Where are we on worms?

Recombinant Fasciola hepatica Fatty Acid Binding Protein as a Novel Anti-Inflammatory Biotherapeutic Drug in an Acute Gram-Negative Nonhuman Primate Sepsis Model

Due to their phylogenetic proximity to humans, nonhuman primates (NHPs) are considered an adequate choice for a basic and preclinical model of sepsis. Gram-negative bacteria are the primary causative of sepsis. During infection, bacteria continuously release the potent toxin lipopolysaccharide (LPS) into the bloodstream, which triggers an uncontrolled systemic inflammatory response leading to death. Our previous research has demonstrated in vitro and in vivo using a mouse model of septic shock that Fh15, a recombinant variant of the Fasciola hepatica fatty acid binding protein, acts as an antagonist of Toll-like receptor 4 (TLR4) suppressing the LPS-induced proinflammatory cytokine storm. The present communication is a proof-of concept study aimed to demonstrate that a low-dose of Fh15 suppresses the cytokine storm and other inflammatory markers during the early phase of sepsis induced in rhesus macaques by intravenous (i.v.) infusion with lethal doses of live Escherichia coli. Fh15 was administered as an isotonic infusion 30 min prior to the bacterial infusion. Among the novel findings reported in this communication, Fh15 (i) significantly prevented bacteremia, suppressed LPS levels in plasma, and the production of C-reactive protein and procalcitonin, which are key signatures of inflammation and bacterial infection, respectively; (ii) reduced the production of proinflammatory cytokines; and (iii) increased innate immune cell populations in blood, which suggests a role in promoting a prolonged steady state in rhesus macaques even in the presence of inflammatory stimuli. This report is the first to demonstrate that a F. hepatica-derived molecule possesses potential as an anti-inflammatory drug against sepsis in an NHP model.

IMPORTANCE Sepsis caused by Gram-negative bacteria affects 1.7 million adults annually in the United States and is one of the most important causes of death at intensive care units. Although the effective use of antibiotics has resulted in improved prognosis of sepsis, the pathological and deathly effects have been attributed to the persistent inflammatory cascade. There is a present need to develop anti-inflammatory agents that can suppress or neutralize the inflammatory responses and prevent the lethal consequences of sepsis. We demonstrated here that a small molecule of 14.5 kDa can suppress the bacteremia, endotoxemia, and many other inflammatory markers in an acute Gram-negative sepsis rhesus macaque model. These results reinforce the notion that Fh15 constitutes an excellent candidate for drug development against sepsis.

Current and emerging therapies for coeliac disease

Coeliac disease is a common enteropathy that occurs in genetically susceptible individuals in response to the ingestion of gluten proteins present in wheat, rye and barley. Currently, the only available treatment for the condition is a strict, life-long gluten-free diet that, despite being safe and often effective, is associated with several challenges. Due to the high cost, particularly restrictive nature and perception of decreased quality of life associated with the diet, some patients are continuously exposed to gluten, which prevents an adequate disease control. Moreover, a subgroup of patients does not respond to the diet adequately, and healing of the small-bowel mucosa can be incomplete. Thus, there is a need for alternative treatment forms. The increasingly understood pathogenetic process of coeliac disease has enabled the identification of various targets for future therapies. Multiple investigational therapies ranging from tolerogenic to immunological approaches are in the pipeline, and several drug candidates have entered phase II/III clinical trials. This Review gives a broad overview of the different investigative treatment modalities for coeliac disease and summarizes the latest advances in this field.

Trichinella spiralis: inflammation modulator

The hygiene hypothesis posits that the decreased incidence of parasitic infection in developed countries may underlie an increased prevalence of allergic and autoimmune diseases in these countries. As unique inflammation modulator of intracellular parasitism, Trichinella spiralis, or its excretory-secretory (ES) product, shows improved responses to allergies, autoimmune diseases, inflammatory bowel disease, type 1 diabetes, rheumatic arthritis and autoimmune encephalomyelitis by exerting immunomodulatory effects on both innate and adaptive immune cells in animal models. Research has shown that T. spiralis differs from other helminths in manipulation of the host immune response not only by well-known characteristics of its life cycle, but also by its inflammation modulation pathway. How the parasite achieves inflammation modulation has not been fully elucidated yet. This review will generalize the mechanism and focuses on ES immunomodulatory molecules of T. spiralis that may be important for developing new therapeutics for inflammatory disorders.

The intestinal milieu influences the immunoproteome of male and female Heligmosomoides polygyrus bakeri L4 stage

The gastrointestinal nematode Heligmosomoides polygyrus bakeri shows enhanced survival in mice with colitis. As the antibody response plays an important role in antiparasitic immunity, antibodies against male and female L4 H. polygyrus were examined in mice with and without colitis. Levels of specific antibodies in the mucosa and serum were determined by enzyme-linked immunosorbent assay and immunogenic proteins of male and female parasites were identified using 2D electrophoresis and mass spectrometry. The function of identified proteins was explored with Blast2Go. Nematodes in mice with colitis induced higher levels of specific immunoglobulin G (IgG1) and IgA, a lower level of IgE in the small intestine and a higher level of IgE in serum against female L4. Infected mice with colitis recognized 12 proteins in male L4 and 10 in female L4. Most of the recognized proteins from male L4 were intermediate filament proteins, whereas the proteins from female L4 were primarily actins and galectins. Nematodes from mice with colitis were immunogenically different from nematodes from control mice. This phenomenon gives new insights into helminth therapy as well as host-parasite interactions.

