Immune modulation by Schistosoma mansoni antigens in NOD mice: effects on both innate and adaptive immune systems

Schistosoma-related molecules as a new strategy to combat type 1 diabetes through immune regulation

The study of immune regulation mechanisms induced by parasites may help develop new treatment methods for inflammatory diseases including type 1 diabetes, which is related to type 1 immune responses. The negative correlation between schistosomiasis infection and type 1 diabetes has been confirmed, and the mechanism of Schistosoma-mediated prevention of type 1 diabetes may be related to the adaptive and innate immune systems. Schistosoma-related molecules affect immune cell composition and macrophage polarization and stimulate an increase in natural killer T cells. Furthermore, Schistosoma-related molecules can regulate the adaptive immune responses related to the prevention of type 1 diabetes and change the Th1/Th2 and Th17/Treg axis. Our previous review showed the role of regulatory T cells in the protective of type 1 diabetes mediated by Schistosoma. Here, we aim to review the other mechanisms of schistosomiasis infection and Schistosoma-related products in regulating the immune response associated with the treatment of type 1 diabetes.

Microbes little helpers and suppliers for therapeutic asthma approaches

Bronchial asthma is a prevalent and increasingly chronic inflammatory lung disease affecting over 300 million people globally. Initially considered an allergic disorder driven by mast cells and eosinophils, asthma is now recognized as a complex syndrome with various clinical phenotypes and immunological endotypes. These encompass type 2 inflammatory endotypes characterized by interleukin (IL)-4, IL-5, and IL-13 dominance, alongside others featuring mixed or non-eosinophilic inflammation. Therapeutic success varies significantly based on asthma phenotypes, with inhaled corticosteroids and beta-2 agonists effective for milder forms, but limited in severe cases. Novel antibody-based therapies have shown promise, primarily for severe allergic and type 2-high asthma. To address this gap, novel treatment strategies are essential for better control of asthma pathology, prevention, and exacerbation reduction. One promising approach involves stimulating endogenous anti-inflammatory responses through regulatory T cells (Tregs). Tregs play a vital role in maintaining immune homeostasis, preventing autoimmunity, and mitigating excessive inflammation after pathogenic encounters. Tregs have demonstrated their ability to control both type 2-high and type 2-low inflammation in murine models and dampen human cell-dependent allergic airway inflammation. Furthermore, microbes, typically associated with disease development, have shown immune-dampening properties that could be harnessed for therapeutic benefits. Both commensal microbiota and pathogenic microbes have demonstrated potential in bacterial-host interactions for therapeutic purposes. This review explores microbe-associated approaches as potential treatments for inflammatory diseases, shedding light on current and future therapeutics.

Effect of macrophage polarization on parasitic protection against type 1 diabetes mellitus

Type 1 diabetes mellitus is a chronic disease caused by the destruction of pancreatic beta cells. Based on the hygiene hypothesis, a growing body of evidence suggests a negative association between parasitic infections and diabetes in humans and animal models. The mechanism of parasite-mediated prevention of type 1 diabetes mellitus may be related to the adaptive and innate immune systems. Macrophage polarization is a new paradigm for the treatment of type 1 diabetes mellitus, and different host macrophage subsets play various roles during parasite infection. Proinflammatory cytokines are released by M1 macrophages, which are important in the development of type 1 diabetes mellitus. Parasite-activated M2 macrophages prevent the development of type 1 diabetes mellitus and can influence the development of adaptive immune responses through several mechanisms, including Th2 cells and regulatory T cells. Here, we review the role and mechanism of macrophage polarization in parasitic protection against type 1 diabetes mellitus.

The interaction of Schistosoma mansoni infection with diabetes mellitus and obesity in mice

Human schistosomiasis is one of the most prevalent parasitic diseases worldwide. Various host factors can affect the host-parasite interactions. Therefore, the aim of the present work was to determine the parasitological, histopathological, biochemical, and immunological status of Schistosoma mansoni-infected hosts with metabolic disorders to identify the underlying possible mechanisms of these comorbidities. The study animals were divided into four groups. Group I represented the control groups, namely, the normal control group, the S. mansoni-infected control group, and the noninfected type 1 diabetes (T1DM), type 2 diabetes (T2DM), and obesity groups. The mice of the other three groups underwent induction of T1DM (Group II), T2DM (Group III) and obesity (Group IV) before being infected with S. mansoni. All mice were subjected to body weight measurement, blood glucose and insulin assessment, parasitological evaluation of adult worm count, tissue egg count and intestinal oogram. Histopathological and immunohistochemical study using anti-glial fibrillary acidic protein (GFAP) in hepatic stellate cells (HSCs) and image analysis of Masson's trichrome-stained liver sections using ImageJ (Fiji) software were carried out. Additionally, immunological analysis of tumour necrosis factor (TNF) beta, interleukin-5 (IL-5), IL-10, Forkhead box P3 (FOXP3) and pentraxin 3 (PTX3) levels besides biochemical study of total lipid profile were evaluated. The present study revealed a significant increase in the adult worm count and tissue egg output in the obesity group compared to the infected control group. The oogram of counted eggs showed prevalence of immature eggs in T1DM group, while T2DM and obese groups showed prevalence of mature eggs. The fibrosis area percentage showed significant increase in T2DM and obese groups while it was decreased in T1DM group in comparison to infected control group. Our data also showed significant increase in the levels of TNF-β, IL-5, PTX3 in T1DM, T2DM and obesity groups in comparison to infected control group, whilst the levels of FOXP3 and IL-10 were increased in the infected groups in comparison to their noninfected controls. Moreover, infected T1DM, T2DM and obesity groups showed higher blood glucose and lipid profile in comparison to the infected control group. However, these parameters were improved in comparison to their noninfected controls. In sum, induction of T2DM and obesity increased tissue egg counts, mature egg percentage, and fibrosis density, while schistosome infection induced changes in the lipid profile and blood glucose levels in infected diabetic and obese groups and impacted favorably insulin levels in obese mice. By better understanding the complexities of host-parasite interactions, efforts to reduce the burden of these debilitating diseases can be improved.

Immunotherapy for type 1 diabetes mellitus by adjuvant-free Schistosoma japonicum-egg tip-loaded asymmetric microneedle patch (STAMP)

Background

Type 1 diabetes mellitus (T1DM) is an autoimmune disease mediated by autoreactive T cells and dominated by Th1 response polarization. Insulin replacement therapy faces great challenges to this autoimmune disease, requiring highly frequent daily administration. Intriguingly, the progression of T1DM has proven to be prevented or attenuated by helminth infection or worm antigens for a relatively long term. However, the inevitable problems of low safety and poor compliance arise from infection with live worms or direct injection of antigens. Microneedles would be a promising candidate for local delivery of intact antigens, thus providing an opportunity for the clinical immunotherapy of parasitic products.

Methods

We developed a Schistosoma japonicum-egg tip-loaded asymmetric microneedle patch (STAMP) system, which serves as a new strategy to combat TIDM. In order to improve retention time and reduce contamination risk, a specific imperfection was introduced on the STAMP (asymmetric structure), which allows the tip to quickly separate from the base layer, improving reaction time and patient’s comfort. After loading Schistosoma japonicum-egg as the immune regulator, the effects of STAMP on blood glucose control and pancreatic pathological progression improvement were evaluated in vivo. Meanwhile, the immunoregulatory mechanism and biosafety of STAMP were confirmed by histopathology, qRT-PCR, ELISA and Flow cytometric analysis.

