S3I-201, a selective stat3 inhibitor, ameliorates clinical symptoms in a mouse model of experimental autoimmune encephalomyelitis through the regulation of multiple intracellular signalling in Th1, Th17, and treg cells.

CD4+ T cells, specifically Th cells (Th1 and Th17) and regulatory T cells (Tregs), play a pivotal role in the pathogenesis of multiple sclerosis (MS), a demyelinating autoimmune disease of the CNS. STAT3 inhibitors are potential therapeutic targets for several immune disorders. In this study, we investigated the role of a well-known STAT3 inhibitor, S3I-201, in experimental autoimmune encephalomyelitis (EAE), a model of MS. Following induction of EAE, mice were intraperitoneally administered S3I-201 (10 mg/kg) each day, beginning on day 14 and continuing till day 35 and were evaluated for clinical signs. Flow cytometry was used to investigate further the effect of S3I-201 on Th1 (IFN-γ, STAT1, pSTAT1, and T-bet), Th17 (IL-17A, STAT3, pSTAT3, and RORγt), and regulatory T cells (Treg, IL-10, TGF-ß1, and FoxP3) expressed in splenic CD4+ T cells. Moreover, we analyzed the effects of S3I-201 on mRNA and protein expression of IFN-γ, T-bet, IL-17A, STAT1, STAT3, pSTAT1, pSTAT3, RORγ, IL-10, TGF-ß1, and FoxP3 in the brains of EAE mice. The severity of clinical scores decreased in S3I-201-treated EAE mice compared to vehicle-treated EAE mice. S3I-201 treatment significantly decreased CD4+IFN-γ+, CD4+STAT1+, CD4+pSTAT1+, CD4+T-bet+, CD4+IL-17A+, CD4+STAT3+, CD4+pSTAT3+, and CD4+RORγt+ and increased CD4+IL-10+, CD4+TGF-ß1+, and CD4+FoxP3+ in the spleens of EAE mice. Additionally, S3I-201 administration in EAE mice significantly decreased the mRNA and protein expression of Th1 and Th17 and increased those of Treg. These results suggest that S3I-201 may have novel therapeutic potential against MS.

The Th1 cell regulatory circuitry is largely conserved between human and mouse.

Gene expression programs controlled by lineage-determining transcription factors are often conserved between species. However, infectious diseases have exerted profound evolutionary pressure, and therefore the genes regulated by immune-specific transcription factors might be expected to exhibit greater divergence. T-bet (Tbx21) is the immune-specific, lineage-specifying transcription factor for T helper type I (Th1) immunity, which is fundamental for the immune response to intracellular pathogens but also underlies inflammatory diseases. We compared T-bet genomic targets between mouse and human CD4+ T cells and correlated T-bet binding patterns with species-specific gene expression. Remarkably, we found that the majority of T-bet target genes are conserved between mouse and human, either via preservation of binding sites or via alternative binding sites associated with transposon-linked insertion. Species-specific T-bet binding was associated with differences in transcription factor-binding motifs and species-specific expression of associated genes. These results provide a genome-wide cross-species comparison of Th1 gene regulation that will enable more accurate translation of genetic targets and therapeutics from pre-clinical models of inflammatory and infectious diseases and cancer into human clinical trials.

Th1 polarization defines the synovial fluid T cell compartment in oligoarticular juvenile idiopathic arthritis.

Oligoarticular juvenile idiopathic arthritis (oligo JIA) is the most common form of chronic inflammatory arthritis in children, yet the cause of this disease remains unknown. To understand immune responses in oligo JIA, we immunophenotyped synovial fluid T cells with flow cytometry, bulk RNA-Seq, single-cell RNA-Seq (scRNA-Seq), DNA methylation studies, and Treg suppression assays. In synovial fluid, CD4+, CD8+, and γδ T cells expressed Th1-related markers, whereas Th17 cells were not enriched. Th1 skewing was prominent in CD4+ T cells, including Tregs, and was associated with severe disease. Transcriptomic studies confirmed a Th1 signature in CD4+ T cells from synovial fluid. The regulatory gene expression signature was preserved in Tregs, even those exhibiting Th1 polarization. These Th1-like Tregs maintained Treg-specific methylation patterns and suppressive function, supporting the stability of this Treg population in the joint. Although synovial fluid CD4+ T cells displayed an overall Th1 phenotype, scRNA-Seq uncovered heterogeneous effector and regulatory subpopulations, including IFN-induced Tregs, peripheral helper T cells, and cytotoxic CD4+ T cells. In conclusion, oligo JIA is characterized by Th1 polarization that encompasses Tregs but does not compromise their regulatory identity. Targeting Th1-driven inflammation and augmenting Treg function may represent important therapeutic approaches in oligo JIA.

