the presence of dysfunction of at least 1 organ associated with hypertension. The common pathophysiological pathway includes endothelial cell activation, intravascular inflammation, and syncytiotrophoblast stress. There is evidence to support, among others, immunologic causes of preeclampsia. Unlike defense immunology, reproductive immunology is not based on immunologic recognition systems of self/non-self and missing-self but on immunotolerance and maternal-fetal cellular interactions. The main mechanisms of immune escape from fetal to maternal immunity at the maternal-fetal interface are a reduction in the expression of major histocompatibility complex molecules by trophoblast cells, the presence of complement regulators, increased production of indoleamine 2,3-dioxygenase, activation of regulatory T cells, and an increase in immune checkpoints. These immune protections are more similar to the immune responses observed in tumor biology than in allograft biology. The role of immune and nonimmune decidual cells is critical for the regulation of trophoblast invasion and vascular remodeling of the uterine spiral arteries. Regulatory T cells have been found to play an important role in suppressing the effectiveness of other T cells and contributing to local immunotolerance. Decidual natural killer cells have a cytokine profile that is favored by the presence of HLA-G and HLA-E and contributes to vascular remodeling. Studies on the evolution of mammals show that HLA-E, HLA-G, and HLA-C1/C2, which are expressed by trophoblasts and their cognate receptors on decidual natural killer cells, are necessary for the development of a hemochorial placenta with vascular remodeling. The activation or inhibition of decidual natural killer cells depends on the different possible combinations between killer cell immunoglobulin-like receptors, expressed by uterine natural killer cells, and the HLA-C1/C2 antigens, expressed by trophoblasts. Polarization of decidual macrophages in phenotype 2 and decidualization of stromal cells are also essential for high-quality vascular remodeling. Knowledge of the various immunologic mechanisms required for adequate vascular remodeling and their dysfunction in case of preeclampsia opens new avenues of research to identify novel biological markers or therapeutic targets to predict or prevent the onset of preeclampsia.

Epigenetic Dysregulation in the Pathogenesis of Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is a multisystem autoimmune disease in which immune disorders lead to autoreactive immune responses and cause inflammation and tissue damage. Genetic and environmental factors have been shown to trigger SLE. Recent evidence has also demonstrated that epigenetic factors contribute to the pathogenesis of SLE. Epigenetic mechanisms play an important role in modulating the chromatin structure and regulating gene transcription. Dysregulated epigenetic changes can alter gene expression and impair cellular functions in immune cells, resulting in autoreactive immune responses. Therefore, elucidating the dysregulated epigenetic mechanisms in the immune system is crucial for understanding the pathogenesis of SLE. In this paper, we review the important roles of epigenetic disorders in the pathogenesis of SLE.

Immune Homeostasis: A Novel Example of Teamwork

All living organisms must maintain homeostasis to survive, reproduce, and pass their traits on to the next generation. If homeostasis is not maintained, it can result in various diseases and ultimately lead to death. Physiologists have coined the term "homeostasis" to describe this process. With the emergence of immunology as a separate branch of medicine, the concept of immune homeostasis has been introduced. Maintaining immune homeostasis is crucial to support overall homeostasis through different immunological and non-immunological routes. Any changes in the immune system can lead to chronic inflammatory or autoimmune diseases, immunodeficiency diseases, frequent infections, and cancers. Ongoing scientific advances are exploring new avenues in immunology and immune homeostasis maintenance. This chapter introduces the concept of immune homeostasis and its maintenance through different mechanisms.

Diacylglycerol kinases: A look into the future of immunotherapy

Cancer still represents the second leading cause of death right after cardiovascular diseases. According to the World Health Organization (WHO), cancer provoked around 10 million deaths in 2020, with lung and colon tumors accounting for the deadliest forms of cancer. As tumor cells become resistant to traditional therapeutic approaches, immunotherapy has emerged as a novel strategy for tumor control. T lymphocytes are key players in immune responses against tumors. Immunosurveillance allows identification, targeting and later killing of cancerous cells. Nevertheless, tumors evolve through different strategies to evade the immune response and spread in a process called metastasis. The ineffectiveness of traditional strategies to control tumor growth and expansion has led to novel approaches considering modulation of T cell activation and effector functions. Program death receptor 1 (PD-1) and cytotoxic T-lymphocyte antigen 4 (CTLA-4) showed promising results in the early 90s and nowadays are still being exploited together with other drugs for several cancer types. Other negative regulators of T cell activation are diacylglycerol kinases (DGKs) a family of enzymes that catalyze the conversion of diacylglycerol (DAG) into phosphatidic acid (PA). In T cells, DGKα and DGKζ limit the PLCγ/Ras/ERK axis thus attenuating DAG mediated signaling and T cell effector functions. Upregulation of either of both isoforms results in impaired Ras activation and anergy induction, whereas germline knockdown mice showed enhanced antitumor properties and more effective immune responses against pathogens. Here we review the mechanisms used by DGKs to ameliorate T cell activation and how inhibition could be used to reinvigorate T cell functions in cancer context. A better knowledge of the molecular mechanisms involved upon T cell activation will help to improve current therapies with DAG promoting agents.

Regulatory TR3-56 Cells in the Complex Panorama of Immune Activation and Regulation

The interplay between immune activation and immune regulation is a fundamental aspect of the functional harmony of the immune system. This delicate balance is essential to triggering correct and effective immune responses against pathogens while preventing excessive inflammation and the immunopathogenic mechanisms of autoimmunity. The knowledge of all the mechanisms involved in immune regulation is not yet definitive, and, probably, the overall picture is much broader than what has been described in the scientific literature so far. Given the plasticity of the immune system and the diversity of organisms, it is highly probable that numerous other cells and molecules are still to be ascribed to the immune regulation process. Here, we report a general overview of how immune activation and regulation interact, based on the involvement of molecules and cells specifically dedicated to these processes. In addition, we discuss the role of TR3-56 lymphocytes as a new cellular candidate in the immune regulation landscape.

Addressing the key issue: Antigen-specific targeting of B cells in autoimmune diseases

Autoimmune diseases are heterogeneous pathologies characterized by a breakdown of immunological tolerance to self, resulting in a chronic and aberrant immune response to self-antigens. The scope and extent of affected tissues can vary greatly per autoimmune disease and can involve multiple organs and tissue types. The pathogenesis of most autoimmune diseases remains unknown but it is widely accepted that a complex interplay between (autoreactive) B and T cells in the context of breached immunological tolerance drives autoimmune pathology. The importance of B cells in autoimmune disease is exemplified by the successful use of B cell targeting therapies in the clinic. For example, Rituximab, a depleting anti-CD20 antibody, has shown favorable results in reducing the signs and symptoms of multiple autoimmune diseases, including Rheumatoid Arthritis, Anti-Neutrophil Cytoplasmic Antibody associated vasculitis and Multiple Sclerosis. However, Rituximab depletes the entire B cell repertoire, leaving patients susceptible to (latent) infections. Therefore, multiple ways to target autoreactive cells in an antigen-specific manner are currently under investigation. In this review, we will lay out the current state of antigen-specific B cell inhibiting or depleting therapies in the context of autoimmune diseases.

