[Novel tropomyosin consensus B and T epitopes involved in cross-reactivity between 10 different species. An in silico study]. / Nuevos epítopes B y T, consenso de tropomiosina involucradas en reactividad cruzada entre diez especies diferentes. Un estudio in silico.

OBJECTIVE: This study aimed to identify by in silico methods tropomyosin consensus B and T epitopes of shrimp species, house dust mites, insects, and nematodes associated with allergic diseases in tropical countries. METHODS: In silico analysis included tropomyosin from mites (Der p 10, Der f 10, Blo t 10), insects (Aed a 10, Per a 7, Bla g 7), shrimp (Lit v 1, Pen m 1, Pen a 1), and nematode (Asc l 3) all sequences were taken from the UniProt database. Linear IgE epitopes were predicted with AlgPred 2.0 and validated with BepiPred 3.0. MHC-II binding T cell epitopes were predicted using the IEDB server, which implements nine predictive methods (consensus method, combinatorial library, NN-align-2.3, NN- align-2.2, SMM-align, Sturniolo, NetMHCIIpan 3.1, and NetMHCIIpan 3.2) these predictions focused on 10 HLA-DR and 2 HLA-DQ alleles associated with allergic diseases. Subsequently, consensus B and T epitopes present in all species were identified. RESULTS: We identified 12 sequences that behaved as IgE-epitopes and B-cell epitopes, three of them: 160RKYDEVARKLAMVEA174, 192ELEEELRVVGNNLKSLEVSEEKAN215, 251KEVDRLEDELV261 were consensus in all species. Eleven peptides (T-epitopes) showed strong binding (percentile rank ≤ 2.0) to HLA-DRB1*0301, *0402, *0411, *0701, *1101, *1401, HLA-DQA1*03:01/DQB1*03:02, and HLA- DQA1*05:01/DQB1*02:01. Only two T-epitopes were consensus in all species: 167RKLAMVEADLERAEERAEt GEsKIVELEEELRV199, and 218EEeY KQQIKT LTaKLKEAEARAEFAERSV246. Subsequently, we identified 2 B and T epitope sequences and reached a consensus between species 167RKLAMVEA174 and 192ELEEELRV199. CONCLUSIONS: These data describe three sequences that may explain the IgE cross-reactivity between the analyzed species. In addition, the consensus B and T epitopes can be used for further in vitro investigations and may help to design multiple-epitope protein-based immunotherapy for tropomyosin-related allergic diseases.

OBJETIVO: Este estudio tuvo como objetivo identificar mediante métodos in silico epítopes B y T consenso de tropomiosina de especies de camarón, ácaros del polvo doméstico, insectos y nematodos asociados a enfermedades alérgicas en países tropicales. MÉTODOS: El análisis in silico incluyó tropomiosina de ácaros (Der p 10, Der f 10, Blo t 10), insectos (Aed a 10, Per a 7, Bla g 7), camarones (Lit v 1, Pen m 1, Pen a 1), y nematodo (Asc l 3). Todas las secuencias se tomaron de la base de datos UniProt. Los epítopes IgE lineales se predijeron con AlgPred 2.0 y se validaron con BepiPred 3.0. Los epítopes de células T de unión a MHC-II se predijeron utilizando el servidor IEDB, que implementa nueve métodos predictivos (método de consenso, biblioteca combinatoria, NN-align-2.3, NN-align-2.2, SMM-align, Sturniolo, NetMHCIIpan 3.1 y NetMHCIIpan 3.2). Estas predicciones se centraron en diez alelos HLA-DR y 2 HLA-DQ asociados con enfermedades alérgicas. Posteriormente, se identificaron epítopes consenso B y T presentes en todas las especies. RESULTADOS: Se identificaron 12 secuencias que se comportaron como epítopes de IgE y, también, como epítopes de células B. Tres de ellas: 160RKYDEVARKLAMVEA174, 192ELEEELRVVGNNLKSLEVSEEKAN213 y 251KEVDRLEDELV261, fueron consenso en todas las especies. Once péptidos mostraron una fuerte unión (rango percentil ≤ 2,0) a HLA-DRB1*0301, *0402, *0411, *0701, *1101, *1401 y a HLA HLA-DQA1*03:01/DQB1*03:02, o HLA-DQA1*05:01/DQB1*02:01. Solo se encontraron dos secuencias: 167RKLAMVEADLERAEERAEtGEsKIVELEEELRV199 con fuerte afinidad por HLA-DQA1*03:01/DQB1*03:02, y HLA-DQA1*05:01/DQB1*02:01. Se identificaron dos secuencias que son epítopos B y T, y son consenso entre especies: 167RKLAMVEA174 y 192ELEEELRV199. CONCLUSIONES: Estos datos describen tres secuencias que pueden explicar la reactividad cruzada de IgE entre las especies analizadas. Además, los epítopos B y T consenso se pueden usar para investigaciones in vitro adicionales, y pueden ayudar a diseñar inmunoterapia basada en proteínas de múltiepítopes para enfermedades alérgicas relacionadas con la tropomiosina.

