Echinococcus multilocularis: Proteomic analysis of the protoscoleces by two-dimensional electrophoresis and mass spectrometry

Enhancing the therapeutic potential of P29 protein-targeted monoclonal antibodies in the management of alveolar echinococcosis through CDC-mediated mechanisms

Alveolar echinococcosis (AE) is a highly lethal helminth infection. Current chemotherapeutic strategies for AE primarily involve the use of benzimidazoles (BZs) such as mebendazole (MDZ) and albendazole (ABZ), which exhibit limited efficacy. In a previous study, the vaccine of recombinant Echinococcus granulosus P29 (rEgP29) showed significant immunoprotection against E. granulosus in both mice and sheep. In the current study, we utilized hybridoma technology to generate five monoclonal antibodies (mAbs) against P29, among which 4G10F4 mAb exhibited the highest antigen-specific binding capacity. This mAb was selected for further investigation of anti-AE therapy, both in vivo and in vitro. In vitro, 4G10F4 inhibited a noteworthy inhibition of E. multilocularis protoscoleces and primary cells viability through complement-dependent cytotoxicity (CDC) mechanism. In vivo, two experiments were conducted. In the first experiment, mice were intraperitoneally injected with Em protoscoleces, and subsequently treated with 4G10F4 mAb (2.5/5/10 mg/kg) at 12 weeks postinfection once per week for 8 times via tail vein injection. Mice that were treated with 4G10F4 mAb only in dosage of 5mg/kg exhibited a significant lower mean parasite burden (0.89±0.97 g) compared to isotype mAb treated control mice (2.21±1.30 g). In the second experiment, mice were infected through hepatic portal vein and treated with 4G10F4 mAb (5mg/kg) at one week after surgery once per week for 8 times. The numbers of hepatic metacestode lesions of the 4G10F4 treatment group were significantly lower in comparison to the isotype control group. Pathological analysis revealed severe disruption of the inner structure of the metacestode in both experiments, particularly affecting the germinal and laminated layers, resulting in the transformation into infertile vesicles after treatment with 4G10F4. In addition, the safety of 4G10F4 for AE treatment was confirmed through assessment of mouse weight and evaluation of liver and kidney function. This study presents antigen-specific monoclonal antibody immunotherapy as a promising therapeutic approach against E. multilocularis induced AE.

Proteomic analysis of Neobenedenia sp. and Rhabdosynochus viridisi (Monogenea, Monopisthocotylea): Insights into potential vaccine targets and diagnostic markers for finfish aquaculture

Monogeneans are parasitic flatworms that represent a significant threat to the aquaculture industry. Species like Neobenedenia melleni (Capsalidae) and Rhabdosynochus viridisi (Diplectanidae) have been identified as causing diseases in farmed fish. In the past years, molecular research on monogeneans of the subclass Monopisthocotylea has focused on the generation of genomic and transcriptomic information and the identification in silico of some protein families of veterinary interest. Proteomic analysis has been suggested as a powerful tool to investigate proteins in parasites and identify potential targets for vaccine development and diagnosis. To date, the proteomic dataset for monogeneans has been restricted to a species of the subclass Polyopisthocotylea, while in monopisthocotyleans there is no proteomic data. In this study, we present the first proteomic data on two monopisthocotylean species, Neobenedenia sp. and R. viridisi, obtained from three distinct sample types: tissue, excretory-secretory products (ESPs), and eggs. A total of 1691 and 1846 expressed proteins were identified in Neobenedenia sp. and R. viridisi, respectively. The actin family was the largest protein family, followed by the tubulin family and the heat shock protein 70 (HSP70) family. We focused mainly on ESPs because they are important to modulate the host immune system. We identified proteins of the actin, tubulin, HSP70 and HSP90 families in both tissue and ESPs, which have been recognized for their antigenic activities in parasitic flatworms. Furthermore, our study uncovered the presence of proteins within ESPs, such as annexin, calcium-binding protein, fructose bisphosphate aldolase, glutamate dehydrogenase, myoferlin, and paramyosin, that are targets for immunodiagnostic and vaccine development and hold paramount relevance in veterinary medicine. This study expands our knowledge of monogeneans and identified proteins that, in other platyhelminths are potential targets for vaccines and drug discovery.

Comparative Analysis of Proteins of Functionally Different Body Parts of the Fish Parasites Triaenophorus nodulosus and Triaenophorus crassus

PURPOSE

Studies of proteins expressed in the morphological structures of the parasite are necessary for elucidating the biological functions of unknown proteins and understanding the molecular basis of parasitism. The research aim was to investigate the spatial distribution of major proteins in scolex, immature and gravid proglottids of Triaenophorus nodulosus and Triaenophorus crassus.

METHODS

Protein extracts of worm body parts were analyzed using two-dimensional difference gel electrophoresis (DIGE) and mass spectrometry.

RESULTS

Comparison of the protein repertoire of the adult worm and the encysted plerocercoid revealed differences between the worm body parts, life stages and parasite species. The content of proteins associated with the cytoskeleton and musculature (actin, myosin regulatory light chain, and tropomyosin 2) decreased with distance from the scolex. Mature proglottids were rich in transforming growth factor-beta-induced protein, propionyl-CoA carboxylase, glutamate dehydrogenase and beta-tubulin. Interspecific variation in T. nodulosus and T. crassus was found in the content of the myosin, paramyosin, the major vault protein and an uncharacterized secreted protein TRINITY_DN24645. Differential expression of TRINITY_DN24645, paramyosin and tropomyosin 2 was found between plerocercoids and adult worms.

CONCLUSION

The present study provides the first characteristics of the spatial distribution of the major proteins of T. crassus and T. nodulosus. Comparison of the protein composition of plerocercoids and adult parasites indicates a significant similarity in the proteomic organization of Triaenophorus sp. in the second intermediate and final hosts. The gradual change in the morphological organization of tapeworms in the longitudinal direction coincided with the expression of some structural and metabolic proteins.

Trichuris trichiura egg extract proteome reveals potential diagnostic targets and immunomodulators

Embryonated eggs are the infectious developmental stage of Trichuris trichiura and are the primary stimulus for the immune system of the definitive host. The intestinal-dwelling T. trichiura affects an estimated 465 million people worldwide with an estimated global burden of disease of 640 000 DALYs (Disability Adjusted Life Years). In Latin America and the Caribbean, trichuriasis is the most prevalent soil transmitted helminthiasis in the region (12.3%; 95% CI). The adverse health consequences impair childhood school performance and reduce school attendance resulting in lower future wage-earning capacity. The accumulation of the long-term effects translates into poverty promoting sequelae and a cycle of impoverishment. Each infective T. trichiura egg carries the antigens needed to face the immune system with a wide variety of proteins present in the shell, larvae’s surface, and the accompanying fluid that contains their excretions/secretions. We used a proteomic approach with tandem mass spectrometry to investigate the proteome of soluble non-embryonated egg extracts of T. trichiura obtained from naturally infected African green monkeys (Chlorocebus sabaeus). A total of 231 proteins were identified, 168 of them with known molecular functions. The proteome revealed common proteins families which are known to play roles in energy and metabolism; the cytoskeleton, muscle and motility; proteolysis; signaling; the stress response and detoxification; transcription and translation; and lipid binding and transport. In addition to the study of the T. trichiura non-embryonated egg proteome, the antigenic profile of the T. trichiura non-embryonated egg and female soluble proteins against serum antibodies from C. sabaeus naturally infected with trichuriasis was investigated. We used an immunoproteomic approach by Western blot and tandem mass spectrometry from the corresponding SDS-PAGE gels. Vitellogenin N and VWD and DUF1943 domain containing protein, poly-cysteine and histidine tailed protein isoform 2, heat shock protein 70, glyceraldehyde-3-phosphate dehydrogenase, actin, and enolase, were among the potential immunoactive proteins. To our knowledge, this is the first study on the T. trichiura non-embryonated egg proteome as a novel source of information on potential targets for immunodiagnostics and immunomodulators from a neglected tropical disease. This initial list of T. trichiura non-embryonated egg proteins (proteome and antigenic profile) can be used in future research on the immunobiology and pathogenesis of human trichuriasis and the treatment of human intestinal immune-related diseases.