Immunomodulatory effect of Syphacia obvelata in treatment of experimental DSS-induced colitis in mouse model

The ability of helminth parasite infections to manipulate the immune system of their host towards T regulatory responses has been proposed to suppress the inflammatory response. The aim of this study was to investigate the protective and therapeutic effect of Syphacia obvelata in the treatment of experimental DSS -induced colitis. 50 male C57BL/6 mice were divided into 5 groups: healthy uninfected controls, DSS colitis, receiving only S. obv, preventive (S. obv + DSS) and therapeutic group (DSS + S.obv). Colitis intensity was investigated by measuring body weight changes, stool consistency/bleeding and colon length. To evaluate the immune responses induced by this nematode, TNF-α, IL-10, IL-17, IFN-γ and expressing of FoxP3⁺ T cells were measured in mesenteric lymph nodes and Peyer’s patches cells. Mice in preventive and therapeutic groups treated with S. obv egg significantly ameliorated the severity of the DSS colitis, indicated by the reduced disease manifestations, improved histopathological scores correlated with the up regulation of Treg responses and down regulation of proinflammatory cytokines. S. obv can prevention and reverse on-going murine DSS colitis. The data suggest that induction of Tregs and change in cytokine profiles during helminthic therapies were responsible for reversed inflammatory events in IBD.

Treatment with P28GST, a schistosome-derived enzyme, after acute colitis induction in mice: Decrease of intestinal inflammation associated with a down regulation of Th1/Th17 responses

Background

P28GST, a 28Kd glutathione S-transferase enzymatic protein derived from a schistosome helminth prevents experimental colitis when administered subcutaneously in the presence of adjuvant by decreasing pro-inflammatory Th1/Th17 response. Given the antioxidant properties of P28GST, we evaluated its anti-inflammatory potential when administered locally after colitis induction in the absence of adjuvant.

Methods

Colitis was induced in BALB/c mice by rectal administration of TNBS, followed by two intraperitoneal injections of P28GST at day 1 and day 2. Mice were sacrificed 48h after TNBS administration and evaluated for macroscopic and histological scores, myeloperoxidase (MPO) quantification and cytokine messenger RNA expression in the colonic tissues.

Results

Both clinical and histological scores significantly decreased in mice treated with P28GST at 5 or 50μg/kg when compared to vehicle- treated mice. A significant reduction of MPO was detected in colonic tissues from P28GST–treated mice, similarly to mice treated with methylprednisolone as the reference treatment. Pro-inflammatory cytokines TNF, IL-1β, and IL-6, mRNA as well as serum levels were down-regulated in mice colonic tissues treated with P28GST at 5 or 50μg/kg. In addition, a significant decrease of mRNA expression levels of T-bet, and ROR-γ, respective markers of Th1 and Th17 cells was observed. Whereas no significant effect was detected on Gata3 mRNA, a marker of Th2 cells, the Arg/iNOS mRNA levels significantly increased in P28GST-treated mice, suggesting the induction of M2 macrophages.

Conclusions

These findings provide evidence that P28GST injected locally after colitis induction induces a potent decrease of colitis inflammation in mice, associated to downregulation of Th1/Th17 response, and induction of anti-inflammatory alternatively activated macrophages.

Analysis of the Trichuris suis excretory/secretory proteins as a function of life cycle stage and their immunomodulatory properties

Parasitic worms have a remarkable ability to modulate host immune responses through several mechanisms including excreted/secreted proteins (ESP), yet the exact nature of these proteins and their targets often remains elusive. Here, we performed mass spectrometry analyses of ESP (TsESP) from larval and adult stages of the pig whipworm Trichuris suis (Ts) and identified ~350 proteins. Transcriptomic analyses revealed large subsets of differentially expressed genes in the various life cycle stages of the parasite. Exposure of bone marrow-derived macrophages and dendritic cells to TsESP markedly diminished secretion of the pro-inflammatory cytokines TNFα and IL-12p70. Conversely, TsESP exposure strongly induced release of the anti-inflammatory cytokine IL-10, and also induced high levels of nitric oxide (NO) and upregulated arginase activity in macrophages. Interestingly, TsESP failed to directly induce CD4+ CD25+ FoxP3+ regulatory T cells (Treg cells), while OVA-pulsed TsESP-treated dendritic cells suppressed antigen-specific OT-II CD4+ T cell proliferation. Fractionation of TsESP identified a subset of proteins that promoted anti-inflammatory functions, an activity that was recapitulated using recombinant T. suis triosephosphate isomerase (TPI) and nucleoside diphosphate kinase (NDK). Our study helps illuminate the intricate balance that is characteristic of parasite-host interactions at the immunological interface, and further establishes the principle that specific parasite-derived proteins can modulate immune cell functions.