Integrated Transcriptome Profiling Revealed That Elevated Long Non-Coding RNA-AC007278.2 Expression Repressed CCR7 Transcription in Systemic Lupus Erythematosus.

Purpose: Systemic lupus erythematosus (SLE) is a serious autoimmune disease. Its molecular pathogenesis, especially the long non-coding RNA (lncRNA) function, remains unclear. We want to investigate the lncRNA dysregulation profile and their molecular mechanisms in SLE. Methods: In this study, we analyzed the transcriptome profiles (RNA-seq) of peripheral blood mononuclear cells (PBMCs) from SLE patients and two published transcriptome datasets to explore lncRNA profiles. The differentially expressed lncRNAs were confirmed by quantitative real-time PCR in another set of female patients. We constructed the lncRNA-mRNA regulatory networks by performing weighted gene co-expression network analysis (WGCNA). Dysregulated lncRNA AC007278.2 was repressed by short hairpin RNA (shRNA) in Jurkat cells. Dual-luciferase reporter gene assay was performed to investigate the regulatory mechanism of AC007278.2 on target gene CCR7. Results: We observed dominant up-regulation of transcripts, including mRNAs and lncRNAs, in SLE patients. By WGCNA method, we identified three modules that were highly related to SLE. We then focused on one lncRNA, AC007278.2, with a T-helper 1 lineage-specific expression pattern. We observed consistently higher AC007278.2 expression in SLE patients. Co-expression network revealed that AC007278.2 participated in the innate immune response and inflammatory bowel disease pathways. By knocking down AC007278.2 expression, we found that AC007278.2 could regulate the expression of inflammatory and cytokine stimulus response-related genes, including CCR7, AZU1, and TNIP3. AC007278.2 inhibits the functional CCR7 promoter to repress its transcription, thereby regulating autoimmunity and follicular T-helper cell differentiation. Conclusion: In summary, our study indicated the important regulatory role of lncRNAs in SLE. AC007278.2 may be treated as a novel biomarker for SLE diagnosis and treatment.

Early Transcriptional Liver Signatures in Experimental Visceral Leishmaniasis.

Transcriptional analysis of complex biological scenarios has been used extensively, even though sometimes the results of such analysis may prove imprecise or difficult to interpret due to an overwhelming amount of information. In this study, a large-scale real-time qPCR experiment was coupled to multivariate statistical analysis in order to describe the main immunological events underlying the early L. infantum infection in livers of BALB/c mice. High-throughput qPCR was used to evaluate the expression of 223 genes related to immunological response and metabolism 1, 3, 5, and 10 days post infection. This integrative analysis showed strikingly different gene signatures at 1 and 10 days post infection, revealing the progression of infection in the experimental model based on the upregulation of particular immunological response patterns and mediators. The gene signature 1 day post infection was not only characterized by the upregulation of mediators involved in interferon signaling and cell chemotaxis, but also the upregulation of some inhibitory markers. In contrast, at 10 days post infection, the upregulation of many inflammatory and Th1 markers characterized a more defined gene signature with the upregulation of mediators in the IL-12 signaling pathway. Our results reveal a significant connection between the expression of innate immune response and metabolic and inhibitory markers in early L. infantum infection of the liver.

The energy sensor AMPK orchestrates metabolic and translational adaptation in expanding T helper cells.

