• Echinococcus granulosus antigen B
• STAT3
• T cells
• immune thrombocytopenia

• Animals
• STAT3 Transcription Factor/immunology
• STAT3 Transcription Factor/antagonists & inhibitors
• STAT3 Transcription Factor/metabolism
• Mice
• Purpura, Thrombocytopenic, Idiopathic/immunology
• Purpura, Thrombocytopenic, Idiopathic/pathology
• Echinococcus granulosus/immunology
• T-Lymphocytes, Regulatory/immunology
• Antigens, Helminth/immunology
• Antigens, Helminth/pharmacology
• Disease Models, Animal
• TNF Receptor-Associated Factor 6/immunology
• Mice, Inbred C57BL

• 2024B03038-1 Key Research and Development Project of the Xinjiang Uygur Autonomous Region of China
• 82160031 National Natural Science Foundation of China
• XJ2025G182 Graduate Innovation Project of Xinjiang Uygur Autonomous Region[grant number
• SKL-HIDCA-2024-BC7 State Key Laboratory of Pathogenesis, Prevention and Treatment of High Incidence Diseases in Central Asia Fund
• 2023YFY-QKMS-01 The Youth Voyage Fund Program of The First Affiliated Hospital of Xinjiang Medical University

• Echinococcus granulosus
• Antigen B (EgAgB)
• Immune response
• Macrophage
• Sepsis

• Sepsis/drug therapy
• Sepsis/immunology
• Sepsis/pathology
• Disease Models, Animal
• Mice, Inbred BALB C
• Lipoproteins/administration & dosage
• Lipoproteins/immunology
• Antigens, Helminth/administration & dosage
• Antigens, Helminth/immunology
• Recombinant Proteins/administration & dosage
• Recombinant Proteins/immunology
• Inflammation Mediators
• Injections, Intraperitoneal
• Macrophages/drug effects
• Macrophages/immunology
• Macrophages/metabolism
• Toll-Like Receptor 2/metabolism
• Myeloid Differentiation Factor 88/metabolism
• Signal Transduction/drug effects
• Signal Transduction/immunology
• Protein Subunits/administration & dosage
• Protein Subunits/immunology
• Specific Pathogen-Free Organisms
• Male

• No. Byycx21087 Postgraduate Scientific Research Innovation Program of Bengbu Medical College
• No. KJ2021A0687 Program of Natural Science Foundation of the Anhui Higher Education Institutions
• No. KJ2021A0742 Program of Natural Science Foundation of the Anhui Higher Education Institutions
• No. AHIAI2022K02 Key Research Platform Open Project of Bengbu Medical College
• No. z202114 Major Project of Wuxi Municipal Health Commission
• No. by51201205 512 Talents Development Project of Bengbu Medical College

• Echinococcus granulosus
• HLBP family
• antigen B
• cestodes
• immunomodulation
• lipoprotein
• macrophage

• Humans
• Animals
• Mice
• Echinococcus granulosus/genetics
• Echinococcus granulosus/metabolism
• Interleukin-6/metabolism
• Lipopolysaccharides/metabolism
• Macrophage Activation
• Lipoproteins/genetics
• Lipoproteins/metabolism
• Macrophages
• Cytokines/metabolism

• 2DBD nuclear receptor
• Cystic echinococcosis
• Dimerization
• Echinococcus granulosus

• Animals
• Echinococcus granulosus/genetics
• Parasites/metabolism
• Dimerization
• Echinococcosis/parasitology
• Larva/genetics
• Larva/metabolism
• Receptors, Cytoplasmic and Nuclear/genetics
• Receptors, Cytoplasmic and Nuclear/metabolism

• EAE
• cytokines
• multiple sclerosis
•  Antigen B

• FABPs
• FAR
• Lipid binding proteins
• NPAs
• Nematodes
• Platyhelminthes

• Echinococcus granulosus
• Mass spectrometry
• Ovine
• Shotgun proteomics
• Taenia hydatigena
• Taenia multiceps

• Animals
• Cyst Fluid
• Echinococcus
• Echinococcus granulosus
• Proteomics
• Sheep
• Taenia

Cystic and alveolar echinococcosis caused by the tapeworms Echinococcus granulosus sensu stricto (s.s.) and E. multilocularis, respectively, are important zoonotic diseases. Protease inhibitors are crucial for the survival of both Echinococcus spp. Kunitz-type inhibitors play a regulatory role in the control of protease activity. In this study,we identified Kunitz-type domain protease inhibitors(KDPIs) present in the genomes of these two tapeworms and analyzed the gene sequences using computational, structural bioinformatics and phylogenetic approaches to evaluate the evolutionary relationships of these genes. Hi-seq transcriptome analysis showed that E. granulosuss.s. KDPIs were differentially expressed in the different developmental stages. We validated some of the genes expressed in adult worm, protoscolex and cyst germinal membrane of E. granulosuss.s. and E. multilocularis by quantitative PCR.