Lactic acid bacteria that activate immune gene expression in Caenorhabditis elegans can antagonise Campylobacter jejuni infection in nematodes, chickens and mice.

BACKGROUND: Campylobacter jejuni is the major micro-bacillary pathogen responsible for human coloenteritis. Lactic acid bacteria (LAB) have been shown to protect against Campylobacter infection. However, LAB with a good ability to inhibit the growth of C. jejuni in vitro are less effective in animals and animal models, and have the disadvantages of high cost, a long cycle, cumbersome operation and insignificant immune response indicators. Caenorhabditis elegans is increasingly used to screen probiotics for their anti-pathogenic properties. However, no research on the use of C. elegans to screen for probiotic candidates antagonistic to C. jejuni has been conducted to date. RESULTS: This study established a lifespan model of C. elegans, enabling the preselection of LAB to counter C. jejuni infection. A potential protective mechanism of LAB was identified. Some distinct LAB species offered a high level of protection to C. elegans against C. jejuni. The LAB strains with a high protection rate reduced the load of C. jejuni in C. elegans. The transcription of antibacterial peptide genes, MAPK and Daf-16 signalling pathway-related genes was elevated using the LAB isolates with a high protection rate. The reliability of the lifespan model of C. elegans was verified using mice and chickens infected with C. jejuni. CONCLUSIONS: The results showed that different LAB had different abilities to protect C. elegans against C. jejuni. C. elegans provides a reliable model for researchers to screen for LAB that are antagonistic to C. jejuni on a large scale.

Wolbachia: endosymbiont of onchocercid nematodes and their vectors.

BACKGROUND: Wolbachia is an obligate intracellular maternally transmitted, gram-negative bacterium which forms a spectrum of endosymbiotic relationships from parasitism to obligatory mutualism in a wide range of arthropods and onchocercid nematodes, respectively. In arthropods Wolbachia produces reproductive manipulations such as male killing, feminization, parthenogenesis and cytoplasmic incompatibility for its propagation and provides an additional fitness benefit for the host to protect against pathogens, whilst in onchocercid nematodes, apart from the mutual metabolic dependence, this bacterium is involved in moulting, embryogenesis, growth and survival of the host. METHODS: This review details the molecular data of Wolbachia and its effect on host biology, immunity, ecology and evolution, reproduction, endosymbiont-based treatment and control strategies exploited for filariasis. Relevant peer-reviewed scientic papers available in various authenticated scientific data bases were considered while writing the review. CONCLUSIONS: The information presented provides an overview on Wolbachia biology and its use in the control and/or treatment of vectors, onchocercid nematodes and viral diseases of medical and veterinary importance. This offers the development of new approaches for the control of a variety of vector-borne diseases.

Transcriptomic Insights into the Insect Immune Response to Nematode Infection.