The importance of cellular metabolic adaptation in inducing robust T cell responses is well established. However, the mechanism by which T cells link information regarding nutrient supply to clonal expansion and effector function is still enigmatic. Herein, we report that the metabolic sensor adenosine monophosphate-activated protein kinase (AMPK) is a critical link between cellular energy demand and translational activity and, thus, orchestrates optimal expansion of T cells in vivo. AMPK deficiency did not affect T cell fate decision, activation, or T effector cell generation; however, the magnitude of T cell responses in murine in vivo models of T cell activation was markedly reduced. This impairment was global, as all T helper cell subsets were similarly sensitive to loss of AMPK which resulted in reduced T cell accumulation in peripheral organs and reduced disease severity in pathophysiologically as diverse models as T cell transfer colitis and allergic airway inflammation. T cell receptor repertoire analysis confirmed similar clonotype frequencies in different lymphoid organs, thereby supporting the concept of a quantitative impairment in clonal expansion rather than a skewed qualitative immune response. In line with these findings, in-depth metabolic analysis revealed a decrease in T cell oxidative metabolism, and gene set enrichment analysis indicated a major reduction in ribosomal biogenesis and mRNA translation in AMPK-deficient T cells. We, thus, provide evidence that through its interference with these delicate processes, AMPK orchestrates the quantitative, but not the qualitative, manifestation of primary T cell responses in vivo.

Tick saliva-induced programmed death-1 and PD-ligand 1 and its related host immunosuppression.

The tick Rhipicephalus microplus is a harmful parasite of cattle that causes considerable economic losses to the cattle breeding industry. Although R. microplus saliva (Rm-saliva) contains several immunosuppressants, any association between Rm-saliva and the expression of immunoinhibitory molecules, such as programmed death (PD)-1 and PD-ligand 1 (PD-L1), has not been described. In this study, flow cytometric analyses revealed that Rm-saliva upregulated PD-1 expression in T cells and PD-L1 expression in CD14+ and CD11c+ cells in cattle. Additionally, Rm-saliva decreased CD69 expression in T cells and Th1 cytokine production from peripheral blood mononuclear cells. Furthermore, PD-L1 blockade increased IFN-γ production in the presence of Rm-saliva, suggesting that Rm-saliva suppresses Th1 responses via the PD-1/PD-L1 pathway. To reveal the upregulation mechanism of PD-1/PD-L1 by Rm-saliva, we analyzed the function of prostaglandin E2 (PGE2), which is known as an inducer of PD-L1 expression, in Rm-saliva. We found that Rm-saliva contained a high concentration of PGE2, and PGE2 treatment induced PD-L1 expression in CD14+ cells in vitro. Immunohistochemical analyses revealed that PGE2 and PD-L1 expression was upregulated in tick-attached skin in cattle. These data suggest that PGE2 in Rm-saliva has the potential to induce the expression of immunoinhibitory molecules in host immune cells.

The Role of Helper T Cells in Psoriasis.

Psoriasis is a complex, chronic relapsing and inflammatory skin disorder with a prevalence of approximately 2% in the general population worldwide. Psoriasis can be triggered by infections, physical injury and certain drugs. The most common type of psoriasis is psoriasis vulgaris, which primarily features dry, well-demarcated, raised red lesions with adherent silvery scales on the skin and joints. Over the past few decades, scientific research has helped us reveal that innate and adaptive immune cells contribute to the chronic inflammatory pathological process of psoriasis. In particular, dysfunctional helper T cells (Th1, Th17, Th22, and Treg cells) are indispensable factors in psoriasis development. When stimulated by certain triggers, antigen-presenting cells (APCs) can release pro-inflammatory factors (IL-23, IFN-α and IL-12), which further activate naive T cells and polarize them into distinct helper T cell subsets that produce numerous cytokines, such as TNF, IFN-γ, IL-17 and IL-22, which act on keratinocytes to amplify psoriatic inflammation. In this review, we describe the function of helper T cells in psoriasis and summarize currently targeted anti-psoriatic therapies.

Immunomodulatory Activity of the Marine Sponge, Haliclona (Soestella) sp. (Haplosclerida: Chalinidae), from Sri Lanka in Wistar Albino Rats: Immunosuppression and Th1-Skewed Cytokine Response.