Cysteine carboxyethylation generates neoantigens to induce HLA-restricted autoimmunity

Autoimmune diseases such as ankylosing spondylitis (AS) can be driven by emerging neoantigens that disrupt immune tolerance. Here, we developed a workflow to profile posttranslational modifications involved in neoantigen formation. Using mass spectrometry, we identified a panel of cysteine residues differentially modified by carboxyethylation that required 3-hydroxypropionic acid to generate neoantigens in patients with AS. The lysosomal degradation of integrin αIIb [ITGA2B (CD41)] carboxyethylated at Cys96 (ITGA2B-ceC96) generated carboxyethylated peptides that were presented by HLA-DRB1*04 to stimulate CD4⁺ T cell responses and induce autoantibody production. Immunization of HLA-DR4 transgenic mice with the ITGA2B-ceC96 peptide promoted colitis and vertebral bone erosion. Thus, metabolite-induced cysteine carboxyethylation can give rise to pathogenic neoantigens that lead to autoreactive CD4⁺ T cell responses and autoantibody production in autoimmune diseases.

Radiotherapy/Chemotherapy-Immunotherapy for Cancer Management: From Mechanisms to Clinical Implications

Cancer immunotherapy has drawn much attention because it can restart the recognition and killing function of the immune system to normalize the antitumor immune response. However, the role of radiotherapy and chemotherapy in cancer treatment cannot be ignored. Due to cancer heterogeneity, combined therapy has become a new trend, and its efficacy has been confirmed in many studies. This review discussed the clinical implications and the underlying mechanisms of cancer immunotherapy in combination with radiotherapy or chemotherapy, offering an outline for clinicians as well as inspiration for future research.

2D Copper(II) Metalated Metal-Organic Framework Nanocomplexes for Dual-enhanced Photodynamic Therapy and Amplified Antitumor Immunity

The immunosuppressive tumor microenvironment (TME) poses tremendous challenges for efficient immunotherapy. Smart nanomedicine is designed to modulate immunosuppressive TMEs based on the combination of dual-enhanced photodynamic therapy (PDT) triggered immunogenic cell death (ICD) and relieved hypoxic microenvironment. Copper(II) metalated metal-organic framework nanosheets (Cu-TCPP(Al)) are the foundation of the nanomedicine, and platinum nanoparticles (Pt NPs) and folate are subsequently introduced onto the Cu-TCPP(Al) surface (Cu-TCPP(Al)-Pt-FA). Upon targeted cellular uptake, intracellular GSH concentration is decreased because of the specific adsorption between GSH and Cu^II; meanwhile, Pt NPs possess catalase-like activity, which can continuously depose intracellular H₂O₂ to O₂ to alleviate the hypoxic TME. The two factors synergistically improve the ROS concentration for dual-enhanced PDT. The highly toxic ROS can correspondingly cause amplified oxidative stress and then trigger the ICD. The ICD process stimulates antigen-presenting cells and activates the systemic antitumor immune response. Furthermore, the relieved hypoxic TME increases the infiltration of cytotoxic T lymphocytes (CTLs) at the tumor site, which can promote the transformation of the immunosuppressive M2 macrophage to immunoactive M1 phenotype. The easily prepared yet versatile nanomedicine possesses an excellent antitumor effect with the cooperation of dual-enhanced PDT and immunotherapy.

Rationale and Clinical Research Progress on PD-1/PD-L1-Based Immunotherapy for Metastatic Triple-Negative Breast Cancer

Metastatic triple-negative breast cancer (mTNBC), a highly aggressive and malignant tumor, currently lacks an effective treatment. There has been some progress in the treatment of mTNBC with programmed death receptor-1/programmed death ligand-1 (PD-1/PD-L1) immunotherapy in recent years. The combination of PD-1/PD-L1 inhibitors with other therapies is a noteworthy treatment strategy. Immunotherapy in combination with chemotherapy or small-molecule inhibitors still faces many challenges. Additionally, there are some new immunotherapy targets in development. We aimed to further evaluate the effectiveness and usefulness of immunotherapy for treating mTNBC and to propose new immunotherapy strategies. This review explains the rationale and results of existing clinical trials evaluating PD-1/PD-L1 inhibitors alone or in combination for the treatment of mTNBC. For patients with aggressive tumors and poor health, PD-1/PD-L1 inhibitors, either alone or in combination with other modalities, have proven to be effective. However, more research is needed to explore more effective immunotherapy regimens that will lead to new breakthroughs in the treatment of mTNBC.

Activated-memory T cells influence naïve T cell fate: a noncytotoxic function of human CD8 T cells

T cells are endowed with the capacity to sense their environment including other T cells around them. They do so to set their numbers and activation thresholds. This form of regulation has been well-studied within a given T cell population - i.e., within the naïve or memory pool; however, less is known about the cross-talk between T cell subsets. Here, we tested whether memory T cells interact with and influence surrounding naïve T cells. We report that human naïve CD8 T cells (T_N) undergo phenotypic and transcriptional changes in the presence of autologous activated-memory CD8 T cells (T_Mem). Following in vitro co-culture with activated central memory cells (T_CM), ~3% of the T_N acquired activation/memory canonical markers (CD45RO and CD95) in an MHC-I dependent-fashion. Using scRNA-seq, we also observed that ~3% of the T_N acquired an activated/memory signature, while ~84% developed a unique activated transcriptional profile hybrid between naïve and activated memory. Pseudotime trajectory analysis provided further evidence that T_N with an activated/memory or hybrid phenotype were derived from T_N. Our data reveal a non-cytotoxic function of T_Mem with potential to activate autologous T_N into the activated/memory pool. These findings may have implications for host-protection and autoimmunity that arises after vaccination, infection or transplantation.

Immune Tolerance vs. Immune Resistance: The Interaction Between Host and Pathogens in Infectious Diseases

The immune system is most likely developed to reduce the harmful impact of infections on the host homeostasis. This defense approach is based on the coordinated activity of innate and adaptive immune system components, which detect and target infections for containment, killing, or expulsion by the body's defense mechanisms. These immunological processes are responsible for decreasing the pathogen burden of an infected host to maintain homeostasis that is considered to be infection resistance. Immune-driven resistance to infection is connected with a second, and probably more important, defensive mechanism: it helps to minimize the amount of dysfunction imposed on host parenchymal tissues during infection without having a direct adverse effect on pathogens. Disease tolerance is a defensive approach that relies on tissue damage control systems to prevent infections from causing harm to the host. It also uncouples immune-driven resistance mechanisms from immunopathology and disease, allowing the body to fight infection more effectively. This review discussed the cellular and molecular processes that build disease tolerance to infection and the implications of innate immunity on those systems. In addition, we discuss how symbiotic relationships with microbes and their control by particular components of innate and adaptive immunity alter disease tolerance to infection.

