Immune checkpoints and cancer immunotherapies: insights into newly potential receptors and ligands.

Checkpoint markers and immune checkpoint inhibitors have been increasingly identified and developed as potential immunotherapeutic targets in various human cancers. Despite valuable efforts to discover novel immune checkpoints and their ligands, the precise roles of their therapeutic functions, as well as the broad identification of their counterpart receptors, remain to be addressed. In this context, it has been suggested that various putative checkpoint receptors can be induced upon activation. In the tumor microenvironment, T cells, as crucial immune response against malignant diseases as well as other immune central effector cells, such as natural killer cells, are regulated via co-stimulatory or co-inhibitory signals from immune or tumor cells. Studies have shown that exposure of T cells to tumor antigens upregulates the expression of inhibitory checkpoint receptors, leading to T-cell dysfunction or exhaustion. Although targeting immune checkpoint regulators has shown relative clinical efficacy in some tumor types, most trials in the field of cancer immunotherapies have revealed unsatisfactory results due to de novo or adaptive resistance in cancer patients. To overcome these obstacles, combinational therapies with newly discovered inhibitory molecules or combined blockage of several checkpoints provide a rationale for further research. Moreover, precise identification of their receptors counterparts at crucial checkpoints is likely to promise effective therapies. In this review, we examine the prospects for the application of newly emerging checkpoints, such as T-cell immunoglobulin and mucin domain 3, lymphocyte activation gene-3, T-cell immunoreceptor with Ig and ITIM domains (TIGIT), V-domain Ig suppressor of T-cell activation (VISTA), new B7 family proteins, and B- and T-cell lymphocyte attenuator, in association with immunotherapy of malignancies. In addition, their clinical and biological significance is discussed, including their expression in various human cancers, along with their roles in T-cell-mediated immune responses.

Features and roles of T helper 22 cells in immunological diseases and malignancies.

T helper 22 (Th22) cell populations are a newly identified subset of CD4+  T cells that primarily mediate biological effects on the epithelial barrier through interleukin (IL)-22. Although, new studies showed that both Th22 and IL-22 are closely associated with the pathogenesis of inflammatory, autoimmune and allergic disease as well as malignancies. In this review, we aim to describe the development and characteristics of Th22 cells as well as their roles in the immunopathogenesis of immune-related disorders and cancer.

Anti-Inflammatory Effect of KW-2449 on Autoimmune Encephalomyelitis: An Experimental Study on Mice.

BACKGROUND: The KW-2449 is a novel multikinase inhibitor that inhibits FLT3, ABL, ABL-T315I, and Aurora A. FLT3 and Aurora A kinases play an important role in the pathogenesis of multiple sclerosis (MS). KW-2449 could modulate immune cells, but the immunomodulatory effects of KW-2449 on experimental autoimmune encephalomyelitis (EAE) have not been investigated yet. The aim of the present study is to investigate the effects of KW-2449 on EAE mouse model. METHODS: In this study, C57BL/6 EAE mice were orally treated with (10 mg/kg/day) KW-2449 solution and compared with EAE and control mice. Following the treatment, histological analyses were performed on the brain and cerebellum to evaluate the pathological score. The gene expression levels of tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), and chemokine (C-C motif) ligand 2 (CCL2) were measured using qRT-PCR. The serum levels of TNF-α, IL-6, CCL-2 and MMP-2 were determined by using quantitative enzyme-linked immunosorbent assay (ELISA). RESULTS: The results indicated that the clinical score, the infiltration of inflammatory cells and the demyelination in EAE mice treated with KW-2449 decreased significantly compared to control groups. KW-2449 also decreased TNF-α, IL-6, CCL-2 inflammatory cytokines, and MMP-2 in both brain mRNA expressions and serum levels of EAE mice. CONCLUSION: The KW-2449, aging as a multi-kinase inhibitor, modulates the inflammatory responses of cytokine cascades either in the brain or in plasma and reduces EAE pathogenesis manifestation.

The Potential Role of Pro-Inflammatory and Anti-Inflammatory Cytokines in Epilepsy Pathogenesis.