Natural secondary metabolites of sponges of the genus Haliclona are associated with an array of biological activity with therapeutic usage. We investigated the immunopharmacological properties of a presumably novel marine sponge species from Sri Lanka, Haliclona (Soestella) sp. Sponge material was collected from southern Sri Lanka by scuba diving. Sponge identification was based on spicule and skeleton morphology using light microscopy. Selected in vivo and ex vivo tests investigated nonfunctional and functional immunomodulatory activity of the Haliclona (Soestella) sp. crude extract (HSCE) in the Wistar rat model. Compared to the controls, rats orally gavaged daily for 14 consecutive days with 15 mg/kg dose of the HSCE manifested a significant reduction of immune cell counts of total WBCs (by 17%; p < 0.01), lymphocytes (38%), platelets (52%), splenocytes (20%), and bone marrow cells (BMC; 60%) (p < 0.001), with a concurrent increase in the neutrophil : lymphocyte ratio (p < 0.05); RBC counts abated by 53% (p < 0.001). A significant reduction of the splenosomatic index was evident with the 10 and 15 mg/kg doses (p < 0.001). Rat plasma TNF-α cytokine level was augmented by tenfold (p < 0.001), IL-6 level by twofold (p < 0.01) with the 15 mg/kg HSCE treatment, while IL-10 was detectable in rat plasma only with this treatment; the corresponding Th1 : Th2 cytokine ratio (TNF-α : IL-10) was indicative of an unequivocal Th1-skewed cytokine response (p < 0.01). Ex vivo bone marrow cell and splenocyte proliferation were significantly and dose dependently impaired by HSCE (IC50 0.719 and 0.931 µg/mL, respectively; p < 0.05). Subacute toxicity testing established that HSCE was devoid of general toxic, hepatotoxic, and nephrotoxic effects. In conclusion, HSCE was orally active, nontoxic, and effectively suppressed nonfunctional and functional immunological parameters of Wistar rats, suggestive of the potential use of the HSCE as an immunosuppressant drug lead.

Th1-Polarized, Dengue Virus-Activated Human Mast Cells Induce Endothelial Transcriptional Activation and Permeability.

Dengue virus (DENV), an arbovirus, strongly activates mast cells (MCs), which are key immune cells for pathogen immune surveillance. In animal models, MCs promote clearance of local peripheral DENV infections but, conversely, also promote pathological vascular leakage when widely activated during systemic DENV infection. Since DENV is a human pathogen, we sought to ascertain whether a similar phenomenon could occur in humans by characterizing the products released by human MCs (huMCs) upon direct (antibody-independent) DENV exposure, using the phenotypically mature huMC line, ROSA. DENV did not productively infect huMCs but prompted huMC release of proteases and eicosanoids and induced a Th1-polarized transcriptional profile. In co-culture and trans-well systems, huMC products activated human microvascular endothelial cells, involving transcription of vasoactive mediators and increased monolayer permeability. This permeability was blocked by MC-stabilizing drugs, or limited by drugs targeting certain MC products. Thus, MC stabilizers are a viable strategy to limit MC-promoted vascular leakage during DENV infection in humans.

Gene Expression in Spontaneous Experimental Autoimmune Encephalomyelitis Is Linked to Human Multiple Sclerosis Risk Genes.

Recent genome-wide association studies have identified over 230 genetic risk loci for multiple sclerosis. Current experimental autoimmune encephalomyelitis (EAE) models requiring active induction of disease may not be optimally suited for the characterization of the function of these genes. We have thus used gene expression profiling to study whether spontaneous opticospinal EAE (OSE) or MOG-induced EAE mirrors the genetic contribution to the pathogenesis of multiple sclerosis more faithfully. To this end, we compared gene expression in OSE and MOG EAE models and analyzed the relationship of both models to human multiple sclerosis risk genes and T helper cell biology. We observed stronger gene expression changes and an involvement of more pathways of the adaptive immune system in OSE than MOG EAE. Furthermore, we demonstrated a more extensive enrichment of human MS risk genes among transcripts differentially expressed in OSE than was the case for MOG EAE. Transcripts differentially expressed only in diseased OSE mice but not in MOG EAE were significantly enriched for T helper cell-specific transcripts. These transcripts are part of immune-regulatory pathways. The activation of the adaptive immune system and the enrichment of both human multiple sclerosis risk genes and T helper cell-specific transcripts were also observed in OSE mice showing only mild disease signs. These expression changes may, therefore, be indicative of processes at disease onset. In summary, more human multiple sclerosis risk genes were differentially expressed in OSE than was observed for MOG EAE, especially in TH1 cells. When studying the functional role of multiple sclerosis risk genes and pathways during disease onset and their interactions with the environment, spontaneous OSE may thus show advantages over MOG-induced EAE.