Adaptive Immune Responses, Immune Escape and Immune-Mediated Pathogenesis during HDV Infection

The hepatitis delta virus (HDV) is the smallest known human virus, yet it causes great harm to patients co-infected with hepatitis B virus (HBV). As a satellite virus of HBV, HDV requires the surface antigen of HBV (HBsAg) for sufficient viral packaging and spread. The special circumstance of co-infection, albeit only one partner depends on the other, raises many virological, immunological, and pathophysiological questions. In the last years, breakthroughs were made in understanding the adaptive immune response, in particular, virus-specific CD4+ and CD8+ T cells, in self-limited versus persistent HBV/HDV co-infection. Indeed, the mechanisms of CD8+ T cell failure in persistent HBV/HDV co-infection include viral escape and T cell exhaustion, and mimic those in other persistent human viral infections, such as hepatitis C virus (HCV), human immunodeficiency virus (HIV), and HBV mono-infection. However, compared to these larger viruses, the small HDV has perfectly adapted to evade recognition by CD8+ T cells restricted by common human leukocyte antigen (HLA) class I alleles. Furthermore, accelerated progression towards liver cirrhosis in persistent HBV/HDV co-infection was attributed to an increased immune-mediated pathology, either caused by innate pathways initiated by the interferon (IFN) system or triggered by misguided and dysfunctional T cells. These new insights into HDV-specific adaptive immunity will be discussed in this review and put into context with known well-described aspects in HBV, HCV, and HIV infections.

Diet and Hygiene in Modulating Autoimmunity During the Pandemic Era

The immune system is an efficiently toned machinery that discriminates between friends and foes for achieving both host defense and homeostasis. Deviation of immune recognition from foreign to self and/or long-lasting inflammatory responses results in the breakdown of tolerance. Meanwhile, educating the immune system and developing immunological memory are crucial for mounting defensive immune responses while protecting against autoimmunity. Still to elucidate is how diverse environmental factors could shape autoimmunity. The emergence of a world pandemic such as SARS-CoV-2 (COVID-19) not only threatens the more vulnerable individuals including those with autoimmune conditions but also promotes an unprecedented shift in people's dietary approaches while urging for extraordinary hygiene measures that likely contribute to the development or exacerbation of autoimmunity. Thus, there is an urgent need to understand how environmental factors modulate systemic autoimmunity to better mitigate the incidence and or severity of COVID-19 among the more vulnerable populations. Here, we discuss the effects of diet (macronutrients and micronutrients) and hygiene (the use of disinfectants) on autoimmunity with a focus on systemic lupus erythematosus.

Radiotherapy for HPV-related cancers: prediction of therapeutic effects based on the mechanism of tumor immunity and the application of immunoradiotherapy

Human papillomavirus (HPV)-related cancer is one of the diseases entities for which the applications of radiotherapy have been increasing. Recently, the process of carcinogenesis from HPV infection and the mechanism of tumor immunity that develops during disease progression have been elucidated. In this review, we will describe the mechanism of tumor immunity and how chemoradiotherapy may overcome and improve the efficacy of tumor immunity. We will also discuss the usefulness of proteins involved with tumor immunity as a predictive marker of radiotherapy response, and present an overview of ongoing clinical trials of combinations of immune checkpoint inhibitors and radiotherapy to demonstrate the promising combination therapy that has been currently emerging.

Role of the Immune System Elements in Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a relatively rare disease, but, today, its incidence tends to increase. The severe course of the disease and poor patient survival rate make PAH a major diagnostic and therapeutic challenge. For this reason, a thorough understanding of the pathogenesis of the disease is essential to facilitate the development of more effective therapeutic targets. Research shows that the development of PAH is characterized by a number of abnormalities within the immune system that greatly affect the progression of the disease. In this review, we present key data on the regulated function of immune cells, released cytokines and immunoregulatory molecules in the development of PAH, to help improve diagnosis and targeted immunotherapy.

Toward Personalized Radiation Therapy of Liver Metastasis: Importance of Serial Blood Biomarkers

PURPOSE

To assess the added value of serial blood biomarkers in liver metastasis stereotactic body radiation therapy (SBRT).

MATERIALS AND METHODS

Eighty-nine patients were retrospectively included. Pre- and midtreatment blood samples were analyzed for potential biomarkers of the treatment response. Three biomarker classes were studied: gene mutation status, complete blood count, and inflammatory cytokine concentration in plasma. One-year local failure (LF) and 2-year overall survival (OS) were chosen as study end points. Multivariate logistic regression was used for response prediction. Added predictive benefit was assessed by quantifying the difference between the predictive performance of a baseline model (clinicopathologic and dosimetric predictors) and that of the biomarker-enhanced model, using three metrics: (1) likelihood ratio, (2) predictive variance, and (3) area under the receiver operating characteristic curve (AUC).

RESULTS

The most important predictors of LF were mutation in KRAS gene (hazard ratio [HR] = 2.92, 95% CI, [1.17 to 7.28], P = .02) and baseline and midtreatment concentration of plasma interleukin-6 (HR = 1.15 [1.04 to 1.26] and 1.06 [1.01 to 1.13], P = .01). Absolute lymphocyte count and platelet-to-lymphocyte ratio at baseline as well as neutrophil-to-lymphocyte ratio at baseline and before fraction 3 (HR = 1.33 [1.16 to 1.51] and 1.19 [1.09 to 1.30]) had the most significant association with OS (P = .0003). Addition of baseline GEN and inflammatory plasma cytokine biomarkers in predicting LF, respectively, increased AUC by 0.06 (from 0.73 to 0.79) and 0.07 (from 0.77 to 0.84). In predicting OS, inclusion of midtreatment complete blood count biomarkers increased AUC from 0.72 to 0.80, along with significant boosts in likelihood ratio and predictive variance.

CONCLUSION

Inclusion of serial blood biomarkers leads to significant gain in predicting response to liver metastasis stereotactic body radiation therapy and can guide treatment personalization.

Plasmodium infection inhibits triple negative 4T1 breast cancer potentially through induction of CD8+ T cell-mediated antitumor responses in mice

We previously reported that Plasmodium infection promotes antitumor immunity in a murine Lewis lung cancer. In this study, we investigated the effects of Plasmodium infection on the tumor inhibition and antitumor CD8⁺ T cell responses in a murine triple negative breast cancer (TNBCA) model. The results showed that Plasmodium infection significantly inhibited tumor growth, and increased the survival rate of the tumor-bearing mice. Both effector and memory CD8⁺ T cells were increased in peripheral blood and tumor-draining lymph node (DLN) in the infected mice. The co-stimulatory (CD40L, GITR and OX-40) and co-inhibitory (PD-1, CTLA-4, TIM-3, LAG3) immune checkpoints were up-regulated on CD8⁺ T cells in infected mice. Importantly, Py induced remarkable effects on the infiltration of CD8⁺ T cells in the tumor and granzym B⁺ CD8⁺ T cells in tumor-bearing mice while not in tumor-free mice. In summary, the results suggested that the effects of Plasmodium infection on murine 4T1 breast cancer might be related to the induction of CD8⁺ T cell-mediated antitumor immune responses. This finding may provide a novel strategy for the treatment of triple negative breast cancer.

