Autoimmune Mouse Model Research Articles

Discovery of the IL-23/IL-17 Signaling Pathway and the Treatment of Psoriasis.

Psoriasis vulgaris is a common, heterogeneous, chronic inflammatory skin disease characterized by thickened, red, scaly plaques and systemic inflammation. Psoriasis is also associated with multiple comorbid conditions, such as joint destruction, cardiovascular disease, stroke, hypertension, metabolic syndrome, and chronic kidney disease. The discovery of IL-17-producing T cells in a mouse model of autoimmunity transformed our understanding of inflammation driven by T lymphocytes and associations with human inflammatory diseases, such as psoriasis. Under the regulation of IL-23, T cells that produce high levels of IL-17 create a self-amplifying, feed-forward inflammatory response in keratinocytes that drives the development of thickened skin lesions infiltrated with a mixture of inflammatory cell populations. Recently, the Food and Drug Administration approved multiple highly effective psoriasis therapies that disrupt IL-17 (secukinumab, ixekizumab, and brodalumab) and IL-23 (guselkumab and tildrakizumab) signaling in the skin, thus leading to a major paradigm shift in the way that psoriatic disease is managed.

The role of ROR\u03b1 in salivary gland lesions in patients with primary Sj\xf6gren\u2019s syndrome

BackgroundThe orphan nuclear receptors retinoic acid-related receptor α and γt (RORα and RORγt) are critical in the development of T helper 17 (Th17) cells, and ROR-specific synthetic ligands have proven efficacy in several mouse models of autoimmunity. However, the pathological significance of RORα in primary Sjögren’s syndrome (pSS) remains to be elucidated. The present study was designed to clarify the significance of RORα in the pathogenesis of pSS.MethodsRORα expression in the labial salivary gland (LSG) was determined by immunohistochemical analysis using a quantitative scoring system in 34 patients with pSS. The correlation between RORα expression in LSGs and the focus score (FS) was determined, and Th17 and IL-17 receptor A (1L-17RA) levels in LSGs were determined. To investigate the effect of RORs and the therapeutic potential of targeting RORs in pSS, we administered SR1001, a selective RORα/γt inverse agonist, to non-obese diabetic (NOD) mice.ResultsThe expression of RORα was significantly increased in LSGs of patients with pSS and intensified with disease stage/FS, showing a similar increasing trend with IL-17A and IL-17RA. SR1001 significantly improved salivary gland secretory function and relieved sialadenitis in treated mice.ConclusionOur data reveal the importance of RORα in controlling pathologic lymphocytic infiltration of the salivary glands and suggest that RORα may be a druggable target in treating pSS.

Graves\u2019 orbitopathy occurs sex-independently in an autoimmune hyperthyroid mouse model

Graves’ orbitopathy (GO) is the most common extra thyroidal complication of Graves’ disease (GD) and occurs predominantly in women but more severe in men. The reason for this effect of gender on GO is unknown. Herein we studied the manifestation of GO in both sexes of an induced mouse model in absence of additional risk factors present in patients like advanced age, genetic variabilities or smoking. Male and female mice were immunized with human TSHR A-subunit encoding plasmid. Both sexes comparably developed autoimmune hyperthyroidism characterized by TSHR stimulating autoantibodies, elevated T4 values, hyperplastic thyroids and hearts. Autoimmune mice developed inflammatory eye symptoms and proptosis, although males earlier than females. Serial in vivo1H/19F-magnetic resonance imaging revealed elevated inflammatory infiltration, increased fat volume and glycosaminoglycan deposition in orbits of both sexes but most significantly in female mice. Histologically, infiltration of T-cells, extension of brown fat and overall collagen deposition were characteristics of GO in male mice. In contrast, female mice developed predominately macrophage infiltration in muscle and connective tissue, and muscle hypertrophy. Apart from sex-dependent variabilities in pathogenesis, disease classification revealed minor sex-differences in incidence and total outcome. In conclusion, sex does not predispose for autoimmune hyperthyroidism and associated GO.