Insects in nature interact with a wide variety of microbial enemies including nematodes. These include entomopathogenic nematodes that contain mutualistic bacteria and together are able to infect a broad range of insects in order to complete their life cycle and multiply, filarial nematodes which are vectored by mosquitoes, and other parasitic nematodes. Entomopathogenic nematodes are commonly used in biological control practices and they form excellent research tools for understanding the genetic and functional bases of nematode pathogenicity and insect anti-nematode immunity. In addition, clarifying the mechanism of transmission of filarial nematodes by mosquitoes is critical for devising strategies to reduce disease transmission in humans. In all cases and in order to achieve these goals, it is vital to determine the number and type of insect host genes which are differentially regulated during infection and encode factors with anti-nematode properties. In this respect, the use of transcriptomic approaches has proven a key step for the identification of insect molecules with anti-nematode activity. Here, we review the progress in the field of transcriptomics that deals with the insect response to nematode infection. This information is important because it will expose conserved pathways of anti-nematode immunity in humans.

Measurements of Innate Immune Function in C. elegans.

The microscopic nematode Caenorhabditis elegans has emerged as a powerful system to characterize evolutionarily ancient mechanisms of pathogen sensing, innate immune activation, and protective host responses. Experimentally, C. elegans can be infected with a wide variety of human pathogens, as well as with natural pathogens of worms that were isolated from wild-caught nematodes. Here, we focus on an experimental model of bacterial pathogenesis that utilizes the human opportunistic bacterial pathogen Pseudomonas aeruginosa and present an algorithm that can be used to study mechanisms of immune function in nematodes. An initial comparison of the susceptibility of a C. elegans mutant to P. aeruginosa infection with its normal lifespan permits an understanding of a mutant's effect on pathogen susceptibility in the context of potential pleotropic consequences on general worm fitness. Assessing the behavior of nematodes in the presence of P. aeruginosa can also help determine if a gene of interest modulates pathogen susceptibility by affecting the host's ability to avoid a pathogen. In addition, quantification of the pathogen load in the C. elegans intestine during infection, characterization of immune effector transcription that are regulated by host defense pathways and an initial assessment of tissue specificity of immune gene function can refine hypotheses about the mechanism of action of a gene of interest. Together, these protocols offer one approach to characterize novel host defense mechanisms in a simple metazoan host.

Role of eosinophils in protective immunity against secondary nematode infections.

Infections with parasites, especially those involving nematodes that invade tissues, induce a strong Th2-type immune response, which increases immunoglobulin E and eosinophil levels in the blood and tissues. Eosinophils are not effective against all possible helminth infections, but are known to be effective against nematode larvae. In particular, when a host is re-infected by a species of nematode that it previously encountered, the activation of acquired immunity causes robust accumulation and activation of eosinophils that damages the nematode larvae. Eosinophil production and activation processes are mainly induced by interleukin (IL)-5, which is produced by Th2 cells and group 2 innate lymphoid cells, and eosinophils have been shown to generally participate in host defense, inflammation, and immunomodulation. Recently, several papers have reported host defense by non-antigen-specific immune activation, in which group 2 innate lymphoid cells and Th2 cells produce interleukin (IL)-5 and IL-13 in response to IL-33 stimulation. This immune activation is produced by migrating larvae of a species that differs from the species previously encountered. Eosinophils also play an important role in the eradication of migrating larvae. Thus, eosinophils contribute to host defense in both antigen-specific and non-antigen-specific manners.

Reduced egg shedding in nematode-resistant ewes and projected epidemiological benefits under climate change.