A total of 19 genes from E. multilocularis and 23 genes from E. granulosuss.s. were predicted to be KDPIs with the most containing a single Kunitz-domain. A maximum likelihood method phylogenetic tree indicated that the E. granulosuss.s. and E. multilocularis Kunitz domain peptides were divided into three branches containing 9 clusters. The ratio of positively charged residues and neutral residues are different between E. multilocularis and E. granulosuss.s. KDPIs. We also found that E. multilocularis had higher percentage of sequences containing signal peptides (17/19, 89.47%) than that of E. granulosuss.s. (14/23, 60.87%). Transcript analysis showed all the E. granulosuss.s. KDPI genes were expressed differentially in four developmental stages of the worm. Transcription analysis showed that 9 KDPIs (including EG_07244,EGR_08716 and EGR_10096) were highly upregulated in adult worm, and 2 KDPIs (EG_09268 and EG_09490) were highly expressed in the cyst germinal membrane. Quantitative gene expression analysis(qPCR) of four genes confirmed the expression of these genes. EGR_08716 and its homologous gene (EmuJ_001137000) were highly and specifically expressed in adult worms of the two worms.

A total 19 and 23 KDPIs were identified in the genomes of E. multilocularis and E. granulosus s.s. , respectively. The differential expression of these KDPIs in different stages may indicate their different roles in the different hosts. The difference in characterization of KDPIs may be associated with the different pathology of metacestode stage of these two parasites.

The online version contains supplementary material available at 10.1186/s12864-021-08219-4.

Cystic echinococcosis (CE) is a neglected zoonotic disease caused by Echinococcus granulosus sensu lato. Diagnosis and monitoring of CE rely primarily on imaging while serology is used as a confirmatory test. However, imaging is not always conclusive and currently available serological assays have suboptimal sensitivity and specificity, lack standardization, and are not useful for patients´ follow-up. Seroassays for CE are usually based on hydatid fluid (HF), a complex, variable antigenic mixture, and cross-reactivity exists especially with alveolar echinococcosis. Recombinant proteins based on immunogenic antigens most abundant in HF, such as AgB1, AgB2 and Ag5, have been used to overcome these limitations. None of them so far showed potential to replace HF; however, their performance have been largely tested on a limited number of samples, and comparison of different antigens using the same cohort has been rarely performed. The combination of several immunogenic epitopes in a single recombinant protein could enhance test sensitivity. For the diagnosis and follow-up of patients with CE, we compared the performance of the crude HF, previously described recombinant 2B2t antigen, and GST-tagged version of 2B2t, and novel designed recombinants (GST-Ag5t and the GST-DIPOL chimera containing AgB1, AgBB2 and Ag5 epitopes) by IgG-ELISA format. Samples belong to a retrospective cohort of 253 well-characterized patients with CE, previously described for the evaluation of the 2B2t antigen, 92 patients with alveolar echinococcosis, and 82 healthy donors. The reference standard for CE diagnosis was the presence of a CE lesion as diagnosed by ultrasonography. The highest sensitivity was obtained with HF [86.7%, 95% confidence interval (CI): 81.2–91.0], followed by GST-2B2t (70.0%, 95% CI: 63.1–76.2), 2B2t (65.5%, 95% CI: 58.5–72.0), GST-Ag5t (64.5%, 95% CI: 57.5–71.1) and GST-DIPOL (63.1%, 95% CI: 56.0–69.7). The GST-2B2t had the best specificity (95.8%, 95% CI: 88.3–99.1) and the lowest cross-reactivity (38.7%, 95% CI: 27.6–50.6). Good response to treatment also correlated to negative test results in the GST-2B2t ELISA. While none of the tested recombinant antigen appears suitable to replace HF for the diagnosis of CE, GST-2B2t should be further explored as a confirmation test, based on its high specificity and low cross-reactivity, and for the follow-up after treatment in those patients with positive serology for this antigen.

Cystic echinococcosis (CE) is a neglected parasitic zoonosis. Its diagnosis and follow-up require evaluation with imaging. Currently available serological tests are applied to confirm the diagnosis in doubtful cases, although having limitations in diagnostic accuracy, and they are not useful for patients’ follow-up. Seroassays for CE are usually based on hydatid fluid (HF) obtained from infected animals, with consequent problems of heterogeneity and low specificity. The use of semi-purified HF derivatives or recombinant antigens has been attempted to improve these aspects, but with an unacceptable loss in sensitivity. Most newly developed antigens have been tested on a limited number of samples, not always well characterized, and have been rarely compared using the same samples cohort. Here, we tested and compared three recombinant antigens (2B2t, GST-2B2t and GST-Ag5t), and a recombinant chimeric antigen (DIPOL) based on three highly immunogenic components of HF (B1, B2 and Ag5), in an attempt to increase the sensitivity of recombinant antigen-based seroassays for the diagnosis and follow-up of patients with CE. We found that GST-2B2t had higher sensitivity than the other antigenic preparations, but still not as high as HF, and that GST-2B2t and GST-DIPOL had statistically higher specificity than any of the other tested antigens. GST-2B2t also showed potential for the follow-up of patients with CE after drug treatment.