A non-redundant role for RORα in TH17 cell development and TH17-driven inflammatory disorders

Abstract Dysregulated TH17 immune responses have been associated with the pathogenesis of several autoimmune diseases. While full development of TH17 cells requires both nuclear receptors RORα and RORγt, most of the work surrounding TH17 cells has focused on the lineage defining transcription factor RORγt. However, TH17 cells are not absent in RORγ−/− mice, suggesting that RORα plays an important role. Despite this, RORα is considered redundant to RORγt and little is known about its function in TH17 cells. The aim of this study was to determine whether RORα played a significant role in TH17 cell development and TH17-driven inflammatory disorders. Using molecular, genetic, and pharmacological approaches our data suggests that RORα has non-redundant functions to RORγt driving TH17 cell development. Loss or overexpression of RORα in CD4+ T cells significantly decreased or increased IL-17A, respectively, despite no change in RORγt expression. Using two mouse models of autoimmunity known to be TH17 driven [experimental autoimmune encephalomyelitis (EAE) and adoptive transfer model of colitis], we found that loss of RORα significantly inhibited the development of EAE and colitis, largely as a consequence of decreased frequencies of pro-inflammatory TH17 cells and increased frequencies of anti-inflammatory Foxp3+ T regulatory cells. Finally, using a RORα-selective small molecule that we developed, we found that modulation of RORα activity significantly inhibited the development of autoimmunity. Our data suggests that RORα plays a non-redundant role to RORγt in TH17 cell development. Studies focusing on assessing RORα activity alone or along with RORγt may lend novel insight into future therapeutic design for TH17-mediated autoimmunity.

The REV-ERBs: Negative Regulators of Th17 Cell Development and Autoimmunity

Abstract Th17 cells have been associated with the pathogenesis of several autoimmune diseases, including multiple sclerosis. While the nuclear receptor (NR) RORγt is considered the lineage determining transcription factor for Th17 cells, the REV-ERBs (REV-ERBα and REV-ERBβ), two other members of the NR superfamily, are often co-expressed in the same tissues as members of the ROR subfamily of NRs (i.e. RORγt) and bind to the same DNA response elements. In contrast to the RORs, which are transcriptional activators, the REV-ERBs are transcriptional repressors, suggesting mutual cross talk and co-regulation of their shared target genes. While the REV-ERBs are best known for their roles in the circadian rhythm and metabolic processes, their role in Th17 cell development and Th17 mediated inflammatory diseases is largely unexplored. Our data indicates that over expression of the REV-ERBs inhibits Th17 cell differentiation whereas genetic deletion of the REV-ERBs perturbs Th17 cell differentiation. Using two commonly used mouse models of autoimmunity known to be Th17 driven [experimental autoimmune encephalomyelitis (EAE) and adoptive transfer model of colitis], we found that loss of REV-ERB expression exacerbates EAE and colitis compared to WT controls, largely as a consequence of an increased number of pro-inflammatory Th17 cells. Finally, using REV-ERB-selective small molecules that we have developed, we discovered that pharmacological modulation of REV-ERB activity significantly inhibits the development of autoimmunity. Overall, our data suggests that the REV-ERBs are potent negative regulators of Th17 differentiation and identifies the REV-ERBs as viable therapeutic targets for the treatment of Th17-mediated autoimmune diseases.

Enforcing anergy of autoreactive B cells through inhibition of the PI3K pathway

Abstract Variations in expression and/or function of a number of genes confer increased risk of development of autoimmunity. Among these variations is the expression of negative regulators of the PI3K pathway, whose activity is critical in maintaining B cell anergy. Anergy, in which autoreactive B cells are unresponsive to antigen, is maintained via upregulation of the inositol phosphatases PTEN and/or SHIP-1, which hydrolyze PI(3,4,5)P3, the product of PI3K, yielding PI(4,5)P2 and PI(3,4)P2, respectively. Levels of these negative regulators are reduced in SLE due to aberrant regulation by miRNA-7 and miRNA-155. Deletion of miRNA155, which raises SHIP-1 expression, has been shown to reduce autoantibody responses in the lpr autoimmune mouse model of Lupus. Acute deletion of SHIP-1 or PTEN in autoreactive B cells leads to autoimmunity. We report that it is possible to pharmacologically correct defects in PI3K pathway regulation which confer risk of autoimmunity, thus preventing autoimmunity while conferring minimal disruption of adaptive immune function. This intervention does not prevent autoimmunity caused by compromise of other risk allele emulating conditions, such as reduced SHP-1 expression. We hypothesize that PI3K inhibitors can be used therapeutically to compensate for decreased negative regulation of the PI3K pathway. The knowledge gained from these studies will aid in the development of precision treatments for autoimmunity that act by correcting effects of specific risk alleles.