Results

Here, the newly developed STAMP was able to significantly reduce blood glucose and attenuate the pancreatic injury in T1DM mice independent of the adjuvants. The isolated Schistosoma japonicum-eggs micron slowly degraded in the skin and continuously released egg antigen for at least 2 weeks, ensuring localization and safety of antigen stimulation. This phenomenon should be attributed to the shift of Th2 immune response to reduce Th1 polarization.

Conclusion

Our results exhibited that STAMP could significantly regulate the blood glucose level and attenuate pancreatic pathological injury in T1DM mice by balancing the Th1/Th2 immune responses, which is independent of adjuvants. This technology opens a new window for the application of parasite products in clinical immunotherapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12951-022-01581-9.

Administration of Hookworm Excretory/Secretory Proteins Improves Glucose Tolerance in a Mouse Model of Type 2 Diabetes

Diabetes is recognised as the world’s fastest growing chronic condition globally. Helminth infections have been shown to be associated with a lower prevalence of type 2 diabetes (T2D), in part due to their ability to induce a type 2 immune response. Therefore, to understand the molecular mechanisms that underlie the development of T2D-induced insulin resistance, we treated mice fed on normal or diabetes-promoting diets with excretory/secretory products (ES) from the gastrointestinal helminth Nippostrongylus brasiliensis. We demonstrated that treatment with crude ES products from adult worms (AES) or infective third-stage larvae (L3ES) from N. brasiliensis improved glucose tolerance and attenuated body weight gain in mice fed on a high glycaemic index diet. N. brasiliensis ES administration to mice was associated with a type 2 immune response measured by increased eosinophils and IL-5 in peripheral tissues but not IL-4, and with a decrease in the level of IL-6 in adipose tissue and corresponding increase in IL-6 levels in the liver. Moreover, treatment with AES or L3ES was associated with significant changes in the community composition of the gut microbiota at the phylum and order levels. These data highlight a role for N. brasiliensis ES in modulating the immune response associated with T2D, and suggest that N. brasiliensis ES contain molecules with therapeutic potential for treating metabolic syndrome and T2D.

Sugar Coating: Utilisation of Host Serum Sialoglycoproteins by Schistosoma mansoni as a Potential Immune Evasion Mechanism

Parasitic helminths resort to various mechanisms to evade and modulate their host’s immune response, several of which have been described for Schistosoma mansoni. We recently reported the presence of sialic acid residues on the surface of adult S. mansoni extracellular vesicles (EVs). We now report that these sialylated molecules are mammalian serum proteins. In addition, our data suggest that most sialylated EV-associated proteins do not elicit a humoral response upon injection into mice, or in sera obtained from infected animals. Sialic acids frequently terminate glycans on the surface of vertebrate cells, where they serve important functions in physiological processes such as cell adhesion and signalling. Interestingly, several pathogens have evolved ways to mimic or utilise host sialic acid beneficially by coating their own proteins, thereby facilitating cell invasion and providing protection from host immune effectors. Together, our results indicate that S. mansoni EVs are coated with host glycoproteins, which may contribute to immune evasion by masking antigenic sites, protecting EVs from removal from serum and aiding in cell adhesion and entry to exert their functions.

Analysis of Schistosoma mansoni Extracellular Vesicles Surface Glycans Reveals Potential Immune Evasion Mechanism and New Insights on Their Origins of Biogenesis

Parasitic helminths are master manipulators of host immunity. Their strategy is complex and involves the release of excreted/secreted products, including extracellular vesicles (EVs). The protein and miRNA contents of EVs have been characterised for many parasitic helminths but, despite reports suggesting the importance of EV surface carbohydrate structures (glycans) in the interactions with target cells and thus subsequent effector functions, little is known about parasite EV glycomics. Using lectin microarrays, we identified several lectins that exhibit strong adhesion to Schistosoma mansoni EVs, suggesting the presence of multiple glycan structures on these vesicles. Interestingly, SNA-I, a lectin that recognises structures with terminal sialic acid, displayed strong affinity for S. mansoni EVs, which was completely abolished by neuraminidase treatment, suggesting sialylation in the EV sample. This finding is of interest, as sialic acids play important roles in the context of infection by aiding immune evasion, affecting target recognition, cell entry, etc., but are not thought to be synthesised by helminths. These data were validated by quantitative analysis of free sialic acid released from EVs following treatment with neuraminidase. Lectin histochemistry and fluorescence in situ hybridisation analyses on whole adult worms suggest the involvement of sub-tegumental cell bodies, as well as the digestive and excretory systems, in the release of EVs. These results support previous reports of EV biogenesis diversity in trematodes and potentially highlight new means of immune modulation and evasion employed by schistosomes.

Fetomaternal immune cross talk modifies T-cell priming through sustained changes to DC function

BACKGROUND

Prenatal exposure to infections can modify immune development. These environmental disturbances during early life potentially alter the incidence of inflammatory disorders as well as priming of immune responses. Infection with the helminth Schistosoma mansoni is widely studied for its ability to alter immune responsiveness and is associated with variations in coinfection, allergy, and vaccine efficacy in endemic populations.

OBJECTIVE

Exposure to maternal schistosomiasis during early life, even without transmission of infection, can result in priming effects on offspring immune responses to bystander antigenic challenges as related to allergic responsiveness and vaccination, with this article seeking to further clarify the effects and underlying immunologic imprinting.

METHODS

Here, we have combined a model of chronic maternal schistosomiasis infection with a thorough analysis of subsequent offspring immune responses to allergy and vaccination models, including viral challenge and steady-state changes to immune cell compartments.

RESULTS

We have demonstrated that maternal schistosomiasis alters CD4+ responses during allergic sensitization and challenge in a skewed IL-4/B-cell-dominant response to antigenic challenge associated with limited inflammatory response. Beyond that, we have uncovered previously unidentified alterations to CD8+ T-cell responses during immunization that are dependent on vaccine formulation and have functional impact on the efficacy of vaccination against viral infection in a murine hepatitis B virus model.

CONCLUSION

In addition to steady-state modifications to CD4+ T-cell polarization and B-cell priming, we have traced these modified CD8+ responses to an altered dendritic cell phenotype sustained into adulthood, providing evidence for complex priming effects imparted by infection via fetomaternal cross talk.

Helminth protection against type-1 diabetes: an insight into immunomodulatory effect of helminth-induced infection

Helminths are the old dirty friends of humans from decades and may live undetected by the immune system for years in the tissues. They have evolved as good experts at subverting the immune system. Despite of their pathogenicity, they provide protection to their host against certain inflammatory diseases such as diabetes by modulating the immune mechanisms. These parasites are extra-cellular and induce Th2 response which triggers the adaptive immune cells as well as innate immune cells to work synergistically allowing Tregs to work in a toll-like receptor-dependent manure. T-helper cells type-2 also secrete certain anti-inflammatory cytokines including IL-4, IL-10, IL-13 and TGF-β which also provide protection against type-1 diabetes. Several helminths such as T. crassiceps, S. venezuelensis, filarial worms, Schistosoma spp. and T. spiralis have been reported to prevent diabetes in mouse models as well as in some clinical trials. Immunomodulatory talent of helminths is receiving greater attention to prevent diabetes. Herein, an attempt has been made to review and highlight the possible immuno-modulatory mechanisms by which helminths provide protection against diabetes. Moreover, this review also emphasizes on the use of helminth-derived molecules or synthetic derivatives of helminth-antigens in clinical trials to overcome rapidly growing autoimmune disorders including diabetes.