• Animals
• Antibodies, Helminth/blood
• Antigens, Helminth/genetics
• Antigens, Helminth/immunology
• Cohort Studies
• Cross Reactions
• Echinococcosis/diagnosis
• Echinococcosis/immunology
• Echinococcus granulosus/immunology
• Enzyme-Linked Immunosorbent Assay/methods
• Female
• Humans
• Immunoassay
• Italy
• Male
• Recombinant Proteins/immunology
• Retrospective Studies
• Sensitivity and Specificity
• Serologic Tests/methods

• FP7 International Cooperation
• Ministerio de Ciencia, Innovación y Universidades

• Antigen B
• Cattle
• Echinococcus granulosus
• Polymorphism
• Sheep

• Antigen B
• Coenurus cerebralis
• Indirect ELISA
• Metacestode
• Taenia multiceps
• Thioredoxin peroxidase

Echinococcoses, caused by metacestodes of Echinococcus granulosus (cystic echinococcosis; CE) and E. multilocularis (alveolar echinococcosis; AE), represent major emerging parasitic diseases. These enzootic helminthiases invoke significant public health concerns and social burdens in endemic areas. The diseases are prevalent in the Qinghai-Tibetan Plateau, China, while community-based epidemiological studies have been scarcely reported. We surveyed echinococcosis patients in the southeastern Qinghai Province, China, to better understand the concurrent epidemiological situation in this area.

During July and August of 2013 and 2014, we screened echinococcosis patients at Yushu and Golog Prefectures, Qinghai Province, China, in a diagnostic campaign. A total of 2856 people (male:female ratio, 1:1.12; mean age, 34.6 years; age range, 6–88 years) were ultrasonographically examined for the presence of hepatic echinococcal cysts. We also collected serum samples from patients and analyzed antibody reactivity against recombinant forms of diverse E. granulosus antigen Bs (rEgAgB1-5) by enzyme-linked immunosorbent assay.

We detected 134 patients whose imaging scans were compatible with CE (115 cases) and AE (20 patients). One patient might have been infected with both CE and AE. The overall incidence was 4.7% (CE, 4.0%; AE, 0.7%). A large proportion (67.5%) of CE patients was diagnosed at active and transitional CE1-CE3 stages in their late 30s. The AE cases were generally detected at advanced stage in patients at early 20s (60%). Analysis of the receiver operating characteristic curve and Youden’s index indicated that rEgAgB2 was the most promising biomarker, followed by rEgAgB3 and rEgAgB1. Overall, sensitivity and specificity of rEgAgB1-3 were 84.5–92.7% and 91.9–94.6%, respectively. rEgAgB4 and 5 showed low sensitivity with high cross-reactivity.

Our results strongly suggest that disability-adjusted life years related to echinococcoses in Qinghai-Tibetan areas might be more serious than previously considered. Control and prevention strategy against CE and AE are highly required in these areas. In addition to ultrasonography, serological tests might provide supportive data. However, serological data should be carefully interpreted for differential diagnosis, especially in areas where both CE and AE are co-endemic.

The online version of this article (10.1186/s13071-019-3569-6) contains supplementary material, which is available to authorized users.

• Antigen B isoforms
• E. multilocularis
• Echinococcoses
• Echinococcus granulosus
• Immunoreactivity
• Qinghai-Tibetan Plateau
• Ultrasonography

Cystic hydatid disease is a zoonosis caused by the larval stage (hydatid) of Echinococcus granulosus (Cestoda, Taeniidae). The hydatid develops in the viscera of intermediate host as a unilocular structure filled by the hydatid fluid, which contains parasitic excretory/secretory products. The lipoprotein Antigen B (AgB) is the major component of E. granulosus metacestode hydatid fluid. Functionally, AgB has been implicated in immunomodulation and lipid transport. However, the mechanisms underlying AgB functions are not completely known.

In this study, we investigated AgB interactions with different mammalian cell types and the pathways involved in its internalization. AgB uptake was observed in four different cell lines, NIH-3T3, A549, J774 and RH. Inhibition of caveolae/raft-mediated endocytosis causes about 50 and 69% decrease in AgB internalization by RH and A549 cells, respectively. Interestingly, AgB colocalized with the raft endocytic marker, but also showed a partial colocalization with the clathrin endocytic marker. Finally, AgB colocalized with an endolysosomal tracker, providing evidence for a possible AgB destination after endocytosis.