Within the pathophysiology of epilepsy, as a chronic brain disorder, the involvement of neuroinflammation has been extensively implied. Recurrent seizures of epilepsy have been associated with elevated levels of immune mediators that seem to play a pivotal role in triggering them. Neurons, glia, and endothelial cells of the blood-brain barrier (BBB) take part in such inflammatory processes by expressing receptors of associated mediators through autocrine and paracrine stimulation of intracellular signaling pathways. In this milieu, elevated cytokine levels in serum and brain tissue have been reported in patients with an epileptic profile. Noteworthy, interleukin (IL)-1ß, IL-6, and tumor necrosis factor-alpha (TNF-α) are the proinflammatory cytokines mostly associated, in literature, with the pathogenesis of epilepsies. In this review, we examine the function of these cytokines in connection with transforming growth factor-beta (TGF-ß), IL-8, IL-12, IL-18, and macrophage inflammatory protein (MIP) as potential proinflammatory mediators in the neuropathology of epilepsy.

The Effects of G2013 (α-L-guluronic Acid) in a Pentylenetetrazole-induced Kindling Animal Model of Epilepsy.

Background: Recent studies have reported observing antioxidant, anti-inflammatory, and anti-aging properties of α-L-Guluronic acid (G2013) in animal and human studies. It has been theorized that the antioxidant and anti-inflammatory properties of G2013 might be beneficial in epilepsy treatment. Objective: We sought to determine G2013's effects on epileptic activity in a kindling-induced animal model. Methods: Thirty rats were randomly divided evenly into three groups (10 rats in each group): 1) the G2013 group, which was treated with daily injections of G2013 for five days prior to the start of the study; during the 14-day study period, the G2013 rats were given single, daily injections of G2013 that preceded single daily injections of pentylenetetrazole (PTZ), a compound used to induce seizures; 2) the Normal group, which only received injections of saline during the 14-day study, with no seizure induction; and 3) the Control group, which received PTZ injections alone (for seizure induction) for the 14-day study period. The latency between seizure stages and duration of seizures in the G2013 and Control groups were measured using a 5-stage seizure severity scale. Brain samples were taken from all three groups and analyzed histopathologically for parenchymal and meningeal inflammatory cell infiltration. Additionally, the brain samples were analyzed to determine gene expression levels of interleukin-1-beta (IL-1ß), IL-6, IL-10), tumor necrosis factor (TNF), chemokine (C-C motif) ligand-2 (CCL2), cyclooxygenase-2 (COX-2), and interferon-gamma (IFN-γ). Results: The G2013 group demonstrated lower latency between Stages 2 and 5 seizures, with significantly longer mean duration of Stage 5 seizures, compared to the Control group. No significant differences were observed between the three groups histopathologically nor were there any observed differences in gene expression levels. Conclusion: Our results demonstrated a greater predisposition to PTZ-induced seizures in the rats who received G2013 and PTZ compared to rats who received PTZ alone, suggesting that G2013's epileptogenic property overshadows its anti-inflammatory effects when applied to a kindled animal model of study.

Diagnostic Approach to the Patients with Suspected Primary Immunodeficiency.

BACKGROUND AND OBJECTIVE: Primary immunodeficiency diseases (PIDs) are a group of more than 350 disorders affecting distinct components of the innate and adaptive immune systems. In this review, the classic and advanced stepwise approach towards the diagnosis of PIDs are simplified and explained in detail. RESULTS: Susceptibility to recurrent infections is the main hallmark of almost all PIDs. However, noninfectious complications attributable to immune dysregulation presenting with lymphoproliferative and/or autoimmune disorders are not uncommon. Moreover, PIDs could be associated with misleading presentations including allergic manifestations, enteropathies, and malignancies. CONCLUSION: Timely diagnosis is the most essential element in improving outcome and reducing the morbidity and mortality in PIDs. This wouldn't be possible unless the physicians keep the diagnosis of PID in mind and be sufficiently aware of the approach to these patients.

The effects of cadmium exposure in the induction of inflammation.