The relationship between Schistosoma and glycolipid metabolism

Diabetes and obesity have become the most popular metabolic diseases in the world. A large number of previous studies have shown that glucose and lipid metabolism disorder is an important risk factor and a main cause of diabetes and obesity. Schistosoma is a parasite transmitted by freshwater snails. It can induce a series of inflammatory and immune reactions after infecting the human body, causing schistosomiasis. However, in recent years, studies have found that Schistosoma infection or Schistosoma related products can improve or prevent some immune and inflammatory diseases, such as severe asthma, inflammatory bowel disease, diabetes and so on. Further experiments have also revealed that Schistosoma can promote the secretion of anti-inflammatory factors and regulate the glucose and lipid metabolism in the host body by polarizing immune cells such as T cells, B cells and dendritic cells (DCs). In this review, we summarize studies that investigated Schistosoma and Schistosoma-derived products and their relationship with glycolipid metabolism and related diseases, highlighting potential protective mechanisms.

Parasite-based interventions in systemic lupus erythematosus (SLE): A systematic review

BACKGROUND

The hygiene hypothesis proposed in 1989 expresses that allergic and infectious diseases are inversely related. Accordingly, it has been demonstrated that infection with some microorganisms such as parasites and helminths can provide a potential immunity and prevent the onset of some life-threatening autoimmune diseases like systemic lupus erythematosus (SLE). Therefore, in this comprehensive study, we systematically reviewed and discussed the use of live parasites or parasitic products in the treatment of mouse models of SLE.

METHODS

The present systematic review was performed using the following search terms: ("systemic lupus erythematosus" OR "SLE" OR "lupus") AND ("parasite" OR "protozoa" OR "helminths" OR "worms" OR "helminth" OR "worm") in PubMed, Scopus, and Web of Science online databases. We included studies reporting the effect of any intervention using parasites or parasitic-based products on animal models of SLE, which were published until January 20th, 2021 without any language or date restrictions. For each included study, we extracted the authors' names, publication year, type of animal, number of groups, types of intervention, sample size, changes in immunologic cells, auto-Abs, cytokines, and blood cells count, urine analysis, histological analysis of kidney/spleen/liver, outcome and survival. (PROSPERO CRD42020160460).

RESULTS

A total of 17 eligible articles were included in this systematic review. Sixteen out of the 17 studies reported immunomodulating changes in immunologic cells, cytokines, and/or auto-Abs in mouse models of SLE after using parasitic interventions compared to not-infected or control groups. Moreover, 14 studies reported decreased level of proteinuria and/or favorable kidney, liver, or spleen histological changes.

CONCLUSION

In conclusion, we have demonstrated that parasites like Hymenolepis microstoma, TPC and ES-62 from Acanthocheilonema viteae, Plasmodium chabaudi, Schistosoma mansoni, and Toxoplasma gondii have favorable immunomodulating effects on SLE outcomes in lupus-prone mice.

Suckling by Schistosoma mansoni-infected mothers restored IgG2a and TGF-β production, but not IL-6 and delayed-type hypersensitivity in IL-12/IL-23-deficient mice

INTRODUCTION

Suckling by schistosomotic mice improves anti-ovalbumin (OA) antibody production, while delayed-type hypersensitivity (DTH) remains unaffected. This property of milk from schistosomotic mice was investigated in IL-12/IL-23-deficient mice (IL-12p40KO).

METHODS

We compared anti-OA DTH, IgG2a and cytokines in wild-type and IL-12p40KO mice suckled by infected (SIM) or non-infected (CONTROL) mothers.

RESULTS

SIM mice showed similar intensity and eosinophils in the DTH, which was abolished in IL-12p40KO and IL-12p40KO-SIM mice. In IL-12p40KO-SIM, IgG2a and TGF-β levels were higher, but IL-6 levels were lower.

CONCLUSIONS

Milk from schistosomotic mothers may evoke IgG2a without eliciting DTH in IL-12/IL-23 deficiencies, by changing TGF-β/IL-6 levels.

Schistosome Infection and Schistosome-Derived Products as Modulators for the Prevention and Alleviation of Immunological Disorders

Parasitic helminths, comprising the flatworms (tapeworms and flukes) and nematodes (roundworms), have plagued humans persistently over a considerable period of time. It is now known that the degree of exposure to these and other pathogens inversely correlates with the incidence of both T helper 1 (Th1)-mediated autoimmunity and Th2-mediated allergy. Accordingly, there has been recent increased interest in utilizing active helminth worm infections and helminth-derived products for the treatment of human autoimmune and inflammatory diseases and to alleviate disease severity. Indeed, there is an accumulating list of novel helminth derived molecules, including proteins, peptides, and microRNAs, that have been shown to exhibit therapeutic potential in a variety of disease models. Here we consider the blood-dwelling schistosome flukes, which have evolved subtle immune regulatory mechanisms that promote parasite survival but at the same time minimize host tissue immunopathology. We review and discuss the recent advances in using schistosome infection and schistosome-derived products as therapeutics to treat or mitigate human immune-related disorders, including allergic asthma, arthritis, colitis, diabetes, sepsis, cystitis, and cancer.

Association of previous schistosome infection with fatty liver and coronary heart disease: A cross-sectional study in china

BACKGROUND

More than 11 million people were estimated to have been infected by Schistosoma japonicum in China before the 1950s. However, few studies have been conducted to evaluate the longitudinal effects of previous schistosome infection (PSI).

OBJECTIVE

We aimed to evaluate the association of PSI with fatty liver and coronary heart disease in China.

METHODS

A cross-sectional study was conducted in regions which were all reportedly heavily endemic for S japonicum in China. All data were collected using a questionnaire administered and health examinations by well-trained medical professionals. 2867 participants aged 40 years and older were enrolled. Among these, 731 patients with PSI were selected as study subjects and 2136 subjects served as controls. Comparisons between groups were performed with or without an adjustment for a covariate, using Student's t tests for continuous variables and chi-square testing for categorical variables. Multivariable logistic models were used to estimate the associations between PSI and fatty liver or coronary heart disease.

RESULTS

The PSI participants had significantly lower levels of triglyceride, low-density lipoprotein cholesterol, fasting blood glucose, uric acid, serum creatinine, urea nitrogen, platelet, total protein and globulin as well as a lower prevalence of fatty liver (13.3% vs 53.6%, P < .001) and coronary heart disease (3.4% vs 6.0%, P < .05) compared with the uninfected, contemporaneous controls (without PSI), whereas the PSI participants had higher levels of high-density lipoprotein cholesterol, direct bilirubin and a higher prevalence of hepatic dysfunction compared with those without PSI (P < .05).

CONCLUSION

We found PSI significantly negatively associated with fatty liver and coronary heart disease. However, further studies on schistosomiasis may provide new directions for prevention and treatment of fatty liver and coronary heart disease.

The Impact of Helminth Infection on the Incidence of Metabolic Syndrome: A Systematic Review and Meta-Analysis

BACKGROUND

There are a growing number of publications that report an absence of inflammatory based disease among populations that are endemic to parasitic worms (helminths) demonstrating the ability of these parasites to potentially regulate human immune responses. The aim of this systematic review and meta-analysis was to determine the impact of helminth infection on metabolic outcomes in human populations.

METHODS

Using PRISMA guidelines, six databases were searched for studies published up to August 2020. Random effects meta-analysis was performed to estimate pooled proportions with 95% confidence intervals using the Review Manager Software version 5.4.1.

RESULTS

Fourteen studies were included in the review. Fasting blood glucose was significantly lower in persons with infection (MD -0.22, 95% CI -0.40- -0.04, P=0.02), HbA1c levels were lower, although not significantly, and prevalence of the metabolic syndrome (P=0.001) and type 2 diabetes was lower (OR 1.03, 95% CI 0.34-3.09, P<0.0001). Infection was negatively associated with type 2 diabetes when comparing person with diabetes to the group without diabetes (OR 0.44, 95% CI 0.29-0.67, P=0.0001).

