Helminth antigens enable CpG-activated dendritic cells to inhibit the symptoms of collagen-induced arthritis through Foxp3+ regulatory T cells

Fasciola hepatica GST mu-class suppresses the cytokine storm induced by E. coli-lipopolysaccharide, whereas it modulates the dynamic of peritoneal macrophages in a mouse model and suppresses the classical activation of macrophages

IMPORTANCE

Sepsis is the consequence of a systemic bacterial infection that exacerbates the immune cell's activation via bacterial products, resulting in the augmented release of inflammatory mediators. A critical factor in the pathogenesis of sepsis is the primary component of the outer membrane of Gram-negative bacteria known as lipopolysaccharide (LPS), which is sensed by TLR4. For this reason, scientists have aimed to develop antagonists able to block TLR4 and, thereby the cytokine storm. We report here that a mixture of mu-class isoforms from the F. hepatica GST protein family administered intraperitoneally 1 h prior to a lethal LPS injection can modulate the dynamics and abundance of large peritoneal macrophages in the peritoneal cavity of septic mice while significantly suppressing the LPS-induced cytokine storm in a mouse model of septic shock. These results suggest that native F. hepatica glutathione S-transferase is a promising candidate for drug development against endotoxemia and other inflammatory diseases.

Fasciola hepatica extract suppresses fibroblast-like synoviocytes in vitro and alleviates experimental arthritis

BACKGROUND

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by synovial inflammation, fibroblast-like synoviocytes (FLS) activation and joint destruction. Fasciola hepatica is a platyhelminth that releases excretory-secretory immunomodulatory products capable of suppressing the Th1 immune response. Despite the effectiveness of available treatments for inducing disease remission, current options are not successful in all patients and may cause side effects. Thus, we evaluated the therapeutic potential of F. hepatica extract on FLS from RA patients and arthritis models.

METHODS

FLS were isolated from synovial fluid of RA patients, cultured, and exposed to F. hepatica extract (60, 80, and 100 µg/ml) for different time points to assess cell viability, adherence, migration and invasion. For in vivo experiments, mice with antigen (AIA) and collagen (CIA) induced arthritis received a 200 µg/dose of F. hepatica extract daily. Statistical analysis was performed by ANOVA and Student's t-test using GraphPad Prism 6.0.

RESULTS

In vitro assays showed that extract decreased FLS cell viability at concentration of 100 µg/ml (83.8% ± 5.0 extract vs. 100.0% ± 0.0 control; p < 0.05), adherence in 20% (92.0 cells ± 5.8 extract vs. 116.3 cells ± 7.9 control; p < 0.05), migratory potential (69.5% ± 17.6 extract vs. 100.0% control; p < 0.05), and cell invasiveness potential through the matrigel (76.0% ± 8.4 extract vs. 100.0% control; p < 0.01). The extract reduced leukocyte migration by 56% (40 × 10⁴ leukocytes/knee ± 19.00) compared to control (90.90 × 10⁴ leukocytes/knee ± 12.90) (p < 0.01) and nociception (6.37 g ± 0.99 extract vs. 3.81 g ± 1.44 control; p < 0.001) in AIA and delayed clinical onset of CIA (11.75 ± 2.96 extract vs. 14.00 ± 2.56 control; p = 0.126).

CONCLUSION

Our results point out a potential immunomodulatory effect of F. hepatica extract in RA models. Therefore, the characterization of promising new immunomodulatory molecules should be pursued, as they can promote the development of new therapies. Trial registration Collection of synovial liquid and in vitro procedures were approved by the Ethics Committee with Certificate of Presentation of Ethical Appreciation in Plataforma Brasil (CAAE: 89044918.8.0000.5327; date of registration: 26/07/2018).

Diazepam Impairs Innate and Adaptive Immune Responses and Ameliorates Experimental Autoimmune Encephalomyelitis

Currently there is increasing attention on the modulatory effects of benzodiazepines on the immune system. Here, we evaluate how Diazepam (DZ) affects both innate and adaptive immunity. We observed that treatment with DZ and Lipopolysaccharide (LPS) on macrophages or dendritic cells (DCs) induced a defective secretion of IL-12, TNF-α, IL-6 and a lesser expression of classical activation markers as NO production and CD40 in comparison with LPS condition. More importantly, mice pre-treated with DZ and then challenged to LPS induced-septic shock showed reduced death. The DZ treatment shifted the LPS-induced pro-inflammatory cytokine production of peritoneal cells (PCs) to an anti-inflammatory profile commanded by IL-10. In agreement with this, DZ treatment prevented LPS-induced DC ability to initiate allogeneic Th1 and Th17 responses in vitro when compared with LPS-matured DC. Since these inflammatory responses are the key in the development of the experimental autoimmune encephalomyelitis (EAE), we treated EAE mice preventively with DZ. Mice that received DZ showed amelioration of clinical signs and immunological parameters of the disease. Additionally, DZ reduced the release of IFN-γ and IL-17 by splenocytes from untreated sick mice in vitro. For this reason, we decided to treat diseased mice therapeutically with DZ when they reached the clinical score of 1. Most importantly, this treatment ameliorated clinical signs, reduced the MOG-specific inflammatory cytokine production and prevented axonal damage. Altogether, these results indicate that DZ is a potent immunomodulator capable of controlling undesired innate and adaptive immune responses, both at the beginning of these responses and also once they have started.

Combination effect of laser diode for photodynamic therapy with doxycycline on a wistar rat model of periodontitis

Background

Periodontitis is a chronic inflammatory disease characterized by progressive damage on the structure of tooth-supporting tissues. The aim of the study is determining the combination photodynamic effect of diode laser 405 nm treatments and the administration of doxycycline 0.1% within 1, 3, 5, and 7 days on a Wistar rat model of periodontitis.

Methods

Samples were induced with Porphyromonas gingivalis ATCC33277 to allow periodontitis development and were treated with combination of doxycycline and laser diode, then statistical analysis was carried out (One-Way ANOVA test and the post-hoc Duncan test; Kruskal–Wallis test and Mann–Whitney follow-up test for non-parametric data). Samples were divided into five groups, laser exposure used was 405-nm diode laser with energy density of 8 J/cm². The expression level of histomorphometric was calculated by measuring the number of macrophages, lymphocytes, fibroblasts and the distance between the CEJ-AV.