IL-2 regulates tumor-reactive CD8+ T cell exhaustion by activating the aryl hydrocarbon receptor

CD8⁺ T cell exhaustion dampens antitumor immunity. Although several transcription factors have been identified that regulate T cell exhaustion, the molecular mechanisms by which CD8⁺ T cells are triggered to enter an exhausted state remain unclear. Here, we show that interleukin-2 (IL-2) acts as an environmental cue to induce CD8⁺ T cell exhaustion within tumor microenvironments. We find that a continuously high level of IL-2 leads to the persistent activation of STAT5 in CD8⁺ T cells, which in turn induces strong expression of tryptophan hydroxylase 1, thus catalyzing the conversion to tryptophan to 5-hydroxytryptophan (5-HTP). 5-HTP subsequently activates AhR nuclear translocation, causing a coordinated upregulation of inhibitory receptors and downregulation of cytokine and effector-molecule production, thereby rendering T cells dysfunctional in the tumor microenvironment. This molecular pathway is not only present in mouse tumor models but is also observed in people with cancer, identifying IL-2 as a novel inducer of T cell exhaustion.

Highly Sensitive Flow Cytometric Detection of Residual B-Cells After Rituximab in Anti-Neutrophil Cytoplasmic Antibodies-Associated Vasculitis Patients

Background

B-cell depletion with rituximab (RTX) is an effective treatment for anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitis (AAV) patients. Nevertheless, relapses are frequent after RTX, often preceded by B-cell repopulation suggesting that residual autoreactive B-cells persist despite therapy. Therefore, this study aimed to identify minimal residual autoimmunity (MRA) in the B-cell compartment of AAV patients treated with RTX.

Methods

EuroFlow-based highly-sensitive flow cytometry (HSFC) was employed to study B-cell and plasma cell (PC) subsets in-depth in AAV patients before and after RTX treatment. Additionally, peripheral blood mononuclear cells (PBMCs) of these RTX-treated AAV patients were cultured and in vitro stimulated with CpG, IL-2, and IL-21 to induce antibody-secreting cells (ASC). (ANCA)-IgG was measured in these supernatants by ELISA.

Results

By employing EuroFlow-based HSFC, we detected circulating CD19⁺ B-cells at all timepoints after RTX treatment, in contrast to conventional low-sensitive flow cytometry. Pre-germinal center (Pre-GC) B-cells, memory B-cells and CD20⁺CD138⁻ plasmablasts (PBs) were rapidly and strongly reduced, while CD20⁻CD138⁻ PrePC and CD20^-CD138⁺ mature (m)PCs were reduced slower and remained detectable. Both memory B-cells and CD20⁻ PCs remained detectable after RTX. Serum ANCA-IgG decreased significantly upon RTX. Changes in ANCA levels strongly correlated with changes in naive, switched CD27⁺ and CD27⁻ (double-negative) memory B-cells, but not with plasma cells. Lastly, we demonstrated in vitro ANCA production by AAV PBMCs, 24 and 48 weeks after RTX treatment reflecting MRA in the memory compartment of AAV patients.

Conclusion

We demonstrated that RTX induced strong reductions in circulating B-cells, but never resulted in complete B-cell depletion. Despite strongly reduced B-cell numbers after RTX, ANCA-specific memory B-cells were still detectable in AAV patients. Thus, MRA is identifiable in AAV and can provide a potential novel approach in personalizing RTX treatment in AAV patients.

Genetic-Code-Expansion Strategies for Vaccine Development

By providing long-term protection against infectious diseases, vaccinations have significantly reduced death and morbidity worldwide. In the 21st century, (bio)technological advances have paved the way for developing prophylactic vaccines that are safer and more effective as well as enabling the use of vaccines as therapeutics to treat human diseases. Here, we provide a focused review of the utility of genetic code expansion as an emerging tool for the development of vaccines. Specifically, we discuss how the incorporation of immunogenic noncanonical amino acids can aid in eliciting immune responses against adverse self-proteins and highlight the potential of an expanded genetic code for the construction of replication-incompetent viruses. We close the review by discussing the future prospects and remaining challenges for the application of these approaches in the development of both prophylactic and therapeutic vaccines in the near future.

Model-Based Cellular Kinetic Analysis of Chimeric Antigen Receptor-T Cells in Humans

Chimeric antigen receptor (CAR)-T cell therapy has achieved considerable success in treating B-cell hematologic malignancies. However, the challenges of extending CAR-T therapy to other tumor types, particularly solid tumors, remain appreciable. There are substantial variabilities in CAR-T cellular kinetics across CAR-designs, CAR-T products, dosing regimens, patient responses, disease types, tumor burdens, and lymphodepletion conditions. As a "living drug," CAR-T cellular kinetics typically exhibit four distinct phases: distribution, expansion, contraction, and persistence. The cellular kinetics of CAR-T may correlate with patient responses, but which factors determine CAR-T cellular kinetics remain poorly defined. Herein, we developed a cellular kinetic model to retrospectively characterize CAR-T kinetics in 217 patients from 7 trials and compared CAR-T kinetics across response status, patient populations, and tumor types. Based on our analysis results, CAR-T cells exhibited a significantly higher cell proliferation rate and capacity but a lower contraction rate in patients who responded to treatment. CAR-T cells proliferate to a higher degree in hematologic malignancies than in solid tumors. Within the assessed dose ranges (10⁷ -10⁹ cells), CAR-T doses were weakly correlated with CAR-T cellular kinetics and patient response status. In conclusion, the developed CAR-T cellular kinetic model adequately characterized the multiphasic CAR-T cellular kinetics and supported systematic evaluations of the potential influencing factors, which can have significant implications for the development of more effective CAR-T therapies.

Cell Survival Failure in Effector T Cells From Patients With Systemic Lupus Erythematosus Following Insufficient Up-Regulation of Cold-Shock Y-Box Binding Protein 1

OBJECTIVE

The importance of cold-shock Y-box binding protein 1 (YB-1) for cell homeostasis is well-documented based on prior observations of its association with certain cancer entities. This study was undertaken to explore the role of YB-1 in T cell homeostasis and survival and the potential contribution of YB-1 to the pathogenesis of systemic lupus erythematosus (SLE).