CONCLUSIONS

While infection with helminths was generally associated with improved metabolic function, there were notable differences in efficacy between parasite species. Based on the data assessed, live infection with S. mansoni resulted in the most significant positive changes to metabolic outcomes.

SYSTEMATIC REVIEW REGISTRATION

Website: PROSPERO Identified: CRD42021227619.

Clinical Use of Schistosoma mansoni Antigens as Novel Immunotherapies for Autoimmune Disorders

The hygiene hypothesis states that improved hygiene and the resulting disappearance of once endemic diseases is at the origin of the enormous increase in immune related disorders such as autoimmune diseases seen in the industrialized world. Helminths, such as Schistosoma mansoni, are thought to provide protection against the development of autoimmune diseases by regulating the host's immune response. This modulation primarily involves induction of regulatory immune responses, such as generation of tolerogenic dendritic cells and alternatively activated macrophages. This points toward the potential of employing helminths or their products/metabolites as therapeutics for autoimmune diseases that are characterized by an excessive inflammatory state, such as multiple sclerosis (MS), type I diabetes (T1D) and inflammatory bowel disease (IBD). In this review, we examine the known mechanisms of immune modulation by S. mansoni, explore preclinical and clinical studies that investigated the use of an array helminthic products in these diseases, and propose that helminthic therapy opens opportunities in the treatment of chronic inflammatory disorders.

Expansion of Host Regulatory T Cells by Secreted Products of the Tapeworm Echinococcus multilocularis

Background

Alveolar echinococcosis (AE), caused by the metacestode larval stage of the fox-tapeworm Echinococcus multilocularis, is a chronic zoonosis associated with significant modulation of the host immune response. A role of regulatory T-cells (Treg) in generating an immunosuppressive environment around the metacestode during chronic disease has been reported, but the molecular mechanisms of Treg induction by E. multilocularis, particularly parasite immunoregulatory factors involved, remain elusive so far.

Methodology/Principal Findings

We herein demonstrate that excretory/secretory (E/S) products of the E. multilocularis metacestode promote the formation of Foxp3+ Treg from CD4+ T-cells in vitro in a TGF-β-dependent manner, given that this effect was abrogated by treatment with antibody to mammalian TGF-β. We also show that host T-cells secrete elevated levels of the immunosuppressive cytokine IL-10 in response to metacestode E/S products. Within the E/S fraction of the metacestode we identified an E. multilocularis activin A homolog (EmACT) that displays significant similarities to mammalian Transforming Growth Factor-β (TGF-β/activin subfamily members. EmACT obtained from heterologous expression failed to directly induce Treg expansion from naïve T cells but required addition of recombinant host TGF-β to promote CD4+ Foxp3+ Treg conversion in vitro. Furthermore, like in the case of metacestode E/S products, EmACT-treated CD4+ T-cells secreted higher levels of IL-10. These observations suggest a contribution of EmACT to in vitro expansion of Foxp3+ Treg by the E. multilocularis metacestode. Using infection experiments we show that intraperitoneally injected metacestode tissue expands host Foxp3+ Treg, confirming the expansion of this cell type in vivo during parasite establishment.

Conclusion/Significance

In conclusion, we herein demonstrate that E. multilocularis larvae secrete factors that induce the secretion of IL-10 by T-cells and contribute to the expansion of TGF-b-driven Foxp3+ Treg, a cell type that has been reported crucial for generating a tolerogenic environment to support parasite establishment and proliferation. Among the E/S factors of the parasite we identified a factor with structural and functional homologies to mammalian activin A which might play an important role in these activities.

CD8+ regulatory T cells are critical in prevention of autoimmune-mediated diabetes

Type 1 diabetes (T1D) is an autoimmune disease in which insulin-producing pancreatic β-cells are destroyed. Intestinal helminths can cause asymptomatic chronic and immunosuppressive infections and suppress disease in rodent models of T1D. However, the underlying regulatory mechanisms for this protection are unclear. Here, we report that CD8⁺ regulatory T (Treg) cells prevent the onset of streptozotocin -induced diabetes by a rodent intestinal nematode. Trehalose derived from nematodes affects the intestinal microbiota and increases the abundance of Ruminococcus spp., resulting in the induction of CD8⁺ Treg cells. Furthermore, trehalose has therapeutic effects on both streptozotocin-induced diabetes and in the NOD mouse model of T1D. In addition, compared with healthy volunteers, patients with T1D have fewer CD8⁺ Treg cells, and the abundance of intestinal Ruminococcus positively correlates with the number of CD8⁺ Treg cells in humans.

Helminth infections are associated with a reduction in inflammatory pathology in rodent models of type 1 diabetes. Here, the authors show patient data and that trehalose (produced by H. polygyrus) can alter the microbiome of mice, inducing regulatory CD8⁺ T cells and reducing susceptibility to autoimmune diabetes.

Immunomodulation of Murine Chronic DSS-Induced Colitis by Tuftsin-Phosphorylcholine

Helminths or their products can immunomodulate the host immune system, and this phenomenon may be applied as the basis of new anti-inflammatory treatments. Previously, we have shown the efficacy of tuftsin-phosphorylcholine (TPC), based on a helminth product, in four animal models of autoimmune diseases: arthritis, colitis, systemic lupus erythematosus, and experimental autoimmune encephalomyelitis. We demonstrated that TPC reduced inflammatory process ex vivo in peripheral blood lymphocytes (PBLs) and in biopsies from giant-cell arteritis. In the present study, we assessed the therapeutic potential of TPC treatment on a chronic colitis murine model. C57BL/6 mice with chronic colitis were treated with TPC after the third cycle of 2% dextran sodium sulfate (DSS). Oral TPC treatment resulted in amelioration of the colitis clinical manifestations exemplified by reduced disease activity index (DAI) score, expansion of mesenteric lymph nodes (MLN) T regulatory cells (shown by Fluorescence Activated Cell Sorting (FACS)), significant reduction in the expression of pro-inflammatory cytokines (IL-1β, IL17, IL-6, TNFα), and elevation in the expression of anti-inflammatory cytokine IL-10 (shown by RT-PCR). This study demonstrated the potential immunomodulatory effects of oral administration of TPC in a chronic colitis murine model. Further clinical trials are needed in order to evaluate this novel approach for the treatment of patients with inflammatory bowel disease.

Schistosoma japonicum Soluble Egg Antigen Protects Against Type 2 Diabetes in Lepr db/db Mice by Enhancing Regulatory T Cells and Th2 Cytokines

Type 2 diabetes is a metabolic disorder characterized by persistently elevated glucose levels. There is no effective treatment strategy for this condition, and it poses a massive economic burden globally. Schistosoma soluble egg antigen (SEA)-induced immunomodulatory mechanisms have been reported in the treatment of autoimmune disease. This study aimed to determine the ability of Schistosoma japonicum SEA to protect against type 2 diabetes in Lepr^db/db mice and understand the associated mechanisms. The mice were divided into four groups: C57BL/6 (the normal group), SEA (C57BL/6 mice treated with SEA), Lepr^db/db, and SEA and Lepr^db/db co-treatment groups. The mice in the SEA and co-treatment groups were injected with 50 μg of SEA (twice a week for 6 weeks), and the same volume of PBS was used as control. Blood glucose, insulin, and HOMA-IR levels were measured in all mice, which were sacrificed 6 weeks after the last SEA administration. Flow cytometry was used to detect the percentages of regulatory T cells in splenocytes. ELISA was used to detect the levels of IFN-γ, IL-2, IL-4, and IL-5 in cell culture supernatants. Compared with the mice in the Lepr^db/db group, the mice in the SEA + Lepr^db/db group exhibited significantly reduced insulin resistance, as evidenced by the enhancement of wound healing. The frequency of spleen regulatory T cells increased significantly after SEA administration; meanwhile, the secretion of IL-4 and IL-5 in spleen cells was elevated. These results indicate that SEA can reduce insulin resistance and provide new targets for the treatment of type 2 diabetes. The potential mechanisms might be associated with increases in regulatory T cells and Th2 cytokines in Lepr^db/db mice, which warrants further investigation.