The benign helminth Hymenolepis diminuta ameliorates chemically induced colitis in a rat model system

The tapeworm Hymenolepis diminuta is a model for the impact of helminth colonization on the mammalian immune system and a candidate therapeutic agent for immune mediated inflammatory diseases (IMIDs). In mice, H. diminuta protects against models of inflammatory colitis by inducing a strong type 2 immune response that is activated to expel the immature worm. Rats are the definitive host of H. diminuta, and are colonized stably and over long time periods without harming the host. Rats mount a mild type 2 immune response to H. diminuta colonization, but this response does not generally ameliorate colitis. Here we investigate the ability of different life cycle stages of H. diminuta to protect rats against a model of colitis induced through application of the haptenizing agent dinitrobenzene sulphonic acid (DNBS) directly to the colon, and monitor rat clinical health, systemic inflammation measured by TNFα and IL-1β, and the gut microbiota. We show that immature H. diminuta induces a type 2 response as measured by increased IL-4, IL-13 and IL-10 expression, but does not protect against colitis. In contrast, rats colonized with mature H. diminuta and challenged with severe colitis (two applications of DNBS) have lower inflammation and less severe clinical symptoms. This effect is not related the initial type 2 immune response. The gut microbiota is disrupted during colitis and does not appear to play an overt role in H. diminuta-mediated protection.

T-Bet Is Dependent on Stat-4 Inhibiting Acute Colitis but Not Stat-1 Using L4 Somatic Antigen of Heligmosomoides polygyrus

Helminths may alter the immunoinflammatory reactions of colitis. Proteins derived from H. polygyrus have prospective therapy for colitis. The goal of this study was to interpret the protective mechanisms of L4 somatic antigen (LSA) from Heligmosomoides polygyrus against an inflammatory response to the pathogenesis of DNBS-induced colitis. Colitis was actuated in mice by rectal instillation of DNBS. The mice were randomly divided into five groups containing control, DNBS alone, and three groups, with different doses of LSA (50, 100, and 200 μg/mL), respectively. Mice initiated colitis by rectal administration of DNBS and after that were immunized with LSA for 14 days. Mice treated with LSA inhibited wasting disease compared with DNBS only group. The percentages of cells producing IFN-γ were reduced by LSA treatment. The level of T lymphocytes CD4⁺IFN-γ⁺ cells in the LPL was significantly diminished by LSA at both 100 and 200 μg/mL groups (p<0.05). The mRNA expression of T-bet was significantly declined in LSA immunized mice, but not RORγ-T mRNA, whereas GATA-3 expression tended to increase. The activation of STAT-4 significantly reduced LSA-treated mice but not STAT-1. It can be concluded that T-bet is required for optimal production of IFN-γ in colitis.

Role in Allergic Diseases of Immunological Cross-Reactivity between Allergens and Homologues of Parasite Proteins

Implied under the rubric of the hygiene hypothesis is that helminth infection can protect against allergic disease. It is well known that helminths induce processes associated with type 2 immune responses, but they also induce important regulatory responses that can modulate these type 2-associated responses-modulation that influences responses to bystander antigens including allergens. Indeed, most epidemiological studies demonstrate a beneficial effect of helminth infection on atopy, but there are also convincing data to demonstrate that helminth infection can precipitate or worsen allergic inflammation/disease. Reasons for these disparate findings are much debated, but there is a school of thought that suggests that helminth-triggered type 2-associated responses, including IgE to cross-reactive aeroallergens, can offset the regulatory effects imposed by the same organisms. The cross-reactivity among helminths and allergenic tropomyosins dominated the antigen/allergen cross-reactivity field, but recent data suggest that cross-reactivity is much more common than previously appreciated. It has been demonstrated that a high degree of molecular similarity exists between allergens and helminth proteins. Thus, an understanding of the mechanisms underlying the response induced by helminth infection and their impact on the induction of allergic disease in the host are critical for designing therapies using iatrogenic infections or parasite products to treat inflammatory diseases and for developing vaccines against helminth parasites.

Impact of Enterobius vermicularis infection and mebendazole treatment on intestinal microbiota and host immune response

Background

Previous studies on the association of enterobiasis and chronic inflammatory diseases have revealed contradictory results. The interaction of Enterobius vermicularis infection in particular with gut microbiota and induced immune responses has never been thoroughly examined.

Methodology/Findings

In order to answer the question of whether exposure to pinworm and mebendazole can shift the intestinal microbial composition and immune responses, we recruited 109 (30 pinworm-negative, 79 pinworm-infected) first and fourth grade primary school children in Taichung, Taiwan, for a gut microbiome study and an intestinal cytokine and SIgA analysis. In the pinworm-infected individuals, fecal samples were collected again at 2 weeks after administration of 100 mg mebendazole. Gut microbiota diversity increased after Enterobius infection, and it peaked after administration of mebendazole. At the phylum level, pinworm infection and mebendazole deworming were associated with a decreased relative abundance of Fusobacteria and an increased proportion of Actinobacteria. At the genus level, the relative abundance of the probiotic Bifidobacterium increased after enterobiasis and mebendazole treatment. The intestinal SIgA level was found to be lower in the pinworm-infected group, and was elevated in half of the mebendazole-treated group. A higher proportion of pre-treatment Salmonella spp. was associated with a non-increase in SIgA after mebendazole deworming treatment.