Who came first the worm or its egg? In the case of whipworm, we know it is the egg. The infective life cycle stage of the human whipworm (Trichuris trichiura) is the primary stimulus for the immune system of the definitive host. Each infective whipworm egg carries the information needed to face the immune system of the host with a wide variety of proteins present in the shell, larvae’s surface, and the accompanying fluid that contains their excretions/secretions. We investigated the soluble proteins of the non-embryonated egg using an immunoproteomic approach and then selected the top five proteins using a series of bioinformatic analysis. We used these top five proteins to recognize potential targets for immunodiagnostics and immunomodulation while comparing them to known female worm proteins. We found that the proteins we selected were involved in lipid transport, energy and metabolism, and muscle and motility. One protein has unknown function.

iTRAQ-based comparative proteomic analysis in different developmental stages of Echinococcus granulosus

Cystic echinococcosis, caused by infection with the larval stage of the cestode Echinococcus granulosus, is a chronic zoonosis. The lifecycle of the E. granulosus parasite includes three consecutive stages that require specific gene regulation or protein expression to survive environmental shifts between definitive hosts and intermediate hosts. The aim of the present study is to screen and analyze the stage differential antigens to be considered for vaccine development against E. granulosus. By using the iTRAQ (isobaric tags for relative and absolute quantification) method, the differentially expressed proteins were selected from the three consecutive developmental stages of E. granulosus: oncosphere, adult tapeworms, and protoscolex. Through a bioinformatics analysis including Clusters of Orthologous Groups (COG), Gene Ontology (GO), and pathway metabolic annotation, we identified some proteins of interest from each stage. The results showed that a large number of differentially expressed proteins (375: oncosphere vs. adult, 346: oncosphere vs. protoscolex, and 391: adult vs. protoscolex) were identified from the three main lifecycle stages. Analysis of the differential protein pathways showed that these differential proteins are mainly enriched in metabolic pathways, Huntington’s diseases, Alzheimer’s diseases, and ribosome metabolic pathways. Interestingly, among these differential proteins, expression levels of paramyosin, HSP60, HSP70, HSP90, cathepsin L1, cathepsin D, casein kinase, and calmodulin were significantly higher in the oncosphere than in the adult or protoscolex (p < 0.05). We hope our findings will help to identify potential targets for diagnosis or for therapeutic and prophylactic intervention.

Identification and Immunological Characterization of Somatic Proteins from Adults of Toxocara cati by Proteomics Technique

Background:

Toxocara cati is considered as one of the main etiological agents of toxocariasis with global and regional importance. As there is no information on proteomics of T. cati, herein, we reported the results obtained by proteomic analysis of somatic proteins extract, using a mass spectrometry (LC–MS/MS) approach.

Methods:

Somatic extract fractions were separated by two-dimensional SDS-PAGE and were electro blotted on to PVDF membranes for immunoblot analysis, then collected the immunogenic spots which response of antibodies of the paratenic hosts (mice) to the antigens (Mashhad, 2017), and analyzed by LC–MS/MS. The LC-MS/MS data were analyzed by Mascot database, Taxonomy Toxocara, and common contaminants, in Omics Center, Biotechnology Medical University of Graz (Austria, 2018).

Result:

The protein spots were isolated between 15–140 kDa ranges using 3–10 non-linear IPG strips and Brilliant Blue Coomassie. Ten proteins were characterized as immunogenic proteins, seven of them were identified and three of them were unknown proteins.

Conclusion:

This study provided additional information about the somatic antigens of T. cati, which can lead to the development of new strategies for novel immuno-modulators, drug targets, subunit vaccines and immunodiagnostic kits for toxocariasis.

Proteomic Insights into the Biology of the Most Important Foodborne Parasites in Europe

Foodborne parasitoses compared with bacterial and viral-caused diseases seem to be neglected, and their unrecognition is a serious issue. Parasitic diseases transmitted by food are currently becoming more common. Constantly changing eating habits, new culinary trends, and easier access to food make foodborne parasites' transmission effortless, and the increase in the diagnosis of foodborne parasitic diseases in noted worldwide. This work presents the applications of numerous proteomic methods into the studies on foodborne parasites and their possible use in targeted diagnostics. Potential directions for the future are also provided.

Proteomic analysis of soluble protein extract of adult Toxocara cati

Toxocara cati is a cat roundworm and the causative agent of toxocariasis as a cosmopolitan zoonotic disease. As no information has been reported so far, identification of T. cati proteins can be useful for the development of new diagnostic strategies. This study was conducted to identify the major proteins in the adult T. cati tegument using bi-dimensional electrophoresis (2-DE) and shotgun proteomics. A total proteins were identified, among them the metabolic enzymes were the largest group, including: Enolase, triose phosphate isomerase, fructose-bisphosphate aldolase, aldehyde dehydrogenase. The other important protein groups recognized in T. cati, belong to the HSP-family, the structure and motor proteins, such as actin. The role of these proteins have been implicated in parasite-host interactions and modulating cellular immune response, immune regulation in evasion mechanisms of the host immune response. Characterizing T. cati adult proteins play a key role not only in host-parasite interactions, but also in the discovery of drug targets, subunit vaccines against toxocariasis, immunodiagnostic kits for toxocariasis and the identification of novel immuno-modulators that can form the next generation of therapeutic possibilities for inflammatory diseases.

Proteomics Analysis of Hydatigera taeniaeformis Metacestode Stage

Hydatigera taeniaeformis (H. taeniaeformis) is one of the most robust of tapeworm parasites that is widely distributed around the world. Information of proteins of H. taeniaeformis has not previously been reported. Using liquid chromatography tandem-mass spectrometry (LC-MS/MS) analysis, the proteome of H. taeniaeformis metacestode was profiled and a total of 408 proteins were identified. Of these, 26.5% (108/408) were annotated to be associated with metabolic pathways. Consistently, Gene Ontology analysis showed that those identified proteins were mainly classified into metabolic process of the biological processes. A set of metabolic enzymes, including Fructose-1,6-bisphosphate aldolase, enolase, Glucan phosphorylase, and phosphoenolpyruvate carboxykinase, were abundant in H. taeniaeformis metacestodes. In addition, some rare but interesting proteins like antigens (such as tegument protein and Antigen B) were identified. The two recombinant proteins of tegument protein and Antigen B were well-recognized by the sera from the H. taeniaeformis-infected mice. The H. taeniaeformis metacestode proteome might help to find new candidates for the immunodiagnosis and vaccine development and provide valuable information on H. taeniaeformis biology.