The results indicate that caveolae/raft-mediated endocytosis is the main route to AgB internalization, and that a clathrin-mediated entry may also occur at a lower frequency. A possible fate for AgB after endocytosis seems to be the endolysosomal system. Cellular internalization and further access to subcellular compartments could be a requirement for AgB functions as a lipid carrier and/or immunomodulatory molecule, contributing to create a more permissive microenvironment to metacestode development and survival.

Antigen B (AgB) is an oligomeric lipoprotein highly abundant in Echinococcus granulosus hydatid fluid. AgB has already been characterized as an immunomodulatory protein, capable of inducing a permissive immune response to parasite development. Also, an important role in lipid acquisition is attributed to AgB, because it has been found associated to different classes of host lipids. However, the mechanisms of interaction employed by AgB to perform its functions remain undetermined. In this study, we demonstrate that mammalian cells are able to internalize E. granulosus AgB in culture and found that specific mechanisms of endocytosis are involved. Our results extend the understanding of AgB biological role indicating cellular internalization as a mechanism of interaction, which in turn, may represent a target to intervention.

• Animals
• Antigens, Helminth/metabolism
• Cell Line
• Echinococcosis/parasitology
• Echinococcosis/physiopathology
• Echinococcus granulosus/genetics
• Echinococcus granulosus/metabolism
• Endocytosis
• Helminth Proteins/metabolism
• Humans
• Mice

• Conselho Nacional de Desenvolvimento Científico e Tecnológico
• Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
• Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul

• Antigen B1
• Echinococcus granulosus
• Fars province
• Genetic Variation
• Iran

• Autoimmunity
• Cytokines
• Dendritic cells
• Echinococcus granulosus
• Immunity
• Lymphocytes

Cystic echinococcosis is an important parasitic zoonosis caused by the dog tapeworm Echinococcus granulosus. Little is known about adult worm development at the molecular level. Transcription analysis showed that the E. granulosus hormone receptor 3-like (EgHR3) gene was expressed in protoscoleces and adult worms, indicating its role in early adult development. In this study, we cloned and characterized EgHR3 showing that its cDNA contains an open reading frame (ORF) of 1890 bp encoding a 629 amino acid protein, which has a DNA-binding domain (DBD) and a ligand-binding domain (LBD). Immunolocalization revealed the protein was localized in the parenchyma of protoscoleces and adult worms. Real-time PCR analysis showed that EgHR3 was expressed significantly more in adults than in other stages of development (p<0.01) and that its expression was especially high in the early stage of adult worm development induced by bile acids. EgHR3 siRNA silenced 69–78% of the level of transcription in protoscoleces, which resulted in killing 43.6–60.9% of protoscoleces after 10 days of cultivation in vitro. EgHR3 may play an essential role in early adult worm development and in maintaining adult biological processes and may represent a novel drug or vaccine target against echinococcosis.

Alveolar and cystic echinococcoses, caused by the metacestodes of Echinococcus multilocularis and E. granulosus, are prevalent in several regions and invoke deleterious zoonotic helminthiases. Hydatid fluid (HF), which contains proteinaceous and non-proteinaceous secretions of the parasite- and host-derived components, critically affects the host-parasite interplay and disease progression. We conducted HF proteome profiling of fully mature E. multilocularis vesicle (nine months postinfection) and E. granulosus cyst (stage 2). We identified 120 and 153 proteins, respectively, in each fluid. Fifty-six and 84 proteins represented distinct species; 44 and 66 were parasites, and 12 and 18 were host-derived proteins. The five major parasite protein populations, which included antigen B isoforms, metabolic enzymes, proteases and inhibitors, extracellular matrix molecules (ECMs), and developmental proteins, were abundantly distributed in both fluids and also exclusively in one sample or the other. Carbohydrate-metabolizing enzymes were enriched in E. granulosus HF. In the E. multilocularis HF, proteins that constitute ECMs, which might facilitate adhesion and cytogenesis, were highly expressed. Those molecules had physical and functional relationships along with their biochemical properties through protein-protein interaction networks. Twelve host-derived proteins were largely segregated to serum components. The major proteins commonly and uniquely detected in these HFs and their symbiotic interactome relationships might reflect their biological roles in similar but distinct modes of maturation, invasion, and the longevity of the parasites in the hosts.