Results

The results showed that the combination treatment of doxycycline and laser exposure yielded immunomodulatory effects. The expression level of fibroblast and the distance between CEJ-AV bone showed that the combination of doxycycline and laser therapy exerted healing effect in rat models of periodontitis on day 5 and 7.

Conclusion

The combination of doxycycline 0.1% and diode laser therapy provides a healing effect in rats models of periodontitis.

Infection History Determines Susceptibility to Unrelated Diseases

Epidemiological data suggest that previous infections can alter an individual's susceptibility to unrelated diseases. Nevertheless, the underlying mechanisms are not completely understood. Substantial research efforts have expanded the classical concept of immune memory to also include long-lasting changes in innate immunity and antigen-independent reactivation of adaptive immunity. Collectively, these processes provide possible explanations on how acute infections might induce long-term changes that also affect immunity to unrelated diseases. Here, we review lasting changes the immune compartment undergoes upon infection and how infection experience alters the responsiveness of immune cells towards universal signals. This heightened state of alert enhances the ability of the immune system to combat even unrelated infections but may also increase susceptibility to autoimmunity. At the same time, infection-induced changes in the regulatory compartment may dampen subsequent immune responses and promote pathogen persistence. The concepts presented here outline how infection-induced changes in the immune system may affect human health.

Anti-inflammatory Trained Immunity Mediated by Helminth Products Attenuates the Induction of T Cell-Mediated Autoimmune Disease

Recent studies have suggested that the innate immune system can display characteristics of immunological memory and this has been called “innate immune memory” or “trained immunity.” Certain fungal products have been shown to induce epigenetic imprinting on monocytes/macrophages that results in heightened inflammatory responses to subsequent stimuli. Here we report that innate immune cells can be trained to be more anti-inflammatory following exposure to products of a helminth pathogen. Macrophages trained in vitro with Fasciola hepatica total extract (FHTE) had enhanced IL-10 and IL-1RA, but reduced TNF production upon re-stimulation with FHTE or TLR ligands and this was reversed by inhibitors of DNA methylation. In contrast, macrophages trained with β-glucan or Bacillus Calmette–Guérin had enhanced TNF production upon re-stimulation with Pam3cys or LPS. Furthermore, FHTE-trained macrophages had enhanced expression of markers of alternative activated macrophages (AAM). Macrophages from mice treated with FHTE expressed markers of AAM and had heightened IL-10 and IL-1RA production in response to FHTE or TLR ligands and had suppressed TNF and IL-12p40 production. Macrophages from mice treated with FHTE had reduced APC function and inhibited IL-17 production and the encephalitogenic activity of T cells in the experimental autoimmune encephalomyelitis (EAE) model. In addition, mice pre-treated with FHTE were resistant to induction of EAE and this was associated with a significant reduction in IL-17-producing γδ and CD4 T cells infiltrating the CNS. Our findings reveal that cells of the innate immune system can be trained in vitro or in vivo to be more anti-inflammatory by exposure to helminth products and this protects mice against the induction of a T cell-mediated autoimmune disease.

STAT6 and IL-10 are required for the anti-arthritic effects of Schistosoma mansoni via different mechanisms

To investigate possible roles of T helper type 2 (Th2) cytokines in the anti-arthritic effects of a blood fluke, Schistosoma mansoni (Sm), for mouse collagen-induced arthritis (CIA), wild-type (WT), signal transducer and activator of transcription 6 (STAT6) knock-out (KO) and interleukin (IL)-10 KO mice were infected with Sm. Three weeks after infection, the mice were immunized with bovine type II collagen (IIC). Arthritis severity was monitored by scoring, measurement of paw thickness and the presence of ankylosis. Serum anti-IIC IgG levels, splenic cytokine production and cytokine gene expression in the popliteal lymph nodes (PLNs) were measured and compared among WT and gene-KO mice. Consistent with our previous findings, Sm infection reduced the arthritis severity in WT mice. Splenic production of IL-17A and tumor necrosis factor (TNF)-α was reduced by the infection. In contrast, Sm infection markedly exacerbated CIA in STAT6 KO mice. In the KO mice, IL-17A production was increased by the infection. Conversely, Sm infection did not affect the exacerbated arthritis in IL-10 KO mice, although IL-17A production was reduced by the helminth. Our results suggest that signaling via STAT6 (presumably IL-4 and/or IL-13) and IL-10 is required for the suppression of CIA by Sm infection, but through different mechanisms. STAT6 was essential for helminth-induced reduction of IL-17A, whereas regulation of the basal arthritis severity by IL-10 was needed in order for it to be sufficiently suppressed by the helminth.

Helminth-based therapies for rheumatoid arthritis: A systematic review and meta-analysis

OBJECTIVE

Proteins from parasitic worms have been posed as novel therapies for rheumatoid arthritis (RA) and other auto-inflammatory diseases. However, with so many potential therapeutics, it is important that drug discovery be based on the specific phyla or species which show the most promising effects. Therefore, the aim of this systematic review and meta-analysis was to evaluate the reported effects of helminthic secretory proteins and derivative therapy on RA in an animal model.

METHODS

Medline, Scopus and Web of Science were searched to identify studies evaluating helminthic therapy in the collagen-induced arthritis model of RA. A meta-analysis was undertaken to determine the overall effect of the proteins. Subgroup analyses were also undertaken to investigate individual treatments.

RESULTS

Seven articles were included in the analysis. Overall, helminthic therapy significantly reduced arthritis score (SMD -1.193, 95% CI -1.525, -0.860). Subgroup analyses found a significant reduction in arthritis score following treatment with helminth protein ES-62 (SMD -1.186, 95% CI -1.633, -0.738) and phosphorylcholine-based treatment (SMD -0.997, 95% CI -1.423, -0.571). Subgroup analyses found ES-62 treatment significantly decreased IFN-γ levels (SMD -1.611, 95% CI -2.734, -0.487) and significantly increased levels of IL-10 (SMD 0.946, 95% CI 0.127, 1.765).

CONCLUSIONS

Therapeutics from parasitic worms are a promising avenue for drug discovery, especially with all included studies reporting a significant improvement in arthritis score. Based on pooled data presented in this study, the nematode Acanthocheilonema viteae seems to be of particular interest for therapeutics.