Trypanosoma cruzi Calreticulin: Immune Evasion, Infectivity, and Tumorigenesis

To successfully infect, Trypanosoma cruzi evades and modulates the host immune response. T. cruzi calreticulin (TcCalr) is a multifunctional, endoplasmic reticulum (ER)-resident chaperone that, translocated to the external microenvironment, mediates crucial host-parasite interactions. TcCalr binds and inactivates C1 and mannose-binding lectin (MBL)/ficolins, important pattern- recognition receptors (PRRs) of the complement system. Using an apoptotic mimicry strategy, the C1-TcCalr association facilitates the infection of target cells. T. cruzi infection also seems to confer protection against tumorigenesis. Thus, recombinant TcCalr has important antiangiogenic properties, detected in vitro, ex vivo, and in ovum, most likely contributing at least in part, to its antitumor properties. Consequently, TcCalr is useful for investigating key issues of host-parasite interactions and possible new immunological/pharmacological interventions in the areas of Chagas' disease and experimental cancer.

The application of proteomic methods (MALDI-toff MS) for studying protein profiles of some nematodes (dirofilaria and ascaris) for differentiating species

INTRODUCTION

Matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-toff MS) is a reliable method for diagnosing a number of bacterial and fungal infections. It is also effective as a method of rapid diagnosis of several parasitic agents. We used MALDI-toff MS to study the protein profiles of four nematodes: Dirofilaria repens, Dirofilaria. immitis, Ascaris suum and Ascaris lumbricoides.

METHODS

We studied the protein profiles of dirofilaria (five of each species: D. repens and D. immitis) and ascaris (five of each species: A. suum and A. lumbricoides), using a proteomic analysis based on MALDI-toff MS.

RESULTS

Analysis of protein extracts of dirofilaria and ascaris showed spectra with high-intensity peaks in the range of 2-20 kDa. The quality of the spectra (clear graphical reflection of mass/charge to luminous intensity, consistent in repeated analyzes) and the intensity of the spectral peaks were consistent in all samples of the same species. The spectra profiles of D. repens and D. immitis differed in eight major peaks which makes it possible to differentiate species according to the protein profile. The spectra profiles obtained from A. suum and A. lumbricoides proteins differed slightly in 3 major peaks in both species and were discovered in m/z 13000; 13400 and 14400. The protein peaks in diapason 3000 kD-7300 kD specific for all genus ascaris are constant.

CONCLUSIONS

MALDI-toff MS-based proteomic analysis can serve as an effective taxonomic tool for parasitological studies.

Immunoproteomics and Surfaceomics of the Adult Tapeworm Hymenolepis diminuta

In cestodiasis, mechanical and molecular contact between the parasite and the host activates the immune response of the host and may result in inflammatory processes, leading to ulceration and intestinal dysfunctions. The aim of the present study was to identify antigenic proteins of the adult cestode Hymenolepis diminuta by subjecting the total protein extracts from adult tapeworms to 2DE immunoblotting (two-dimensional electrophoresis combined with immunoblotting) using sera collected from experimentally infected rats. A total of 36 protein spots cross-reacting with the rat sera were identified using LC-MS/MS. As a result, 68 proteins, including certain structural muscle proteins (actin, myosin, and paramyosin) and moonlighters (heat shock proteins, kinases, phosphatases, and glycolytic enzymes) were identified; most of these were predicted to possess binding and/or catalytic activity required in various metabolic and cellular processes, and reported here as potential antigens of the adult cestode for the first time. As several of these antigens can also be found at the cell surface, the surface-associated proteins were extracted and subjected to in-solution digestion for LC-MS/MS identification (surfaceomics). As a result, a total of 76 proteins were identified, from which 31 proteins, based on 2DE immunoblotting, were predicted to be immunogenic. These included structural proteins actin, myosin and tubulin as well as certain moonlighting proteins (heat-shock chaperones) while enzymes with diverse catalytic activities were found as the most dominating group of proteins. In conclusion, the present study shed new light into the complexity of the enteric cestodiasis by showing that the H. diminuta somatic proteins exposed to the host possess immunomodulatory functions, and that the immune response of the host could be stimulated by diverse mechanisms, involving also those triggering protein export via yet unknown pathways.

Immunomodulation by Helminths: Intracellular Pathways and Extracellular Vesicles

Helminth parasites are masters at manipulating host immune responses, using an array of sophisticated mechanisms. One of the major mechanisms enabling helminths to establish chronic infections is the targeting of pattern recognition receptors (PRRs) including toll-like receptors, C-type lectin receptors, and the inflammasome. Given the critical role of these receptors and their intracellular pathways in regulating innate inflammatory responses, and also directing adaptive immunity toward Th1 and Th2 responses, recognition of the pathways triggered and/or modulated by helminths and their products will provide detailed insights about how helminths are able to establish an immunoregulatory environment. However, helminths also target PRRs-independent mechanisms (and most likely other yet unknown mechanisms and pathways) underpinning the battery of different molecules helminths produce. Herein, the current knowledge on intracellular pathways in antigen presenting cells activated by helminth-derived biomolecules is reviewed. Furthermore, we discuss the importance of helminth-derived vesicles as a less-appreciated components released during infection, their role in activating these host intracellular pathways, and their implication in the development of new therapeutic approaches for inflammatory diseases and the possibility of designing a new generation of vaccines.

The somatic proteins of Toxocara canis larvae and excretory-secretory products revealed by proteomics

Toxocariasis is a widespread helminth infection of dogs and cats, caused by Toxocara canis and Toxocara cati larvae, respectively. Toxocara spp. can cause zoonotic infections in humans by invading tissues and organs causing pathology. Toxocara spp. larvae release excretory-secretory molecules (TES) into the body of their host that are fundamental to the host-parasite interaction and could be used as targets for novel diagnostics and vaccines. In the present study, we identified 646 T. canis proteins from TES and larval extract using 1D-SDS PAGE followed by mass spectrometry. A wide range of proteins was identified that may play a role both in the induction of the host immune response and host pathology, and in parasite metabolism and survival. Among these proteins there are potential candidates for novel diagnostics and vaccines for dogs and cats toxocariases.