• alveolar echinococcosis
• cystic echinococcosis
• hydatid fluid
• protein-protein interaction networks
• proteome

• Alveolar echinococcosis
• Excretion/secretion products
• Hydatid fluid
• Parasite proteomics
• Parasite-host interactions

• Antigen B
• E. granulosus
• ELISA
• Livestock
• Oman
• Sero-epidemiology

• Animals
• Antibodies
• Antigens
• Cytokines
• DNA
• Echinococcus
• Followup
• Laboratory diagnosis
• Lymphoproliferation
• Patients

The larva of cestodes belonging to the Echinococcus granulosus sensu lato (s.l.) complex causes cystic echinococcosis (CE). It is a globally distributed zoonosis with significant economic and public health impact. The most immunogenic and specific Echinococcus-genus antigen for human CE diagnosis is antigen B (AgB), an abundant lipoprotein of the hydatid cyst fluid (HF). The AgB protein moiety (apolipoprotein) is encoded by five genes (AgB1-AgB5), which generate mature 8 kDa proteins (AgB8/1-AgB8/5). These genes seem to be differentially expressed among Echinococcus species. Since AgB immunogenicity lies on its protein moiety, differences in AgB expression within E. granulosus s.l. complex might have diagnostic and epidemiological relevance for discriminating the contribution of distinct species to human CE. Interestingly, AgB2 was proposed as a pseudogene in E. canadensis, which is the second most common cause of human CE, but proteomic studies for verifying it have not been performed yet. Herein, we analysed the protein and lipid composition of AgB obtained from fertile HF of swine origin (E. canadensis G7 genotype). AgB apolipoproteins were identified and quantified using mass spectrometry tools. Results showed that AgB8/1 was the major protein component, representing 71% of total AgB apolipoproteins, followed by AgB8/4 (15.5%), AgB8/3 (13.2%) and AgB8/5 (0.3%). AgB8/2 was not detected. As a methodological control, a parallel analysis detected all AgB apolipoproteins in bovine fertile HF (G1/3/5 genotypes). Overall, E. canadensis AgB comprised mostly AgB8/1 together with a heterogeneous mixture of lipids, and AgB8/2 was not detected despite using high sensitivity proteomic techniques. This endorses genomic data supporting that AgB2 behaves as a pseudogene in G7 genotype. Since recombinant AgB8/2 has been found to be diagnostically valuable for human CE, our findings indicate that its use as antigen in immunoassays could contribute to false negative results in areas where E. canadensis circulates. Furthermore, the presence of anti-AgB8/2 antibodies in serum may represent a useful parameter to rule out E. canadensis infection when human CE is diagnosed.

Cystic echinococcosis (CE), a worldwide-spread zoonosis, affects livestock mammals and humans with significant economic and public health impact. It is caused by the infection with the larva of cestodes belonging to Echinococcus granulosus complex, a series of parasite species with preference for different hosts. Among them, Echinococcus canadensis larva uses mainly camels, goats and pigs as hosts. Species/genotypes belonging to E. canadensis are considered the second most common cause of human CE, but its contribution may be underestimated since causes asymptomatic or more benign infections than other E. granulosus complex species. The most relevant antigen for CE diagnosis is a lipoprotein called antigen B (AgB). AgB antigenicity is linked to its protein moiety that is encoded by several genes. One of these genes, AgB2, seems to be differentially expressed within E. granulosus complex. Using high sensitivity proteomic tools we analysed the composition of AgB obtained from E. canadensis larva, detecting the protein products of all AgB genes, except AgB2. Since AgB subunits have been widely used as antigens in immunoassays for human CE diagnosis, our results indicate that using AgB2 protein product in these assays may lead to false-negative results, particularly in geographical areas where E. canadensis species/genotypes circulate.

• Animals
• Echinococcosis/parasitology
• Echinococcosis/veterinary
• Echinococcus/chemistry
• Echinococcus/genetics
• Echinococcus/immunology
• Echinococcus/isolation & purification
• Electrophoresis, Gel, Two-Dimensional
• Genotype
• Helminth Proteins/chemistry
• Helminth Proteins/genetics
• Helminth Proteins/immunology
• Lipoproteins/chemistry
• Lipoproteins/genetics
• Lipoproteins/immunology
• Mass Spectrometry
• Proteomics
• Swine
• Swine Diseases/parasitology

• Agencia Nacional de Investigación e Innovación
• Comisión Sectorial de Investigación Científica

• EG95
• Echinococcus
• Th2
• antigen 5
• antigen B
• carbohydrate
• immune regulation
• laminated layer

The hydatid disease parasite Echinococcus granulosus has a restricted lipid metabolism, and needs to harvest essential lipids from the host. Antigen B (EgAgB), an abundant lipoprotein of the larval stage (hydatid cyst), is thought to be important in lipid storage and transport. It contains a wide variety of lipid classes, from highly hydrophobic compounds to phospholipids. Its protein component belongs to the cestode-specific Hydrophobic Ligand Binding Protein family, which includes five 8-kDa isoforms encoded by a multigene family (EgAgB1-EgAgB5). How lipid and protein components are assembled into EgAgB particles remains unknown. EgAgB apolipoproteins self-associate into large oligomers, but the functional contribution of lipids to oligomerization is uncertain. Furthermore, binding of fatty acids to some EgAgB subunits has been reported, but their ability to bind other lipids and transfer them to acceptor membranes has not been studied.