METHODS

In the peripheral blood from 25 SLE patients and 25 healthy donors, the expression of YB-1 and frequency of T cell apoptosis was analyzed by quantitative polymerase chain reaction (qPCR) and fluorescence-activated cell sorting of CD4+ T cells ex vivo and also analyzed in T cells in vitro after 6 days of stimulation with anti-CD3-coupled or anti-CD3/anti-CD28-coupled microspheres. YB-1 was overexpressed using lentiviral transduction with wild-type green fluorescent protein (wtGFP) YB-1, and knockdown of YB-1 was achieved using specific short hairpin RNA (shRNA) (3-fold reduction; P < 0.0001).

RESULTS

YB-1 expression was significantly lower in apoptosis-prone T cells and in activated T cells from SLE patients compared to YB-1 expression in nonapoptotic T cells and activated T cells from healthy donors (P = 0.001). Knockdown of YB-1 in T cells consequently led to expression of proapoptotic molecules and caspase 3 activation (1.6-fold), and subsequently, to apoptosis. Furthermore, YB-1 promoted survival pathways involving enhanced protein expression of the kinase Akt (2-fold) and Bcl-2 (3-fold), even when Fas/CD95 was triggered. YB-1-mediated T cell survival was reversed by Akt and phosphatidylinositol 3-kinase (PI3K) inactivation. In SLE patients, rescue of YB-1 expression strongly promoted survival of T cells and even prevented cell death in T cells that were extremely apoptosis-prone.

CONCLUSION

Our data show that failure of YB-1 up-regulation in T cells from SLE patients led to enhanced apoptosis. These findings imply that YB-1 plays a crucial role in the disturbed homeostasis of activated T cells leading to hematopoietic alterations in SLE. These insights may help facilitate the development of new treatment strategies for SLE.

Modeling of the immune response in the pathogenesis of solid tumors and its prognostic significance

BACKGROUND

Tumor initiation and subsequent progression are usually long-term processes, spread over time and conditioned by diverse aspects. Many cancers develop on the basis of chronic inflammation; however, despite dozens of years of research, little is known about the factors triggering neoplastic transformation under these conditions. Molecular characterization of both pathogenetic states, i.e., similarities and differences between chronic inflammation and cancer, is also poorly defined. The secretory activity of tumor cells may change the immunophenotype of immune cells and modify the extracellular microenvironment, which allows the bypass of host defense mechanisms and seems to have diagnostic and prognostic value. The phenomenon of immunosuppression is also present during chronic inflammation, and the development of cancer, due to its duration, predisposes patients to the promotion of chronic inflammation. The aim of our work was to discuss the above issues based on the latest scientific insights. A theoretical mechanism of cancer immunosuppression is also proposed.

CONCLUSIONS

Development of solid tumors may occur both during acute and chronic phases of inflammation. Differences in the regulation of immune responses between precancerous states and the cancers resulting from them emphasize the importance of immunosuppressive factors in oncogenesis. Cancer cells may, through their secretory activity and extracellular transport mechanisms, enhance deterioration of the immune system which, in turn, may have prognostic implications.

Immune system and cholangiocytes: A puzzling affair in primary biliary cholangitis

Primary biliary cholangitis (PBC) is a cholestatic liver disease characterized by the destruction of the small and medium bile ducts. Its pathogenesis is still unknown. Despite the genome wide association study findings, the therapies targeting the cytokines pathway, tested so far, have failed. The concept of the biliary epithelium as a key player of the PBC pathogenesis has emerged over the last few years. It is now well accepted that the biliary epithelial cells (BECs) actively participate to the genesis of the damage. The chronic stimulation of BECs via microbes and bile changes the cell phenotype toward an active state, which, across the production of proinflammatory mediators, can recruit, retain, and activate immune cells. The consequent immune system activation can in turn damage BECs. Thus, the crosstalk between both innate and adaptive immune cells and the biliary epithelium creates a paracrine loop responsible for the disease progression. In this review, we summarize the evidence provided in literature about the role of BECs and the immune system in the pathogenesis of PBC. We also dissect the relationship between the immune system and the BECs, focusing on the unanswered questions and the future potential directions of the translational research and the cellular therapy in this area.

Pure abscopal effect of radiotherapy in a salivary gland carcinoma: Case report, literature review, and a search for new approaches

We report the case of an 84-year-old woman with poorly differentiated non-small cell carcinoma of the right parotid who presented with headache, was found to have a primary right parotid gland cancer as well as metastatic disease, and underwent palliative radiotherapy to the primary site. The patient received no chemotherapy or immunotherapy, but both the primary site and several non-irradiated foci in the lungs regressed or completely resolved. The patient remained free of disease for about one year before progression. The case is a rare instance of abscopal regression of metastatic disease in the absence of pharmacologic immunomodulation. A literature review surveys the history of the abscopal effect of radiation therapy, attempts to understand the mechanisms of its successes and failures, and points to new approaches that can inform and improve the outcomes of radioimmunotherapy.

Type 1 diabetes pathogenesis and the role of inhibitory receptors in islet tolerance

Type 1 diabetes (T1D) affects over a million Americans, and disease incidence is on the rise. Despite decades of research, there is still no cure for this disease. Exciting beta cell replacement strategies are being developed, but in order for such approaches to work, targeted immunotherapies must be designed. To selectively halt the autoimmune response, researchers must first understand how this response is regulated and which tolerance checkpoints fail during T1D development. Herein, we discuss the current understanding of T1D pathogenesis in humans, genetic and environmental risk factors, presumed roles of CD4+ and CD8+ T cells as well as B cells, and implicated autoantigens. We also highlight studies in non-obese diabetic mice that have demonstrated the requirement for CD4+ and CD8+ T cells and B cells in driving T1D pathology. We present an overview of central and peripheral tolerance mechanisms and comment on existing controversies in the field regarding central tolerance. Finally, we discuss T cell- and B cell-intrinsic tolerance mechanisms, with an emphasis on the roles of inhibitory receptors in maintaining islet tolerance in humans and in diabetes-prone mice, and strategies employed to date to harness inhibitory receptor signaling to prevent or reverse T1D.

The Role of Tumor-Derived Vesicles in the Regulation of Antitumor Immunity

In this article, we present a comprehensive, updated, and elucidative review of the current knowledge on the function played by tumor-derived vesicles (TDVs) in the crosstalk between tumor and immune cells. Characterization of the structure, biogenesis, and the major functions of TDVs is reported. The review focuses on particular ways of suppression or activation of CD4+/CD8+ T cells by tumor-derived vesicles. Tumor-derived vesicles play an important role in the suppression of antitumor immunity. During the last 15 years, vesicle research has elucidated and improved our knowledge about the role of the vesicles in intercellular communication. Nevertheless, there are still blinds spots concerning vesicle heterogeneity and isolation methods, their uptake by target cells, and the role of mRNA in T-cell transformation or suppression. Along with the substantial progress in understanding of the role of tumor-derived vesicles in intercellular communication, novel antitumor therapy strategies based on vesicle inhibition in a tumor microenvironment are likely to appear very soon.