Metazoan Parasite Vaccines: Present Status and Future Prospects

Eukaryotic parasites and pathogens continue to cause some of the most detrimental and difficult to treat diseases (or disease states) in both humans and animals, while also continuously expanding into non-endemic countries. Combined with the ever growing number of reports on drug-resistance and the lack of effective treatment programs for many metazoan diseases, the impact that these organisms will have on quality of life remain a global challenge. Vaccination as an effective prophylactic treatment has been demonstrated for well over 200 years for bacterial and viral diseases. From the earliest variolation procedures to the cutting edge technologies employed today, many protective preparations have been successfully developed for use in both medical and veterinary applications. In spite of the successes of these applications in the discovery of subunit vaccines against prokaryotic pathogens, not many targets have been successfully developed into vaccines directed against metazoan parasites. With the current increase in -omics technologies and metadata for eukaryotic parasites, target discovery for vaccine development can be expedited. However, a good understanding of the host/vector/pathogen interface is needed to understand the underlying biological, biochemical and immunological components that will confer a protective response in the host animal. Therefore, systems biology is rapidly coming of age in the pursuit of effective parasite vaccines. Despite the difficulties, a number of approaches have been developed and applied to parasitic helminths and arthropods. This review will focus on key aspects of vaccine development that require attention in the battle against these metazoan parasites, as well as successes in the field of vaccine development for helminthiases and ectoparasites. Lastly, we propose future direction of applying successes in pursuit of next generation vaccines.

Comparative Proteomic Analysis of Hymenolepis diminuta Cysticercoid and Adult Stages

Cestodiases are common parasitic diseases of animals and humans. As cestodes have complex lifecycles, hexacanth larvae, metacestodes (including cysticercoids), and adults produce proteins allowing them to establish invasion and to survive in the hostile environment of the host. Hymenolepis diminuta is the most commonly used model cestode in experimental parasitology. The aims of the present study were to perform a comparative proteomic analysis of two consecutive developmental stages of H. diminuta (cysticercoid and adult) and to distinguish proteins which might be characteristic for each of the stages from those shared by both stages. Somatic proteins of H. diminuta were isolated from 6-week-old cysticercoids and adult tapeworms. Cysticercoids were obtained from experimentally infected beetles, Tenebrio molitor, whereas adult worms were collected from experimentally infected rats. Proteins were separated by GeLC-MS/MS (one dimensional gel electrophoresis coupled with liquid chromatography and tandem mass spectrometry). Additionally protein samples were digested in-liquid and identified by LC-MS/MS. The identified proteins were classified according to molecular function, cellular components and biological processes. Our study showed a number of differences and similarities in the protein profiles of cysticercoids and adults; 233 cysticercoid and 182 adult proteins were identified. From these proteins, 131 were present only in the cysticercoid and 80 only in the adult stage samples. Both developmental stages shared 102 proteins; among which six represented immunomodulators and one is a potential drug target. In-liquid digestion and LC-MS/MS complemented and confirmed some of the GeLC-MS/MS identifications. Possible roles and functions of proteins identified with both proteomic approaches are discussed.

Identification of immunogenic proteins of the cysticercoid of Hymenolepis diminuta

Background

A wide range of molecules are used by tapeworm metacestodes to establish successful infection in the hostile environment of the host. Reports indicating the proteins in the cestode-host interactions are limited predominantly to taeniids, with no previous data available for non-taeniid species. A non-taeniid, Hymenolepis diminuta, represents one of the most important model species in cestode biology and exhibits an exceptional developmental plasticity in its life-cycle, which involves two phylogenetically distant hosts, arthropod and vertebrate.

Results

We identified H. diminuta cysticercoid proteins that were recognized by sera of H. diminuta-infected rats using two-dimensional gel electrophoresis (2DE), 2D-immunoblotting, and LC-MS/MS mass spectrometry. Proteomic analysis of 42 antigenic spots revealed 70 proteins. The largest number belonged to structural proteins and to the heat-shock protein (HSP) family. These results show a number of the antigenic proteins of the cysticercoid stage, which were present already in the insect host prior to contact with the mammal host. These are the first parasite antigens that the mammal host encounters after the infection, therefore they may represent some of the molecules important in host-parasite interactions at the early stage of infection.

Conclusions

These results could help in understanding how H. diminuta and other cestodes adapt to their diverse and complex parasitic life-cycles and show universal molecules used among diverse groups of cestodes to escape the host response to infection.

Electronic supplementary material

The online version of this article (10.1186/s13071-017-2519-4) contains supplementary material, which is available to authorized users.

Quantitative multiplexed proteomics of Taenia solium cysts obtained from the skeletal muscle and central nervous system of pigs

In human and porcine cysticercosis caused by the tapeworm Taenia solium, the larval stage (cysts) can infest several tissues including the central nervous system (CNS) and the skeletal muscles (SM). The cyst’s proteomics changes associated with the tissue localization in the host tissues have been poorly studied. Quantitative multiplexed proteomics has the power to evaluate global proteome changes in response to different conditions. Here, using a TMT-multiplexed strategy we identified and quantified over 4,200 proteins in cysts obtained from the SM and CNS of pigs, of which 891 were host proteins. To our knowledge, this is the most extensive intermixing of host and parasite proteins reported for tapeworm infections.Several antigens in cysticercosis, i.e., GP50, paramyosin and a calcium-binding protein were enriched in skeletal muscle cysts. Our results suggested the occurrence of tissue-enriched antigen that could be useful in the improvement of the immunodiagnosis for cysticercosis. Using several algorithms for epitope detection, we selected 42 highly antigenic proteins enriched for each tissue localization of the cysts. Taking into account the fold changes and the antigen/epitope contents, we selected 10 proteins and produced synthetic peptides from the best epitopes. Nine peptides were recognized by serum antibodies of cysticercotic pigs, suggesting that those peptides are antigens. Mixtures of peptides derived from SM and CNS cysts yielded better results than mixtures of peptides derived from a single tissue location, however the identification of the ‘optimal’ tissue-enriched antigens remains to be discovered. Through machine learning technologies, we determined that a reliable immunodiagnostic test for porcine cysticercosis required at least five different antigenic determinants.

Human and porcine cysticercosis caused by Taenia solium is a parasite disease still endemic in developing countries. The cysts can be located in different host tissues, including different organs of the central nervous system and the skeletal muscles. The molecular mechanisms associated with the tissue localization of the cysts are not well understood. Here, we described the proteome changes of the cysts obtained from different host tissues from infected pigs using quantitative multiplex proteomics. We explored the diversity of host proteins identified in the cyst’s protein extracts and we also explored the immune-localization of several host-related proteins within the cysts, and propose their possible function. We identified several proteins and antigens enriched for a given tissue localization. Several synthetic peptides designed from these tissue-enriched antigens were tested trough ELISA. Using a combination of peptide mixtures and machine learning technologies we were able to distinguish non cysticercotic and cysticercotic pig’s sera. The tissue-enriched proteins/antigens could be useful for the development of improved immuno-diagnostic tests capable of discriminate the tissue-localization of the cysts.

Screening of antigenic vesicular fluid proteins of Echinococcus multilocularis as potential viability biomarkers to monitor drug response in alveolar echinococcosis patients

PURPOSE

The only drugs available to treat alveolar echinococcosis (AE) are mostly parasitostatic and in many cases prescribed for life. Decision criteria for discontinuation rely on the absence of parasitic viability. The aim of the present study is to search for candidate proteins that may exhibit good potential as biomarkers for viability.

EXPERIMENTAL DESIGN

Sixteen serum samples (five healthy controls, 11 patients with AE), are used. AE-patients are classified into three groups "Cured" (n = 2), "ABZ-responders" (n = 4) and "ABZ-nonresponders" (n = 5). Immunoreactive proteins from vesicular fluid (VF) are identified and quantified by LC-MS/MS analysis after immunoprecipitation (IP) using all 16 serum samples.

