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Yildiz K, Sursal Simsek N, Gurcan IS. Determination of extracellular traps structures from sheep polymorphonuclear leukocytes to Echinococcus granulosus protoscoleces. Exp Parasitol 2022; 239:108283. [DOI: 10.1016/j.exppara.2022.108283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 04/28/2022] [Accepted: 05/18/2022] [Indexed: 11/29/2022]
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Ozturk EA, Manzano-Román R, Sánchez-Ovejero C, Caner A, Angın M, Gunduz C, Karaman Ü, Altintas N, Bozkaya H, Unalp O, Dokumcu Z, Divarci E, Casulli A, Altintas N, Siles-Lucas M, Unver A. Comparison of the multi-epitope recombinant antigen DIPOL and hydatid fluid for the diagnosis of patients with cystic echinococcosis. Acta Trop 2022; 225:106208. [PMID: 34687646 DOI: 10.1016/j.actatropica.2021.106208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 09/21/2021] [Accepted: 10/13/2021] [Indexed: 11/01/2022]
Abstract
The use of serological tests containing multiple immunodominant antigens rather than single antigens have the potential to improve the diagnostic performance in Cystic Echinococcoses (CE) as a complement tool to clear the inconclusive imaging data. Here, we comparatively evaluated the diagnostic value of Hydatid Fluid (HF) and the recently described recombinant multi-epitope antigen DIPOL in IgG-ELISA in a clinically defined cohort of CE patients. The serum samples from 149 CE patients were collected just before surgical or Percutaneous- Aspiration- Injection- Reaspiration (PAIR) procedures. Additionally, serum samples of patients with other parasitic infections (n=49) and healthy individuals (n=21) were also included in the study as controls. To investigate the association between the genotype of the parasite and DIPOL, cyst materials from 20 CE patients were sequenced. In terms of overall sensitivity, HF was higher than DIPOL (82.55%,78.52%, respectively). However, while the sensitivity of HF was higher than DIPOL in patients with active and transitional cysts (83.3%, 75.4%, respectively), sensitivity of DIPOL in inactive cysts was higher compared to HF (95.6%, 78.3%, respectively). The sensitivity of DIPOL depending on cyst stage was statistically significant (P= 0.041). In terms of specificity, DIPOL was found to be better than HF (97.71%, 91.43%, respectively). By genotyping, the majority of 20 patients showed G1 genotype (80%). All patients harboring G3 and G1/G3 cyst genotypes were positive with both antigens, while 87.5% of patients with G1 genotype were seropositive with HF and 75% with DIPOL. The overall sensitivity and high specificity of DIPOL suggest that this recombinant protein containing immunodominant epitopes is a potential substitute for the HF by serological tests for the diagnosis of CE.
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Khan A, Ahmed H, Simsek S, Shahzad K, Celik F, Afzal MS, Khan MR, Liu H, Shen Y, Cao J. Haplotype comparisons of Echinococcus granulosus sensu lato via mitochondrial gene sequences ( co1, cytb, nadh1) among Pakistan and its neighbouring countries. Parasitology 2021; 148:1019-1029. [PMID: 33896429 PMCID: PMC11010185 DOI: 10.1017/s0031182021000688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 04/08/2021] [Accepted: 04/15/2021] [Indexed: 11/07/2022]
Abstract
Echinococcus granulosus sensu lato (s.l.) is a zoonotic parasite that causes cystic echinococcosis (CE) in humans. However, E. granulosus sensu stricto (s.s.) is considered the predominant species in CE infections worldwide. According to the population genetic diversity and structure of E. granulosus s.l., gene flow can explain the parasite drift among the neighbouring countries of Pakistan. The mitochondrial (mt) co1 (n = 47), nadh1 (n = 37) and cytb (n = 35) nucleotide sequences of E. granulosus s.l. isolates from Pakistan, Iran, China and India were retrieved from the National Centre for Biotechnology Information database to determine the genealogical relationships. The sequences were grouped as the mt-co1 (genotypes G1 and G3, G6-G7), mt-cytb (genotypes G1 and G3), and mt-nadh1(genotypes G1 and G3). The data were analysed using bioinformatic tools. A total of 19 polymorphic sites for the mt-co1 sequence (374 bp) were observed of which 31.6% (6/19) were parsimony-informative sites. Unique singleton haplotypes within the E. granulosus s.s. haplotype network based on the mt-co1 gene were highly prevalent (68.4%; 13/19) in Pakistani isolates followed by Chinese, Indian and Iranian isolates; four polymorphic sites were detected in the E. canadensis (G6/G7). In E. canadensis mt-co1 haplotype network, 75% (3/4) unique singleton haplotypes were from the Iranian isolates. Twelve polymorphic sites were found using the mt-cytb sequence (547 bp); 25% (3/12) were parsimony-informative and there were 66.7% (8/12) unique singleton haplotypes within the mt-cytb haplotype network in E. granulosus s.s. with the most reported from Pakistan followed by Iran and China. 20 polymorphic sites were detected in E. granulosus s.s. mt-nadh1 sequences (743 bp); 20% (4/20) were parsimony-informative. There were 66.7% (8/12) main single haplotypes within the mt-nadh1 haplotype network, with the most reported from Pakistan followed by that from India, Iran and China. The sequence analyses show low nucleotide diversity and high haplotype diversity in general.