PO-1037: Intestinal radiation plays a pivotal role in CTLA-4 Ab induced an autoimmune enteritis mouse model

PO-1037: Intestinal radiation plays a pivotal role in CTLA-4 Ab induced an autoimmune enteritis mouse model

High fiber dietary and sodium butyrate attenuate experimental autoimmune hepatitis through regulation of immune regulatory cells and intestinal barrier

Autoimmune hepatitis (AIH) is chronic autoimmune liver disease accompanied with the imbalance of Treg/Th17 and increased intestinal permeability. We investigated the effects of a high fiber diet and sodium butyrate on the Treg/Th17 and intestinal barrier function in an experimental autoimmune hepatitis. Intraperitoneal injection of hepatic antigen (S100) was used to induce experimental autoimmune hepatitis mice model and mice were divided into normal control, S100 model control, S100 plus high fiber diet and S100 plus sodium butyrate. Serum aminotransferases and liver histology were examined. Short chain fatty acids in feces were determined by HPLC. The ratio of CD4 + C25 + Foxp3+ Treg and CD4 + IL-17 + Th17 were evaluated by flow cytometry. Tight junction proteins Zonula ocluden, Occludin and Claudin-1 were used to assess intestinal barrier function, so does Escherichia coli protein in the liver. Mice fed with either high fiber diet or sodium butyrate showed significantly lower levers of serum aminotransferases and minor liver injury compared to that of model control. Moreover, the ratio of Treg/Th17 was significantly higher in high fiber diet and sodium butyrate fed mice than that in model control. Furthermore, high fiber diet and sodium butyrate significantly increased intestinal tight junction proteins and decreased Escherichia Coli protein in the liver. In conclusion, high fiber diet and sodium butyrate can attenuate development of autoimmune hepatitis through regulation of immune regulatory cells and intestinal barrier function.

T cells specific for post-translational modifications escape intrathymic tolerance induction

Establishing effective central tolerance requires the promiscuous expression of tissue-restricted antigens by medullary thymic epithelial cells. However, whether central tolerance also extends to post-translationally modified proteins is not clear. Here we show a mouse model of autoimmunity in which disease development is dependent on post-translational modification (PTM) of the tissue-restricted self-antigen collagen type II. T cells specific for the non-modified antigen undergo efficient central tolerance. By contrast, PTM-reactive T cells escape thymic selection, though the PTM variant constitutes the dominant form in the periphery. This finding implies that the PTM protein is absent in the thymus, or present at concentrations insufficient to induce negative selection of developing thymocytes and explains the lower level of tolerance induction against the PTM antigen. As the majority of self-antigens are post-translationally modified, these data raise the possibility that T cells specific for other self-antigens naturally subjected to PTM may escape central tolerance induction by a similar mechanism.

Increased TLR7 Signaling of BCR-Activated B Cells in Chronic Graft-Versus Host Disease (cGVHD)