Conclusions/Significance

Childhood exposure to pinworm plus mebendazole is associated with increased bacterial diversity, an increased abundance of Actinobacteria including the probiotic Bifidobacterium, and a decreased proportion of Fusobacteria. The gut SIgA level was lower in the pinworm-infected group, and was increased in half of the individuals after mebendazole deworming treatment.

Whether human pinworm infection plus mebendazole deworming treatment can shift intestinal microbiota to a composition that is beneficial to the host and influence their mucosal immune response is currently unclear. In a cohort of 109 primary school children, we discovered that Enterobius vermicularis infection is associated with increased intestinal microbial diversity, a lowered relative abundance of Fusobacteria and an enriched proportion of Actinobacteria, including the probiotic Bifidobacterium. Mebendazole deworming was found to be correlated with a further increase in bacterial diversity. However, lower gut SIgA levels were detected in the pinworm infected group, and they were increased in only half of the subjects after mebendazole treatment.

Globule Leukocytes and Other Mast Cells in the Mouse Intestine

Only 2 major mast cell (MC) subtypes are commonly recognized in the mouse: the large connective tissue mast cells (CTMCs) and the mucosal mast cells (MMCs). Interepithelial mucosal inflammatory cells, most commonly identified as globule leukocytes (GLs), represent a third MC subtype in mice, which we term interepithelial mucosal mast cells (ieMMCs). This term clearly distinguishes ieMMCs from lamina proprial MMCs (lpMMCs) while clearly communicating their common MC lineage. Both lpMMCs and ieMMCs are rare in normal mouse intestinal mucosa, but increased numbers of ieMMCs are seen as part of type 2 immune responses to intestinal helminth infections and in food allergies. Interestingly, we found that increased ieMMCs were consistently associated with decreased mucosal inflammation and damage, suggesting that they might have a role in controlling helminth-induced immunopathology. We also found that ieMMC hyperplasia can develop in the absence of helminth infections, for example, in Treg-deficient mice, Arf null mice, some nude mice, and certain graft-vs-host responses. Since tuft cell hyperplasia plays a critical role in type 2 immune responses to intestinal helminths, we looked for (but did not find) any direct relationship between ieMMC and tuft cell numbers in the intestinal mucosa. Much remains to be learned about the differing functions of ieMMCs and lpMMCs in the intestinal mucosa, but an essential step in deciphering their roles in mucosal immune responses will be to apply immunohistochemistry methods to consistently and accurately identify them in tissue sections.

Preservación de huevos de Necator americanus con acetato de sodio-ácido acético-formalina (SAF). Estudio de caso

Introducción. La técnica de Kato Katz es el método recomendado para realizar el recuento de huevos en materia fecal y determinar la intensidad parasitaria por helmintos. La calidad de los resultados se ve afectada por la tardanza en el procesamiento de la muestra, por lo que se requiere de preservantes que faciliten la lectura posterior a las 24 horas de recolección de la muestra.Objetivo. Demostrar validez de la solución con acetato de sodio-ácido acético-formalina (SAF) como preservante de huevos de Necator americanus por medio del estudio de un caso clínico.Materiales y métodos. Descripción de caso clínico con diagnóstico de parásitos intestinales por coprológico, intensidad de la infección por la técnica de Kato Katz, evaluación de la presencia de huevos N. americanus por la técnica de Kato Katz durante 10 meses en muestra preservada en SAF y determinación de especie de Uncinaria sp.por qPCR.Resultados. Los huevos de N. americanus se conservan de manera adecuada en morfología durante los primeros cinco meses.Conclusiones. A fin de ejecutar la técnica de Kato Katz, la fijación con SAF demostró ser adecuada para el mantenimiento de la intensidad parasitaria y morfología de los huevos de N. americanus en un período de hasta cinco meses.

A Randomised, Double-blind, Placebo-controlled Trial of Trichuris suis ova in Active Crohn's Disease

BACKGROUND AND AIMS

To investigate the efficacy and safety of three different dosages of embryonated, viable eggs of Trichuris suis [TSO] versus placebo for induction of remission in mildly-to-moderately active ileocolonic, uncomplicated Crohn's disease [CD].

METHODS

Adults with active CD [n = 252] randomly received six fortnightly doses of 250, 2500, or 7500 TSO/15 ml suspension/day [TSO 250, TSO 2500, TSO 7500], or 15 ml placebo solution/day, in a double-blind fashion, with 4 weeks' follow-up. Primary endpoint was the rate of clinical remission [Crohn's Disease Activity Index [CDAI] < 150] at end of treatment, ie at Week 12 or withdrawal. Secondary endpoints included the course of clinical remission, rate of clinical response, change in CDAI, change in markers of inflammation, mucosal healing, and Physician's Global Assessment.

RESULTS

Clinical remission at Week 12 occurred in 38.5%, 35.2%, and 47.2% of TSO 250, TSO 2500, and TSO 7500 patients, respectively, and in 42.9% of placebo recipients. TSO induced a dose-dependent immunological response. There was no response regarding laboratory markers of inflammation. Other secondary efficacy variables also showed no advantage of TSO over placebo for treatment of active CD. Administration of TSO did not result in any serious adverse drug reaction. Review of non-serious suspected adverse drug reactions following TSO did not reveal any safety concerns.