Helminth Antigen-Conditioned Dendritic Cells Generate Anti-Inflammatory Cd4 T Cells Independent of Antigen Presentation via Major Histocompatibility Complex Class II

A recently identified feature of the host response to infection with helminth parasites is suppression of concomitant disease. Dendritic cells (DCs) exposed to antigens from the tapeworm Hymenolepis diminuta significantly reduce the severity of dinitrobenzene sulfonic acid-induced colitis in mice. Here we elucidate mechanisms underlying this cellular immunotherapy. We show a requirement for Ccr7 expression on transferred H. diminuta antigen-treated (HD)-DCs, suggesting that homing to secondary lymphoid tissues is important for suppression of colitis. Furthermore, sodium metaperiodate-sensitive helminth-derived glycans are required to drive the anti-colitic response in recipient mice. Induction of Th2-type cytokines and Gata-3⁺Cd4⁺ cells in secondary lymphoid tissues is dependent on major histocompatibility complex class II (MHC II) protein expression on transferred DCs, although remarkably, transfer of MHC II^-/- HD-DCs still attenuated dinitrobenzene sulfonic acid-induced colitis in recipient mice. Moreover, transfer of Cd4⁺ splenic T cells retrieved from mice administered MHC II^-/- HD-DCs suppressed dinitrobenzene sulfonic acid-induced colitis in recipient mice. Our studies reveal that HD-DCs can suppress colitis via an alternative MHC II-independent pathway that involves, in part, mobilization of T-cell responses. These data support the utility of HD-DCs in blocking colitis, revealing a requirement for Ccr7 and providing for HD-DC autologous immunotherapy for disease in which MHC II expression and/or function is compromised.

Nanomedicine Approaches Against Parasitic Worm Infections

Nanomedicine approaches have the potential to transform the battle against parasitic worm (helminth) infections, a major global health scourge from which billions are currently suffering. It is anticipated that the intersection of two currently disparate fields, nanomedicine and helminth biology, will constitute a new frontier in science and technology. This progress report surveys current innovations in these research fields and discusses research opportunities. In particular, the focus is on: (1) major challenges that helminth infections impose on mankind; (2) key aspects of helminth biology that inform future research directions; (3) efforts to construct nanodelivery platforms to target drugs and genes to helminths hidden in their hosts; (4) attempts in applying nanotechnology to enable vaccination against helminth infections; (5) outlooks in utilizing nanoparticles to enhance immunomodulatory activities of worm-derived factors to cure allergy and autoimmune diseases. In each section, achievements are summarized, limitations are explored, and future directions are assessed.

Suppression of Th1 and Th17 Responses and Induction of Treg Responses by IL-18-Expressing Plasmid Gene Combined with IL-4 on Collagen-Induced Arthritis

OBJECTIVES

IL-18 is a proinflammatory cytokine with multiple immunoregulatory properties. We studied the effect of IL-18 gene therapy on the development of murine collagen-induced arthritis (CIA).

METHODS

Plasmid pCAGGS-IL-18 along or in combination with IL-10 or IL-4 was administered to CIA mice. The incidence and severity of arthritis of the paws were determined by a visual scale. Joint destruction was determined by histology. The levels of a panel of cytokines and transcription factors in the synovium were determined by reverse transcription polymerase chain reaction and quantitative RT-PCR. Quantitative RT-PCR was employed to detect the mRNA expression of TLRs and their pathway on the surface of DCs.

RESULTS

IL-18 gene therapy had no therapeutic effect on CIA mice. Additional coadministration with low dosage of recombinant IL-4 ameliorated the disease progression. Histopathological examination of the joints showed intact cartilage surface in IL-18 gene combined with IL-4-treated mice. The synovium of IL-18 gene combined with rIL4-treated mice had lower expression of TNF-α, IFN-γ, and IL-17 and higher expression of IL-10. The mechanism of this response appeared to involve modulation of transcription factors FoxP3 and GATA-3. The DCs in the spleen and lymph nodes of IL-18 gene combined with rIL4-treated mice had lower expression of TLR2, MyD88, and NF-kB.

CONCLUSIONS

Our findings indicate that pIL-18 gene combined with IL-4 ameliorates arthritis in the CIA mouse by suppression of Th1 and Th17 cytokines and increasing expression of FoxP3 and GATA-3. The plasmid backbone and multiple immunoregulatory properties of IL-18 appear to play a major role in the pIL-18 coadministration with rIL-4-mediated immunomodulation of arthritis through blocking the TLR2/MyD88/NF-kappa B signaling pathway.

Fasciola and fasciolosis in ruminants in Europe: Identifying research needs

Fasciola hepatica is a trematode parasite with a global distribution, which is responsible for considerable disease and production losses in a range of food producing species. It is also identified by WHO as a re-emerging neglected tropical disease associated with endemic and epidemic outbreaks of disease in human populations. In Europe, F. hepatica is mostly associated with disease in sheep, cattle and goats. This study reviews the most recent advances in our understanding of the transmission, diagnosis, epidemiology and the economic impact of fasciolosis. We also focus on the impact of the spread of resistance to anthelmintics used to control F. hepatica and consider how vaccines might be developed and applied in the context of the immune-modulation driven by the parasite. Several major research gaps are identified which, when addressed, will contribute to providing focussed and where possible, bespoke, advice for farmers on how to integrate stock management and diagnosis with vaccination and/or targeted treatment to more effectively control the parasite in the face of increasing the prevalence of infection and spread of anthelmintic resistance that are likely to be exacerbated by climate change.

Helminth Infections: Recognition and Modulation of the Immune Response by Innate Immune Cells

The survival of helminths in the host over long periods of time is the result of a process of adaptation or dynamic co-evolution between the host and the parasite. However, infection with helminth parasites causes damage to the host tissues producing the release of danger signals that induce the recruitment of various cells, including innate immune cells such as macrophages (Mo), dendritic cells (DCs), eosinophils, basophils, and mast cells. In this scenario, these cells are able to secrete soluble factors, which orchestrate immune effector mechanisms that depend on the different niches these parasites inhabit. Here, we focus on recent advances in the knowledge of excretory-secretory products (ESP), resulting from helminth recognition by DCs and Mo. Phagocytes and other cells types such as innate lymphocyte T cells 2 (ILC2), when activated by ESP, participate in an intricate cytokine network to generate innate and adaptive Th2 responses. In this review, we also discuss the mechanisms of innate immune cell-induced parasite killing and the tissue repair necessary to assure helminth survival over long periods of time.