Altered expression of CD39 on memory regulatory T cells in type 1 diabetes patients

BACKGROUND

Type 1 diabetes (T1D) is an autoimmune disease resulting from an attack by autoreactive T lymphocytes against pancreatic islet β- cells. In recent studies, regulatory T cells (Tregs) have been implicated in the process of T1D. Furthermore, cluster of differentiation 39 (CD39), which is involved in the suppression of inflammation, has been shown to be expressed on Tregs. However, the pathological importance of CD39 to the memory Treg population remains unclear.

METHODS

This study investigated Treg subsets, focusing on resting, effector, and memory Tregs, and determined CD39 expression on Tregs. In addition, changes in Treg subsets and Treg-associated cytokine secretion after CD3/CD28 stimulation of peripheral blood mononuclear cells were evaluated in diabetic patients and healthy controls. The suppressive function of Tregs was measured using the mixed lymphocyte reaction (MLR) test.

RESULTS

There was a higher percentage of memory Tregs in T1D patients than healthy controls. However, Tregs in T1D patients showed impaired suppression, with low forkhead box P3 (Foxp3) expression and low serum interleukin (IL)-10 levels. Furthermore, CD39 expression on Tregs, and on memory Tregs in particular, was lower in T1D patients than healthy controls. After stimulation, the percentage of resting Tregs was decreased and that of effector/memory Tregs was increased in both healthy controls and T1D patients, but CD39 expression on effector/memory Tregs was still lower and there was no increase in IL-10 secretion in T1D patients.

CONCLUSIONS

The defective suppressive function of Tregs in T1D patients is due to lower expression of CD39 on memory Tregs.

Inverse Associations of Schistosoma mansoni Infection and Metabolic Syndromes in Humans: A Cross-Sectional Study in Northeast Ethiopia

Background:

Recent animal and retrospective human studies have demonstrated that Schistosoma mansoni infection may have potential to protect against development of metabolic syndromes. Thus, the aim of this study was to assess metabolic panel among S. mansoni egg positives and egg negatives in stool examinations. This study was a cross-sectional study, conducted involving 120 participants from S. mansoni endemic town (Kemise) and 61 from non-endemic town (Kombolcha), Northeast Ethiopia. Stool samples were collected and examined for S. mansoni and other helminths using Kato-Katz method. Furthermore, blood samples were collected and used for determination of blood sugar, lipid profile tests, insulin, and C-reactive protein. Data were analyzed using SPSS software version 20. Chi-square test, independent mean t-test, and logistic regression models were employed on data. P values less than .05 were considered as statistically significant.

Results:

S. mansoni infected participants (n = 41; all from Kemise) had significantly lower levels of fasting blood sugar, low prevalence of dyslipidemia (at least one or more abnormal lipid profile tests; total cholesterol, low-density lipoprotein cholesterol [LDL-C], high-density lipoprotein cholesterol [HDL-C], and triglycerides) as compared with controls (n = 79 in Kemise and 61 in Kombolcha). Moreover, logistic regression model indicated that with the adjusted odds ratios, there was significant inverse association between S. mansoni infection and impaired fasting glucose (adjusted odds ratio −0.181, 95% confidence interval: 0.042-0.774).

Conclusions:

Low fasting blood sugar and reduced prevalence of dyslipidemia in S. mansoni egg positive participants might suggest inverse association of S. mansoni infection and development of metabolic syndromes. Furthermore, large-scale studies are recommended to assess the role of S. mansoni egg and/or worm antigens in modulating the host metabolic profile and reducing the risk of metabolic syndromes, including diabetes mellitus and cardiovascular diseases.

Helminths protect against type 1 diabetes: effects and mechanisms

Type 1 diabetes (T1D) is an autoimmune disease in which cells of the immune system destroy pancreatic β cells, which secrete insulin. The high prevalence of T1D in developed societies may be explained by environmental changes, including lower exposure to helminths. Indeed, infection by helminths such as Schistosoma, Filaria, and Heligmosomoides polygyrus and their by-products has been reported to ameliorate or prevent the development of T1D in human and animal models. Helminths can trigger distinct immune regulatory pathways, often involving adaptive immune cells that include T helper 2 (Th2) cells and regulatory T cells (Tregs) and innate immune cells that include dendritic cells, macrophages, and invariant natural killer T cells, which may act synergistically to induce Tregs in a Toll-like receptor-dependent manner. Cytokines such as interleukin (IL)-4, IL-10, and transforming growth factor (TGF)-β also play an important role in protection from T1D. Herein, we provide a comprehensive review of the effects and mechanisms underlying protection against T1D by helminths.

Immune response to purified protein derivative in infants from helminth-sensitized mothers - A cases series

BACKGROUND

Maternal exposure to antibodies, cytokines or parasitic antigens during gestation may alter the degree of immune competence of offspring. Here we describe the production of cytokines and chemokines, and the ability to activation of the immune response in infants from mothers sensitized to helminths.

METHODS

It were selected five infants born to helminth-seropositive mothers but who were negative for current helminth infection. Whole blood was cultured without stimulus, with phytohemagglutinin mitogen (5 μg/ml, 24 h) or with purified protein derivative (PPD) (1 μg/ml, 24 h), and the supernatant was assessed for presence of Th1/Th2 cytokines (IFN-γ, TNF-α, IL-10, IL-5, IL-4 and IL-2) and chemokines (CXCL10, CCL2, CXCL9, CCL5 and CXCL8) by cytometric bead array.

RESULTS

All infants produced CCL5. Two infants demonstrated a mixed profile of Th1 (CXCL9) and Th2 (CCL2) chemokines in the presence of CXCL10, while one infant showed skewing towards Th2 without CXCL10 and two of them had been impaired immune response (children from sensitized to Schistosoma mansoni mothers).

CONCLUSION

Infants with Th1 and Th2 profile chemokines demonstrated a good response to vaccination, indicated by CXCL10 levels, but not infants predominantly Th2-skewed profile. These results highlight that children from mothers sensitized to S. mansoni may lead to ineffective immune response to PPD, while mothers sensitized to Ascaris lumbricoides showed no such impairment.

Maternal schistosomiasis: IL-2, IL-10 and regulatory T lymphocytes to unrelated antigen in adult offspring mice

INTRODUCTION

We evaluated IL-10, IL-2 and regulatory T cells (Treg), in response to ovalbumin (OA), in offspring from schistosomotic mouse mothers.

METHODS

We used animals born (BIM) or suckled (SIM) from infected mothers; and mice born/suckled from infected (BSIM) or non-infected mothers (CONTROL). After OA+adjuvant immunization, spleen cells were cultured, with or without OA, and doubly marked for cytometry.

RESULTS

BIM showed fewer CD4+/IL-2+ and more B220+/IL-10+ cells, whereas the SIM group showed increased Treg frequency. BSIM had fewer B220+/IL-10+ and Treg cells.

CONCLUSIONS

Separately, gestation or nursing induced immunosuppressive cells in infected mothers, but improved anti-OA immunity when combined.