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Affiliation(s)
- Aisha Khan
- National Institute of Parasitic Diseases, Chinese Centre for Disease Control and Prevention (Chinese Center for Tropical Diseases Research); Key Laboratory of Parasite and Vector Biology; National Health Commission of the People's Republic of China; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases; Shanghai; China
- The School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Department of Biosciences, COMSATS University Islamabad, Islamabad, Pakistan
| | - Haroon Ahmed
- Department of Biosciences, COMSATS University Islamabad, Islamabad, Pakistan
| | - Sami Simsek
- Department of Parasitology, Faculty of Veterinary Medicine, University of Firat, Elazig, Turkey
| | - Khuram Shahzad
- Department of Biosciences, COMSATS University Islamabad, Islamabad, Pakistan
| | - Figen Celik
- Department of Parasitology, Faculty of Veterinary Medicine, University of Firat, Elazig, Turkey
| | - Muhammad Sohail Afzal
- Department of Lifesciences, School of Science, University of Management & Technology (UMT), Lahore, Pakistan
| | - Mobushir Riaz Khan
- School of Environmental Science, Charles Sturt University, Albury, NSW, Australia
| | - Hua Liu
- National Institute of Parasitic Diseases, Chinese Centre for Disease Control and Prevention (Chinese Center for Tropical Diseases Research); Key Laboratory of Parasite and Vector Biology; National Health Commission of the People's Republic of China; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases; Shanghai; China
- The School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yujuan Shen
- National Institute of Parasitic Diseases, Chinese Centre for Disease Control and Prevention (Chinese Center for Tropical Diseases Research); Key Laboratory of Parasite and Vector Biology; National Health Commission of the People's Republic of China; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases; Shanghai; China
- The School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jianping Cao
- National Institute of Parasitic Diseases, Chinese Centre for Disease Control and Prevention (Chinese Center for Tropical Diseases Research); Key Laboratory of Parasite and Vector Biology; National Health Commission of the People's Republic of China; WHO Collaborating Centre for Tropical Diseases; National Center for International Research on Tropical Diseases; Shanghai; China
- The School of Global Health, Chinese Center for Tropical Diseases Research, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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Identification of antigen B (AgB) Gene polymorphism in cattle and sheep isolates of Echinococcus granulosus and investigation of effects on serological diagnosis. Acta Trop 2019; 199:105099. [PMID: 31356785 DOI: 10.1016/j.actatropica.2019.105099] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 07/16/2019] [Accepted: 07/17/2019] [Indexed: 11/24/2022]
Abstract
Cystic Echinococcosis (CE) is a worldwide common helminth disease caused by the larval form of Echinococcus granulosus. The aim of this study is to determine the genetic differences between distinct isolates of E. granulosus obtained from cattle and sheep and determine the polymorphism of the AgB1 gene by DNA sequence analysis, as well as investigating its relationship with serological response using ELISA and Western Blot tests. For this aim, germinal membranes of hydatid cysts of 30 cattle and 30 sheep from the provinces of Elazig and Erzincan in Turkey and serum samples of these animals were collected. Following isolation of the total genomic DNA, the 12S rRNA gene of all isolates was amplified by PCR for genetic characterization, and the mt-CO1 gene region was examined by DNA sequence analysis. The gDNAs were then amplified by PCR using AgB1-specific primers, and genetic variation was investigated by DNA sequence analysis. At the final stage, all serum samples were analyzed by ELISA and Western Blot tests using a partially purified hydatid cyst fluid antigen. As a result, 114 (95%) of the 120 isolates were determined to be E. granulosus sensu stricto by using 12S rRNA-PCR. Subsequently, the DNA sequence analysis of the remaining 6 samples of the mt-CO1 gene revealed that all samples were E. granulosus sensu stricto. According to the DNA sequence analysis that followed, nucleotide changes in the AgB1 gene were observed in 13 (10.8%) of 120 samples. With this study, 9 (69.2%) out of 13 hydatid cysts in which polymorphism was detected by DNA sequence analysis in their AgB1 gene were found to be positive with ELISA, and 6 (46.1%) were found positive by WB. While 80 (74.7%) of 107 non-polymorphic samples in the AgB1 gene were found to be positive with ELISA, and 75 (70.9%) were positive with WB. As a result, variation in different ratios was determined in the AgB1 gene of E. granulosus sensu stricto, and it was determined that this had a partial effect on serological response.