Parasite-Derived Proteins for the Treatment of Allergies and Autoimmune Diseases

The morbidity associated with atopic diseases and immune dysregulation disorders such as asthma, food allergies, multiple sclerosis, atopic dermatitis, type 1 diabetes mellitus, and inflammatory bowel disease has been increasing all around the world over the past few decades. Although the roles of non-biological environmental factors and genetic factors in the etiopathology have been particularly emphasized, they do not fully explain the increase; for example, genetic factors in a population change very gradually. Epidemiological investigation has revealed that the increase also parallels a decrease in infectious diseases, especially parasitic infections. Thus, the reduced prevalence of parasitic infections may be another important reason for immune dysregulation. Parasites have co-evolved with the human immune system for a long time. Some parasite-derived immune-evasion molecules have been verified to reduce the incidence and harmfulness of atopic diseases in humans by modulating the immune response. More importantly, some parasite-derived products have been shown to inhibit the progression of inflammatory diseases and consequently alleviate their symptoms. Thus, parasites, and especially their products, may have potential applications in the treatment of autoimmune diseases. In this review, the potential of parasite-derived products and their analogs for use in the treatment of atopic diseases and immune dysregulation is summarized.

Triggering immunological memory against the tapeworm Hymenolepis diminuta to protect against colitis

Infection with parasitic helminths can ameliorate the severity of concomitant inflammatory disease. To use the tapeworm, Hymenolepis diminuta, and to extend this concept by assessing whether triggering a memory response against the worm inhibits dinitrobenzene sulphonic acid (DNBS)-induced colitis in Balb/c mice. Initial studies revealed that oral infection with 1, 3 or 5 H. diminuta cysticercoids 8 days before intrarectal administration of DNBS (3 mg) resulted in less severe inflammation and that infected mice displayed an increased propensity for T helper-2 immunity. A 1 mg dose of a PBS-soluble extract of the worm (HdAg) delivered intraperitoneally concomitant with DNBS was anticolitic as determined by macroscopic and histological disease scores 72 hour post-DNBS. Mice infected 28 days previously had a memory response as determined by HdAg-evoked increases in interleukin (IL)-4 and IL-10 from in vitro stimulated splenocytes and serum anti-H. diminuta IgG. Moreover, mice infected with 5 H. diminuta 28 days previously were protected from DNBS-induced colitis by secondary infection or 100 μg HdAg (ip.) at the time of DNBS treatment. An additional approach to managing inflammatory disease could be infection with H. diminuta followed by eliciting antiworm recall responses.

Heme-Oxygenase-1 Expression Contributes to the Immunoregulation Induced by Fasciola hepatica and Promotes Infection

Fasciola hepatica, also known as the liver fluke, is a trematode that infects livestock and humans causing fasciolosis, a zoonotic disease of increasing importance due to its worldwide distribution and high economic losses. This parasite immunoregulates the host immune system by inducing a strong Th2 and regulatory T immune response by immunomodulating dendritic cell (DC) maturation and alternative activation of macrophages. In this paper, we show that F. hepatica infection in mice induces the upregulation of heme-oxygenase-1 (HO-1), the rate-limiting enzyme in the catabolism of free heme that regulates the host inflammatory response. We show and characterize two different populations of antigen presenting cells that express HO-1 during infection in the peritoneum of infected animals. Cells that expressed high levels of HO-1 expressed intermediate levels of F4/80 but high expression of CD11c, CD38, TGFβ, and IL-10 suggesting that they correspond to regulatory DCs. On the other hand, cells expressing intermediate levels of HO-1 expressed high levels of F4/80, CD68, Ly6C, and FIZZ-1, indicating that they might correspond to alternatively activated macrophages. Furthermore, the pharmacological induction of HO-1 with the synthetic metalloporphyrin CoPP promoted F. hepatica infection increasing the clinical signs associated with the disease. In contrast, treatment with the HO-1 inhibitor SnPP protected mice from parasite infection, indicating that HO-1 plays an essential role during F. hepatica infection. Finally, HO-1 expression during F. hepatica infection was associated with TGFβ and IL-10 levels in liver and peritoneum, suggesting that HO-1 controls the expression of these immunoregulatory cytokines during infection favoring parasite survival in the host. These results contribute to the elucidation of the immunoregulatory mechanisms induced by F. hepatica in the host and provide alternative checkpoints to control fasciolosis.

Can Parasitic Worms Cure the Modern World's Ills?

There has been increasing recognition that the alarming surge in allergy and autoimmunity in the industrialised and developing worlds shadows the rapid eradication of pathogens, such as parasitic helminths. Appreciation of this has fuelled an explosion in research investigating the therapeutic potential of these worms. This review considers the current state-of-play with a particular focus on exciting recent advances in the identification of potential novel targets for immunomodulation that can be exploited therapeutically. Furthermore, we contemplate the prospects for designing worm-derived immunotherapies for an ever-widening range of inflammatory diseases, including, for example, obesity, cardiovascular disease, and ageing as well as neurodevelopmental disorders like autism.

Dendritic cells provide a therapeutic target for synthetic small molecule analogues of the parasitic worm product, ES-62

ES-62, a glycoprotein secreted by the parasitic filarial nematode Acanthocheilonema viteae, subverts host immune responses towards anti-inflammatory phenotypes by virtue of covalently attached phosphorylcholine (PC). The PC dictates that ES-62 exhibits protection in murine models of inflammatory disease and hence a library of drug-like PC-based small molecule analogues (SMAs) was synthesised. Four sulfone-containing SMAs termed 11a, 11e, 11i and 12b were found to reduce mouse bone marrow-derived dendritic cell (DC) pathogen-associated molecular pattern (PAMP)-induced pro-inflammatory cytokine production, inhibit NF-κB p65 activation, and suppress LPS-induced up-regulation of CD40 and CD86. Active SMAs also resulted in a DC phenotype that exhibited reduced capacity to prime antigen (Ag)-specific IFN-γ production during co-culture with naïve transgenic TCR DO.11.10 T cells in vitro and reduced their ability, following adoptive transfer, to prime the expansion of Ag-specific T lymphocytes, specifically TH17 cells, in vivo. Consistent with this, mice receiving DCs treated with SMAs exhibited significantly reduced severity of collagen-induced arthritis and this was accompanied by a significant reduction in IL-17+ cells in the draining lymph nodes. Collectively, these studies indicate that drug-like compounds that target DCs can be designed from parasitic worm products and demonstrate the potential for ES-62 SMA-based DC therapy in inflammatory disease.