Schistosoma Infection and Schistosoma-Derived Products Modulate the Immune Responses Associated with Protection against Type 2 Diabetes

Studies on parasite-induced immunoregulatory mechanisms could contribute to the development of new therapies for inflammatory diseases such as type 2 diabetes (T2D), which is a chronic inflammatory disease characterized by persistent elevated glucose levels due to insulin resistance. The association between previous Schistosoma infection and T2D has been confirmed—Schistosoma infection and Schistosoma-derived products modulate the immune system, including innate and acquired immune responses, contributing to T2D disease control. Schistosoma infections and Schistosoma-derived molecules affect the immune cell composition in adipose tissue, dampening inflammation and improving glucose tolerance. This protective role includes the polarization of immune cells to alternatively activated macrophages, dendritic cells, eosinophils, and group 2 innate lymphoid cells. Furthermore, Schistosoma infection and Schistosoma products are effective for the treatment of T2D, as they increase the number of type 2 helper T cells (Th2) and regulatory T cells (Tregs) and decrease type 1 helper T cells (Th1) and type 17 helper T cells (Th17) cells. Thus, our aim was to comprehensively review the mechanism through which Schistosoma infection and Schistosoma products modulate the immune response against T2D.

The Mannose Receptor in Regulation of Helminth-Mediated Host Immunity

Infection with parasitic helminths affects humanity and animal welfare. Parasitic helminths have the capacity to modulate host immune responses to promote their survival in infected hosts, often for a long time leading to chronic infections. In contrast to many infectious microbes, however, the helminths are able to induce immune responses that show positive bystander effects such as the protection to several immune disorders, including multiple sclerosis, inflammatory bowel disease, and allergies. They generally promote the generation of a tolerogenic immune microenvironment including the induction of type 2 (Th2) responses and a sub-population of alternatively activated macrophages. It is proposed that this anti-inflammatory response enables helminths to survive in their hosts and protects the host from excessive pathology arising from infection with these large pathogens. In any case, there is an urgent need to enhance understanding of how helminths beneficially modulate inflammatory reactions, to identify the molecules involved and to promote approaches to exploit this knowledge for future therapeutic interventions. Evidence is increasing that C-type lectins play an important role in driving helminth-mediated immune responses. C-type lectins belong to a large family of calcium-dependent receptors with broad glycan specificity. They are abundantly present on immune cells, such as dendritic cells and macrophages, which are essential in shaping host immune responses. Here, we will focus on the role of the C-type lectin macrophage mannose receptor (MR) in helminth-host interactions, which is a critically understudied area in the field of helminth immunobiology. We give an overview of the structural aspects of the MR including its glycan specificity, and the functional implications of the MR in helminth-host interactions focusing on a few selected helminth species.

Taenia crassiceps Antigens Control Experimental Type 1 Diabetes by Inducing Alternatively Activated Macrophages

Type 1 diabetes (T1D) is an autoimmune disease caused by the selective destruction of the pancreatic β-cells, causing inability to produce insulin. Proinflammatory cytokines such as IL-1β, IL-6, TNF-α, IFN-γ, IL-12, IL-17, and NO can be released by CD4 and CD8⁺ lymphocytes as well as by classically activated macrophages (CAMϕs), which are important in the development of T1D. Helminth infections have been shown to prevent T1D, mainly through Th2-biased responses and increased recruitment of regulatory cell populations. Previously, we have shown that Taenia crassiceps infection in mice significantly reduces hyperglycemia, insulitis, and the incidence of T1D. In this study, we determined whether T. crassiceps-derived products such as soluble (TcS) or excreted/secreted (TcES) antigens might have a beneficial influence on the development of experimental T1D. Treatment with different doses before or after induction of T1D was analyzed. Mice that were pretreated with TcS were unable to develop T1D, whereas those receiving TcES early after T1D induction displayed significantly reduced insulitis and hyperglycemia along with increased recruitment of alternatively activated macrophages (AAMϕs) and myeloid-derived suppressor cells (MDSCs). Finally, we examined the modulatory role of AAMϕs on T1D by depleting macrophages with clodronate-loaded liposomes, demonstrating that AAMϕs are key cells in T1D regulation.

Innate scavenger receptor-A regulates adaptive T helper cell responses to pathogen infection

The pattern recognition receptor (PRR) scavenger receptor class A (SR-A) has an important function in the pathogenesis of non-infectious diseases and in innate immune responses to pathogen infections. However, little is known about the role of SR-A in the host adaptive immune responses to pathogen infection. Here we show with mouse models of helminth Schistosoma japonicum infection and heat-inactivated Mycobacterium tuberculosis stimulation that SR-A is regulated by pathogens and suppresses IRF5 nuclear translocation by direct interaction. Reduced abundance of nuclear IRF5 shifts macrophage polarization from M1 towards M2, which subsequently switches T-helper responses from type 1 to type 2. Our study identifies a role for SR-A as an innate PRR in regulating adaptive immune responses.

Therapeutic potential of helminths in autoimmune diseases: helminth-derived immune-regulators and immune balance

Helminths have accompanied human throughout history by releasing immune-evasion molecules that could counteract an aberrant immune response within the host. In the past decades, helminth infections are becoming less prevalent possibly due to the developed sanitation. Meanwhile, the incidence of autoimmune diseases is increasing, which cannot be exclusively explained by the changes of susceptibility genes. While the hygiene hypothesis casts light on the problem. The infections of helminths are believed to interact with and regulate human immunity with the byproduct of suppressing the autoimmune diseases. Thus, helminths are potential to treat or cure the autoimmune diseases. The therapeutic progresses and possible immune suppression mechanisms are illustrated in the review. The helminths that are studied most intensively include Heligmosomoides polygyrus, Hymenolepis diminuta, Schistosoma mansoni, Trichinella spiralis, and Trichuris suis. Special attentions are paid on the booming animal models and clinical trials that are to detect the efficiency of immune-modulating helminth-derived molecules on autoimmune diseases. These trials provide us with a prosperous clinical perspective, but the precise mechanism of the down-regulatory immune response remains to be clarified. More efforts are needed to be dedicated until these parasite-derived immune modulators could be used in clinic to treat or cure the autoimmune diseases under a standard management.

The global diabetes epidemic: what does it mean for infectious diseases in tropical countries?

Tropical countries are experiencing a substantial rise in type 2 diabetes, which is often undiagnosed or poorly controlled. Since diabetes is a risk factor for many infectious diseases, this increase probably adds to the large infectious disease burden in tropical countries. We reviewed the literature to investigate the interface between diabetes and infections in tropical countries, including the WHO-defined neglected tropical diseases. Although solid data are sparse, patients with diabetes living in tropical countries most likely face increased risks of common and health-care-associated infections, as well as infected foot ulcers, which often lead to amputation. There is strong evidence that diabetes increases the severity of some endemic infections such as tuberculosis, melioidosis, and dengue virus infection. Some HIV and antiparasitic drugs might induce diabetes, whereas helminth infections appear to afford some protection against future diabetes. But there are no or very scarce data for most tropical infections and for possible biological mechanisms underlying associations with diabetes. The rise in diabetes and other non-communicable diseases puts a heavy toll on health systems in tropical countries. On the other hand, complications common to both diabetes and some tropical infections might provide an opportunity for shared services-for example, for eye health (trachoma and onchocerciasis), ulcer care (leprosy), or renal support (schistosomiasis). More research about the interaction of diabetes and infections in tropical countries is needed, and the infectious disease burden in these countries is another reason to step up global efforts to improve prevention and care for diabetes.