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Ebrahimipour M, Afgar A, Barati M, Mohammadi MA, Harandi MF. Evaluation of the antigenic epitopes of EgAgB/1 and EgAgB/4 subunit antigens in G1 and G6 genotypes of Echinococcus granulosus using bioinformatics. GENE REPORTS 2019. [DOI: 10.1016/j.genrep.2019.01.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Petrone L, Vanini V, Amicosante M, Corpolongo A, Gomez Morales MA, Ludovisi A, Ippolito G, Pozio E, Teggi A, Goletti D. A T-cell diagnostic test for cystic echinococcosis based on Antigen B peptides. Parasite Immunol 2018; 39. [PMID: 29171068 PMCID: PMC5846893 DOI: 10.1111/pim.12499] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 10/23/2017] [Indexed: 12/23/2022]
Abstract
Cystic echinococcosis (CE) immunodiagnosis is still imperfect. We recently set-up a whole-blood test based on the interleukin (IL)-4 response to the native Antigen B (AgB) of Echinococcus granulosus. However, AgB is encoded by a multigene family coding for five putative subunits. Therefore, the aims of this study were to analyse the IL-4 response to peptides spanning the immunodominant regions of the five AgB subunits and to evaluate the accuracy of this assay for CE diagnosis. Peptides corresponding to each subunit were combined into five pools. A pool containing all peptides was also used (total pool). IL-4 evaluated by enzyme-linked immunosorbent assay was significantly higher in patients with CE compared to those without (NO-CE subjects) when whole-blood was stimulated with AgB1 and with the total pool. Moreover, IL-4 levels in response to the total pool were significantly increased in patients with active cysts. Receiver Operator Curve analysis identified a cut-off point of 0.59 pg/mL predicting active cysts diagnosis with 71% sensitivity and 82% specificity in serology-positive CE patients. These data, if confirmed in a larger cohort, offer the opportunity to develop new diagnostic tools for CE based on a standardized source of AgB as the peptides.