RESULTS

Shotgun analysis of VF lead to the identification of 107 E. multilocularis proteins. Comparative proteomics reveal nine proteins more abundant in IP eluates from ABZ-nonresponder patients (cathepsin b, prosaposin a preprotein, actin modulator protein, fucosidase alpha L1 tissue, gluthatione-S-tranferase, beta galactosidase, elongation factor 2, H17g protein tegumental antigen, and NiemannPick C2 protein).

CONCLUSIONS AND CLINICAL RELEVANCE

Detection of antibodies against these proteins by ELISA could be helpful to monitor the course of alveolar echinococcosis under albendazole (ABZ) treatment.

Proteomic analysis of Taenia ovis metacestodes by high performance liquid chromatography-coupled tandem mass spectrometry

Taenia ovis metacestodes reside in the muscle of sheep and goats, and may cause great economic loss due to condemnation of carcasses if not effectively controlled. Although advances have been made in the control of T. ovis infection, our knowledge of T. ovis biology is limited. Herein the protein profiling of T. ovis metacestodes was determined by liquid chromatography-linked tandem mass spectrometry. A total of 966 proteins were identified and 25.1% (188/748) were annotated to be associated with metabolic pathways. Consistently, GO analysis returned a metabolic process (16.27%) as one of two main biological process terms. Moreover, it was found that 24 proteins, including very low-density lipoprotein receptor, enolase, paramyosin and endophilin B1, were abundant in T. ovis metacestodes. These proteins may be associated with motility, metabolism, signaling, stress, drug resistance and immune responses. Furthermore, comparative analysis of 5 cestodes revealed the presence of Taenia-specific enolases. These data provide clues for better understanding of T. ovis biology, which is informative for effective control of infection.

MALDI-TOF mass spectrometry as a potential tool for Trichomonas vaginalis identification

Background

Trichomonas vaginalis is a flagellated protozoan causing trichomoniasis, a sexually transmitted human infection, with around 276.4 million new cases estimated by World Health Organization. Culture is the gold standard method for the diagnosis of T. vaginalis infection. Recently, immunochromatographic assays as well as PCR assays for the detection of T. vaginalis antigen or DNA, respectively, have been also available. Although the well-known genome sequence of T. vaginalis has made possible the application of proteomic studies, few data are available about the overall proteomic expression profiling of T. vaginalis. The aim of this study was to investigate the potential application of MALDI-TOF MS as a new tool for the identification of T. vaginalis.

Methods

Twenty-one isolates were analysed by MALDI-TOF MS after the creation of a Main Spectrum Profile (MSP) from a T. vaginalis reference strain (G3) and its subsequent supplementation in the Bruker Daltonics database, not including any profile of protozoa. This was achieved after the development of a new identification method created by modifying the range setting (6–10 kDa) for the MALDI-TOF MS analysis in order to exclude the overlapping of peaks derived from the culture media used in this study.

Results

Two MSP reference spectra were created in 2 different range: 3–15 kDa (standard range setting) and 6–10 kDa (new range setting). Both MSP spectra were deposited in the MALDI BioTyper database for further identification of additional T. vaginalis strains. All the 21 strains analysed in this study were correctly identified by using the new identification method.

Conclusions

In this study it was demonstrated that changes in the MALDI-TOF MS standard parameters usually used to identify bacteria and fungi allowed the identification of the protozoan T. vaginalis. This study shows the usefulness of MALDI-TOF MS in the reliable identification of microorganism grown on complex liquid media such as the protozoan T. vaginalis, on the basis of the proteic profile and not on the basis of single markers, by using a “new range setting” different from that developed for bacteria and fungi.

Mass spectrometry analysis of the excretory-secretory (E-S) products of the model cestode Hymenolepis diminut a reveals their immunogenic properties and the presence of new E-S proteins in cestodes

Hymenolepis diminuta is an important model species in studies of therapeutics, biochemical processes, immune responses and other aspects of cestodiasis. The parasite produces numerous excretory-secretory (E-S) proteins and a glycocalyx covering its body. Our study focused on the mass spectrometry analysis of the E-S material with an objective to determine if E-S contains any new proteins, in particular those that can be identified as: antigens, vaccine candidates and drug targets. These proteins might engage directly in host-parasite interactions. Adult parasites collected from experimentally infected rats were cultured in vitro for 5 and 18h. Immunoblotting was used to verify which E-S protein bands separated in SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis) react with specific antibodies from sera of infected rats. We identified thirty-nine proteins by LC-MS/MS (liquid chromatography mass spectrometry). Results indicated the presence of proteins that have never been identified in cestode E-S material. Immunoblotting showed the immunogenicity of E-S products of H. diminuta, most probably associated with the presence of proteins known as antigens in other flatworm species. Among identified proteins are those engaged in immunomodulatory processes (eg. HSP), in response to oxidative stress (peroxidasin) or metabolism (eg. GAPDH). The predominant functions are associated with metabolism and catalytic activity. This is the first study identifying E-S-proteins in adult tapeworms, thus providing information for better understanding host-parasite interrelationships, and may point out potential targets for vaccines or drug discovery studies, as among the proteins observed in our study are those known to be antigens.

Shared weapons of blood- and plant-feeding insects: Surprising commonalities for manipulating hosts

Insects that reprogram host plants during colonization remind us that the insect side of plant-insect story is just as interesting as the plant side. Insect effectors secreted by the salivary glands play an important role in plant reprogramming. Recent discoveries point to large numbers of salivary effectors being produced by a single herbivore species. Since genetic and functional characterization of effectors is an arduous task, narrowing the field of candidates is useful. We present ideas about types and functions of effectors from research on blood-feeding parasites and their mammalian hosts. Because of their importance for human health, blood-feeding parasites have more tools from genomics and other - omics than plant-feeding parasites. Four themes have emerged: (1) mechanical damage resulting from attack by blood-feeding parasites triggers "early danger signals" in mammalian hosts, which are mediated by eATP, calcium, and hydrogen peroxide, (2) mammalian hosts need to modulate their immune responses to the three "early danger signals" and use apyrases, calreticulins, and peroxiredoxins, respectively, to achieve this, (3) blood-feeding parasites, like their mammalian hosts, rely on some of the same "early danger signals" and modulate their immune responses using the same proteins, and (4) blood-feeding parasites deploy apyrases, calreticulins, and peroxiredoxins in their saliva to manipulate the "danger signals" of their mammalian hosts. We review emerging evidence that plant-feeding insects also interfere with "early danger signals" of their hosts by deploying apyrases, calreticulins and peroxiredoxins in saliva. Given emerging links between these molecules, and plant growth and defense, we propose that these effectors interfere with phytohormone signaling, and therefore have a special importance for gall-inducing and leaf-mining insects, which manipulate host-plants to create better food and shelter.