Global livestock production is facing serious new challenges, including climate-driven changes in parasite epidemiology, and anthelmintic resistance, driving a need for non-chemotherapeutic methods of parasite control. Selecting for genetic resistance to gastrointestinal nematode infection could reduce reliance on chemical intervention and mitigate increases in parasite challenge due to climate change. Ewes of the composite Exlana breed with a range of estimated breeding values (EBVs) based on nematode faecal egg counts (FECs) were monitored during the peri-parturient period on two farms in southwestern England. Ewes with low EBVs ("resistant") had lower FECs during the peri-parturient period than those with high EBVs ("susceptible"): the mean FEC was reduced by 23% and 34% on Farms 1 and 2, respectively, while the peak FEC was reduced by 30% and 37%, respectively. Neither EBV nor FEC were correlated with key performance indicators (estimated milk yield, measured indirectly using 8 week lamb weight, and ewe weight loss during lactation). Simulations predict that the reduced FECs of resistant ewes would result in a comparable reduction in infection pressure (arising from eggs shed by ewes) for their lambs. Furthermore, although the reduced FECs observed were modest, simulations predicted that selecting for nematode resistance in ewes could largely offset predicted future climate-driven increases in pasture infectivity arising from eggs contributed by these ewes. Selective breeding of the maternal line for nematode resistance therefore has potential epidemiological benefits by reducing pasture infectivity early in the grazing season and alleviating the need for anthelmintic treatment of ewes during the peri-parturient period, thus reducing selection pressure for anthelmintic resistance. These benefits are magnified under predicted future climate change. The maternal line warrants more attention in selective breeding programmes for nematode resistance.

Coproantigen Detection Augments Diagnosis of Common Nematode Infections in Dogs.

Microscopic methods which employ active or passive flotation have been used to detect parasite diagnostic stages in the feces of companion animals for many years. More recently, coproantigen ELISAs for the detection of excretory/secretory products from intestinal nematodes have been introduced. These assays can identify the presence of parasites when eggs are not recovered by flotation (e.g. prepatent infection or intermittent egg shedding). The study was designed to assess the added benefit of these coproantigen tests in canine fecal diagnostics. The work was performed at 3 separate sites where canine fecal samples were each independently evaluated by both centrifugal flotation with an expert examiner (CFE) and passive flotation with a less experienced examiner. All samples were also tested using coproantigen ELISA to detect ascarid, hookworm, or whipworm antigen (IDEXX Laboratories, Inc, Westbrook, Maine). A total of 1202 samples were collected; 626 were from shelter dogs and 576 were from pet dogs. CFE recovered ascarid eggs in 58 samples, hookworm eggs in 229 samples, and whipworm eggs in 95 samples. Of the positive samples identified by CFE, the PFE and ELISA identified 40 and 51 ascarid samples, 188 and 203 hookworm samples, and 65 and 67 whipworm positive samples, respectively. The coproantigen ELISA identified 8 ascarid, 82 hookworm, and 22 whipworm positive samples that were not detected by CFE. The combined results of passive flotation and the coproantigen ELISA improved the percent agreement with centrifugal flotation, suggesting that greater sensitivity of detection may be achieved through the use of complementary diagnostic methods. However, errors of misidentification and poor recovery apparently introduced by less experienced examiners using an inferior flotation method remained. A diagnostic approach that combines coproantigen assays with centrifugal flotation and examination by an expert allows detection of more ascarid, hookworm, and whipworm infections.

Parasite survey on a captive wolf population using classical techniques and ELISA coproantigen detection, USA.

As laws change around the United States, wildlife that were once kept as companion animals are now often confiscated by local authorities. They are then euthanized unless a home is found for them at a sanctuary. Wolf sanctuaries are, therefore, becoming increasingly important for their conservation and management. However, little data is available on best practices for the health management of captive wolves, including data on parasitic diseases. Our objective was to assess the prevalence of parasites of captive wolves combining classical coprological techniques and immunoassays based on the detection of coproantigen of selected canid parasites. Fecal samples of 39 animals were collected upon observation of individual animals defecating. All samples were processed using the Fecal Dx® tests, a suite of coproantigen ELISAs for detection of ascarid, hookworm, whipworm, and Giardia (IDEXX Laboratories Inc.). Out of the 39 samples, 38 were processed using the double-centrifugation sugar flotation (DCSF) and 34 using a modification of the Baermann technique. Twenty-eight samples (71.8%) were positive for hookworm, and none positive for the other parasites tested using coproantigen ELISA. Ancylostoma sp. (26, 68.4%), Eucoleus boehmi (13, 34.2%), and Trichuris sp. (2; 5.3%), and Sarcocystis sp. (13, 34.2%) were detected using DCSF. No metastrongyloid lungworm larvae were found. The Cohen's kappa index (0.97) showed excellent agreement between the hookworm coproantigen ELISA and the DCSF using feces preserved in ethanol for a short period of time. This study provides a baseline on the parasites of captive wolves, and shows that recent innovative diagnostics in veterinary parasitology, developed and optimized for dogs, may be used for assessing the health of wolves.