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Affiliation(s)
- L Petrone
- Translational Research Unit, Department of Epidemiology and Preclinical Research, "L. Spallanzani" National Institute for Infectious Diseases (INMI), Rome, Italy
| | - V Vanini
- Translational Research Unit, Department of Epidemiology and Preclinical Research, "L. Spallanzani" National Institute for Infectious Diseases (INMI), Rome, Italy
| | - M Amicosante
- Department of Biomedicine and Prevention, University of Rome "Tor Vergata", Rome, Italy.,ProxAgen Ltd, Sofia, Bulgaria
| | - A Corpolongo
- Clinical Department, National Institute for Infectious Diseases (INMI), Rome, Italy
| | - M A Gomez Morales
- Department of Infectious, Parasitic and Immunomediated Diseases, Istituto Superiore di Sanità (ISS), Rome, Italy
| | - A Ludovisi
- Department of Infectious, Parasitic and Immunomediated Diseases, Istituto Superiore di Sanità (ISS), Rome, Italy
| | - G Ippolito
- Scientific Direction, National Institute for Infectious Diseases (INMI), Rome, Italy
| | - E Pozio
- Department of Infectious, Parasitic and Immunomediated Diseases, Istituto Superiore di Sanità (ISS), Rome, Italy
| | - A Teggi
- Department of Infectious and Tropical Diseases, Sant'Andrea Hospital University of Rome "Sapienza", Rome, Italy
| | - D Goletti
- Translational Research Unit, Department of Epidemiology and Preclinical Research, "L. Spallanzani" National Institute for Infectious Diseases (INMI), Rome, Italy
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Evaluation of Echinococcus granulosus recombinant EgAgB8/1, EgAgB8/2 and EPC1 antigens in the diagnosis of cystic echinococcosis in buffaloes. Vet Parasitol 2018; 252:29-34. [PMID: 29559147 DOI: 10.1016/j.vetpar.2018.01.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 01/21/2018] [Accepted: 01/23/2018] [Indexed: 11/23/2022]
Abstract
Three recombinant proteins of Echinococcus granulosus including two antigen B sub-units EgAgB8/1 and EgAgB8/2 and Echinococcus protoscolex calcium binding protein 1 (EPC1) were expressed in prokaryotic expression vectors. The diagnostic potential of these three recombinant proteins was evaluated in the detection of cystic echinococcosis in buffaloes in IgG-ELISA. The EgAgB8/1 and EgAgB8/2 recombinant proteins reacted fairly with the hydatid infected buffaloes with sensitivity of 75.0% and 78.6%, respectively and specificity of 75.8% while EPC1 recombinant protein showed higher sensitivity (89.3%) but lower specificity (51.5%). Cross-reactivity of these three antigens was assayed with buffalo sera naturally infected with Explanatum explanatum, Paramphistomum epiclitum, Gastrothylax spp., Fasciola gigantica and Sarcocystis spp. EgAgB8/1 and EPC1 antigens cross-reacted with all these sera while EgAgB8/2 showed no cross-reaction with Sarcocystis spp. and reacted with some of the E. explanatum infected buffalo sera. This study explores the potential of three hydatid antigens viz. EgAgB8/1, EgAgB8/2 and EPC1 for their diagnostic potential in buffaloes positive for cystic echinococcosis.
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Díaz Á. Immunology of cystic echinococcosis (hydatid disease). Br Med Bull 2017; 124:121-133. [PMID: 29253150 DOI: 10.1093/bmb/ldx033] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 09/15/2017] [Indexed: 12/18/2022]
Abstract
BACKGROUND The neglected disease cystic echinococcosis is caused by larval Echinococcus granulosus flatworms, which form bladder-like hydatid cysts in liver, lungs, and other organs. SOURCES OF DATA Published literature. AREAS OF AGREEMENT Establishing larvae are susceptible to antibody-dependent killing, as attested by successful animal vaccination, whereas once established they are partially protected by the so-called laminated layer. Host responses are Th2 dominated, with a Th1 component. Diagnostic antigens from cyst fluid are known, but responses appear absent in one-fifth of patients. AREAS OF CONTROVERSY Is evasion mainly based on induction of Th2 or regulatory responses by the parasite? GROWING POINTS The parasite induces regulatory responses. The laminated layer has immune-regulatory properties. AREAS TIMELY FOR DEVELOPING RESEARCH Develop tools for functional genomics; characterize immunologically interesting proteins suggested by genomic information; analyse infection in broader context of granulomatous responses; identify molecules secreted/excreted by intact larvae/cysts towards their outside, including diffusible immune-regulators.