CONCLUSIONS

Administration of 250-7500 TSO fortnightly over 12 weeks was safe and showed a dose-dependent immunological response, but no TSO dose showed a clinically relevant effect over placebo for induction of clinical remission or response in mildly-to-moderately active, ileocolonic CD.

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.

Human Helminths and Allergic Disease: The Hygiene Hypothesis and Beyond

There is much debate about the interaction between helminths and allergic disease. The "Hygiene Hypothesis," a very popular concept among scientists and the lay public, states that infections, especially during childhood, can protect against allergic diseases. Indeed, helminth infections are known to induce regulatory responses in the host that can help the control of inflammation (including allergic inflammation). However, these infections also induce type-2-associated immune responses including helminth-specific IgE that can cross-react against environmental allergens and mediate IgE-driven effector responses. Thus, it is the delicate balance between the parasites' anti- and pro-allergenic effects that define the helminth/allergy interface.

An experimental model of colitis induced by dextran sulfate sodium from acute progresses to chronicity in C57BL/6: correlation between conditions of mice and the environment

AIM

To induce acute colitis progresses to chronicity in C57BL/6 mice by dextran sulfate sodium.

BACKGROUND

Murine models are essential tools to understand IBD pathogenesis. Among different types of chemically induced colitis models, the dextran sulfate sodium (DSS)-induced colitis model is the most common model of IBD, due to its simplicity.

PATIENTS AND METHODS

Male C57BL/6 mice 6-8 weeks old, were collected and matched by age with controls. C57BL/6 mice treated with 2 cycles of 3.5% DSS for 4 days and 4 days of pure water between each cycle. After that, mice were sacrificed and the entire colon was removed. Small sections of the colon were fixed in formaldehyde, embedded in paraffin and sectioned with a microtome. Sections were stained with hematoxylin eosin to analyses the degree of inflammation.

RESULTS

After the first cycle oral administration of DSS, mice with severe and visible rectal bleeding and diarrhea entered into the acute phase. After day 4-5, bleeding and diarrhea were improved and mice entered into the chronic phase with peak levels of weight loss. Macroscopically, the inflammation was predominantly located in the distal colon. Microscopically, examination of the distal colon sections showed a decrease number of goblet cells, loss of crypts, signs of surface epithelial regeneration and moderate to severe infiltration of inflammatory cells in the mucosa.

CONCLUSION

In order to achieve an experimental colitis model, our protocol is recommended for future therapies in IBD experimental modeling.

Immunomodulatory effects of Trichinella spiralis-derived excretory-secretory antigens

Helminth-derived products, either released into the circulation during the course of the infection or isolated after in vitro cultivation of the parasite and applied by the injection, are able to suppress the host immune response to autoantigens and allergens, but mechanisms could differ. Prophylactic application of Trichinella spiralis excretory-secretory muscle larvae (ES L1) products ameliorates experimental autoimmune encephalomyelitis (EAE) with the same success as infection did. However, a shift to the Th2-type response in the periphery and in the central nervous system, accompanied by activation of regulatory mechanisms, had a striking, new feature of increased proportion of unconventional CD4(+)CD25(-)Foxp3(+) regulatory cells both in the periphery and in the central nervous system of animals treated with ES L1 before the induction of EAE.

Role of type 2 immunity in intestinal inflammation

PURPOSE OF REVIEW

Type 2 (Th2) immune responses play important roles in intestinal immunity by contributing to the maintenance of mucosal homeostasis, not only conferring protection against helminthic infection but also participating in pro-inflammatory pathways in chronic intestinal inflammatory disorders, including inflammatory bowel disease. The current review focuses on recent developments regarding the role of Th2 responses in intestinal inflammation.

RECENT FINDINGS

Th2 gut mucosal responses are promoted by mediators that are released following injury to the epithelium, and act as alarmin-type danger signals. Interleukin (IL)-33 is prominent among such factors and demonstrates a dichotomous function, exerting either protective or pro-inflammatory effects, depending on its cellular compartmentalization. The pool of type 2 effector cells has been enriched recently to include not only classical CD4+ Th2 lymphocytes but also a subset of innate lymphocytes (ILC2s) that express the transcriptional factor GATA binding protein 3 and secrete IL-4, IL-5, and IL-13. ILC2s play important roles during infection with helminths and bi-directionally interact with Th2 CD4+ lymphocytes, thus establishing a transition from innate to adaptive immunological pathways. Th2 responses are also involved in pro-inflammatory pathways at the intestinal mucosa, and neutralization of the pivotal cytokines IL-4 and IL-13 has been shown to regulate experimental intestinal inflammation. In striking contrast, however, neutralization of human IL-13 had no therapeutic effect in patients with ulcerative colitis.

SUMMARY

Further studies will be required to delineate the specific mechanisms of type 2 mucosal immunity in inflammatory bowel disease and examine the applicability of Th2-targeted therapies for intestinal inflammation.