After hematopoietic allogeneic stem cell transplantation (HCT), B cells reconstitute in the presence of alloantigen in a nucleic acid (NA)-rich environment. Ongoing tissue and cellular damage results in release of endogenous NA that may serve as ligand for endosomal Toll-Like Receptors (TLRs). Alloantibodies and autoantibodies, including NA-binding antibodies, have been associated with the presence of cGVHD manifestations. In patients after HCT, B cells are constitutively activated via key proximal B Cell Receptor (BCR) signaling molecules, Syk and BLNK (Allen JL et al Blood 2014, Flynn R et al Blood 2015) . In mouse models of autoimmunity, TLR7 or TLR9 can operate in conjunction with the BCR to mediate autoantibody production (Suthers A et al. Front Immunol. 2017). Whether TLR7/9-BCR signaling contributes to cGVHD remains unknown.We studied responses by TLR9 and TLR7 in B cells from patients >12 months post-HCT who had active, inactive or no cGVHD at the time of sample acquisition and were not receiving high dose steroid. In contrast to a previous study (She K et al. BBMT 2007) and consistent with findings by others (de Masson A et al Blood 2015), we did not find a consistent increase in B cell response to TLR9 agonist. Instead we found significantly higher TLR7 transcript expression in B cells from patients with active cGVHD (n=7) compared to no/inactive cGVHD patient B cells (n=11, p=0.042). TLR7 over-expression in mice leads to anti-RNA antibody production by immature B cells (Giltiay NV et al JEM 2013). We employed ELISA to measure antibodies to a known RNA-containing autoantigen, Ro-52 in a group of 66 plasma samples. We found that significantly more patients with active cGVHD (n=32) had anti-Ro-52 antibody compared to inactive cGVHD patients (n=22) or patients without cGVHD (n=12) (Fisher exact test for both comparisons = p<0.0001). This suggests potential opposing roles for TLR9 and TLR7 in cGVHD (Sharma et al, J.Immunol. 2015), and allowed us to hypothesize that B cells in cGVHD were aberrantly activated via TLR7.To determine if TLR7 activation was increased in cGVHD B cells, we measured IL-6 production. Without ex vivo stimulation, cGVHD patient B cells produced significantly more IL-6 (p=0.039) (Fig.1A). After TLR7 stimulation with R848, B cells from patients with active cGVHD had significantly increased IL-6 production compared those from patients without (p= 0.008) or those with inactive cGVHD (p=0.017) (Fig.1A). We next investigated the influence of the BCR-activated state in cGVHD on TLR7 responses and signaling. Using flow cytometry, we measured Ki-67 expression as a marker of activation after ex vivo stimulation with both low level surrogate BCR antigen and R848. We found that B cells from active cGVHD patients were significantly more responsive compared to no cGVHD patients (p=0.015) and healthy donors (p=0.045), revealing increased synergistic BCR-TLR7 signaling in cGVHD B cells (Fig.1B). To further investigate this, we employed qPCR to measure levels of the proximal BCR signaling molecule, Lyn, known to negatively regulate anti-NA antibody production (Lamagna et al. J. Immunol. 2014). We found that Lyn expression was significantly decreased in B cells from active cGVHD patients compared to healthy donor (p=0.001), inactive (p=0.042) or no (p=0.007) cGVHD patients (Fig.1C). Lyn can also negatively regulate TLR7/9 activation by directly associating with Interferon Regulatory Factor 5 (IRF5), which is important for pro-inflammatory cytokine production, including IL-6 (Ban et al, J.Immunol. 2016). Consistent with a role for Lyn in TLR7 activation, we found that IRF5 was significantly increased in active cGVHD patient B cells compared to all other groups (healthy donor, p=0.035; inactive cGVHD, p=0.011; no cGVHD, p=0.006) (Fig.1D). Notably, no difference in expression was found in downstream TLR7 transcription factors, IRF3 and IRF7 . Using a mouse model (Zhang C et al Blood 2006), we found significantly higher IRF5 expression in splenic B cells in animals with cGVHD manifestations (p=0.005). Ongoing mouse work will ascertain mechanistic roles for Lyn and IRF5 in TLR7 signaling by cGVHD B cells. Together data support a potentially pathogenic role of TLR7 signaling in cGVHD B cells. Development of agents that block this newly elucidated TLR7-BCR signaling axis in cGVHD is warranted.This work was supported by National Institutes of Health grant R01 HL129061 [Display omitted] DisclosuresRizzieri:Erytech: Research Funding; Shire: Research Funding.

Biology of LAG3 Checkpoint Blockade

Dr. Vignali will discuss the biology of the inhibitory receptor LAG3, and its contribution to T cell exhaustion and immune regulation on CD8+ and CD4+ intratumoral T cells in mouse models of cancer and autoimmunity, and in a variety of human malignancies. He will also discuss the impact of LAG3 on regulatory T cell function. Given the considerable interest in inhibitory receptors in general, and LAG3 recently, as immunotherapeutic targets, he will also discuss how differential LAG3 expression could impact responsiveness to immunotherapy. DisclosuresVignali:Potenza Therapeutics: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties: Licensed IP, Research Funding; Tizona Therapeutics: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; Oncorus: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Pieris: Membership on an entity's Board of Directors or advisory committees; FStar: Membership on an entity's Board of Directors or advisory committees; BMS: Equity Ownership; Merck: Equity Ownership; Crescendo: Consultancy; Intellia: Consultancy; MPM: Consultancy; Onkaido/Moderna: Consultancy; Servier: Consultancy.