Pterostilbene reduces colonic inflammation by suppressing dendritic cell activation and promoting regulatory T cell development.

Dendritic cells (DCs) and T cells play important roles in immune regulation, and modulating their function is an approach for developing preventive or therapeutic strategies against immune disorders. Herein, the effect of pterostilbene (PSB) (3',5'-dimethoxy-resveratrol)-a resveratrol-related polyphenol found in blueberries-on immune regulation was evaluated. Using an in vitro co-culture system, PSB was found to exert the strongest inhibitory effect among all tested resveratrol derivatives on DC-mediated T cell proliferation; moreover, PSB treatment decreased the Th1 and Th17 populations and increased the regulatory T cell (Treg) population. Upon co-stimulation with anti-CD3 and anti-CD28 antibodies, PSB inhibited CD4+ T cell proliferation and differentiation into Th1 cells. Additionally, PSB acted on DCs to suppress the lipopolysaccharide-induced transactivation of genes encoding antigen presentation-related molecules and inflammatory cytokines by attenuating the DNA-binding ability of the transcription factor PU.1. Furthermore, PSB promoted DC-mediated Foxp3+ Treg differentiation, and PU.1 knockdown increased DC-induced Treg activity. Oral administration of PSB alleviated the symptoms of dextran sulfate sodium-induced colitis and decreased tumor necrosis factor-α expression in mice. Thus, PSB treatment ameliorates colonic inflammation.

Recombinant ubiquitin-conjugating enzyme of Eimeria maxima induces immunogenic maturation in chicken splenic-derived dendritic cells and drives Th1 polarization in-vitro.

Dendritic cells (DCs) are key linkages between innate immunity and acquired immunity. The antigens that promote the functions of DCs might be the effective candidates of novel vaccine. In this research, the ability of ubiquitin-conjugating enzyme (UCE), a recognized common antigens among chicken Eimeria species, to stimulate DCs of chickens were evaluated. We cloned UCE gene from Eimeria maxima (EmUCE), and its protein expression was confirmed by SDS-PAGE and western-blot. Immunofluorescence assay confirmed the binding of rEmUCE on the surface of chicken splenic-derived DCs (ChSP-DCs). Flow cytometric analysis showed that rEmUCE-treated ChSP-DCs increased MHCII, CD1.1, CD11c, CD80, and CD86 phenotypes. qRT-PCR indicated that transcript levels of maturation markers CCL5, CCR7, and CD83 in ChSP-DCs were upregulated in response to rEmUCE. Following rEmUCE treatment, chSP-DCs activated TLR signaling and inhibited Wnt signaling. Moreover, rEmUCE promoted DC-mediated T-cell proliferation in DC/T-cell co-incubation. Interestingly, CD3+/CD4+ T-cells were significantly enhanced when rEmUCE-treated chSP-DCs were co-incubated with T-cells. Cytokine secretion pattern of rEmUCE-stimulated ChSP-DCs revealed that the production of IL-12 and IFN-γ was increased whereas IL-10 and TGF-ß were unchanged. Likewise, the co-incubation of ChSP-DCs with T-cells indicated increased production of IFN-γ but not IL-4. Collectively, rEmUCE could polarize DCs to immunogenic phenotype and shift the immune cells towards Th1 response. Our observations provide valuable insight for future research aimed at vaccine development against avian coccidiosis.

Acetylcholine regulates the development of experimental autoimmune encephalomyelitis via the CD4+ cells proliferation and differentiation.