The state of art of neutrophil extracellular traps in protozoan and helminthic infections.

Neutrophil extracellular traps (NETs) are DNA fibers associated with histones, enzymes from neutrophil granules and anti-microbial peptides. NETs are released in a process denominated NETosis, which involves sequential steps that culminate with the DNA extrusion. NETosis has been described as a new mechanism of innate immunity related to defense against different pathogens. The initial studies of NETs were carried out with bacteria and fungi, but currently a large variety of microorganisms capable of inducing NETs have been described including protozoan and helminth parasites. Nevertheless, we have little knowledge about how NETosis process is carried out in response to the parasites, and about its implication in the resolution of this kind of disease. In the best case, the NETs entrap and kill parasites in vitro, but in others, immobilize the parasites without affecting their viability. Moreover, insufficient studies on the NETs in animal models of infections that would help to define their role, and the association of NETs with chronic inflammatory pathologies such as those occurring in several parasitic infections have left open the possibility of NETs contributing to pathology instead of protection. In this review, we focus on the reported mechanisms that lead to NET release by protozoan and helminth parasites and the evidence that support the role of NETosis in the resolution or pathogenesis of parasitic diseases.

Boer goats appear to lack a functional IgA and eosinophil response against natural nematode infection.

Gastrointestinal nematode infection is one of the major diseases affecting small ruminants. Although some breeds of goats are quite resistant, many breeds of goats are relatively susceptible. This study used a combined parasitological, immunological, bioinformatic and statistical approach to examine the role of goat IgA and eosinophils in protection against Teladorsagia circumcincta. Molecular modelling suggested that the transmembrane domain of the high affinity IgA receptor was dysfunctional in goats. Statistical analyses failed to find any association in naturally infected goats between high IgA or eosinophil responses and low faecal egg counts. Together these results indicate that IgA and eosinophil responses against T. circumcincta are less effective in goats than sheep.

Identification of an entomopathogenic bacterium, Xenorhabdus ehlersii KSY, from Steinernema longicaudum GNUS101 and its immunosuppressive activity against insect host by inhibiting eicosanoid biosynthesis.

Steinernema longicaudum GNUS101, an entomopathogenic nematode, was isolated from soils in Korea. Its internal transcribed space sequence was highly similar to the known S. longicaudum species. Infective juveniles (IJs) of S. longicaudum were highly virulent to lepidopteran and coleopteran insects. Two different bacteria were isolated from the hemolymph of lepidopteran larvae infected with S. longicaudum. They exhibited blue and red colonies on nutrient bromothymol blue agar. The red-colored bacterium was identified as Enterococcus mundtii KHY while the blue-colored bacterium was identified as Xenorhabdus ehlersii KSY based on 16S rRNA sequencing and biochemical characters. The bacterial species showed different growth rates, with X. ehlersii KSY growing more slowly than E. mundtii KHY. Both bacteria were entomopathogenic, but showed differences in suppressing host immune responses. X. ehlersii KSY, but not E. mundtii KHY, showed inhibitory activity against cellular immune responses of Spodoptera exigua larvae including hemocyte-spreading behavior and nodule formation in bacteria-cultured broth. Its immunosuppressive activity was reversed by adding arachidonic acid, an eicosanoid biosynthesis precursor. Furthermore, organic extracts of X. ehlersii KSY using hexane or ethyl acetate showed inhibitory activity against cellular immune responses of S. exigua larvae. Arachidonic acid addition to S. exigua larvae infected with X. ehlersii significantly rescued the survival rate of target insect. Of the two bacteria isolated from S. longicaudum GNUS101, only X. ehlersii induced immunosuppression of target insect by inhibiting eicosanoid biosynthesis.