Autoimmune disease mouse model exhibits pulmonary arterial hypertension.

BackgroundPulmonary arterial hypertension is often associated with connective tissue disease. Although there are some animal models of pulmonary hypertension, an autoimmune disease-based model has not yet been reported. MRL/lpr mice, which have hypergammaglobulinemia, produce various autoimmune antibodies, and develop vasculitis and nephritis spontaneously. However, little is known about pulmonary circulation in these mice. In the present study, we examined the pulmonary arterial pressure in MRL/lpr mice.Methods and resultsWe used female MRL/lpr mice aged between 12 and 14 weeks. Fluorescent immunostaining showed that there was no deposition of immunoglobulin or C3 in the lung tissue of the MRL/lpr mice. Elevation of interferon-γ and interleukin-6 was recognized in the lung tissue of the MRL/lpr mice. Right ventricular systolic pressure, Fulton index and the ratio of right ventricular weight to body weight in the MRL/lpr mice were significantly higher than those in wild type mice with same background (C57BL/6). The medial smooth muscle area and the proportion of muscularized vessels in the lung tissue of the MRL/lpr mice were larger than those of the C57BL/6 mice. Western blot analysis demonstrated markedly elevated levels of prepro-endothelin-1 and survivin as well as decreased endothelial nitric oxide synthase phosphorylation in the lung tissue of the MRL/lpr mice. Terminal deoxynucleotidyl-transferase-mediated dUTP nick end-labeling assay showed the resistance against apoptosis of pulmonary arterial smooth muscle cells in the MRL/lpr mice.ConclusionWe showed that MRL/lpr mice were complicated with pulmonary hypertension. MRL/lpr mice appeared to be a useful model for studying the mechanism of pulmonary hypertension associated with connective tissue diseases.

Gut microbiota from multiple sclerosis patients enables spontaneous autoimmune encephalomyelitis in mice

There is emerging evidence that the commensal microbiota has a role in the pathogenesis of multiple sclerosis (MS), a putative autoimmune disease of the CNS. Here, we compared the gut microbial composition of 34 monozygotic twin pairs discordant for MS. While there were no major differences in the overall microbial profiles, we found a significant increase in some taxa such as Akkermansia in untreated MS twins. Furthermore, most notably, when transplanted to a transgenic mouse model of spontaneous brain autoimmunity, MS twin-derived microbiota induced a significantly higher incidence of autoimmunity than the healthy twin-derived microbiota. The microbial profiles of the colonized mice showed a high intraindividual and remarkable temporal stability with several differences, including Sutterella, an organism shown to induce a protective immunoregulatory profile in vitro. Immune cells from mouse recipients of MS-twin samples produced less IL-10 than immune cells from mice colonized with healthy-twin samples. IL-10 may have a regulatory role in spontaneous CNS autoimmunity, as neutralization of the cytokine in mice colonized with healthy-twin fecal samples increased disease incidence. These findings provide evidence that MS-derived microbiota contain factors that precipitate an MS-like autoimmune disease in a transgenic mouse model. They hence encourage the detailed search for protective and pathogenic microbial components in human MS.

The therapeutic effects of Yongdamsagan-tang on autoimmune hepatitis models

Autoimmune hepatitis (AIH) is an immunity disorder that is the result of antibodies in the liver tissue of the patient that are attacked by activated immune cells due to an unknown cause. In this study, we aimed to investigate the anti-inflammatory effect of Yongdamsagan-tang (YST) extracts and confirm effects on autoimmune hepatitis models as the therapeutic agent using the YST extracted by various solvents. YST, a mixture of 11 herbal extracts, is known in traditional Korean medicine as a widely used treatment for inflammatory diseases. We proposed the AIH-condition in vitro model by the addition of recombinant IL-17A and then observed several markers linked to AIH symptoms, including an increase of IL-6 expression, lipid accumulation, and fibrosis. In AIH-condition hepatic cell model, YST reduced IL-6 expression and lipid accumulation caused by treatment of IL-17 combination in hepatocyte cells. Also, YST blocked several activated fibrosis factors including transforming growth factor-β (TGF- β1), collagen type 1 (Col-α1(I)), and α-smooth muscle actin (α-SMA) in liver stellate cells. Furthermore, pretreatment with YST protected hepatic damage and reduces histological injury by suppressing apoptosis mediator and inflammatory cytokines expression in concanavalin A (Con A)-induced autoimmune hepatitis mice model. The findings here improve our understanding of YST extracted by 80% ethanol, suggesting that YST can be used as a therapeutic treatment for AIH.