Lipid-free EgAgB subunits obtained by reverse-phase HPLC were used to analyse their oligomerization, ligand binding and membrane interaction properties. Size exclusion chromatography and cross-linking experiments showed that EgAgB8/2 and EgAgB8/3 can self-associate, suggesting that lipids are not required for oligomerization. Furthermore, using fluorescent probes, both subunits were found to bind fatty acids, but not cholesterol analogues. Analysis of fatty acid transfer to phospholipid vesicles demonstrated that EgAgB8/2 and EgAgB8/3 are potentially capable of transferring fatty acids to membranes, and that the efficiency of transfer is dependent on the surface charge of the vesicles.

We show that EgAgB apolipoproteins can oligomerize in the absence of lipids, and can bind and transfer fatty acids to phospholipid membranes. Since imported fatty acids are essential for Echinococcus granulosus, these findings provide a mechanism whereby EgAgB could engage in lipid acquisition and/or transport between parasite tissues. These results may therefore indicate vulnerabilities open to targeting by new types of drugs for hydatidosis therapy.

Echinococcus granulosus is a causative agent of hydatidosis, a parasitic disease that affects humans and livestock with significant economic and public health impact worldwide. Antigen B (EgAgB), an abundant product of E. granulosus larvae, is a lipoprotein that carries a wide variety of lipids, including fatty acids and cholesterol. As E. granulosus is unable to synthesize these lipids, EgAgB likely plays an important role in parasite metabolism, participating in both the acquisition of host lipids and their distribution between parasite tissues. The protein component of EgAgB consists of 8 kDa subunits encoded by separate genes. However, the biochemical properties of EgAgB subunits, particularly their ability to bind and transfer lipids, are poorly known. Herein, using in vitro assays, we found that EgAgB subunits were capable of oligomerizing in the absence of lipids and to bind fatty acids, but not cholesterol. Moreover, EgAgB subunits showed the ability to transfer fatty acids to artificial phospholipid membranes. These results indicate new points of attack at which the parasite might be vulnerable to drugs.

• Amino Acid Sequence
• Animals
• Echinococcosis/parasitology
• Fatty Acids/metabolism
• Humans
• Lipids
• Lipoproteins/chemistry
• Lipoproteins/metabolism
• Membranes/metabolism
• Molecular Sequence Data
• Phospholipids/metabolism
• Polymerization
• Protein Subunits

• Wellcome Trust

• Antigen B
• Cestode
• Echinococcus
• HLBP
• Lipoprotein
• Tapeworm

• Amino Acid Sequence
• Animals
• Carrier Proteins/metabolism
• Echinococcosis/parasitology
• Echinococcus granulosus/growth & development
• Echinococcus granulosus/physiology
• Host-Parasite Interactions
• Humans
• Lipoproteins/chemistry
• Lipoproteins/metabolism
• Models, Molecular
• Molecular Sequence Data
• Sequence Alignment

• echinococcus granulosus
• cystic echinococcosis
• hydatid fluid
• immunoproteome
• antigen b
• antigen 5
• stage-specificity

• Animals
• Cyst Fluid/chemistry
• Echinococcosis/parasitology
• Echinococcus granulosus/metabolism
• Female
• Helminth Proteins/genetics
• Helminth Proteins/metabolism
• Humans
• Immunoproteins/chemistry
• Immunoproteins/metabolism
• Male
• Protein Isoforms
• Proteomics
• Transcriptome

Cystic hydatid disease (CHD) is caused by the larval stages of the cestode and affects humans and domestic animals worldwide. Protoscoleces (PSCs) are one component of the larval stages that can interact with both definitive and intermediate hosts. Previous genomic and transcriptomic data have provided an overall snapshot of the genomics of the growth and development of this parasite. However, our understanding of how PSCs subvert the immune response of hosts and maintains metabolic adaptation remains unclear. In this study, we used Roche 454 sequencing technology and in silico secretome analysis to explore the transcriptome profiles of the PSCs from E. granulosus and elucidate the potential functions of the excretory-secretory proteins (ESPs) released by the parasite.

A large number of nonredundant sequences as unigenes were generated (26,514), of which 22,910 (86.4%) were mapped to the newly published E. granulosus genome and 17,705 (66.8%) were distributed within the coding sequence (CDS) regions. Of the 2,280 ESPs predicted from the transcriptome, 138 ESPs were inferred to be involved in the metabolism of carbohydrates, while 124 ESPs were inferred to be involved in the metabolism of protein. Eleven ESPs were identified as intracellular enzymes that regulate glycolysis/gluconeogenesis (GL/GN) pathways, while a further 44 antigenic proteins, 25 molecular chaperones and four proteases were highly represented. Many proteins were also found to be significantly enriched in development-related signaling pathways, such as the TGF-β receptor pathways and insulin pathways.

This study provides valuable information on the metabolic adaptation of parasites to their hosts that can be used to aid the development of novel intervention targets for hydatid treatment and control.