Modulation of pro- and anti-inflammatory cytokines in active and latent tuberculosis by coexistent Strongyloides stercoralis infection

Helminth infections are known to induce modulation of both innate and adaptive immune responses in active and latent tuberculosis (TB). However, the role of helminth infections in modulating systemic cytokine responses in active and latent tuberculosis (LTB) is not known. To define the systemic cytokine levels in helminth-TB coinfection, we measured the circulating plasma levels of Type 1, Type 2, Type 17, other pro-inflammatory and regulatory cytokines in individuals with active TB (ATB) with or without coexistent Strongyloides stercoralis (Ss) infection by multiplex ELISA. Similarly, we also measured the same cytokine levels in individuals with LTB with or without concomitant Ss infection in a cross-sectional study. Our data reveal that individuals with ATB or LTB and coexistent Ss infection have significantly lower levels of Type 1 (IFNγ, TNFα and IL-2) and Type 17 (IL-17A and IL-17F) cytokines compared to those without Ss infection. In contrast, those with ATB and LTB with Ss infection have significantly higher levels of the regulatory cytokines (IL-10 and TGFβ), and those with LTB and Ss infection also have significantly higher levels of Type 2 cytokines (IL-4, IL-5 and IL-13) as well. Finally, those with LTB (but not ATB) exhibit significantly lower levels of other pro-inflammatory cytokines (IFNα, IFNβ, IL-6, IL-12 and GM-CSF). Our data therefore reveal a profound effect of Ss infection on the systemic cytokine responses in ATB and LTB and indicate that coincident helminth infections might influence pathogenesis of TB infection and disease.

The parasitic worm product ES-62 targets myeloid differentiation factor 88-dependent effector mechanisms to suppress antinuclear antibody production and proteinuria in MRL/lpr mice

Objective

The hygiene hypothesis suggests that parasitic helminths (worms) protect against the development of autoimmune disease via a serendipitous side effect of worm-derived immunomodulators that concomitantly promote parasite survival and limit host pathology. The aim of this study was to investigate whether ES-62, a phosphorylcholine-containing glycoprotein secreted by the filarial nematode Acanthocheilonema viteae, protects against kidney damage in an MRL/lpr mouse model of systemic lupus erythematosus (SLE).

Methods

MRL/lpr mice progressively produce high levels of autoantibodies, and the resultant deposition of immune complexes drives kidney pathology. The effects of ES-62 on disease progression were assessed by measurement of proteinuria, assessment of kidney histology, determination of antinuclear antibody (ANA) production and cytokine levels, and flow cytometric analysis of relevant cellular populations.

Results

ES-62 restored the disrupted balance between effector and regulatory B cells in MRL/lpr mice by inhibiting plasmablast differentiation, with a consequent reduction in ANA production and deposition of immune complexes and C3a in the kidneys. Moreover, by reducing interleukin-22 production, ES-62 may desensitize downstream effector mechanisms in the pathogenesis of kidney disease. Highlighting the therapeutic importance of resetting B cell responses, adoptive transfer of purified splenic B cells from ES-62–treated MRL/lpr mice mimicked the protection afforded by the helminth product. Mechanistically, this reflects down-regulation of myeloid differentiation factor 88 expression by B cells and also kidney cells, resulting in inhibition of pathogenic cross-talk among Toll-like receptor–, C3a-, and immune complex–mediated effector mechanisms.

Conclusion

This study provides the first demonstration of protection against kidney pathology by a parasitic worm–derived immunomodulator in a model of SLE and suggests therapeutic potential for drugs based on the mechanism of action of ES-62.

Trichuris suis ova, lecithin and other fancy molecules

During the last 20 years, treatment paradigms as well as drugs used for IBD have changed significantly. However, there are still many unmet needs and a significant number of patients needing better therapy. It is obvious from this situation that many attempts have been made to implement new drugs and treatment algorithms including biologicals, new formulations of old drugs and 'fancy molecules or approaches'. For about 10 years, the application of Trichuris suis ova has been promoted and used in quite a number of patients. Two early studies suggested positive effects in ulcerative colitis as well as in Crohn's disease. These studies were based on experimental data in animal models as well as in vitro experiments. However, two large randomized controlled trials were not able to provide significant clinical effects in active Crohn's disease as compared to placebo, although a biological reaction (eosinophilia) was found. Another approach is the use of locally released phosphatidylcholine in ulcerative colitis. This approach is based on decreased phosphatidylcholine concentrations in the colonic mucus in patients, and showed positive effects in a number of monocentric trials in steroid-refractory and chronic active ulcerative colitis. A dose-finding study gave a positive signal in the highest-dose group and this approach is being tested further in controlled trials. Many other 'fancy molecules' including cannabis, vitamin D, thalidomide, hyaluronic acid, lidocaine, clonidine, chondroitin sulfate, naltrexone and melatonin have been tested in patients with claims of success. For most of those, however, controlled data in appropriate studies are lacking. Many more substances have been used in animal models and are probably applied in individual patients. Results of preliminary studies on some of the molecules mentioned are presented.