Suppression of colitis by adoptive transfer of helminth antigen-treated dendritic cells requires interleukin-4 receptor-α signaling

Infection with helminth parasites has been explored as a treatment for autoimmune and inflammatory diseases. As helminth antigens have potent immunomodulation properties capable of inducing regulatory programs in a variety of cell types, transferring cells treated with helminth antigens represents a novel extension to helminth therapy. Previous work determined that transfer of bone marrow-derived dendritic cells (DC) pulsed with a crude extract of the tapeworm Hymenolepis diminuta (HD) can suppress colitis in recipient mice. The present study explored the mechanism of disease suppression and the importance of interleukin (IL)-4 signaling. Transfer of HD-DCs suppressed dinitrobenzene sulfonic acid (DNBS)-induced colitis through activation of recipient IL-4 receptor-α. The transferred HD-DCs required IL-4Rα and the capacity to secrete IL-10 to drive IL-4 and IL-10 production and to suppress colitis in recipient mice. Treatment of DCs with IL-4 evokes an alternatively activated phenotype, but adoptive transfer of these cells did not affect the outcome of colitis. Collectively, these studies demonstrate the complexity between IL-4 and IL-10 in donor cells and recipient, and the requirement for parasite- and host-derived factors in this novel form of cell therapy. Thus IL-4Rα signaling is revealed as a pathway that could be exploited for helminth antigen cell-based therapy.

Helminth Regulation of Immunity: A Three-pronged Approach to Treat Colitis

By reputation, the parasite is a pariah, an unwelcome guest. Infection with helminth parasites evokes stereotypic immune responses in humans and mice that are dominated by T helper (Th)-2 responses; thus, a hypothesis arises that infection with helminths would limit immunopathology in concomitant inflammatory disease. Although infection with some species of helminths can cause devastating disease and affect the course of microbial infections, analyses of rodent models of inflammatory disease reveal that infection with helminth parasites, or treatment with helminth extracts, can limit the severity of autoinflammatory disease, including colitis. Intriguing, but fewer, studies show that adoptive transfer of myeloid immune cells treated with helminth products/extracts in vitro can suppress inflammation. Herein, 3 facets of helminth therapy are reviewed and critiqued: treatment with viable ova or larvae, treatment with crude extracts of the worm or purified molecules, and cellular immunotherapy. The beneficial effect of helminth therapy often converges on the mobilization of IL-10 and regulatory/alternatively activated macrophages, while there are reports on transforming growth factor (TGF)-β, regulatory T cells and dendritic cells, and recent data suggest that helminth-evoked changes in the microbiota should be considered when defining anticolitic mechanisms. We speculate that if the data from animal models translate to humans, noting the heterogeneity therein, then the choice between use of viable helminth ova, helminth extracts/molecules or antigen-pulsed immune cells could be matched to disease management in defined cohorts of patients with inflammatory bowel disease.

Parasitic infection as a potential therapeutic tool against rheumatoid arthritis

Parasites, which are a recently discovered yet ancient dweller in human hosts, remain a great public health burden in underdeveloped countries, despite preventative efforts. Rheumatoid arthritis is a predominantly cosmopolitan health problem with drastic morbidity rates, although encouraging progress has been achieved regarding treatment. However, although various types of methods and agents have been applied clinically, their broad usage has been limited by their adverse effects and/or high costs. Sustained efforts have been exerted on the 'hygiene hypothesis' since the 1870s. The immunosuppressive nature of parasitic infections may offer potential insight into therapeutic strategies for rheumatoid arthritis, in which the immune system is overactivated. An increasing number of published papers are focusing on the preventive and/or curative effect of various parasitic infection on rheumatoid arthritis from experimental studies to large-scale epidemiological studies and clinical trials. Therefore, the present review aimed to provide a general literature review on the possible beneficial role of parasitic infection on rheumatoid arthritis.

Gene Therapy Induces Antigen-Specific Tolerance in Experimental Collagen-Induced Arthritis

Here, we investigate induction of immunological tolerance by lentiviral based gene therapy in a mouse model of rheumatoid arthritis, collagen II-induced arthritis (CIA). Targeting the expression of the collagen type II (CII) to antigen presenting cells (APCs) induced antigen-specific tolerance, where only 5% of the mice developed arthritis as compared with 95% of the control mice. In the CII-tolerized mice, the proportion of Tregs as well as mRNA expression of SOCS1 (suppressors of cytokine signaling 1) increased at day 3 after CII immunization. Transfer of B cells or non-B cell APC, as well as T cells, from tolerized to naïve mice all mediated a certain degree of tolerance. Thus, sustainable tolerance is established very early during the course of arthritis and is mediated by both B and non-B cells as APCs. This novel approach for inducing tolerance to disease specific antigens can be used for studying tolerance mechanisms, not only in CIA but also in other autoimmune diseases.

Helminth Products Protect against Autoimmunity via Innate Type 2 Cytokines IL-5 and IL-33, Which Promote Eosinophilia

Epidemiologic studies in humans have demonstrated that infection with helminth parasites is associated with a reduced risk of developing autoimmune diseases. Mechanistic studies in mice have linked the protective effect of helminths on autoimmunity to the suppressive activity of helminth-induced regulatory T cells (Tregs) or Th2 cells. In this study, we demonstrate that treatment of mice with Fasciola hepatica excretory-secretory products (FHES) attenuated the clinical signs of experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis. Protection was associated with a significant reduction in the infiltration of pathogenic Th1 and Th17 cells into the brain. Although FHES enhanced anti-inflammatory cytokine and Th2 responses, protection against EAE was independent of IL-4, IL-10, and Tregs. However, administration of FHES induced production of the type 2 cytokines IL-33 and IL-5, which promoted accumulation of eosinophils. FHES-induced expansion of eosinophils and protection against EAE was lost in IL-33(-/-) mice and upon neutralization of IL-5. Furthermore, transfer of FHES-induced or IL-33-induced eosinophils conferred protection against EAE. In addition, treatment of mice with recombinant IL-33 attenuated autoimmunity, and this was dependent on IL-5. To our knowledge, this study is the first to report a role for helminth-induced IL-5 and IL-33 in protection against autoimmunity.