Purpose of the study: Multiple sclerosis is a CD4+ T cell mediated autoimmune disease characterized by inflammatory demyelination in the central nervous system. Acetylcholine (ACh) has been reported to be released by T lymphocytes and plays as an inflammation and immune regulator through the participation of T cells. However, both attenuated and aggravated effects of ACh in inflammation were found. The aim of this study is to further investigate the role of ACh in experimental autoimmune encephalomyelitis (EAE).Materials and methods: The left cervical vagotomy was performed to inhibit ACh release with the sham-operation as control. ACh in cerebral cortex and splenocytes culture supernatants of EAE mice were determined. Interleukin-6, interferon-γ, interleukin-4 and interleukin-17A in brain and splenocytes culture supernatants were evaluated by enzyme-linked immunosorbent assay. The proportion of CD4+ T cells and subsets were assessed by flow cytometry.Results: Compared with the sham-operation group, improved clinical and pathological parameters as well as decreased interleukin-6, interferon-γ, interleukin-4 and interleukin-17A were found in EAE mice with vagotomy suppressing the ACh. Marked reductions of CD4+ and CD4+ChAT+ cells, as well as significant decrease in Th1 with a bias to Th2 in Th1/Th2 balance and increased ChAT+Th2 proportion in the spleen were also observed in vagotomized mice.Conclusions: These findings emphasize that inhibiting ACh release by vagotomy can ameliorate the exacerbation of EAE through suppressing CD4+ T cells proliferation and regulating the differentiation of Th1, Th2 and Th17.

IL-12 signaling drives the differentiation and function of a TH1-derived TFH1-like cell population.

CD4+ T follicular helper (TFH) cells provide help to B cells and promote antibody-mediated immune responses. Increasing evidence supports the existence of TFH populations that secrete cytokines typically associated with the effector functions of other CD4+ T cell subsets. These include T helper 1 (TH1)-biased TFH (TFH1) cells that have recognized roles in both immune responses to pathogens and also the pathogenesis of autoimmune disease. Given their apparent importance to human health, there is interest in understanding the mechanisms that regulate TFH1 cell formation and function. However, their origin and the molecular requirements for their differentiation are unclear. Here, we describe a population of murine TH1-derived, TFH1-like cells that express the chemokine receptor Cxcr3 and produce both the TH1 cytokine interferon-γ and the TFH-associated cytokine interleukin-21 (IL-21). Furthermore, these TFH1-like cells promote B cell activation and antibody production at levels indistinguishable from conventional IL-6-derived TFH-like cells. Regarding their regulatory requirements, we find that IL-12 signaling is necessary for the differentiation and function of this TFH1-like cell population. Specifically, IL-12-dependent activation of STAT4, and unexpectedly STAT3, promotes increased expression of IL-21 and the TFH lineage-defining transcription factor Bcl-6 in TFH1-like cells. Taken together, these findings provide insight into the potential origin and differentiation requirements of TFH1 cells.

Pyruvate kinase M2 is requisite for Th1 and Th17 differentiation.

Th1 and Th17 are important in the pathogenesis of autoimmune diseases and they depend on glycolysis as a source of energy. T cell antigen receptor signaling phosphorylates a serine/threonine kinase, calcium/calmodulin-dependent protein kinase IV (CaMK4), and promotes glycolysis. Based on these findings we hypothesized that CaMK4 promotes glycolysis. Camk4-deficient CD4+ T cells and cells treated with a CaMK4 inhibitor had less glycolysis compared with their counterparts. Pull-down of CaMK4 and mass spectrometry identified pyruvate kinase muscle isozyme (PKM), the final rate-limiting enzyme in glycolysis, as a binding partner. Coimmunoprecipitation and Western blotting showed that CaMK4 interacts directly with PKM2. Camk4-deficient CD4+ T cells displayed decreased pyruvate kinase activity. Silencing or pharmacological inhibition of PKM2 reduced glycolysis and in vitro differentiation to Th1 and Th17 cells, while PKM2 overexpression restored Th17 cell differentiation. Treatment with a PKM2 inhibitor ameliorated experimental autoimmune encephalomyelitis and CD4+ T cells treated with PKM2 inhibitor or Pkm2-shRNA caused limited disease activity in an adoptive cell transfer model of experimental autoimmune encephalomyelitis. Our data demonstrate that CaMK4 binds to PKM2 and promotes its activity, which is requisite for Th1 and Th17 differentiation in vitro and in vivo. PKM2 represents a therapeutic target for T cell-dependent autoimmune diseases.