Engineering Cell Membrane-Based Nanotherapeutics to Target Inflammation

Inflammation is ubiquitous in the body, triggering desirable immune response to defend against dangerous signals or instigating undesirable damage to cells and tissues to cause disease. Nanomedicine holds exciting potential in modulating inflammation. In particular, cell membranes derived from cells involved in the inflammatory process may be used to coat nanotherapeutics for effective targeted delivery to inflammatory tissues. Herein, the recent progress of rationally engineering cell membrane-based nanotherapeutics for inflammation therapy is highlighted, and the challenges and opportunities presented in realizing the full potential of cell-membrane coating in targeting and manipulating the inflammatory microenvironment are discussed.

[rhPDCD5 suppresses pro-inflammatory cytokine secretion and proliferation and induces apoptosis of activated lymphocytes from rats with collagen-induced arthritis]

OBJECTIVE

To investigate the effect of recombinant human PDCD5 (rhPDCD5) treatment in a rat model of bovine II collagen (CII)-induced arthritis (CIA) on inflammatory cytokine secretion, proliferation and apoptosis of activated lymphocytes and explore the mechanisms of rhPDCD5-induced immunosuppression on activated lymphocytes.

METHODS

Female Wistar rats were randomly divided into normal control group, CIA+ ovalbumin (OVA) group, CIA+ rhTNFR: Fc group, and CIA+rhPDCD5 group. The rats in the latter 3 groups received intraperitoneal injections of OVA (14 mg/kg), rhTNFR: Fc (3.5 mg/kg) or rhPDCD5 (14 mg/kg) from day 2 to day 26 following CII injection. On day 28, the spleens of the rats were harvested for preparing single cell suspensions of splenocytes, which were activated by CII (20μg/mL) or anti-CD3 (1μg/mL)+ anti-CD28 (2μg/mL) for 48 h and 72 h. The production of interferon-γ(IFN-γ) and interleukin-17A (IL-17A) by the activated lymphocytes was determined by ELISA of the culture supernatants. The proliferation and apoptosis of the activated lymphocytes were assessed using [³H]-thymidine incorporation assay and flow cytometry, respectively.

RESULTS

Compared with those in CIA + OVA group, IFN-γand IL-17A secretions by the activated lymphocytes from rhPDCD5-treated CIA rats significantly decreased. RhPDCD5 treatment of the CIA rats obviously suppressed the proliferation and promoted apoptosis of the lymphocytes activated by CII or by anti-CD3 + anti-CD28.

CONCLUSIONS

rhPDCD5 reduces pro-inflammatory cytokine secretion, inhibits the proliferation and promotes activation-induced cell death of activated CD4 ⁺ lymphocytes to produce immunosuppression in rat models of CIA.

Immunological role of CD4+CD28null T lymphocytes, natural killer cells, and interferon-gamma in pediatric patients with sickle cell disease: relation to disease severity and response to therapy

Sickle cell disease (SCD) is associated with alterations in immune phenotypes. CD4⁺CD28^null T lymphocytes have pro-inflammatory functions and are linked to vascular diseases. To assess the percentage of CD4⁺CD28^null T lymphocytes, natural killer cells (NK), and IFN-gamma levels, we compared 40 children and adolescents with SCD with 40 healthy controls and evaluated their relation to disease severity and response to therapy. Patients with SCD steady state were studied, focusing on history of frequent vaso-occlusive crisis, hydroxyurea therapy, and IFN-gamma levels. Analysis of CD4⁺CD28^null T lymphocytes and NK cells was done by flow cytometry. Liver and cardiac iron overload were assessed. CD4⁺CD28^null T lymphocytes, NK cells, and IFN-gamma levels were significantly higher in patients than controls. Patients with history of frequent vaso-occlusive crisis and those with vascular complications had higher percentage of CD4⁺CD28^null T lymphocytes and IFN-gamma while levels were significantly lower among hydroxyurea-treated patients. CD4⁺CD28^null T lymphocytes were positively correlated to transfusional iron input while these cells and IFN-gamma were negatively correlated to cardiac T2* and duration of hydroxyurea therapy. NK cells were correlated to HbS and indirect bilirubin. Increased expression of CD4⁺CD28^null T lymphocytes highlights their role in immune dysfunction and pathophysiology of SCD complications.

Adverse and hormetic effects in rats exposed for 12 months to low dose mixture of 13 chemicals: RLRS part III

The aim of the current study was to evaluate the effects of a mixture of thirteen common chemicals on rats, after a one-year exposure to doses around the acceptable daily intake (ADIs), using blood and urinary tests. The influence of low doses of the mixture on weight gain, water consumption, feed consumption and feed efficiency, biochemistry parameters, haematological parameters, blood lymphocytes subsets, serum inflammation profile and urine parameters was evaluated. Our mixture caused a moderate monotonic increase of the males' appetite and a non-monotonic increase of anabolism and a monotonic increase of appetite for the females. Regarding biochemical parameters, the exposure to the test mixture caused non-monotonic increases of AST and ALT, a decrease of PChE in males and plausibly a monotonic biliary obstruction in both sexes. Monocytes significantly increased in low dose groups of both sexes. A significant decrease of all the lymphocytes subclasses and an increased expression of TNF-α protein associated with an increased expression of IFN-γ protein observed in various groups. It became apparent that after twelve months of exposure very low doses of the tested mixture had both non-monotonic and monotonic harmful effects on different levels on rats.

Transcriptional and epigenetic regulation of immune tolerance: roles of the NF-κB family members

Immune tolerance is a highly regulated state and involves diverse mechanisms. Central to the induction of tolerance is the targeted modulation of T-cell activities (both effector and regulatory), in which transcription factors play a significant role. The nuclear factor kappa-B (NF-κB) family is a family of transcription factors that not only are critically involved in diverse T-cell responses but also are regulated by many mechanisms to maintain tolerance and T-cell homeostasis. NF-κB, as a transcription factor, has been extensively studied in recent decades, and the molecular mechanisms that regulate NF-κB activities have been well documented. However, recent studies have revealed exciting new roles for NF-κB; in addition to its transcriptional activity, NF-κB can also activate diverse epigenetic mechanisms that mediate extensive chromatin remodeling of target genes to regulate T-cell activities. In this review article, we highlight recent discoveries and emerging opportunities in targeting NF-κB family members as well as their associated chromatin modifiers in the induction of immune tolerance and in the clinical treatment of immune diseases.