Helminth infection alters IgE responses to allergens structurally related to parasite proteins

Immunological cross-reactivity between environmental allergens and helminth proteins has been demonstrated, although the clinically related implications of this cross-reactivity have not been addressed. To investigate the impact of molecular similarity among allergens and cross-reactive homologous helminth proteins in IgE-based serologic assessment of allergic disorders in a helminth-infected population, we performed ImmunoCAP tests in filarial-infected and noninfected individuals for IgE measurements to allergen extracts that contained proteins with high levels of homology with helminth proteins as well as IgE against representative recombinant allergens with and without helminth homologs. The impact of helminth infection on the levels and function of the IgE to these specific homologous and nonhomologous allergens was corroborated in an animal model. We found that having a tissue-invasive filarial infection increased the serological prevalence of ImmunoCAP-identified IgE directed against house dust mite and cockroach, but not against timothy grass, the latter with few allergens with homologs in helminth infection. IgE ELISA confirmed that filaria-infected individuals had higher IgE prevalences to those recombinant allergens that had homologs in helminths. Mice infected with the helminth Heligmosomoides polygyrus displayed increased levels of IgE and positive skin tests to allergens with homologs in the parasite. These results show that cross-reactivity among allergens and helminth proteins can have practical implications, altering serologic approaches to allergen testing and bringing a new perspective to the "hygiene hypothesis."

Coincident helminth infection modulates systemic inflammation and immune activation in active pulmonary tuberculosis

BACKGROUND

Helminth infections are known to modulate innate and adaptive immune responses in active and latent tuberculosis (TB). However, the role of helminth infections in modulating responses associated with inflammation and immune activation (reflecting disease activity and/or severity) in TB is not known.

METHODOLOGY

We measured markers of inflammation and immune activation in active pulmonary TB individuals (ATB) with co-incidental Strongyloides stercoralis (Ss) infection. These included systemic levels of acute phase proteins, matrix metalloproteinases and their endogenous inhibitors and immune activation markers. As a control, we measured the systemic levels of the same molecules in TB-uninfected individuals (NTB) with or without Ss infection.

PRINCIPAL FINDINGS

Our data confirm that ATB is associated with elevated levels of the various measured molecules when compared to those seen in NTB. Our data also reveal that co-incident Ss infection in ATB individuals is associated with significantly decreased circulating levels of acute phase proteins, matrix metalloproteinases, tissue inhibitors of matrix metalloproteinases as well as the systemic immune activation markers, sCD14 and sCD163. These changes are specific to ATB since they are absent in NTB individuals with Ss infection.

CONCLUSIONS

Our data therefore reveal a profound effect of Ss infection on the markers associated with TB disease activity and severity and indicate that co-incidental helminth infections might dampen the severity of TB disease.

Worm proteins of Schistosoma mansoni reduce the severity of experimental chronic colitis in mice by suppressing colonic proinflammatory immune responses

Although helminthic therapy as a possible new option to treat inflammatory bowel disease is a well-established concept by now, the search for immunomodulatory helminth-derived compounds and their mechanisms of action is still ongoing. We investigated the therapeutic potential and the underlying immunological mechanisms of Schistosoma mansoni soluble worm proteins (SmSWP) in an adoptive T cell transfer mouse model of chronic colitis. Both a curative and a preventive treatment protocol were included in this study. The curative administration of SmSWP (started when colitis was established), resulted in a significant improvement of the clinical disease score, colonoscopy, macroscopic and microscopic inflammation score, colon length and myeloperoxidase activity. The therapeutic potential of the preventive SmSWP treatment (started before colitis was established), was less pronounced compared with the curative SmSWP treatment but still resulted in an improved clinical disease score, body weight loss, colon length and microscopic inflammation score. Both the curative and preventive SmSWP treatment downregulated the mRNA expression of the proinflammatory cytokines IFN-γ and IL-17A and upregulated the mRNA expression of the anti-inflammatory cytokine IL-4 in the colon at the end of the experiment. This colonic immunomodulatory effect of SmSWP could not be confirmed at the protein level. Moreover, the effect of SmSWP appeared to be a local colonic phenomenon, since the flow cytometric T cell characterization of the mesenteric lymph nodes and the cytokine measurements in the serum did not reveal any effect of SmSWP treatment. In conclusion, SmSWP treatment reduced the severity of colitis in the adoptive transfer mouse model via the suppression of proinflammatory cytokines and the induction of an anti-inflammatory response in the colon.

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.

Kv1.3 channel-blocking immunomodulatory peptides from parasitic worms: implications for autoimmune diseases

The voltage-gated potassium (Kv) 1.3 channel is widely regarded as a therapeutic target for immunomodulation in autoimmune diseases. ShK-186, a selective inhibitor of Kv1.3 channels, ameliorates autoimmune diseases in rodent models, and human phase 1 trials of this agent in healthy volunteers have been completed. In this study, we identified and characterized a large family of Stichodactyla helianthus toxin (ShK)-related peptides in parasitic worms. Based on phylogenetic analysis, 2 worm peptides were selected for study: AcK1, a 51-residue peptide expressed in the anterior secretory glands of the dog-infecting hookworm Ancylostoma caninum and the human-infecting hookworm Ancylostoma ceylanicum, and BmK1, the C-terminal domain of a metalloprotease from the filarial worm Brugia malayi. These peptides in solution adopt helical structures closely resembling that of ShK. At doses in the nanomolar-micromolar range, they block native Kv1.3 in human T cells and cloned Kv1.3 stably expressed in L929 mouse fibroblasts. They preferentially suppress the proliferation of rat CCR7(-) effector memory T cells without affecting naive and central memory subsets and inhibit the delayed-type hypersensitivity (DTH) response caused by skin-homing effector memory T cells in rats. Further, they suppress IFNγ production by human T lymphocytes. ShK-related peptides in parasitic worms may contribute to the potential beneficial effects of probiotic parasitic worm therapy in human autoimmune diseases.