The successful infection establishment of parasites depends on their ability to combat their host's immune system while maintaining metabolic adaptation to their hosts. The mechanisms of these processes are not well understood. We used the protoscoleces (PSCs) of E. granulosus as a model system to study this complex host-parasite interaction by investigating the role of excretory-secretory proteins (ESPs) in the physiological adaptation of the parasite. Using Roche 454 sequencing technology and in silico secretome analysis, we predicted 2280 ESPs and analyzed their biological functions. Our analysis of the bioinformatic data suggested that ESPs are integral to the metabolism of carbohydrates and proteins within the parasite and/or hosts. We also found that ESPs are involved in mediating the immune responses of hosts and function within key development-related signaling pathways. We found 11 intracellular enzymes, 25 molecular chaperones and four proteases that were highly represented in the ESPs, in addition to 44 antigenic proteins that showed promise as candidates for vaccine or serodiagnostic development purposes. These findings provide valuable information on the mechanisms of metabolic adaptation in parasites that will aid the development of novel hydatid treatment and control targets.

• Adaptation, Physiological
• Animals
• Carbohydrate Metabolism
• Echinococcus granulosus/metabolism
• Genotype
• Homeostasis
• Humans
• Sequence Analysis, DNA
• Signal Transduction
• Transcriptome
• Vaccines/immunology

In recent years, a significant amount of sequence data (both genomic and transcriptomic) for Echinococcus spp. has been published, thereby facilitating the analysis of genes expressed during a specific stage or involved in parasite development. To perform a suitable gene expression quantification analysis, the use of validated reference genes is strongly recommended. Thus, the aim of this work was to identify suitable reference genes to allow reliable expression normalization for genes of interest in Echinococcus granulosus sensu stricto (s.s.) (G1) and Echinococcus ortleppi upon induction of the early pre-adult development. Untreated protoscoleces (PS) and pepsin-treated protoscoleces (PSP) from E. granulosus s.s. (G1) and E. ortleppi metacestode were used. The gene expression stability of eleven candidate reference genes (βTUB, NDUFV2, RPL13, TBP, CYP-1, RPII, EF-1α, βACT-1, GAPDH, ETIF4A-III and MAPK3) was assessed using geNorm, Normfinder, and RefFinder. Our qPCR data showed a good correlation with the recently published RNA-seq data. Regarding expression stability, EF-1α and TBP were the most stable genes for both species. Interestingly, βACT-1 (the most commonly used reference gene), and GAPDH and ETIF4A-III (previously identified as housekeeping genes) did not behave stably in our assay conditions. We propose the use of EF-1α as a reference gene for studies involving gene expression analysis in both PS and PSP experimental conditions for E. granulosus s.s. and E. ortleppi. To demonstrate its applicability, EF-1α was used as a normalizer gene in the relative quantification of transcripts from genes coding for antigen B subunits. The same EF-1α reference gene may be used in studies with other Echinococcus sensu lato species. This report validates suitable reference genes for species of class Cestoda, phylum Platyhelminthes, thus providing a foundation for further validation in other epidemiologically important cestode species, such as those from the Taenia genus.

• Animals
• Cattle
• Echinococcosis/parasitology
• Echinococcus/genetics
• Echinococcus/growth & development
• Echinococcus/isolation & purification
• Echinococcus granulosus/genetics
• Echinococcus granulosus/growth & development
• Echinococcus granulosus/isolation & purification
• Gene Expression Profiling
• Gene Expression Regulation, Developmental
• Genes, Essential
• Genes, Helminth
• Life Cycle Stages/genetics
• Lipoproteins/genetics
• Peptide Elongation Factor 1/genetics
• RNA, Helminth/genetics
• RNA, Messenger/genetics

• Antigen B2
• Echinococcus granulosus
• Genetic variability
• Iran

There is a rapidly growing body of evidence that production of microvesicles (MVs) is a universal feature of cellular life. MVs can incorporate microRNA (miRNA), mRNA, mtDNA, DNA and retrotransposons, camouflage viruses/viral components from immune surveillance, and transfer cargo between cells. These properties make MVs an essential player in intercellular communication. Increasing evidence supports the notion that MVs can also act as long-distance vehicles for RNA molecules and participate in metabolic synchronization and reprogramming eukaryotic cells including stem and germinal cells. MV ability to carry on DNA and their general distribution makes them attractive candidates for horizontal gene transfer, particularly between multi-cellular organisms and their parasites; this suggests important implications for the co-evolution of parasites and their hosts. In this review, we provide current understanding of the roles played by MVs in intracellular pathogens and parasitic infections. We also discuss the possible role of MVs in co-infection and host shifting.