Influence of the physiological stage of Blackbelly sheep on immunological behaviour against gastrointestinal nematodes.

The influence of the physiological stage of a Blackbelly flock against natural infection by gastrointestinal parasitic nematodes (GIN) was investigated. Data on serum and saliva IgA levels and peripheral cellular immune response were recorded in 51 sheep for 6 months. The flock was divided based on their physiological stage as follows: a) pregnant ewes, b) lactating ewes, c) non-pregnant ewes, d) pre-weaning lambs, e) growing lambs and f) replacement sheep. Additionally, sheep were classified based on the parasite infection as stabled or grazing management system as follows: g) non-infected stabled sheep, h) infected and stabled sheep and i) infected grazing sheep. Faeces and blood samples were collected every fifteen days. The percentage of packed cell volume (PCV), plasma protein, (PP) and leucocyte differential counts (LDC) were recorded. Likewise, serum and saliva IgA levels were measured by the indirect ELISA technique. The number of GIN eggs excreted per g of faeces (EPG) was also determined using the McMaster technique. Data were analysed using the SAS program to identify fixed effect of physiological stages, infection time and interactions. Results showed high EPG values in stabled lactating ewes (2764) and in growing lambs (2950-4550 EPG). Pregnant ewes had higher PCV values (27%) than lactating ewes (23.5%). Infected lambs showed low PCV values (28.5%) and high PP values (5.9 g/dL) compared with non-infected lambs (31% PCV and 5.6 g/dL PP). The two most abundant GIN species identified were Haemonchus contortus (91%) and Trichostrongylus colubriformis (81%). Pregnant and non-pregnant ewes showed 29% and <20% of IgA values, respectively. High EPG, low IgA and eosinophils counts were observed until 180 days of age in infected lambs. In conclusion, the group of infected lactating ewes and lambs showed susceptibility to GIN than the other groups, including the pregnant ewes.

Cyclooxygenases and lipoxygenases are used by the fungus Podospora anserina to repel nematodes.

Oxylipins are secondary messengers used universally in the living world for communication and defense. The paradigm is that they are produced enzymatically for the eicosanoids and non-enzymatically for the isoprostanoids. They are supposed to be degraded into volatile organic compounds (VOCs) and to participate in aroma production. Some such chemicals composed of eight carbons are also envisoned as alternatives to fossil fuels. In fungi, oxylipins have been mostly studied in Aspergilli and shown to be involved in signalling asexual versus sexual development, mycotoxin production and interaction with the host for pathogenic species. Through targeted gene deletions of genes encoding oxylipin-producing enzymes and chemical analysis of oxylipins and volatile organic compounds, we show that in the distantly-related ascomycete Podospora anserina, isoprostanoids are likely produced enzymatically. We show the disappearance in the mutants lacking lipoxygenases and cyclooxygenases of the production of 10-hydroxy-octadecadienoic acid and that of 1-octen-3-ol, a common volatile compound. Importantly, this was correlated with the inability of the mutants to repel nematodes as efficiently as the wild type. Overall, our data show that in this fungus, oxylipins are not involved in signalling development but may rather be used directly or as precursors in the production of odors against potential agressors. SIGNIFICANCE: We analyzse the role in inter-kingdom communication of lipoxygenase (lox) and cyclooxygenase (cox) genes in the model fungus Podospora anserina. Through chemical analysis we define the oxylipins and volatile organic compounds (VOCs)produce by wild type and mutants for cox and lox genes, We show that the COX and LOX genes are required for the production of some eight carbon VOCs. We show that COX and LOX genes are involved in the production of chemicals repelling nematodes. This role is very different from the ones previously evidenced in other fungi.