Role of Exosomes in the Regulation of T-cell Mediated Immune Responses and in Autoimmune Disease

: T-cell mediated immune responses should be regulated to avoid the development of autoimmune or chronic inflammatory diseases. Several mechanisms have been described to regulate this process, namely death of overactivated T cells by cytokine deprivation, suppression by T regulatory cells (Treg), induction of expression of immune checkpoint molecules such as CTLA-4 and PD-1, or activation-induced cell death (AICD). In addition, activated T cells release membrane microvesicles called exosomes during these regulatory processes. In this review, we revise the role of exosome secretion in the different pathways of immune regulation described to date and its importance in the prevention or development of autoimmune disease. The expression of membrane-bound death ligands on the surface of exosomes during AICD or the more recently described transfer of miRNA or even DNA inside T-cell exosomes is a molecular mechanism that will be analyzed.

Recent Advances in Polymeric Nanomedicines for Cancer Immunotherapy

Immunotherapy has emerged as a promising approach to treat cancer, since it facilitates eradication of cancer by enhancing innate and/or adaptive immunity without using cytotoxic drugs. Of the immunotherapeutic approaches, significant clinical potentials are shown in cancer vaccination, immune checkpoint therapy, and adoptive cell transfer. Nevertheless, conventional immunotherapies often involve immune-related adverse effects, such as liver dysfunction, hypophysitis, type I diabetes, and neuropathy. In an attempt to address these issues, polymeric nanomedicines are extensively investigated in recent years. In this review, recent advances in polymeric nanomedicines for cancer immunotherapy are highlighted and thoroughly discussed in terms of 1) antigen presentation, 2) activation of antigen-presenting cells and T cells, and 3) promotion of effector cells. Also, the future perspectives to develop ideal nanomedicines for cancer immunotherapy are provided.

Cell-penetrating Peptides: Efficient Vectors for Vaccine Delivery

Subunit vaccines are composed of pathogen fragments that, on their own, are generally poorly immunogenic. Therefore, the incorporation of an immunostimulating agent, e.g. adjuvant, into vaccine formulation is required. However, there are only a limited number of licenced adjuvants and their immunostimulating ability is often limited, while their toxicity can be substantial. To overcome these problems, a variety of vaccine delivery systems have been proposed. Most of them are designed to improve the stability of antigen in vivo and its delivery into immune cells. Cell-penetrating peptides (CPPs) are especially attractive component of antigen delivery systems as they have been widely used to enhance drug transport into the cells. Fusing or co-delivery of antigen with CPPs can enhance antigen uptake, processing and presentation by antigen presenting cells (APCs), which are the fundamental steps in initiating an immune response. This review describes the different mechanisms of CPP intercellular uptake and various CPP-based vaccine delivery strategies.

Fas receptor induces apoptosis of synovial bone and cartilage progenitor populations and promotes bone loss in antigen-induced arthritis

Rheumatoid arthritis (RA) is an inflammatory joint disease that eventually leads to permanent bone and cartilage destruction. Fas has already been established as the regulator of inflammation in RA, but its role in bone formation under arthritic conditions is not completely defined. The aim of this study was to assess the effect of Fas inactivation on the bone damage during murine antigen-induced arthritis. Subchondral bone of wild-type (WT) and Fas-knockout (Fas^-/-) mice was evaluated by histomorphometry and microcomputerized tomography. Proportions of synovial bone and cartilage progenitors were assessed by flow cytometry. Synovial bone and cartilage progenitors were purified by fluorescence-activated cell sorting and expression of Fas and Fas-induced apoptosis were analyzed in vitro. Results showed that Fas^-/- mice developed attenuated arthritis characterized by preserved epiphyseal bone and cartilage. A proportion of the earliest CD200⁺ bone and cartilage progenitors was reduced in WT mice with arthritis and was unaltered in Fas^-/- mice. During osteoblastic differentiation in vitro, CD200⁺ cells express the highest levels of Fas and are removed by Fas ligation. These results suggest that Fas-induced apoptosis of early CD200⁺ osteoprogenitor population represents potential mechanism underlying the impaired bone formation in arthritis, so their preservation may represent the bone-protective mechanism during arthritis.-Lazić Mosler, E., Lukač, N., Flegar, D., Fadljević, M., Radanović, I., Cvija, H., Kelava, T., Ivčević, S., Šućur, A., Markotić, A., Katavić, V., Marušić, A., Grčević, D., Kovačić, N. Fas receptor induces apoptosis of synovial bone and cartilage progenitor populations and promotes bone loss in antigen-induced arthritis.

Temporal clinical, proteomic, histological and cellular immune responses of dextran sulfate sodium-induced acute colitis

AIM

To investigate the temporal clinical, proteomic, histological and cellular immune profiles of dextran sulfate sodium (DSS)-induced acute colitis.

METHODS

Acute colitis was induced in C57Bl/6 female mice by administration of 1%, 2% or 3% DSS in drinking water for 7 d. Animals were monitored daily for weight loss, stool consistency and blood in the stool, while spleens and colons were harvested on day 8. A time course analysis was performed in mice ingesting 3% DSS, which included colon proteomics through multiplex assay, colon histological scoring by a blinded investigator, and immune response through flow cytometry or immunohistochemistry of the spleen, mesenteric lymph node and colon.

RESULTS

Progressive worsening of clinical colitis was observed with increasing DSS from 1% to 3%. In mice ingesting 3% DSS, colon shortening and increase in pro-inflammatory factors starting at day 3 was observed, with increased spleen weights at day 6 and day 8. This coincided with cellular infiltration in the colon from day 2 to day 8, with progressive accumulation of macrophages F4/80⁺, T helper CD4⁺ (Th), T cytotoxic CD8⁺ (Tcyt) and T regulatory CD25⁺ (Treg) cells, and progressive changes in colonic pathology including destruction of crypts, loss of goblet cells and depletion of the epithelial barrier. Starting on day 4, mesenteric lymph node and/or spleen presented with lower levels of Treg, Th and Tcyt cells, suggesting an immune cell tropism to the gut.

CONCLUSION

These results demonstrate that the severity of experimental colitis is dependent on DSS concentration, correlated with clinical, proteomic, histological and cellular immune response on 3% DSS.

Naringenin Modifies the Development of Lineage-Specific Effector CD4+ T Cells

Disrupted balance in the lineages of CD4⁺ T cell subsets, including pro-inflammatory T helper (Th) cells and anti-inflammatory regulatory T cells (Treg), is a primary pathogenic factor for developing autoimmunity. We have found that this immunomodulatory effect of naringenin on effector T cells and T-cell mediated experimental autoimmune encephalomyelitis (EAE). We therefore explored the effects of naringenin on the development of different effector CD4⁺ T cells. Naïve CD4⁺ T cells were differentiated under respective Th1, Th2, Th17, and Treg polarizing conditions with naringenin. Percent populations of each differentiated CD4⁺ T cell subsets were determined and the corresponding regulating pathways were investigated as underlying mechanisms. Naringenin mainly inhibited CD4⁺ T cell proliferation and differentiation to Th1 and Th17, but did not affect Th2 cells. Impeded Th1 polarization was associated with inhibition of its specific regulator proteins T-bet, p-STAT1, and p-STAT4 by naringenin. Likewise, Th17 regulator proteins RORγt, p-STAT3, and Ac-STAT3 were also inhibited by naringenin. In addition, naringenin promoted Treg polarization and also prevented IL-6-induced suppression of Treg development via down-regulation of p-Smad2/3 as well as inhibition of IL-6 signaling, and the latter was further supported by the in vivo results showing lower soluble IL-6R but higher soluble gp130 levels in plasma of naringenin-fed compared to the control EAE mice. Naringenin impacts CD4⁺ T cell differentiation in a manner that would explain its beneficial effect in preventing/mitigating T cell-mediated autoimmunity.