Activated B Cells Participating in the Anti-Myelin Response Are Excluded from the Inflamed Central Nervous System in a Model of Autoimmunity that Allows for B Cell Recognition of Autoantigen.

Once activated, T cells gain the ability to access both healthy and inflamed nonlymphoid tissues. They are then reactivated to remain in the tissue and exert their effector function only if they encounter their specific Ag. In this study, we set out to determine if the same is true for B cells using a mouse model of CNS autoimmunity that incorporates both T and B cell recognition of a myelin autoantigen. Both T and B cells were common infiltrates of spinal cords in diseased mice. However, unlike T cells, anti-myelin B cells were excluded from the inflamed tissue. Further, CNS B cells did not have a phenotype consistent with Ag-specific activation as it occurs in lymphatic tissue. Instead, they expressed elevated levels of CD80, indicating that B cells may contribute to local inflammation through nonantigen-specific mechanisms.

Breaching peripheral tolerance promotes the production of HIV-1-neutralizing antibodies.

A subset of characterized HIV-1 broadly neutralizing antibodies (bnAbs) are polyreactive with additional specificities for self-antigens and it has been proposed immunological tolerance may present a barrier to their participation in protective humoral immunity. We address this hypothesis by immunizing autoimmune-prone mice with HIV-1 Envelope (Env) and characterizing the primary antibody response for HIV-1 neutralization. We find autoimmune mice generate neutralizing antibody responses to tier 2 HIV-1 strains with alum treatment alone in the absence of Env. Importantly, experimentally breaching immunological tolerance in wild-type mice also leads to the production of tier 2 HIV-1-neutralizing antibodies, which increase in breadth and potency following Env immunization. In both genetically prone and experimentally induced mouse models of autoimmunity, increased serum levels of IgM anti-histone H2A autoantibodies significantly correlated with tier 2 HIV-1 neutralization, and anti-H2A antibody clones were found to neutralize HIV-1. These data demonstrate that breaching peripheral tolerance permits a cross-reactive HIV-1 autoantibody response able to neutralize HIV-1.

IFN-β-induced reactive oxygen species and mitochondrial damage contribute to muscle impairment and inflammation maintenance in dermatomyositis

Dermatomyositis (DM) is an autoimmune disease associated with enhanced type I interferon (IFN) signalling in skeletal muscle, but the mechanisms underlying muscle dysfunction and inflammation perpetuation remain unknown. Transcriptomic analysis of early untreated DM muscles revealed that the main cluster of down-regulated genes was mitochondria-related. Histochemical, electron microscopy, and in situ oxygraphy analysis showed mitochondrial abnormalities, including increased reactive oxygen species (ROS) production and decreased respiration, which was correlated with low exercise capacities and a type I IFN signature. Moreover, IFN-β induced ROS production in human myotubes was found to contribute to mitochondrial malfunctions. Importantly, the ROS scavenger N-acetyl cysteine (NAC) prevented mitochondrial dysfunctions, type I IFN-stimulated transcript levels, inflammatory cell infiltrate, and muscle weakness in an experimental autoimmune myositis mouse model. Thus, these data highlight a central role of mitochondria and ROS in DM. Mitochondrial dysfunctions, mediated by IFN-β induced-ROS, contribute to poor exercise capacity. In addition, mitochondrial dysfunctions increase ROS production that drive type I IFN-inducible gene expression and muscle inflammation, and may thus self-sustain the disease. Given that current DM treatments only induce partial recovery and expose to serious adverse events (including muscular toxicity), protecting mitochondria from dysfunctions may open new therapeutic avenues for DM.