Resistance to gastrointestinal nematodes in dairy sheep: Genetic variability and relevance of artificial infection of nucleus rams to select for resistant ewes on farms.

Breeding sheep for enhanced resistance to gastrointestinal parasites is a promising strategy to limit the use of anthelmintics due to the now widespread resistance of parasites to these molecules. This paper reports the genetic parameters estimated for parasite resistance and resilience traits in the Blond-faced Manech dairy sheep breed and the putative impacts of the selection for resistance to gastrointestinal nematodes (GIN) on farms. Two datasets were used. First, the rams of the selection scheme were artificially infected twice with L3 Haemonchus contortus larvae. Faecal egg counts (FEC) and packed cell volume (PCV) loss were measured 30 days after each infection. Secondly, the FEC, PCV and body condition score (BCS) (1-6 measures per ewe) of naturally infected ewes on farms were measured in the spring, summer and autumn over a two-year period. Genetic parameters were estimated for each dataset independently but also globally based on the pedigree connections between the two datasets. For the experimentally infected sires, the FEC following the second infection was moderately heritable (heritability: 0.35) and strongly correlated with FEC after the first infection (genetic correlation: 0.92). For the naturally infected ewes, FEC was also heritable (0.18). Using the two datasets together, a genetic correlation of 0.56-0.71 was estimated between the FEC values of the experimentally infected rams and naturally infected ewes. Consequently, the genetic variability of parasite resistance is similar whatever the physiological status (males or milking/pregnant ewes) and the infection conditions (experimental infection with one parasite or natural infection with several parasites). In practice, when the sire population is divided into two groups based on their genetic value, the FEC of the ewes born to the 50% most resistant sires is half that of the ewes born to the 50% most susceptible sires. Our study shows the feasibility and efficiency of genetic selection for parasitism resistance based on the sires' FEC records to improve parasite resistance in naturally grazing ewes. For breed improvement, and to increase the selection pressure on parasite resistance, it seems more appropriate to measure FEC values on rams after experimental infection rather than on ewes in natural infection conditions because this limits the number and standardizes the conditions of FEC measurements.

Immune tolerance of vector beetle to its partner plant parasitic nematode modulated by its insect parasitic nematode.

Immune response of insect vectors to transmitted pathogens or insect hosts against parasites are well studied, whereas the mechanism of tripartite interactions remains elusive. In this study, we investigated the immune interactions of the vector beetle Monochamus alternatus ( Ma) to the devastating plant parasitic nematode Bursaphelenchus xylophilus ( Bx) and the insect parasitic nematode Howardula phyllotretae ( Hp). We report the unique immune mechanism by which the vector beetle tolerates many devastating Bx in its trachea, yet that immune tolerance is compromised by the parasitic nematode Hp. Contact with either nematode species triggers epithelial reactive oxygen species (ROS) production in Ma. Only the entry of Bx, not Hp, infection, induces increased expression of antioxidative genes, through which the ROS levels are balanced in the trachea of beetles. Furthermore, we found that up-regulation of antioxidative genes was induced by the interaction of Toll receptors. In contrast, beetles infected by Hp retain high levels of oxidative stress and melanization in trachea, and as a result, decrease Bx loading. This study highlights the role of Toll receptors in mediating the activation of antioxidative genes in immune tolerance to plant parasitic nematodes, and suggests the use of insect parasites as a biologic control.-Zhou, J., Zhao, L.-L., Yu, H.-Y., Wang, Y.-H., Zhang, W., Hu, S.-N., Zou, Z., Sun, J.-H. Immune tolerance of vector beetle to its partner plant parasitic nematode modulated by its insect parasitic nematode.

Host responses to intestinal nematodes.