Towards the development of robot immune system: A combined approach involving innate immune cells and T-lymphocytes

Mobile robots in uncertain and unstructuredenvironments frequently encounter faults. Therefore, an effective fault detection and recovery mechanism is required. One can possibly investigate natural systems to seek inspiration to develop systems that can handle such faults. Authors, in this pursuit, have explored the possibility of designing an artificial immune system, called Robot Immune System (RIS), to maintain a robot's internal health-equilibrium. This contrasts with existing approaches in which specific robotic tasks are performed instead of developing a self-healing robot. In this respect, a fault detection and recovery methodology based on innate and adaptive immune functions has been successfully designed and developed. The immuno-inspired methodology is applied to a simulated robot using Robot Operating System and Virtual Robot Experimentation Platform. Through extensive simulations in increasingly difficult scenarios, the RIS has proven successful in autonomously detecting the abnormal behaviors, performing the recovery actions, and maintaining the homeostasis in the robot. In addition to being multi-tiered, the developed RIS is also a non-deterministic and population-based system.

VIPER regulates naive T cell activation and effector responses: Implication in TLR4 associated acute stage T cell responses

Naive T cells are known to express the modest level of TLR4 while it is known to go down during TCR activation. However, information towards the requirement of TLR4 signaling during TCR or mitogenic activation of naive wild-type T cells remains scanty. Here we have investigated the endogenous functional expression of TLR4 in naive mice T cells during TCR and mitogenic stimulation in presence of VIPER peptide (VP), an established inhibitor of TLR4 signaling. As expected we found that TLR4 expression goes down during TCR and mitogenic activation. Interestingly, we observed that VP treatment restores TLR4 expression on those activated T cells. Moreover, VP was found to regulate such activation of naive T cell as evident by reduction of CD25, CD69 expression, effector cytokines (IL-2, IFN-γ, TNF) production, T cell proliferation and down-regulation of T cell activation-dependent Fas (CD95), FasL (CD95L) expression. Together, our current observation highlights a possible requirement of TLR4 responses in T cells, which might have possible implication towards the pathogenic acute phase activation of naive T cells.

Role of the T and B lymphocytes in pathogenesis of autoimmune thyroid diseases

Autoimmune thyroid disorders (AITD) broadly include Graves' disease and Hashimoto's thyroiditis which are the most common causes of thyroid gland dysfunctions. These disorders develop due to complex interactions between environmental and genetic factors and are characterized by reactivity to self-thyroid antigens due to autoreactive lymphocytes escaping tolerance. Both cell-mediated and humoral responses lead to tissue injury in autoimmune thyroid disease. The differentiation of CD4+ cells in the specific setting of immune mediators (for example cytokines, chemokines) results in differentiation of various T cell subsets. T cell identification has shown a mixed pattern of cytokine production indicating that both subtypes of T helper, Th1 and Th2, responses are involved in all types of AITD. Furthermore, recent studies described T cell subtypes Th17 and Treg which also play an essential role in pathogenesis of AITD. This review will focus on the role of the T regulatory (Treg) and T helper (Th) (especially Th17) lymphocytes, and also of B lymphocytes in AITD pathogenesis. However, we have much more to learn about cellular mechanisms and interactions in AITD before we can develop complete understanding of AITD pathophysiology.

Site-Specific DBCO Modification of DEC205 Antibody for Polymer Conjugation

The design of multifunctional polymer-based vectors, forming pDNA vaccines, offers great potential in cancer immune therapy. The transfection of dendritic immune cells (DCs) with tumour antigen-encoding pDNA leads to an activation of the immune system to combat tumour cells. In this work, we investigated the chemical attachment of DEC205 antibodies (aDEC205) as DC-targeting structures to polyplexes of P(Lys)-b-P(HPMA). The conjugation of a synthetic block copolymer and a biomacromolecule with various functionalities (aDEC205) requires bioorthogonal techniques to avoid side reactions. Click chemistry and in particular the strain-promoted alkyne-azide cycloaddition (SPAAC) can provide the required bioorthogonality. With regard to a SPAAC of both components, we firstly synthesized two different azide-containing block copolymers, P(Lys)-b-P(HPMA)-N₃(stat) and P(Lys)-b-P(HPMA)-N₃(end), for pDNA complexation. In addition, the site-specific incorporation of ring-strained dibenzocyclooctyne (DBCO) moieties to the DEC205 antibody was achieved by an enzymatic strategy using bacterial transglutaminase (BTG). The chemical accessibility of DBCO molecules within aDEC205 as well as the accessibility of azide-functionalities on the polyplex’ surface were investigated by various SPAAC experiments and characterized by fluorescence correlation spectroscopy (FCS).

A modified HLA-A*0201-restricted CTL epitope from human oncoprotein (hPEBP4) induces more efficient antitumor responses

We previously identified human phosphatidylethanolamine-binding protein 4 (hPEBP4) as an antiapoptotic protein with increased expression levels in breast, ovarian and prostate cancer cells, but low expression levels in normal tissues, which makes hPEBP4 an attractive target for immunotherapy. Here, we developed hPEBP4-derived immunogenic peptides for inducing antigen-specific cytotoxic T lymphocytes (CTLs) targeting breast cancer. A panel of hPEBP4-derived peptides predicted by peptide-MHC-binding algorithms was evaluated to characterize their HLA-A2.1 affinity and immunogenicity. We identified a novel immunogenic peptide, P40-48 (TLFCQGLEV), that was capable of eliciting specific CTL responses in HLA-A2.1/K^b transgenic mice, as well as in peripheral blood lymphocytes from breast cancer patients. Furthermore, amino-acid substitutions in the P40-48 sequence improved its immunogenicity against hPEBP4, a self-antigen, thus circumventing tolerance. We designed peptide analogs by preferred auxiliary HLA-A*0201 anchor residue replacement, which induced CTLs that were crossreactive to the native peptide. Several analogs were able to stably bind to HLA-A*0201 and elicit specific CTL responses better than the native sequence. Importantly, adoptive transfer of CTLs induced by vaccination with two analogs more effectively inhibited tumor growth than the native peptide. These data indicate that peptide analogs with high immunogenicity represent promising candidates for peptide-mediated therapeutic cancer vaccines.