Inflammation is a physiological process essential for maintaining homeostatic mechanisms in human, but however, exaggerated inflammatory responses are closely related to many chronic diseases. Cadmium (Cd) is a heavy metal with high toxicity when present in food, water and air has the potential of eliciting inflammatory reactions, with a major health risk to human. This review aimed to elucidate on the major routes of Cd exposure, the main organs affected by the exposure, the degree of toxicity as well as the roles of the toxic effects on the immune system which results to inflammatory responses. Immune modulation by Cd may cause serious adverse health effects in humans. Various studies have highlighted the ability of Cd as an environmental pollutant involved in the modulation of the innate, adaptive and mucosal immune responses in relations to the release of chemokine, gene expression, and susceptibility to microbial infections.

Clinical, Immunologic, and Molecular Spectrum of Patients with LPS-Responsive Beige-Like Anchor Protein Deficiency: A Systematic Review.

BACKGROUND: LPS-responsive beige-like anchor protein (LRBA) deficiency is a primary immunodeficiency and immune dysregulation syndrome caused by biallelic mutations in the LRBA gene. These mutations usually abrogate the protein expression of LRBA, leading to a broad spectrum of clinical phenotypes including autoimmunity, chronic diarrhea, hypogammaglobulinemia, and recurrent infections. OBJECTIVE: Our aim was to systematically collect all studies reporting on the clinical manifestations, molecular and laboratory findings, and management of patients with LRBA deficiency. METHODS: We searched in PubMed, Web of Science, and Scopus without any restrictions on study design and publication time. A total of 109 LRBA-deficient cases were identified from 45 eligible articles. For all patients, demographic information, clinical records, and immunologic and molecular data were collected. RESULTS: Of the patients with LRBA deficiency, 93 had homozygous and 16 had compound heterozygous mutations in LRBA. The most common clinical manifestations were autoimmunity (82%), enteropathy (63%), splenomegaly (57%), and pneumonia (49%). Reduction in numbers of CD4+ T cells and regulatory T cells as well as IgG levels was recorded for 21.6%, 65.6%, and 54.2% of evaluated patients, respectively. B-cell subpopulation analysis revealed low numbers of switched-memory and increased numbers of CD21low B cells in 73.5% and 77.8% of patients, respectively. Eighteen (16%) patients underwent hematopoietic stem cell transplantation due to the severity of complications and the outcomes improved in 13 of them. CONCLUSIONS: Autoimmune disorders are the main clinical manifestations of LRBA deficiency. Therefore, LRBA deficiency should be included in the list of monogenic autoimmune diseases, and screening for LRBA mutations should be routinely performed for patients with these conditions.

Interleukin-1ß and interleukin-6 in Common Variable Immunodeficiency and their association with subtypes of B cells and response to the Pneumovax-23 vaccine.

INTRODUCTION: Common Variable Immunodeficiency (CVID) is the most common symptomatic form of primary immunodeficiencies. Current research data show altered B cells, TLRs, and cytokine profile in CVID patients. The aim of this study was to determine levels of IL-1ß and IL-6 in CVID patients in response to TLRs stimulation and the association of these cytokines with subtypes of B cells and response to Pneumovax-23 vaccination. METHOD: Peripheral blood mononuclear cells of CIVD patients were stimulated with and without TLR2 and TLR4 agonist and specific inhibitors including lipopolysaccharide (LPS), lipoteichoic (LTA), and OxPAPC. The levels of IL-1ß and IL-6 were assessed by ELISA in different treatment groups. Finally, association of cytokines levels was assessed among different subtypes of B cells and types of response to Pneumovax-23 vaccine. RESULTS: Secretion of IL-6 and IL-1ß was significantly diminished in CVID patients (p = 0.015 and p = 0.019), but ligand engagement of TLR2 and TLR4 leads to significant increase in IL-6 and IL-1ß production. IL-6 was significantly lower in Pneumovax-23 hypo responder patients (p = 0.05) and significant correlations between the concentration of IL-6 and the number of switched memory and CD21low expressing B cells were found. CONCLUSION: Secretion of IL-6 and IL-1ß is abolished in CVID patients. However, TLR2 and TLR4 are hyper responsive to stimulation with their cognate ligands resulting in the secretion of higher levels of proinflammatory cytokines. This characteristic of CVID TLRs leads to an improvement of cytokine secretion compared to baseline levels. Also, our novel findings about the association concentrations of serum IL-6 and the frequency of with switched memory and CD21low expressing B cells as well as the poor response to Pneumovax-23 should be substantiated by the use of a higher sample size in future studies.