Helminth infection remains common in developing countries, where residents who suffer from the consequences of such infections can develop serious physical and mental disorders and often persist in the face of serious economic problems. Intestinal nematode infection induces the development of Th2-type immune responses including the B-cell IgE response; additionally, this infection induces an increase in the numbers and activation of various types of effector cells, such as mast cells, eosinophils and basophils, as well as the induction of goblet cell hyperplasia, anti-microbial peptide production and smooth-muscle contraction, all of which contribute to expel nematodes. Innate immunity is important in efforts to eliminate helminth infection; cytokines, including IL-25, IL-33 and thymic stromal lymphopoietin, which are products of epithelial cells and mast cells, induce Th2 cells and group 2 innate lymphoid cells to proliferate and produce Th2 cytokines. Nematodes also facilitate chronic infection by suppression of immune reactions through an increased number of Treg cells. Immunosuppression by parasite infection may ultimately be beneficial for the host animals; indeed, a negative correlation has been found between parasite infection and the prevalence of inflammatory disease in humans.

A sticky end for gastrointestinal helminths; the role of the mucus barrier.

Gastrointestinal (GI) nematodes are a group of successful multicellular parasites that have evolved to coexist within the intestinal niche of multiple species. It is estimated that over 10% of the world's population are chronically infected by GI nematodes, making this group of parasitic nematodes a major burden to global health. Despite the large number of affected individuals, there are few effective treatments to eradicate these infections. Research into GI nematode infections has primarily focused on defining the immunological and pathological consequences on host protection. One important but neglected aspect of host protection is mucus, and the concept that mucus is just a simple barrier is no longer tenable. In fact, mucus is a highly regulated and dynamic-secreted matrix, underpinned by a physical hydrated network of highly glycosylated mucins, which is increasingly recognized to have a key protective role against GI nematode infections. Unravelling the complex interplay between mucins, the underlying epithelium and immune cells during infection are a major challenge and are required to fully define the protective role of the mucus barrier. This review summarizes the current state of knowledge on mucins and the mucus barrier during GI nematode infections, with particular focus on murine models of infection.

Recent Advances in Type-2-Cell-Mediated Immunity: Insights from Helminth Infection.

Type-2-cell-mediated immune responses play a critical role in mediating both host-resistance and disease-tolerance mechanisms during helminth infections. Recently, type 2 cell responses have emerged as major regulators of tissue repair and metabolic homeostasis even under steady-state conditions. In this review, we consider how studies of helminth infection have contributed toward our expanding cellular and molecular understanding of type-2-cell-mediated immunity, as well as new areas such as the microbiome. By studying how these successful parasites form chronic infections without overt pathology, we are gaining additional insights into allergic and inflammatory diseases, as well as normal physiology.

Hsp90-downregulation influences the heat-shock response, innate immune response and onset of oocyte development in nematodes.

Hsp90 is a molecular chaperone involved in the regulation and maturation of kinases and transcription factors. In Caenorhabditis elegans, it contributes to the development of fertility, maintenance of muscle structure, the regulation of heat-shock response and dauer state. To understand the consequences of Hsp90-depletion, we studied Hsp90 RNAi-treated nematodes by DNA microarrays and mass spectrometry. We find that upon development of phenotypes the levels of chaperones and Hsp90 cofactors are increased, while specific proteins related to the innate immune response are depleted. In microarrays, we further find many differentially expressed genes related to gonad and larval development. These genes form an expression cluster that is regulated independently from the immune response implying separate pathways of Hsp90-involvement. Using fluorescent reporter strains for the differentially expressed immune response genes skr-5, dod-24 and clec-60 we observe that their activity in intestinal tissues is influenced by Hsp90-depletion. Instead, effects on the development are evident in both gonad arms. After Hsp90-depletion, changes can be observed in early embryos and adults containing fluorescence-tagged versions of SEPA-1, CAV-1 or PUD-1, all of which are downregulated after Hsp90-depletion. Our observations identify molecular events for Hsp90-RNAi induced phenotypes during development and immune responses, which may help to separately investigate independent Hsp90-influenced processes that are relevant during the nematode's life and development.