Soluble Egg Antigen Activates M2 Macrophages via the STAT6 and PI3K Pathways, and Schistosoma Japonicum Alternatively Activates Macrophage Polarization to Improve the Survival Rate of Septic Mice

Sepsis is one of the most challenging health problems worldwide. Our previous study showed that chronic schistosoma japonica (SJ) infection might increase serum anti-inflammatory factors to play a protective role, thus improving the survival rate of septic mice. Further research revealed that SJ infection promoted J774A.1 macrophage differentiation into M2 macrophages; suppressed LPS-induced activation of M1 macrophages; up-regulated CD163, IL-10, and TGF-β1 expression; inhibited TNF-α and iNOS expression; and blocked the effect of LPS-promoted TNF-α and iNOS expression. Furthermore, adoptive transfer of ex vivo programed M2 macrophages significantly increased the survival rate of septic mice. In vitro studies suggested that soluble egg antigen (SEA) from SJ played the same role as worm infection but had no impact on M1 macrophages. SEA reduced LPS-induced TNF-α and iNOS expression, decreased the inhibitory effect of LPS on IL-10 and TGF-β1 expression, increased STAT6 phosphorylation, and up-regulated PI3K and Akt expression but inhibited SOCS1 expression. When PI3K inhibitors were added, SEA-induced expression of CD163, IL-10, and arg1 might be reduced. Therefore, worm infection has a protective effect in septic mice in which SEA may play a key role via the STAT6 and PI3K pathways. This finding may provide a favorable solution for the treatment of sepsis, especially early cases. J. Cell. Biochem. 118: 4230-4239, 2017. © 2017 Wiley Periodicals, Inc.

Immunomodulation by helminths: Similar impact on type 1 and type 2 diabetes?

The incidence of both type 1 (T1D) and type 2 diabetes (T2D) is drastically increasing, and it is predicted that the global prevalence of diabetes will reach almost 600 million cases by 2035. Even though the pathogenesis of both types of diabetes is distinct, the immune system is actively involved in both forms of the disease. Genetic and environmental factors determine the risk to develop T1D. On the other hand, sedentary life style, surplus of food intake and other lifestyle changes contribute to the increase of T2D incidence. Improved sanitation with high-quality medical treatment is such an environmental factor that has led to a continuous reduction of infectious diseases including helminth infections over the past decades. Recently, a growing body of evidence has implicated a negative association between helminth infections and diabetes in humans as well as animal models. In this review, we discuss studies that have provided evidence for the beneficial impact of helminth infections on T1D and T2D. Possible mechanisms are presented by which helminths prevent T1D onset by mitigating pancreatic inflammation and confer protection against T2D by improving insulin sensitivity, alleviating inflammation, augmenting browning of adipose tissue and improving lipid metabolism and insulin signalling.

Immunopathology in Taenia solium neurocysticercosis

Neurocysticercosis is a clinically and radiologically heterogeneous disease, ranging from asymptomatic infection to a severe, potentially fatal clinical picture. The intensity and extension of the parasite-elicited inflammatory reaction is a key factor for such variability. The main features of the inflammatory process found in the brain and in the peripheral blood of neurocysticercosis patients will be discussed in this review, and the factors involved in its modulation will be herein presented.

Schistosome-Derived Molecules as Modulating Actors of the Immune System and Promising Candidates to Treat Autoimmune and Inflammatory Diseases

It is long known that some parasite infections are able to modulate specific pathways of host's metabolism and immune responses. This modulation is not only important in order to understand the host-pathogen interactions and to develop treatments against the parasites themselves but also important in the development of treatments against autoimmune and inflammatory diseases. Throughout the life cycle of schistosomes the mammalian hosts are exposed to several biomolecules that are excreted/secreted from the parasite infective stage, named cercariae, from their tegument, present in adult and larval stages, and finally from their eggs. These molecules can induce the activation and modulation of innate and adaptive responses as well as enabling the evasion of the parasite from host defense mechanisms. Immunomodulatory effects of helminth infections and egg molecules are clear, as well as their ability to downregulate proinflammatory cytokines, upregulate anti-inflammatory cytokines, and drive a Th2 type of immune response. We believe that schistosomes can be used as a model to understand the potential applications of helminths and helminth-derived molecules against autoimmune and inflammatory diseases.

Diplomatic Assistance: Can Helminth-Modulated Macrophages Act as Treatment for Inflammatory Disease?

Helminths have evolved numerous pathways to prevent their expulsion or elimination from the host to ensure long-term survival. During infection, they target numerous host cells, including macrophages, to induce an alternatively activated phenotype, which aids elimination of infection, tissue repair, and wound healing. Multiple animal-based studies have demonstrated a significant reduction or complete reversal of disease by helminth infection, treatment with helminth products, or helminth-modulated macrophages in models of allergy, autoimmunity, and sepsis. Experimental studies of macrophage and helminth therapies are being translated into clinical benefits for patients undergoing transplantation and those with multiple sclerosis. Thus, helminths or helminth-modulated macrophages present great possibilities as therapeutic applications for inflammatory diseases in humans. Macrophage-based helminth therapies and the underlying mechanisms of their therapeutic or curative effects represent an under-researched area with the potential to open new avenues of treatment. This review explores the application of helminth-modulated macrophages as a new therapy for inflammatory diseases.

Treatment with Trichuris suis soluble products during monocyte-to-macrophage differentiation reduces inflammatory responses through epigenetic remodeling

Helminths have strong immunoregulatory properties that may be exploited in treatment of chronic immune disorders, such as multiple sclerosis and inflammatory bowel disease. Essential players in the pathogenesis of these diseases are proinflammatory macrophages. We present evidence that helminths modulate the function and phenotype of these innate immune cells. We found that soluble products derived from the Trichuris suis (TsSP) significantly affect the differentiation of monocytes into macrophages and their subsequent polarization. TsSPs reduce the expression and production of inflammatory cytokines, including IL-6 and TNF, in human proinflammatory M1 macrophages. TsSPs induce a concomitant anti-inflammatory M2 signature, with increased IL-10 production. Furthermore, they suppress CHIT activity and enhance secretion of matrix metalloproteinase 9. Short-term triggering of monocytes with TsSPs early during monocyte-to-macrophage differentiation imprinted these phenotypic alterations, suggesting long-lasting epigenetic changes. The TsSP-induced effects in M1 macrophages were completely reversed by inhibiting histone deacetylases, which corresponded with decreased histone acetylation at the TNF and IL6 promoters. These results demonstrate that TsSPs have a potent and sustained immunomodulatory effect on human macrophage differentiation and polarization through epigenetic remodeling and provide new insights into the mechanisms by which helminths modulate human immune responses.-Hoeksema, M. A., Laan, L. C., Postma, J. J., Cummings, R. D., de Winther, M. P. J., Dijkstra, C. D., van Die, I., Kooij, G. Treatment with Trichuris suis soluble products during monocyte-to-macrophage differentiation reduces inflammatory responses through epigenetic remodeling.

Schistosoma japonicum HSP60-derived peptide SJMHE1 suppresses delayed-type hypersensitivity in a murine model

Background

Parasite-derived molecules with immunomodulatory properties, which have been optimised during host-parasite co-evolution, exhibit potential applications as novel immunotherapeutics. We have previously demonstrated that Schistosoma japonicum HSP60-derived peptide SJMHE1 induces CD4⁺CD25⁺ regulatory T-cells (Tregs) and that adoptively transferred SJMHE1-induced CD4⁺CD25⁺ Tregs inhibit delayed-type hypersensitivity (DTH) in mice. However, multiple concerns regarding this method render this treatment unsuitable. To gain further insights into the potential effects of SJMHE1, we used ovalbumin (OVA)-induced DTH and evaluated the effect of SJMHE1 on DTH mice.

Methods

BALB/c mice were sensitised with OVA alone or combined with SJMHE1 and then challenged with OVA to induce DTH. We first analysed the potential effects of SJMHE1 by measuring DTH responses, T-cell responses, cytokine secretion, and Treg proportions. We then evaluated the expression levels of IL-10 and TGF-β1 in CD4⁺CD25⁺ T-cells during DTH and Treg generation to identify the mechanism by which SJMHE1 suppresses DTH.