A role for Th1-like Th17 cells in the pathogenesis of inflammatory and autoimmune disorders.

The T helper 17 (Th17) cells contain a dynamic subset of CD4+ T-cells that are able to develop into other different lineage subsets, including the Th1-like Th17 cells. These cells co-express retinoic acid-related orphan receptor gamma t (RORγt) and transcription factor T-box-expressed-in-T-cells (T-bet) and produce both interleukin (IL)-17 and interferon (IFN)-γ. Recent reports have shown that Th1-like Th17 cells play crucial roles in the pathogenesis of autoimmune diseases such as inflammatory bowel disease, multiple sclerosis and rheumatoid arthritis, as well as, some primary immunodeficiency with autoimmune features. Here, the actual mechanisms for Th17 cells plasticity to Th1-like Th17 cells are discussed and reviewed in association to the role that Th1-like Th17 cells have on inflammatory and autoimmune disorders.

Iron supplementation in mouse expands cellular innate defences in spleen and defers lethal malaria infection.

The co-endemicity of malnutrition, erythrocytopathies, transmissible diseases and iron-deficiency contribute to the prevalence of chronic anaemia in many populations of the developing world. Although iron dietary supplementation is applied or recommended in at risk populations, its use is controversial due to undesirable outcomes, particularly regarding the response to infections, including highly prevalent malaria. We hypothesized that a boosted oxidative stress due to iron supplementation have a similar impact on malaria to that of hereditary anaemias, enhancing innate response and conditioning tissues to prevent damage during infection. Thus, we have analysed antioxidant and innate responses against lethal Plasmodium yoelii during the first five days of infection in an iron-supplemented mouse. This murine model showed high iron concentration in plasma with upregulated expression of hemoxygenase-1. The sustained homeostasis after this extrinsic iron conditioning, delayed parasitemia growth that, once installed, developed without anaemia. This protection was not conferred by the intrinsic iron overload of hereditary hemochromatosis. Upon iron-supplementation, a large increase of the macrophages/dendritic cells ratio and the antigen presenting cells was observed in the mouse spleen, independently of malaria infection. Complementary, malaria promoted the splenic B and T CD4 cells activation. Our results show that the iron supplementation in mice prepares host tissues for oxidative-stress and induces unspecific cellular immune responses, which could be seen as an advantage to promote early defences against malaria infection.

Experimental Immunization Based on Plasmodium Antigens Isolated by Antibody Affinity.

Vaccines blocking malaria parasites in the blood-stage diminish mortality and morbidity caused by the disease. Here, we isolated antigens from total parasite proteins by antibody affinity chromatography to test an immunization against lethal malaria infection in a murine model. We used the sera of malaria self-resistant ICR mice to lethal Plasmodium yoelii yoelii 17XL for purification of their IgGs which were subsequently employed to isolate blood-stage parasite antigens that were inoculated to immunize BALB/c mice. The presence of specific antibodies in vaccinated mice serum was studied by immunoblot analysis at different days after vaccination and showed an intensive immune response to a wide range of antigens with molecular weight ranging between 22 and 250 kDa. The humoral response allowed delay of the infection after the inoculation to high lethal doses of P. yoelii yoelii 17XL resulting in a partial protection against malaria disease, although final survival was managed in a low proportion of challenged mice. This approach shows the potential to prevent malaria disease with a set of antigens isolated from blood-stage parasites.

Differential immune response associated to malaria outcome is detectable in peripheral blood following Plasmodium yoelii infection in mice.