The helminth parasite proteome at the host-parasite interface - Informing diagnosis and control

Helminth parasites are a significant health burden for humans in the developing world and also cause substantial economic losses in livestock production across the world. The combined lack of vaccines for the major human and veterinary helminth parasites in addition to the development of drug resistance to anthelmintics in sheep and cattle mean that controlling helminth infection and pathology remains a challenge. However, recent high throughput technological advances mean that screening for potential drug and vaccine candidates is now easier than in previous decades. A better understanding of the host-parasite interactions occurring during infection and pathology and identifying pathways that can be therapeutically targeted for more effective and 'evolution proof' interventions is now required. This review highlights some of the advances that have been made in understanding the host-parasite interface in helminth infections using studies of the temporal expression of parasite proteins, i.e. the parasite proteome, and discuss areas for potential future research and translation.

Prevention and Immunotherapy of Secondary Murine Alveolar Echinococcosis Employing Recombinant EmP29 Antigen

Alveolar echinococcosis (AE) is caused by infection with the larval stage of the tapeworm Echinococcus multilocularis. An increasing understanding of immunological events that account for the metacestode survival in human and murine AE infection prompted us to undertake explorative experiments tackling the potential of novel preventive and/or immunotherapeutic measures. In this study, the immunoprotective and immunotherapeutic ability of recombinant EmP29 antigen (rEmP29) was assessed in mice that were intraperitoneally infected with E. multilocularis metacestodes. For vaccination, three intraperitoneal injections with 20μg rEmP29 emulsified in saponin adjuvants were applied over 6 weeks. 2 weeks after the last boost, mice were infected, and at 90 days post-infection, rEmP29-vaccinated mice exhibited a median parasite weight that was reduced by 75% and 59% when compared to NaCl- or saponin–treated control mice, respectively. For immunotherapeutical application, the rEmP29 (20μg) vaccine was administered to experimentally infected mice, starting at 1 month post-infection, three times with 2 weeks intervals. Mice undergoing rEmP29 immunotherapy exhibited a median parasite load that was reduced by 53% and 49% when compared to NaCl- and saponin–treated control mice, respectively. Upon analysis of spleen cells, both, vaccination and treatment with rEmP29, resulted in low ratios of Th2/Th1 (IL-4/IFN-γ) cytokine mRNA and low levels of mRNA coding for IL-10 and IL-2. These results suggest that reduction of the immunosuppressive environment takes place in vaccinated as well as immunotreated mice, and a shift towards a Th1 type of immune response may be responsible for the observed increased restriction of parasite growth. The present study provides the first evidence that active immunotherapy may present a sustainable route for the control of AE.

Current medical management of AE that relies on surgery and continuous benzimidazole administration is of limited effectiveness. Therefore, alternative preventive and therapeutic tools need to be explored. Here, we demonstrate that vaccination with recombinant antigen EmP29 (rEmP29), prior or after secondary infection of BALB/c mice, resulted in a significant reduction of the median parasite weight when compared to different control groups. We then characterized the transcription level of splenic IL-4 and IFN-γ cytokines as hallmarks for AE-anti-protective humoral immune reaction (Th2) and for AE-effective (restrictive) cellular response (Th1), respectively. Results revealed that vaccinated mice in pre- or post-infection situation exhibited the lowest IL-4/IFN-γ mRNA ratios. In addition, those groups showed also significantly low levels of IL-10-encoding mRNA coding (immunosuppressive cytokine), as well as IL-2. These findings suggest that reduction of parasite load in rEmP29-vaccinated mice (in pre- or post-infection status) might be triggered by a decline of the immunosuppressive environment and a change of the host immune reaction towards a Th1-re-oriented cell-mediated immune defense. A similar non-specific effect appears also to be yielded by the immunostimulating adjuvants. This study provides the first insight into the potential benefits of antigen-specific immunotherapy as new treatment option of AE.

Proteomic analysis of the excretory/secretory products and antigenic proteins of Echinococcus granulosus adult worms from infected dogs

Background

Cystic echinococcosis, which is caused by Echinococcus granulosus, is one of the most widespread zoonotic helminth diseases that affects humans and livestock. Dogs, which harbor adult worms in their small intestines, are a pivotal source of E. granulosus infection in humans and domestic animals. Therefore, novel molecular approaches for the prevention and diagnosis of this parasite infection in dogs need to be developed.

Results

In this study, we performed proteomic analysis to identify excretory/secretory products (ES) and antigenic proteins of E. granulosus adult worms using two-dimensional electrophoresis, tandem matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF/TOF), and Western blotting of sera from infected dogs. This study identified 33 ES product spots corresponding to 9 different proteins and 21 antigenic protein spots corresponding to 13 different proteins. Six antigenic proteins were identified for the first time.

Conclusions

The present study extended the existing proteomic data of E. granulosus and provides further information regarding host-parasite interactions and survival mechanisms. The results of this study contribute to vaccination and immunodiagnoses for E. granulosus infections.

MALDI-TOF mass spectrometry for the detection and differentiation of Entamoeba histolytica and Entamoeba dispar

Detection of Entamoeba histolytica and its differentiation from Entamoeba dispar is an important goal of the clinical parasitology laboratory. The aim of this study was the identification and differentiation of E. histolytica and E. dispar by MALDI-TOF MS, in order to evaluate the application of this technique in routine diagnostic practice. MALDI-TOF MS was applied to 3 amebic reference strains and to 14 strains isolated from feces that had been differentiated by molecular methods in our laboratory. Protein extracts from cultures of these strains (axenic cultures for the 3 reference strains and monoxenic cultures for the 14 field isolates) were analyzed by MALDI-TOF MS and the spectra obtained were analyzed by statistical software. Five peaks discriminating between E. histolytica and E. dispar reference strains were found by protein profile analysis: 2 peaks (8,246 and 8,303 Da) specific for E. histolytica and 3 (4,714; 5,541; 8,207 Da) for E. dispar. All clinical isolates except one showed the discriminating peaks expected for the appropriate species. For 2 fecal samples from which 2 strains (1 E. histolytica and 1 E. dispar) out of the 14 included in this study were isolated, the same discriminating peaks found in the corresponding isolated amebic strains were detected after only 12h (E. histolytica) and 24h (E. dispar) of incubation of the fecal samples in Robinson’s medium without serum. Our study shows that MALDI-TOF MS can be used to discriminate between E. histolytica and E. dispar using in vitro xenic cultures and it also could have potential for the detection of these species in clinical samples.

Proteomic profiling of the infective trophozoite stage of Acanthamoeba polyphaga

Acanthamoeba polyphaga is a free-living protozoan pathogen, whose infective trophozoite form is capable of causing a blinding keratitis and fatal granulomatous encephalitis in humans. The damage caused by A. polyphaga trophozoites in human corneal or brain infections is the result of several different pathogenic mechanisms that have not yet been elucidated at the molecular level. We performed a comprehensive analysis of the proteins expressed by A. polyphaga trophozoites, based on complementary 2-DE MS/MS and gel-free LC-MS/MS approaches. Overall, 202 non-redundant proteins were identified. An A. polyphaga proteomic map in the pH range 3-10 was produced, with protein identification for 184 of 370 resolved spots, corresponding to 142 proteins. Additionally, 94 proteins were identified by gel-free LC-MS/MS. Functional classification revealed several proteins with potential importance for pathogen survival and infection of mammalian hosts, including surface proteins and proteins related to defense mechanisms. Our study provided the first comprehensive proteomic survey of the trophozoite infective stage of an Acanthamoeba species, and established foundations for prospective, comparative and functional studies of proteins involved in mechanisms of survival, development, and pathogenicity in A. polyphaga and other pathogenic amoebae.