Results

SJMHE1 modulated the effector response against OVA-induced DTH and stimulated the production of the anti-inflammatory cytokines IL-10 and TGF-β1 in immunised mice through a mechanism involving CD4⁺CD25⁺ Tregs. SJMHE1-induced CD4⁺CD25⁺ Tregs expressed high levels of CTLA-4, IL-10, and TGF-β1, which substantially contributed to the suppressive activity during DTH. The administration of SJMHE1 to DTH in mice led to the expansion of CD4⁺CD25⁺ Tregs from CD4⁺CD25⁻ T-cells in the periphery, which inhibited DTH responses.

Conclusions

Our study proves that the parasite-driven peptide suppresses DTH in mice, which may confer a new option for inflammation treatment.

Parasitic helminths and their beneficial impact on type 1 and type 2 diabetes

It is estimated that by the year 2035 almost 600 million people will suffer from diabetes. In the case of type 2 diabetes, the strongest increase of diabetes incidence occurs in developing and newly industrialized countries. This increase correlates not only with a progressing sedentary lifestyle and nutritional changes, but also environmental changes. Similarly, the increase of type 1 diabetes incidence in industrialized countries over the past decades cannot be explained by genetic factors alone, suggesting that environmental changes are also involved. One such environmental change is a reduced exposure to pathogens because of improved hygiene. Parasitic helminths modulate the immune system of their hosts and induce type 2 as well as regulatory immune responses. As pro-inflammatory immune responses are crucial for the onset of both type 1 and type 2 diabetes, helminth-induced immunomodulation may prevent diabetes onset and ameliorate insulin sensitivity. Several epidemiological studies in human and experimental animal models support such a protective effect of helminths for autoimmune diabetes. Recent studies further suggest that helminths may also provide such a beneficial effect for type 2 diabetes. In this review we summarize studies that investigated parasitic helminths and helminth-derived products and their impact on both type 1 and type 2 diabetes highlighting potential protective mechanisms.

Helminth therapy for organic diseases?

Autoimmune and chronic inflammatory organic diseases represent a "postindustrial revolution epidemics," and their frequency has increased dramatically in the last century. Today, it is assumed that the increase in hygiene standards reduced the interactions with helminth parasites that coevolved with the immune system and are crucial for its proper functioning. Several helminths have been proposed and tested in the search of the ideal therapeutic. In this review, the authors summarize the translational and clinical studies and review the caveats and possible solutions for the optimization of helminth therapies.

The Schistosoma mansoni T2 ribonuclease omega-1 modulates inflammasome-dependent IL-1β secretion in macrophages

The T2 ribonuclease omega-1 is a powerful Th2-inducing factor secreted by the eggs of the blood fluke Schistosoma mansoni. Omega-1 can modulate pattern recognition receptor-induced inflammatory signatures and alter antigen presentation by dendritic cells. Recent findings have suggested that component(s) contained in or secreted by S. mansoni eggs (soluble egg antigen) can also enhance IL-1β secretion by dendritic cells stimulated with pattern recognition receptor ligands. Here we show that omega-1 enhances IL-1β secretion in macrophages stimulated with Toll-like receptor 2 ligand, and propose omega-1 as the factor in soluble egg antigen capable of regulating inflammasome activity. This effect is dependent on the C-type lectin receptor Dectin-1, caspase-8 and the ASC inflammasome adaptor protein, highlighting the ability of omega-1 to regulate multiple pattern recognition receptor signalling pathways. These mechanistic insights into manipulation of host immunity by a parasite product have implications for the design of anti-inflammatory therapeutic drugs.

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.

CD8α¯ DC is the major DC subset which mediates inhibition of allergic responses by Schistosoma infection

Our and others' previous studies have shown that Schistosoma japonicum (SJ) infection can inhibit allergic reactions. We recently reported that DCs played an important role in SJ infection-mediated inhibition of allergy, which was associated with enhanced IL-10 and T regulatory cell responses. Here, we further compared the role of CD8α(+) DC and CD8α(-) DC subsets for the inhibitory effect. We sorted CD8α(+) DC (SJCD8α(+) DC) and CD8α(-) DC (SJCD8α(-) DC) from SJ-infected mice and tested their ability to modulate allergic responses in vivo. The data showed that the adoptive transfer of SJCD8α(-) DC was much more efficient than SJCD8α(+) DC for the suppression of allergic airway eosinophilia, mucus overproduction, antigen-specific IgE responses, and Th2 cytokines (IL-4 and IL-5). More importantly, we found that the transfer of SJCD8α(-) DC, but not SJCD8α(+) DC, significantly increased IL-10 and TGF-β production following OVA exposure. As control, the transfer of DC subsets from naïve mice had no significant effect on allergic inflammation. In addition, SJCD8α-DC expressed significantly higher IL-10 but lower IL-12, CD80 and CD86 than SJCD8α(+) DC, fitting a tolerogenic phenotype. The results suggest that CD8α(-) DC is the predominant DC subset which is involved in the parasitic infection-mediated inhibition of allergic inflammation and possibly through enhancing immunomodulatory cytokine (IL-10 and TGF-β) production.

Harnessing the helminth secretome for therapeutic immunomodulators

Helminths are the largest and most complex pathogens to invade and live within the human body. Since they are not able to outpace the immune system by rapid antigen variation or faster cell division or retreat into protective niches not accessible to immune effector mechanisms, their long-term survival depends on influencing and regulating the immune responses away from the mode of action most damaging to them. Immunologists have focused on the excretory and secretory products that are released by the helminths, since they can change the host environment by modulating the immune system. Here we give a brief overview of the helminth-associated immune response and the currently available helminth secretome data. We introduce some major secretome-derived immunomodulatory molecules and describe their potential mode of action. Finally, the applicability of helminth-derived therapeutic proteins in the treatment of allergic and autoimmune inflammatory disease is discussed.

Schistosoma japonicum soluble egg antigens induce apoptosis and inhibit activation of hepatic stellate cells: a possible molecular mechanism

Hepatic stellate cells play a key role in the development of hepatic fibrosis. Activated hepatic stellate cells can be reversed to a quiescent-like state or apoptosis can be induced to reverse fibrosis. Some studies have recently shown that Schistosoma mansoni eggs could suppress the activation of hepatic stellate cells and that soluble egg antigens from schistosome eggs could promote immunocyte apoptosis. Hence, in this study, we attempt to assess the direct effects of Schistosoma japonicum soluble egg antigens on hepatic stellate cell apoptosis, and to explore the mechanism by which the apoptosis of activated hepatic stellate cells can be induced by soluble egg antigens, as well as the mechanism by which hepatic stellate cell activation is inhibited by soluble egg antigens. Here, it was shown that S. japonicum-infected mouse livers had increased apoptosis phenomena and a variability of peroxisome proliferator-activated receptor γ expression. Soluble egg antigens induce morphological changes in the hepatic stellate cell LX-2 cell line, inhibit cell proliferation and induce cell-cycle arrest at the G1 phase. Soluble egg antigens also induce apoptosis in hepatic stellate cells through the TNF-related apoptosis-inducing ligand/death receptor 5 and caspase-dependent pathways. Additionally, soluble egg antigens could inhibit the activation of hepatic stellate cells through peroxisome proliferator-activated receptor γ and the transforming growth factor β signalling pathways. Therefore, our study provides new insights into the anti-fibrotic effects of S. japonicum soluble egg antigens on hepatic stellate cell apoptosis and the underlying mechanism by which the liver fibrosis could be attenuated by soluble egg antigens.