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Affiliation(s)
- Álvaro Díaz
- Cátedra de Inmunología, Departamento de Biociencias (Facultad de Química) e Instituto de Química Biológica (Facultad de Ciencias), Universidad de la República, Montevideo, Uruguay
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Rice Bean - A Multipurpose, Underutilized, Potential Nutritive Fodder Legume - A Review. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2017. [DOI: 10.22207/jpam.11.1.57] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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Laboratory Diagnosis of Echinococcus spp. in Human Patients and Infected Animals. ADVANCES IN PARASITOLOGY 2017; 96:159-257. [PMID: 28212789 DOI: 10.1016/bs.apar.2016.09.003] [Citation(s) in RCA: 103] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Among the species composing the genus Echinococcus, four species are of human clinical interest. The most prevalent species are Echinococcus granulosus and Echinococcus multilocularis, followed by Echinococcus vogeli and Echinococcus oligarthrus. The first two species cause cystic echinococcosis (CE) and alveolar echinococcosis (AE) respectively. Both diseases have a complex clinical management, in which laboratory diagnosis could be an adjunctive to the imaging techniques. To date, several approaches have been described for the laboratory diagnosis and followup of CE and AE, including antibody, antigen and cytokine detection. All of these approaches are far from being optimal as adjunctive diagnosis particularly for CE, since they do not reach enough sensitivity and/or specificity. A combination of several methods (e.g., antibody and antigen detection) or of several (recombinant) antigens could improve the performance of the adjunctive laboratory methods, although the complexity of echinococcosis and heterogeneity of clinical cases make necessary a deep understanding of the host-parasite relationships and the parasite phenotype at different developmental stages to reach the best diagnostic tool and to make it accepted in clinical practice. Standardization approaches and a deep understanding of the performance of each of the available antigens in the diagnosis of echinococcosis for the different clinical pictures are also needed. The detection of the parasite in definitive hosts is also reviewed in this chapter. Finally, the different methods for the detection of parasite DNA in different analytes and matrices are also reviewed.
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Ahn CS, Kim JG, Han X, Bae YA, Park WJ, Kang I, Wang H, Kong Y. Biochemical Characterization of Echinococcus multilocularis Antigen B3 Reveals Insight into Adaptation and Maintenance of Parasitic Homeostasis at the Host-Parasite Interface. J Proteome Res 2016; 16:806-823. [PMID: 27959569 DOI: 10.1021/acs.jproteome.6b00799] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Alveolar echinococcosis (AE) caused by Echinococcus multilocularis metacestode is frequently associated with deleterious zoonotic helminthiasis. The growth patterns and morphological features of AE, such as invasion of the liver parenchyme and multiplication into multivesiculated masses, are similar to those of malignant tumors. AE has been increasingly detected in several regions of Europe, North America, Central Asia, and northwestern China. An isoform of E. multilocularis antigen B3 (EmAgB3) shows a specific immunoreactivity against patient sera of active-stage AE, suggesting that EmAgB3 might play important roles during adaptation of the parasite to hosts. However, expression patterns and biochemical properties of EmAgB3 remained elusive. The protein profile and nature of component proteins of E. multilocularis hydatid fluid (EmHF) have never been addressed. In this study, we conducted proteome analysis of EmHF of AE cysts harvested from immunocompetent mice. We observed the molecular and biochemical properties of EmAgB3, including differential transcription patterns of paralogous genes, macromolecular protein status by self-assembly, distinct oligomeric states according to individual anatomical compartments of the worm, and hydrophobic ligand-binding protein activity. We also demonstrated tissue expression patterns of EmAgB3 transcript and protein. EmAgB3 might participate in immune response and recruitment of essential host lipids at the host-parasite interface. Our results might contribute to an in depth understanding of the biophysical and biological features of EmAgB3, thus providing insights into the design of novel targets to control AE.