Dexamethasone downregulated the expression of CSF 14-3-3β protein in mice with eosinophilic meningitis caused by Angiostrongylus cantonensis infection

Angiostrongylus cantonensis is the main causative agent of human eosinophilic meningitis in Southeast Asia and the Pacific Islands. A previous study demonstrated that the 14-3-3β protein is a neuropathological marker in monitoring neuronal damage in meningitis. Steroids are commonly used in patients with eosinophilic meningitis caused by A. cantonensis infection. However, the mechanism by which steroids act in eosinophilic meningitis is unknown. We hypothesized that the beneficial effect of steroids on eosinophilic meningitis is partially mediated by the down-regulation of 14-3-3β protein expression in the cerebrospinal fluid (CSF). In this animal study, we determined the dynamic changes of 14-3-3β protein in mice with eosinophilic meningitis. The 14-3-3β protein in serum and CSF was increased in week 2 and 3 after infections. Dexamethasone administration significantly decreased the amounts of CSF 14-3-3β protein. By developing an in-house ELISA to measure 14-3-3β protein, it was found that the amounts of 14-3-3β protein in the CSF and serum increased over a three-week period after infection. There was a remarkable reduction of 14-3-3β protein in the CSF after 2 weeks of dexamethasone treatment. In conclusion, the administration of corticosteroids in mice with eosinophilic meningitis decreased the expression of 14-3-3β protein in the CSF.

Subtype determination of Blastocystis isolates by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS)

The pathogenic role of the enteric parasite Blastocystis remains controversial. Recent studies have suggested that various subtypes (STs) found in human samples could be correlated to the presence or absence and variability of clinical manifestations, and that STs can differ with respect to drug sensitivity. Polymerase chain reaction (PCR) techniques used to determine these STs are expensive and are usually restricted to research laboratory settings. This study evaluates the potential application of the inexpensive matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) technique to discriminate Blastocystis STs. A database of parasitic protein signatures was constructed for five Blastocystis STs, and the reference spectra were challenged with those from 19 axenic cultures of ST1, ST2, ST3, ST4 and ST8 and those from nine xenic liquid cultures of ST3 and ST4. Samples from axenic cultures were prepared using standard formic acid extraction and direct deposition procedures. The reference spectra revealed five distinct spectral profiles, and the database library allowed for discrimination between all of the cultures with reliability indices ranging from 2.038 to greater than 2.8 when an extraction was performed. The direct deposition procedure resulted in greater variability in the discrimination and direct MALDI-TOF MS identification from xenic liquid cultures was effective in 3 out of 9 samples. MALDI-TOF MS proved to be an effective technology for efficiently discriminating Blastocystis STs in axenic cultures.

High throughput sequencing of the Angiostrongylus cantonensis genome: a parasite spreading worldwide

Angiostrongylus cantonensis is a parasitic nematode of rodents and a leading aetiological agent of eosinophilic meningitis in humans. Definitive diagnosis is difficult, often relying on immunodiagnostic methods which utilize crude antigens. New immunodiagnostic methods based on recombinant proteins are being developed, and ideally these methods would be made available worldwide. Identification of diagnostic targets, as well as studies on the biology of the parasite, are limited by a lack of molecular information on Angiostrongylus spp. available in databases. In this study we present data collected from DNA random high-throughput sequencing together with proteomic analyses and a cDNA walking methodology to identify and obtain the nucleotide or amino acid sequences of unknown immunoreactive proteins. 28 080 putative ORFs were obtained, of which 3371 had homology to other deposited protein sequences. Using the A. cantonensis genomic sequences, 156 putative ORFs, matching peptide sequences obtained from previous proteomic studies, were considered novel, with no homology to existing sequences. Full-length coding sequences of eight antigenic target proteins were obtained. In this study we generated not only the complete nucleotide sequences of the antigenic protein targets but also a large amount of genomic data which may help facilitate future genomic, proteomic, transcriptomic or metabolomic studies on Angiostrongylus.

Proteomic characterization of larval and adult developmental stages in Echinococcus granulosus reveals novel insight into host-parasite interactions

Cystic hydatid disease is an important zoonosis caused by Echinococcus granulosus infection. The expression profiles of its parasitic life stages and host-Echinococcus interactions remain to be elucidated. Here, we identified 157 adult and 1588 protoscolex proteins (1610 in all), including 1290 novel identifications. Paramyosins and an antigen B (AgB) were the dominant adult proteins. Dog proteins (30) identified in adults indicated diminished local inflammation caused by adult infection. The protoscolex expresses proteins that have been reported to be antigens in other parasites, such as 6-phosphofructokinase and calcineurin B. Pathway analyses suggested that E. granulosus uses both aerobic and anaerobic carbohydrate metabolisms to generate ATP. E. granulosus expresses proteins involved in synthesis and metabolism of lipids or steroids. At least 339 of 390 sheep proteins identified in protoscolex were novel identifications not seen in previous analyses. IgGs and lambda light chains were the most abundant antibody species. Sheep proteins were enriched for detoxification pathways, implying that host detoxification effects play a central role during host-parasite interactions. Our study provides valuable data on E. granulosus expression characteristics, allowing novel insights into the molecular mechanisms involved in host-parasite interactions.

BIOLOGICAL SIGNIFICANCE

In this study, the Echinococcus granulosus adult worm proteome was analyzed for the first time. The protein identification of E. granulosus protoscoleces was extended dramatically. We also identified the most abundant host proteins co-purified with Echinococcus. The results provide useful information pertaining to the molecular mechanisms behind host-Echinococcus interaction and Echinococcus biology. This data also increases the potential for identifying vaccine candidates and new therapeutic targets, and may aid in the development of protein probes for selective and sensitive diagnosis of echinococcosis infection. In addition, the data collected here represents a valuable proteomic resource for subsequent genome annotation.

The 31-kDa antigen of Angiostrongylus cantonensis comprises distinct antigenic glycoproteins

Human angiostrongyliasis results from accidental infection with Angiostrongylus, an intra-arterial nematode. Angiostrongylus cantonensis infections result in eosinophilic meningitis, and A. costaricensis infections cause eosinophilic enteritis. Immunological methodologies are critical to the diagnosis of both infections, since these parasites cannot be isolated from fecal matter and are rarely found in cerebrospinal fluid samples. A. costaricensis and A. cantonensis share common antigenic epitopes which elicit antibodies that recognize proteins present in either species. Detection of antibodies to a 31-kDa A. cantonensis protein present in crude adult worm extracts is a sensitive and specific method for immunodiagnosis of cerebral angiostrongyliasis. The objective of the present work was to isolate and characterize the 31-kDa proteins using soluble protein extracts derived from adult female worms using both one- (1DE) and two-dimensional (2DE) gel electrophoresis. Separated proteins were blotted onto nitrocellulose and probed using sera from infected and non-infected controls. The 31-kDa band present in 1DE gels and the 4 spots identified in 2DE gels were excised and analyzed by electrospray ionization mass spectrometry. Using the highest scores obtained following Mascot analysis, amino acid sequences were obtained that matched four unique proteins: tropomyosin, the 14-3-3 phosphoserine-binding protein, a protein containing a nascent polypeptide-associated complex domain, and the putative epsilon subunit of coatomer protein complex isoform 2. Oxidative cleavage of diols using sodium m-periodate demonstrated that carbohydrate moieties are essential for the antigenicity of all four spots of the 31-kDa antigen. In this article we describe the identification of the 31-kDa antigen, and provide DNA sequencing of the targets. In conclusion, these data suggest that reactivity to the 31-kDa proteins may represent antibody recognition of more than one protein, and recombinant protein-based assays for cerebral angiostrongyliasis diagnosis may require eukaryotic expression systems to maintain antigenicity.