• Plasmodium
• co-infection
• exosomes
• horizontal gene transfer
• metabolism synchronization
• miRNA
• microvesicles
• parasite

• Echinococcus granulosus
• Echinococcus multilocularis
• Immune attacks
• Parasite–host interaction
• Platyhelminths

• 28S rRNA
• Fasciola hepatica
• Microfluidics capillary based electrophoresis
• RIN number
• RNA quality

The cestode Echinococcus granulosus - the agent of cystic echinococcosis, a zoonosis affecting humans and domestic animals worldwide - is an excellent model for the study of host-parasite cross-talk that interfaces with two mammalian hosts. To develop the molecular analysis of these interactions, we carried out an EST survey of E. granulosus larval stages. We report the salient features of this study with a focus on genes reflecting physiological adaptations of different parasite stages.

We generated ∼10,000 ESTs from two sets of full-length enriched libraries (derived from oligo-capped and trans-spliced cDNAs) prepared with three parasite materials: hydatid cyst wall, larval worms (protoscoleces), and pepsin/H⁺-activated protoscoleces. The ESTs were clustered into 2700 distinct gene products. In the context of the biology of E. granulosus, our analyses reveal: (i) a diverse group of abundant long non-protein coding transcripts showing homology to a middle repetitive element (EgBRep) that could either be active molecular species or represent precursors of small RNAs (like piRNAs); (ii) an up-regulation of fermentative pathways in the tissue of the cyst wall; (iii) highly expressed thiol- and selenol-dependent antioxidant enzyme targets of thioredoxin glutathione reductase, the functional hub of redox metabolism in parasitic flatworms; (iv) candidate apomucins for the external layer of the tissue-dwelling hydatid cyst, a mucin-rich structure that is critical for survival in the intermediate host; (v) a set of tetraspanins, a protein family that appears to have expanded in the cestode lineage; and (vi) a set of platyhelminth-specific gene products that may offer targets for novel pan-platyhelminth drug development.

This survey has greatly increased the quality and the quantity of the molecular information on E. granulosus and constitutes a valuable resource for gene prediction on the parasite genome and for further genomic and proteomic analyses focused on cestodes and platyhelminths.

Cestodes are a neglected group of platyhelminth parasites, despite causing chronic infections to humans and domestic animals worldwide. We used Echinococcus granulosus as a model to study the molecular basis of the host-parasite cross-talk during cestode infections. For this purpose, we carried out a survey of the genes expressed by parasite larval stages interfacing with definitive and intermediate hosts. Sequencing from several high quality cDNA libraries provided numerous insights into the expression of genes involved in important aspects of E. granulosus biology, e.g. its metabolism (energy production and antioxidant defences) and the synthesis of key parasite structures (notably, the one exposed to humans and livestock intermediate hosts). Our results also uncovered the existence of an intriguing set of abundant repeat-associated non-protein coding transcripts that may participate in the regulation of gene expression in all surveyed stages. The dataset now generated constitutes a valuable resource for gene prediction on the parasite genome and for further genomic and proteomic studies focused on cestodes and platyhelminths. In particular, the detailed characterization of a range of newly discovered genes will contribute to a better understanding of the biology of cestode infections and, therefore, to the development of products allowing their efficient control.

• Animals
• Echinococcus granulosus/genetics
• Echinococcus granulosus/growth & development
• Expressed Sequence Tags
• Larva/genetics
• Larva/growth & development
• Molecular Sequence Data
• Sequence Analysis, DNA
• Transcriptome

• 095831 Wellcome Trust
• MOP84556 CIHR
• Wellcome Trust
• 098051 Wellcome Trust
• Ref 090281 Wellcome Trust

• Animals
• Chemical Fractionation
• Chromatography, Gas
• Echinococcus granulosus/chemistry
• Lipids/analysis
• Lipids/isolation & purification
• Lipoproteins/chemistry
• Lipoproteins/isolation & purification
• Molecular Weight

• Amino Acid Sequence
• Animals
• Cattle
• Echinococcosis/parasitology
• Electrophoresis
• Humans
• Lipoproteins/chemistry
• Lipoproteins/isolation & purification
• Mass Spectrometry
• Microscopy
• Molecular Sequence Data
• Protein Multimerization
• Protein Subunits/chemistry
• Sequence Homology, Amino Acid

• Animals
• Antigens, Helminth/immunology
• Antigens, Helminth/toxicity
• Apoptosis
• CD4 Antigens/analysis
• Cells, Cultured
• Dendritic Cells/immunology
• Dendritic Cells/parasitology
• Echinococcus multilocularis/immunology
• Echinococcus multilocularis/pathogenicity
• Female
• Forkhead Transcription Factors/analysis
• Helminth Proteins/immunology
• Helminth Proteins/toxicity
• Interleukin-2 Receptor alpha Subunit/analysis
• Larva/immunology
• Larva/pathogenicity
• Mice
• Mice, Inbred C57BL
• T-Lymphocyte Subsets/chemistry
• T-Lymphocyte Subsets/immunology