Of worms, mice and man: an overview of experimental and clinical helminth-based therapy for inflammatory bowel disease

The incidence of inflammatory and autoimmune disorders is highest in well-developed countries which is directly related to their higher hygienic standards: it is suggested that the lack of exposure to helminths contributes to the susceptibility for immune-related diseases. Epidemiological, experimental and clinical data support the idea that helminths provide protection against immune-mediated diseases such as inflammatory bowel disease (IBD). The most likely mechanism for the suppression of immune responses by helminths is the release of helminth-derived immunomodulatory molecules. This article reviews the experimental and clinical studies investigating the therapeutic potential of helminth-based therapy in IBD and also focuses on the current knowledge of its immunomodulatory mechanisms of action highlighting innate as well as adaptive immune mechanisms. Identifying the mechanisms by which these helminths and helminth-derived molecules modulate the immune system will help in creating novel drugs for the treatment of IBD and other disorders that result from an overactive immune response.

Increased susceptibility to Trichuris muris infection and exacerbation of colitis in Mdr1a-/- mice

AIM: To investigate the influence of Trichuris muris (T. muris) infection in a mouse model of genetic susceptibility to inflammatory bowel disease, Mdr1a-/-.

METHODS: Mdr1a-/- mice were housed under specific pathogen free conditions to slow the development of colitis and compared to congenic FVB controls. Mice were infected with approximately 200 embryonated ova from T. muris and assessed for worm burden and histological and functional markers of gut inflammation on day 19 post infection.

RESULTS: Mdr1a-/- mice exhibited a marked increase in susceptibility to T. muris infection with a 10-fold increase in colonic worm count by day 19 pi compared to FVB controls. Prior to infection, Mdr1a-/- exhibited low-level mucosal inflammation with evidence of an enhanced Th1 environment. T. muris infection accelerated the progression of colitis in Mdr1a-/- as evidenced by marked increases in several indicators including histological damage score, mucosal CD4⁺ T-cell and DC infiltration and dramatically increased production of pro-inflammatory cytokines.

CONCLUSION: These data provide further evidence of the complex interaction between T. muris and an inflammatory bowel disease (IBD)-susceptible host which may have relevance to the application of helminth therapy in the treatment of human IBD.

Potential treatment of inflammatory bowel disease: a review of helminths therapy

An inflammatory bowel disease (IBD) is most common in highly industrialized Western countries but uncommon in less developed areas of the world where helminths are frequent. The hygiene hypothesis proposes that the recent increase in allergic and autoimmune diseases is due to modern highly hygienic life styles and medical conditions. Loss of routine exposure to parasitic helminths, as a result of increasing lifestyle-associated factors, may be one factor leading to the increased disease prevalence. In animal models and clinical trials of IBD, gastrointestinal nematodes colonization suppresses intestinal inflammation through multiple mechanisms including induction of innate and adaptive regulatory circuits. Studies using helminths like Trichuris suis or Necator americanus showed that these helminths are safe and may be effective therapeutic approaches for the control of IBD and other immune diseases. The aim of present review was to exploring the therapeutic use of helminths for the control of IBD.

Trichuris suis ova in inflammatory bowel disease

Some but not all epidemiological studies suggest that helminth infection in childhood protects against development of inflammatory bowel disease (IBD) in later years. In animal models of IBD, helminths have shown protective effects and changed bacterial flora in the gut. Based on these concepts, small trials and series have been published showing some positive effects of Trichuris suis ova in ulcerative colitis and Crohn's disease. Currently, large randomized placebo-controlled trials are under way. Results remain to be awaited in order to clarify a possible role of T. suis ova in the treatment of IBD.

A clinical review of recent findings in the epidemiology of inflammatory bowel disease

Inflammatory bowel diseases (IBD), including both Crohn's disease and ulcerative colitis, are disorders of chronic inflammation of the gastrointestinal tract marked by episodes of relapse and remission. Over the past several decades, advances have been made in understanding the epidemiology of IBD. The incidence and prevalence of both Crohn's disease and ulcerative colitis have been increasing worldwide across pediatric and adult populations. As IBD is thought to be related to a combination of individual genetic susceptibility, environmental triggers, and alterations in the gut microbiome that stimulate an inflammatory response, understanding the potentially modifiable environmental risk factors associated with the development or the course of IBD could impact disease rates or management in the future. Current hypotheses as to the development of IBD are reviewed, as are a host of environmental cofactors that have been investigated as both protective and inciting factors for IBD onset. Such environmental factors include breast feeding, gastrointestinal infections, urban versus rural lifestyle, medication exposures, stress, smoking, and diet. The role of these factors in disease course is also reviewed. Looking forward, there is still much to be learned about the etiology of IBD and how specific environmental exposures intimately impact the development of disease and also the potential for relapse.