Adoptive transfer of helminth antigen-pulsed dendritic cells protects against the development of experimental colitis in mice

Infection with helminth parasites and treatment with worm extracts can suppress inflammatory disease, including colitis. Postulating that dendritic cells (DCs) participated in the suppression of inflammation and seeking to move beyond the use of helminths per se, we tested the ability of Hymenolepis diminuta antigen-pulsed DCs to suppress colitis as a novel cell-based immunotherapy. Bone marrow derived DCs pulsed with H. diminuta antigen (HD-DCs), or PBS-, BSA-, or LPS-DCs as controls, were transferred into wild-type (WT), interleukin-10 (IL-10) knock-out (KO), and RAG-1 KO mice, and the impact on dinitrobenzene sulphonic acid (DNBS)-induced colitis and splenic cytokine production assessed 72 h later. Mice receiving HD-DCs were significantly protected from DNBS-induced colitis and of the experimental groups only these mice displayed increased Th2 cytokines and IL-10 production. Adoptive transfer of HD-DCs protected neither RAG-1 nor IL-10 KO mice from DNBS-colitis. Furthermore, the transfer of CD4(+) splenocytes from recipients of HD-DCs protected naïve mice against DNBS-colitis, in an IL-10 dependent manner. Thus, HD-DCs are a novel anti-colitic immunotherapy that can educate anti-colitic CD4(+) T cells: mechanistically, the anti-colitic effect of HD-DCs requires that the host has an adaptive immune response and the ability to mobilize IL-10.

Toll-Like Receptor Gene Expression during Trichinella spiralis Infection

In Trichinella spiralis infection, type 2 helper T (Th2) cell-related and regulatory T (Treg) cell-related immune responses are the most important immune events. In order to clarify which Toll-like receptors (TLRs) are closely associated with these responses, we analyzed the expression of mouse TLR genes in the small intestine and muscle tissue during T. spiralis infection. In addition, the expression of several chemokine- and cytokine-encoding genes, which are related to Th2 and Treg cell mediated immune responses, were analyzed in mouse embryonic fibroblasts (MEFs) isolated from myeloid differentiation factor 88 (MyD88)/TIR-associated proteins (TIRAP) and Toll receptor-associated activator of interferons (TRIF) adapter protein deficient and wild type (WT) mice. The results showed significantly increased TLR4 and TLR9 gene expression in the small intestine after 2 weeks of T. spiralis infection. In the muscle, TLR1, TLR2, TLR5, and TLR9 gene expression significantly increased after 4 weeks of infection. Only the expression of the TLR4 and TLR9 genes was significantly elevated in WT MEF cells after treatment with excretory-secretory (ES) proteins. Gene expression for Th2 chemokine genes were highly enhanced by ES proteins in WT MEF cells, while this elevation was slightly reduced in MyD88/TIRAP(-/-) MEF cells, and quite substantially decreased in TRIF(-/-) MEF cells. In contrast, IL-10 and TGF-β expression levels were not elevated in MyD88/TIRAP(-/-) MEF cells. In conclusion, we suggest that TLR4 and TLR9 might be closely linked to Th2 cell and Treg cell mediated immune responses, although additional data are needed to convincingly prove this observation.

Unraveling the Hygiene Hypothesis of helminthes and autoimmunity: origins, pathophysiology, and clinical applications

BACKGROUND

The Hygiene Hypothesis (HH) attributes the dramatic increase in autoimmune and allergic diseases observed in recent decades in Western countries to the reduced exposure to diverse immunoregulatory infectious agents. This theory has since largely been supported by strong epidemiological and experimental evidence.

DISCUSSION

The analysis of these data along with the evolution of the Western world's microbiome enable us to obtain greater insight into microorganisms involved in the HH, as well as their regulatory mechanisms on the immune system. Helminthes and their derivatives were shown to have a protective role. Helminthes' broad immunomodulatory properties have already begun to be exploited in clinical trials of autoimmune diseases, including inflammatory bowel disease, multiple sclerosis, rheumatoid arthritis, and type-1 diabetes.

SUMMARY

In this review, we will dissect the microbial actors thought to be involved in the HH as well as their immunomodulatory mechanisms as emphasized by experimental studies, with a particular attention on parasites. Thereafter, we will review the early clinical trials using helminthes' derivatives focusing on autoimmune diseases.

Anti-Inflammatory Effects and Joint Protection in Collagen-Induced Arthritis after Treatment with IQ-1S, a Selective c-Jun N-Terminal Kinase Inhibitor

c-Jun N-terminal kinases (JNKs) participate in many physiologic and pathologic processes, including inflammatory diseases. We recently synthesized the sodium salt of IQ-1S (11H-indeno[1,2-b]quinoxalin-11-one oxime) and demonstrated that it is a high-affinity JNK inhibitor and inhibits murine delayed-type hypersensitivity. Here we show that IQ-1S is highly specific for JNK and that its neutral form is the most abundant species at physiologic pH. Molecular docking of the IQ-1S syn isomer into the JNK1 binding site gave the best pose, which corresponded to the position of cocrystallized JNK inhibitor SP600125 (1,9-pyrazoloanthrone). Evaluation of the therapeutic potential of IQ-1S showed that it inhibited matrix metalloproteinase 1 and 3 gene expression induced by interleukin-1β in human fibroblast-like synoviocytes and significantly attenuated development of murine collagen-induced arthritis (CIA). Treatment with IQ-1S either before or after induction of CIA resulted in decreased clinical scores, and joint sections from IQ-1S-treated CIA mice exhibited only mild signs of inflammation and minimal cartilage loss compared with those from control mice. Collagen II-specific antibody responses were also reduced by IQ-1S treatment. By contrast, the inactive ketone derivative 11H-indeno[1,2-b]quinoxalin-11-one had no effect on CIA clinical scores or collagen II-specific antibody titers. IQ-1S treatment also suppressed proinflammatory cytokine and chemokine levels in joints and lymph node cells. Finally, treatment with IQ-1S increased the number of Foxp3(+)CD4(+)CD25(+) regulatory T cells in lymph nodes. Thus, IQ-1S can reduce inflammation and cartilage loss associated with CIA and can serve as a small-molecule modulator for mechanistic studies of JNK function in rheumatoid arthritis.