Malaria infection in humans elicits a wide range of immune responses that can be detected in peripheral blood, but we lack detailed long-term follow-up data on the primary and subsequent infections that lead to naturally acquired immunity. Studies on antimalarial immune responses in mice have been based on models yielding homogenous infection profiles. Here, we present a mouse model in which a heterogeneous course of Plasmodium yoelii lethal malaria infection is produced in a non-congenic ICR strain to allow comparison among different immunological and clinical outcomes. Three different disease courses were observed ranging from a fatal outcome, either early or late, to a self-resolved infection that conferred long-term immunity against re-infection. Qualitative and quantitative changes produced in leukocyte subpopulations and cytokine profiles detected in peripheral blood during the first week of infection revealed that monocytes, dendritic cells and immature B cells were the main cell subsets present in highly-parasitized mice dying in the first week after infection. Besides, CD4(+)CD25(high) T cells expanded at an earlier time point in early deceased mice than in surviving mice and expressed higher levels of intracellular Foxp3 protein. In contrast, survivors showed a limited increase of cytokines release and stable circulating innate cells. From the second week of infection, mice that would die or survive showed similar immune profiles, although CD4(+)CD25(high) T cells number increased earlier in mice with the worst prognosis. In surviving mice the expansion of activated circulating T cell and switched-class B cells with a long-term protective humoral response from the second infection week is remarkable. Our results demonstrate that the follow-up studies of immunological blood parameters during a malaria infection can offer information about the course of the pathological process and the immune response.

Differential carbonylation of cytoskeletal proteins in blood group O erythrocytes: potential role in protection against severe malaria.

The molecular basis for the prevalence of blood group O in regions where malaria is endemic remains unclear. In some genetic backgrounds oxidative modifications have been linked to a reduced susceptibility to severe malaria disease. Through redox proteomics, we detected differences in carbonylated membrane proteins among the different blood groups, both in Plasmodium-infected and uninfected erythrocytes (RBC). Carbonylation profiles of RBC membrane proteins revealed that group O blood shows a reduced protein oxidation pattern compared to groups A, B and AB. Upon infection with Plasmodium falciparum Dd2, erythrocytes of all blood groups showed increased oxidation of membrane proteins. By examining 4-hydroxy-2-nonenal (4-HNE) modified proteins by LC-MS/MS (liquid chromatography/mass spectrometry) we observed that, upon malaria infection, the protein components of lipid rafts and cytoskeleton were the main targets of 4-HNE carbonylation in all blood groups. Ankyrins and protein bands 4.2 and 4.1 were differentially carbonylated in group O as compared to A and B groups. During trophozoite maturation in group O erythrocytes, a steady increase was observed in the number of 4-HNE-modified proteins, suggesting a parasite-driven 4-HNE-carbonylation process. Our findings indicate a possible correlation between the protection against severe malaria in blood group O individuals and a specific pattern of 4-HNE-carbonylation of cytoskeleton proteins.

Plasmodium yoelii blood-stage antigens newly identified by immunoaffinity using purified IgG antibodies from malaria-resistant mice.

As the search for an effective human malaria vaccine continues, understanding immune responses to Plasmodium in rodent models is perhaps the key to unlocking new vaccine strategies. The recruitment of parasite-specific antibodies is an important component of natural immunity against infection in blood-stage malaria. Here, we describe the use of sera from naturally surviving ICR mice after infection with lethal doses of Plasmodium yoelii yoelii 17XL to identify highly immunogenic blood-stage antigens. Immobilized protein A/G was used for the affinity-chromatography purification of the IgGs present in pooled sera from surviving mice. These protective IgGs, covalently immobilized on agarose columns, were then used to isolate reactive antigens from whole P. yoelii yoelii 17XL protein extracts obtained from the blood-stage malaria infection. Through proteomics analysis of the recovered parasite antigens, we were able to identify two endoplasmic reticulum lumen proteins: protein disulfide isomerase and a member of the heat shock protein 70 family. Also identified were the digestive protease plasmepsin and the 39 kDa-subunit of eukaryotic translation initiation factor 3, a ribosome associated protein. Of these four proteins, three have not been previously identified as antigenic during blood-stage malaria infection. This procedure of isolating and identifying parasite antigens using serum IgGs from malaria-protected individuals could be a novel strategy for the development of multi-antigen-based vaccine therapies.