Inactivation of the KSRP gene modifies collagen antibody induced arthritis

The KH type splicing regulatory protein (KSRP) is a nucleic acid binding protein, which negatively regulates the stability and/or translatability of many mRNA species encoding immune-relevant proteins. As KSRP is expressed in immune cells including T and B cells, neutrophils, macrophages and dendritic cells, we wanted to analyze its importance for the development of autoimmune diseases.We chose collagen antibody-induced arthritis (CAIA) as an appropriate autoimmune disease mouse model in which neutrophils and macrophages constitute the main effector cell populations. We compared arthritis induction in wild type (WT) and KSRP−/− mice and paws were taken for histological sections and qPCR analysis. Furthermore, we determined the frequencies of spleen immune cells by flow cytometry. Cytokine levels in spleen cell supernatants were determined by cytometric bead array analyses (CBA).After CAIA induction we unexpectedly observed in WT animals much stronger swelling of the paws than in KSRP−/− mice. In accordance, histological staining of paw sections of KSRP−/− animals revealed much lower frequencies of infiltrating immune cells in the joints compared to WT animals. Furthermore, CAIA-treatment resulted in reduced expression of several inflammatory factors (like CXCL-1, iNOS, TNF-α and S100A8) as well as immune cell marker genes (e.g. LFA-1, CD68, Ly6G) in the joints of KSRP−/− mice.Spleen cells of KSRP−/− mice showed lower frequencies of myeloid cells. On cytokine level IFN-γ production was increased in spleen cells of KSRP−/− mice compared to WT samples.These data surprisingly suggest that the absence of KSRP protects against the induction of inflammatory arthritis.

Enhanced Bruton's Tyrosine Kinase Activity in Peripheral Blood B Lymphocytes From Patients With Autoimmune Disease.

Bruton's tyrosine kinase (BTK) transmits crucial survival signals from the B cell receptor (BCR) in B cells. Pharmacologic BTK inhibition effectively diminishes disease symptoms in mouse models of autoimmunity; conversely, transgenic BTK overexpression induces systemic autoimmunity in mice. We undertook this study to investigate BTK expression and activity in human B cells in the context of autoimmune disease. Using intracellular flow cytometry, we quantified BTK expression and phosphorylation in subsets of peripheral blood B cells from 30 patients with rheumatoid arthritis (RA), 26 patients with primary Sjögren's syndrome (SS), and matched healthy controls. In circulating B cells, BTK protein expression levels correlated with BTK phosphorylation. BTK expression was up-regulated upon BCR stimulation in vitro and was significantly higher in CD27+ memory B cells than in CD27-IgD+ naive B cells. Importantly, BTK protein and phospho-BTK were significantly increased in B cells from anti-citrullinated protein antibody (ACPA)-positive RA patients but not in B cells from ACPA-negative RA patients. BTK was increased both in naive B cells and in memory B cells and correlated with frequencies of circulating CCR6+ Th17 cells. Likewise, BTK protein was increased in B cells from a major fraction of patients with primary SS and correlated with serum rheumatoid factor levels and parotid gland T cell infiltration. Interestingly, targeting T cell activation in patients with primary SS using the CTLA-4Ig fusion protein abatacept restored BTK protein expression in B cells to normal levels. These data indicate that autoimmune disease in humans is characterized by enhanced BTK activity, which is linked not only to autoantibody formation but also to T cell activity.

TIM-3 as a Target for Cancer Immunotherapy and Mechanisms of Action.

Cancer immunotherapy has produced impressive clinical results in recent years. Despite the success of the checkpoint blockade strategies targeting cytotoxic T lymphocyte antigen 4 (CTLA-4) and programmed death receptor 1 (PD-1), a large portion of cancer patients have not yet benefited from this novel therapy. T cell immunoglobulin and mucin domain 3 (TIM-3) has been shown to mediate immune tolerance in mouse models of infectious diseases, alloimmunity, autoimmunity, and tumor Immunity. Thus, targeting TIM-3 emerges as a promising approach for further improvement of current immunotherapy. Despite a large amount of experimental data showing an immune suppressive function of TIM-3 in vivo, the exact mechanisms are not well understood. To enable effective targeting of TIM-3 for tumor immunotherapy, further in-depth mechanistic studies are warranted. These studies will also provide much-needed insight for the rational design of novel combination therapy with other checkpoint blockers. In this review, we summarize key evidence supporting an immune regulatory role of TIM-3 and discuss possible mechanisms of action.