Fasciola hepatica Kunitz type molecule decreases dendritic cell activation and their ability to induce inflammatory responses

The complete repertoire of proteins with immunomodulatory activity in Fasciola hepatica (Fh) has not yet been fully described. Here, we demonstrated that Fh total extract (TE) reduced LPS-induced DC maturation, and the DC ability to induce allogeneic responses. After TE fractionating, a fraction lower than 10 kDa (F<10 kDa) was able to maintain the TE properties to modulate the DC pro- and anti-inflammatory cytokine production induced by LPS. In addition, TE or F<10 kDa treatment decreased the ability of immature DC to stimulate the allogeneic responses and induced a novo allogeneic CD4+CD25+Foxp3+ T cells. In contrast, treatment of DC with T/L or F<10 kDa plus LPS (F<10/L) induced a regulatory IL-27 dependent mechanism that diminished the proliferative and Th1 and Th17 allogeneic responses. Finally, we showed that a Kunitz type molecule (Fh-KTM), present in F<10 kDa, was responsible for suppressing pro-inflammatory cytokine production in LPS-activated DC, by printing tolerogenic features on DC that impaired their ability to induce inflammatory responses. These results suggest a modulatory role for this protein, which may be involved in the immune evasion mechanisms of the parasite.

Induction of regulatory cells by helminth parasites: exploitation for the treatment of inflammatory diseases

Helminth parasites are highly successful pathogens, chronically infecting a quarter of the world's population, causing significant morbidity but rarely causing death. Protective immunity and expulsion of helminths is mediated by T-helper 2 (Th2) cells, type 2 (M2) macrophages, type 2 innate lymphoid cells, and eosinophils. Failure to mount these type 2 immune responses can result in immunopathology mediated by Th1 or Th17 cells. Helminths have evolved a wide variety of approaches for immune suppression, especially the generation of regulatory T cells and anti-inflammatory cytokines interleukin-10 and transforming growth factor-β. This is a very effective strategy for subverting protective immune responses to prolong their survival in the host but has the bystander effect of modulating immune responses to unrelated antigens. Epidemiological studies in humans have shown that infection with helminth parasites is associated with a low incidence of allergy/asthma and autoimmunity in developing countries. Experimental studies in mice have demonstrated that regulatory immune responses induced by helminth can suppress Th2 and Th1/Th17 responses that mediate allergy and autoimmunity, respectively. This has provided a rational explanation of the 'hygiene hypothesis' and has also led to the exploitation of helminths or their immunomodulatory products in the development of new immunosuppressive therapies for inflammatory diseases in humans.

Helminth infections decrease host susceptibility to immune-mediated diseases

Helminthic infection has become rare in highly industrialized nations. Concurrent with the decline in helminthic infection has been an increase in the prevalence of inflammatory disease. Removal of helminths from our environment and their powerful effects on host immunity may have contributed to this increase. Several helminth species can abrogate disease in murine models of inflammatory bowel disease, type 1 diabetes, multiple sclerosis, and other conditions. Helminths evoke immune regulatory pathways often involving dendritic cells, regulatory T cells, and macrophages that help to control disease. Cytokines, such as IL-4, IL-10, and TGF-β, have a role. Notable is the helminthic modulatory effect on innate immunity, which impedes development of aberrant adaptive immunity. Investigators are identifying key helminth-derived immune modulatory molecules that may have therapeutic usefulness in the control of inflammatory disease.

The mechanisms behind helminth's immunomodulation in autoimmunity

The incidence of autoimmune diseases has risen throughout the last half a century, mostly in the industrialized world. Helminths and their derivatives were found to have a protective role in autoimmunity and inflammatory conditions, as they manipulate the immune network, attenuating the host's cellular and humoral responses. Indeed, various helminth species used in several human and animal models were shown to limit inflammatory activity in a variety of diseases including inflammatory bowel disease, multiple sclerosis, type 1 diabetes, and rheumatoid arthritis. Our review will focus on the main mechanisms by which helminths and their secreted molecules modulate the host's immune system. The main pathways induce a shift from Th1 to Th2 phenotype, accelerate T regulatory and B regulatory phenotypes, and attenuate the levels of the inflammatory cytokines, leading to a tolerable scenario.

Reciprocal effects of Schistosoma mansoni infection on spontaneous autoimmune arthritis in IL-1 receptor antagonist-deficient mice

Schistosome infections have been shown to prevent inflammation in induced-type arthritis models. However, its effects on spontaneous arthritis remain unknown. We here investigated the effects of Schistosoma mansoni (Sm) infection on spontaneous autoimmune arthritis in IL-1 receptor antagonist (IL-1Ra)-deficient mice. Sm infection partially reduced the severity of arthritis in male IL-1Ra-deficient mice. The splenic responses of IL-17 and TNF-α were reduced, while those of IL-4 and IL-10 were enhanced by the infection. However, Sm infection increased IgG rheumatoid factor and anti-dsDNA IgG serum levels. These results suggest that Sm infection has both ameliorating and exacerbating effects on autoimmunity in IL-1Ra-deficient mice.

In vivo expression of recombinant pregnancy-specific glycoprotein 1a inhibits the symptoms of collagen-induced arthritis

PROBLEM

The contribution of Pregnancy-specific glycoproteins (PSG), the major variant of PSG released into the circulation during pregnancy, to the pregnancy-dependent improvement of rheumatoid arthritis (RA) has still not been elucidated.

METHOD OF STUDY

Collagen-induced arthritis (CIA) was used to test the hypothesis that PSG1a when released into circulation has a modulatory role on the Th1-pathogenic response, thus improving the CIA symptoms. In vivo expression of PSG1a was induced by injection of the vaccinia (Vac)-based expression vector harboring the complete open-reading frame of PSG1a cDNA.

RESULTS

In vivo PSG1a expression during the induction of CIA ameliorated the clinical symptoms, thereby reducing the arthritis score and incidence. Significantly lower levels of IL-17, IL-6, and IFN-γ, but higher levels of TGF-β and IL-10 were secreted by collagen type II-stimulated spleen mononuclear cells from Vac-PSG1a-treated mice compared with control mice. Moreover, Vac-PSG1a treatment promoted the increase in splenic CD4+CD25+Foxp3+ Treg cells.