NF-κB/mTOR/MYC Axis Drives PRMT5 Protein Induction After T Cell Activation via Transcriptional and Non-transcriptional Mechanisms.

Multiple sclerosis is an autoimmune disease of the central nervous system (CNS) mediated by CD4+ T cells and modeled via experimental autoimmune encephalomyelitis (EAE). Inhibition of PRMT5, the major Type II arginine methyltransferase, suppresses pathogenic T cell responses and EAE. PRMT5 is transiently induced in proliferating memory inflammatory Th1 cells and during EAE. However, the mechanisms driving PRMT5 protein induction and repression as T cells expand and return to resting is currently unknown. Here, we used naive mouse and memory mouse and human Th1/Th2 cells as models to identify mechanisms controlling PRMT5 protein expression in initial and recall T cell activation. Initial activation of naive mouse T cells resulted in NF-κB-dependent transient Prmt5 transcription and NF-κB, mTOR and MYC-dependent PRMT5 protein induction. In murine memory Th cells, transcription and miRNA loss supported PRMT5 induction to a lesser extent than in naive T cells. In contrast, NF-κB/MYC/mTOR-dependent non-transcriptional PRMT5 induction played a major role. These results highlight the importance of the NF-κB/mTOR/MYC axis in PRMT5-driven pathogenic T cell expansion and may guide targeted therapeutic strategies for MS.

Cognate Interaction With CD4+ T Cells Instructs Tumor-Associated Macrophages to Acquire M1-Like Phenotype.

The immunosuppressive tumor microenvironment (TME) established by tumor cells, stromal cells and inhibitory immune cells counteracts the function of tumor reactive T cells. Tumor associated macrophages (TAMs) showing functional plasticity contribute to this process as so called M2-like macrophages can suppress the function of effector T cells and promote their differentiation into regulatory T cells (Tregs). Furthermore, tumor antigen specific CD4+ T effector cells can essentially sustain anti-tumoral immune responses as shown for various tumor entities, thus suggesting that cognate interaction between tumor antigen-specific CD4+ Th1 cells and TAMs might shift the intra-tumoral M1/M2 ratio toward M1. This study demonstrates repolarization of M2-like PECs upon MHC II-restricted interaction with tumor specific CD4+ Th1 cells in vitro as shown by extensive gene and protein expression analyses. Moreover, adoptive transfer of OVA-specific OT-II cells into C57BL/6 mice bearing OVA expressing IAb-/- tumors resulted in increased accumulation of M1-like TAMs with enhanced M1 associated gene and protein expression profiles. Thus, this paper highlights a so far underestimated function of the CD4+ Th1/TAM axis in re-conditioning the immunosuppressive tumor microenvironment.

Brucella canis induces canine CD4+ T cells multi-cytokine Th1/Th17 production via dendritic cell activation.

Brucella canis is a small intracellular Gram-negative bacterium that frequently leads to chronic infections highly resistant to antibiotic therapy in dogs. Also, it causes mild human brucellosis compared to other zoonotic Brucella spp. Herein we characterize the cellular immune response elicited by B. canis by analysing human and canine CD4+ T cells after stimulation with autologous monocyte-derived dendritic cells (MoDCs). Human and canine B. canis-primed MoDCs stimulated autologous CD4+ T cells; however, a Th1 response was triggered by human MoDCs, whereas canine MoDCs induced Th1/Th17 responses, with increased CD4+ T cells producing IFN-γ and IL-17A simultaneously. Each pattern of cellular response may contribute to host susceptibility, helping to understand the differences in B. canis virulence between these two hosts. In addition, other aspects of canine immunology are unveiled by highlighting the participation of IL-17A-producing canine MoDCs and CD4+ T cells producing IFN-γ and IL-17A.