Anthelmintic metabolism in parasitic helminths: proteomic insights

Anthelmintics are the cornerstone of parasitic helminth control. Surprisingly, understanding of the biochemical pathways used by parasitic helminths to detoxify anthelmintics is fragmented, despite the increasing global threat of anthelmintic resistance within the ruminant and equine industries. Reductionist biochemistry has likely over-estimated the enzymatic role of glutathione transferases in anthelmintic metabolism and neglected the potential role of the cytochrome P-450 superfamily (CYPs). Proteomic technologies offers the opportunity to support genomics, reverse genetics and pharmacokinetics, and provide an integrated insight into both the cellular mechanisms underpinning response to anthelmintics and also the identification of biomarker panels for monitoring the development of anthelmintic resistance. To date, there have been limited attempts to include proteomics in anthelmintic metabolism studies. Optimisations of membrane, post-translational modification and interaction proteomic technologies in helminths are needed to especially study Phase I CYPs and Phase III ABC transporter pumps for anthelmintics and their metabolites.

The identification of antigenic proteins: 14-3-3 protein and propionyl-CoA carboxylase in Clonorchis sinensis

Clonorchis sinensis, the causative agent of clonorchiasis, is widespread in East and Southeast Asia, including China, Vietnam and the Republic of Korea. We identified antigenic proteins from adult C. sinensis liver flukes using immunoproteomic analysis. In this study, we found 23 candidate antigenic proteins with a pI in the range of 5.4-6.2 in total lysates of C. sinensis. The antigenic protein spots reacted against sera from clonorchiasis patients and were identified as cysteine proteases, glutathione transferases, gelsolin, propionyl-CoA carboxylase (PCC), prohibitin and 14-3-3 protein (14-3-3) using LC-coupled ESI-MS/MS and an EST database for C. sinensis. PCC and 14-3-3 were identified for the first time as serological antigens for the diagnosis of C. sinensis. To validate the antigenicity of PCC and 14-3-3, recombinant proteins were immunoblotted with sera from clonorchiasis patients. The structural, functional and immunological characteristics of the putative amino acid sequence were predicted by bioinformatics analysis. Our novel finding will contribute to the development of diagnostics for clonorchiasis. These results suggest that immunoproteomic approaches are valuable tools to identify antigens that could be used as targets for effective parasitic infection control strategies.

Favourable prognostic value of antibodies anti-HSP20 in patients with cystic echinococcosis: a differential immunoproteomic approach

Seeking biomarkers reflecting disease development in cystic echinococcosis (CE), we used a proteomic approach linked to immunological characterisation for the identification of respective antigens. Two-dimensional gel electrophoresis (2-DE) of sheep hydatid fluid, followed by immunoblot analysis (IB) with sera from patients with distinct phases of disease, enabled us to identify by mass spectrometry heat shock protein 20 (HSP20) as a potential marker of active CE. Using IB, antibodies specific to the 34 kDa band of HSP20 were detected in sera from 61/95 (64%) patients with CE, but not in sera from healthy subjects. IB revealed anti-HSP20 antibodies in a higher percentage of sera from patients with active disease than in sera from patients with inactive disease (81 vs. 24%; P = 10(-4)). These primary results were confirmed in a long-term follow-up study after pharmacological and surgical treatment. Herewith anti-HSP20 antibody levels significantly decreased over the course of treatment in sera from patients with cured disease, relative to sera from patients with progressive disease (P = 0·017). Thus, during CE, a comprehensive strategy of proteomic identification combined with immunological validation represents a promising approach for the identification of biomarkers useful for the prognostic assessment of treatment of CE patients.

Proteomic survey of the cestode Mesocestoides corti during the first 24 hours of strobilar development

Despite the fact that cestodes represent major etiological agents of both human and domestic animal diseases, little is known about the molecular aspects of cestode development. In this work, Mesocestoides corti, a model cestode species, was studied from the early development of its larval form (tetrathyridium) into adult worms (strobilation) using different proteomic approaches. The protein profiles of M. corti tetrathyridia induced or not induced to undergo strobilation were compared. Proteomic mapping by two-dimensional gel electrophoresis showed the resolution of 248 and 154 spots from tetrathyridia that were subjected or not subjected to strobilation induction, respectively, allowing for the detection of at least nine spots exclusive to each group. Spot analysis by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) or MALDI-TOF MS/MS identified four reference proteins (six spots). LC-MS/MS analyses of protein extracts identified 66 proteins, eight of which were found exclusively in non-induced tetrathyridia, while 13 were found exclusively in strobilation-induced tetrathyridia. Among the proteins exclusively identified in strobilation-induced worms, there was a predominance of proteins with functions relating to chaperone activity and protein synthesis and turnover. Quantitative differential expression analysis between M. corti tetrathyridia prior to and after strobilation induction revealed six proteins upregulated in strobilation-induced worms; these proteins were involved in metabolic pathways, cell proliferation, and cytoskeletal rearrangement. Overall, despite the absence of a sequenced M. corti genome, using sequences from other platyhelminthes, we were able to establish comprehensive protein profiles for tetrathyridia prior to and after strobilation induction and identify several proteins potentially involved in the early events leading to strobilation.

Proteomic analysis of the Echinococcus granulosus metacestode during infection of its intermediate host

Cystic hydatid disease (CHD) is caused by infection with the Echinococcus granulosus metacestode and affects both humans and livestock. In this work, we performed a proteomic analysis of the E. granulosus metacestode during infection of its intermediate bovine host. Parasite proteins were identified in different metacestode components (94 from protoscolex, 25 from germinal layer and 20 from hydatid cyst fluid), along with host proteins (58) that permeate into the hydatid cyst, providing new insights into host-parasite interplay. E. granulosus and platyhelminth EST data allowed successful identification of proteins potentially involved in downregulation of host defenses, highlighting possible evasion mechanisms adopted by the parasite to establish infection. Several intracellular proteins were found in hydatid cyst fluid, revealing a set of newly identified proteins that were previously thought to be inaccessible for inducing or modulating the host immune response. Host proteins identified in association with the hydatid cyst suggest that the parasite may bind/adsorb host molecules with nutritional and/or immune evasion purposes, masking surface antigens or inhibiting important effector molecules of host immunity, such as complement components and calgranulin. Overall, our results provide valuable information on parasite survival strategies in the adverse host environment and on the molecular mechanisms underpinning CHD immunopathology.