CONCLUSION

Pre-clinical Vac-PSG1a treatment suppressed the Th1- and Th17-type-specific responses, leading to an increase in splenic Treg cells as well as IL-10- and TGF-β-secreting cells, with the CIA symptoms being ameliorated.

Review: Genetics of helminth resistance in sheep

Karrow, N. A., Goliboski, K., Stonos, N., Schenkel, F. and Peregrine, A. 2014. Review: Genetics of helminth resistance in sheep. Can. J. Anim. Sci. 94: 1–9. Gastrointestinal helminth parasites are an important source of economic loss to sheep producers. A rapid increase in anthelmintic resistance has occurred around the globe; therefore, the industry is exploring alternative strategies such as genetic selection to control losses attributed to helminth infection. Since helminths have co-evolved with sheep for millions of years, natural selection for enhanced helminth resistance has occurred within certain breeds from various parts of the world. These breeds of sheep are being used to better understand the genetic aspects of helminth resistance. If the genetic variants that contribute to this phenotype can be identified, it may be possible to use selection strategies to introduce resistance alleles into other breeds or to increase their frequency within breeds. This review will provide an up-to-date overview of the pathology of helminth disease, the immune response to helminth infection, and the search for genes that confer helminth resistance.

Effect of bone marrow-derived CD11b(+)F4/80 (+) immature dendritic cells on the balance between pro-inflammatory and anti-inflammatory cytokines in DBA/1 mice with collagen-induced arthritis

OBJECTIVE

To explore the effect of bone marrow-derived CD11b(+)F4/80(+) immature dendritic cells (BM CD11b(+)F4/80(+)iDC) on the balance between pro-inflammatory and anti-inflammatory cytokines in DBA/1 mice with collagen-induced arthritis (CIA).

METHODS

BM CD11b(+)F4/80(+)iDC were induced with rmGM-CSF and rmIL-4, and were identified by the expressions of toll-like receptor 2 (TLR-2), indoleamine 2,3-deoxygenase (IDO), interleukin (IL)-10, transforming growth factor (TGF)-β1 and mixed leukocyte reaction (MLR). CIA was established in DBA/1 mice by immunization with type II collagen. CIA mice were injected intravenously with BM CD11b(+)F4/80(+)iDC three times after immunization. The effect of BM CD11b(+)F4/80(+)iDC on CIA was evaluated by the arthritis index, joint histopathology, body weight, thymus index, thymocytes proliferation, IL-1β, tumor necrosis factor (TNF)-α, IL-17, IL-10 and TGF-β1 levels.

RESULTS

BM CD11b(+)F4/80(+)iDC induced with rmGM-CSF and rmIL-4 expressed high levels of TLR-2, IDO, IL-10 and TGF-β1. Infusion of BM CD11b(+)F4/80(+)iDC in CIA mice significantly reduced the arthritis index and pathological scores of joints, recovered the weight, decreased the thymus index and inhibited thymocyte proliferation. Levels of IL-1β, TNF-α and IL-17 were decreased in BM CD11b(+)F4/80(+)iDC-treated mice.

CONCLUSIONS

BM CD11b(+)F4/80(+)iDC can be induced successfully with rmGM-CSF and rmIL-4. BM CD11b(+)F4/80(+)iDC treatment can ameliorate the development and severity of CIA by regulating the balance between pro-inflammatory cytokines and anti-inflammatory cytokines.

Dendritic cells treated with chloroquine modulate experimental autoimmune encephalomyelitis

Chloroquine (CQ), an antimalarial drug, has been shown to modulate the immune system and reduce the severity of experimental autoimmune encephalomyelitis (EAE). The mechanisms of disease suppression are dependent on regulatory T cell induction, although Tregs-independent mechanisms exist. We aimed to evaluate whether CQ is capable to modulate bone marrow-derived dendritic cells (DCs) both phenotypically and functionally as well as whether transfer of CQ-modulated DCs reduces EAE course. Our results show that CQ-treated DCs presented altered ultrastructure morphology and lower expression of molecules involved in antigen presentation. Consequently, T cell proliferation was diminished in coculture experiments. When transferred into EAE mice, DC-CQ was able to reduce the clinical manifestation of the disease through the modulation of the immune response against neuroantigens. The data presented herein indicate that chloroquine-mediated modulation of the immune system is achieved by a direct effect on DCs and that DC-CQ adoptive transfer may be a promising approach for avoiding drug toxicity.

Tolerogenic dendritic cells as a therapy for treating lupus

Systemic lupus erythematosus (SLE) is a chronic autoimmune disorder that is characterized by the over production of auto-antibodies against nuclear components. Thus, SLE patients have increased morbidity and, mortality compared to healthy individuals. Available therapies are not curative and are associated with unwanted adverse effects. During the last few years, important advances in immunology research have provided rheumatologists with new tools for designing novel therapies for treating autoimmunity. However, the complex nature of SLE has played a conflicting role, hindering breakthroughs in therapeutic development. Nonetheless, new advances about SLE pathogenesis could open a fruitful line of research. Dendritic cells (DCs) have been established as essential players in the mechanisms underlying SLE, making them attractive therapeutic targets for fine-tuning the immune system. In this review, we discuss the recent advances made in revealing the mechanisms of SLE pathogenesis, with a focus on the use of DCs as a target for therapy development.

Immunomodulation by helminth parasites: defining mechanisms and mediators

Epidemiological and interventional human studies, as well as experiments in animal models, strongly indicate that helminth parasitic infections can confer protection from immune dysregulatory diseases such as allergy, autoimmunity and colitis. Here, we review the immunological pathways that helminths exploit to downregulate immune responses, both against bystander specificities such as allergens and against antigens from the parasites themselves. In particular, we focus on a highly informative laboratory system, the mouse intestinal nematode, Heligmosomoides polygyrus, as a tractable model of host-parasite interaction at the cellular and molecular levels. Analysis of the molecules released in vitro (as excretory-secretory products) and their cellular targets is identifying individual parasite molecules and gene families implicated in immunomodulation, and which hold potential for future human therapy of immunopathological conditions.