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Affiliation(s)
- Chun-Seob Ahn
- Department of Molecular Parasitology, Sungkyunkwan University School of Medicine , Suwon 16419, Korea
| | - Jeong-Geun Kim
- Department of Molecular Parasitology, Sungkyunkwan University School of Medicine , Suwon 16419, Korea
| | - Xiumin Han
- Qinghai Province Institute for Endemic Diseases Prevention and Control , Xining 811602, China
| | - Young-An Bae
- Department of Microbiology, Gachon University Graduate School of Medicine , Incheon 21936, Korea
| | - Woo-Jae Park
- Department of Biochemistry, Gachon University Graduate School of Medicine , Incheon 21936, Korea
| | - Insug Kang
- Department of Molecular Biology and Biochemistry, School of Medicine, Kyung Hee University , Seoul 02447, Korea
| | - Hu Wang
- Qinghai Province Institute for Endemic Diseases Prevention and Control , Xining 811602, China
| | - Yoon Kong
- Department of Molecular Parasitology, Sungkyunkwan University School of Medicine , Suwon 16419, Korea
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Díaz A, Casaravilla C, Barrios AA, Ferreira AM. Parasite molecules and host responses in cystic echinococcosis. Parasite Immunol 2016; 38:193-205. [PMID: 26425838 DOI: 10.1111/pim.12282] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 09/22/2015] [Indexed: 01/03/2023]
Abstract
Cystic echinococcosis is the infection by the larvae of cestode parasites belonging to the Echinococcus granulosus sensu lato species complex. Local host responses are strikingly subdued in relation to the size and persistence of these larvae, which develop within mammalian organs as 'hydatid cysts' measuring up to tens of cm in diameter. In a context in which helminth-derived immune-suppressive, as well as Th2-inducing, molecules garner much interest, knowledge on the interactions between E. granulosus molecules and the immune system lags behind. Here, we discuss what is known and what are the open questions on E. granulosus molecules and structures interacting with the innate and adaptive immune systems, potentially or in demonstrated form. We attempt a global biological approach on molecules that have been given consideration primarily as protective (Eg95) or diagnostic antigens (antigen B, antigen 5). We integrate glycobiological information, which traverses the discussions on antigen 5, the mucin-based protective laminated layer and immunologically active preparations from protoscoleces. We also highlight some less well-known molecules that appear as promising candidates to possess immune-regulatory activities. Finally, we point out gaps in the molecular-level knowledge of this infectious agent that hinder our understanding of its immunology.
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Affiliation(s)
- A Díaz
- Cátedra de Inmunología, Departamento de Biociencias (Facultad de Química) and Instituto de Química Biológica (Facultad de Ciencias), Universidad de la República, Montevideo, Uruguay
| | - C Casaravilla
- Cátedra de Inmunología, Departamento de Biociencias (Facultad de Química) and Instituto de Química Biológica (Facultad de Ciencias), Universidad de la República, Montevideo, Uruguay
| | - A A Barrios
- Cátedra de Inmunología, Departamento de Biociencias (Facultad de Química) and Instituto de Química Biológica (Facultad de Ciencias), Universidad de la República, Montevideo, Uruguay
| | - A M Ferreira
- Cátedra de Inmunología, Departamento de Biociencias (Facultad de Química) and Instituto de Química Biológica (Facultad de Ciencias), Universidad de la República, Montevideo, Uruguay
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Serological Diagnosis and Follow-Up of Human Cystic Echinococcosis: A New Hope for the Future? BIOMED RESEARCH INTERNATIONAL 2015; 2015:428205. [PMID: 26504805 PMCID: PMC4609352 DOI: 10.1155/2015/428205] [Citation(s) in RCA: 76] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 08/30/2015] [Indexed: 12/13/2022]
Abstract
Cystic echinococcosis (CE) is an important helminthic zoonotic disease caused by the Echinococcus granulosus complex. In humans, CE is a chronic disease driven by the growth of echinococcal cysts in different organs. Prognosis of this disease depends on multiple factors, including location, number, size, and stage of the cysts, making CE a disease of complex management. CE is usually asymptomatic for years and attracts limited attention from funding organizations and health authorities. For this reason, only experts' recommendations are available but no evidence-based conclusions have been drawn for CE clinical management. One of those pitfalls refers to the lack of evidence to support the use of serological tools for the diagnosis and follow-up of CE patients. In this respect, crude antigens are used to detect specific antibodies in patients, giving rise to false positive results. The advent of molecular techniques allowing the production of recombinant proteins has provided a number of candidate antigens that could overcome the problems associated with the use of crude parasite extracts in the serological assays. In this review, we present the last advances in this field, proposing the use of serology to support cyst stage-specific diagnosis and follow-up.
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Silva-Álvarez V, Franchini GR, Pórfido JL, Kennedy MW, Ferreira AM, Córsico B. Lipid-free antigen B subunits from echinococcus granulosus: oligomerization, ligand binding, and membrane interaction properties. PLoS Negl Trop Dis 2015; 9:e0003552. [PMID: 25768648 PMCID: PMC4358968 DOI: 10.1371/journal.pntd.0003552] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 01/21/2015] [Indexed: 02/06/2023] Open
Abstract
Background 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. Methodology/Principal Findings 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. Conclusions/Significance 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.
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Affiliation(s)
- Valeria Silva-Álvarez
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP) (UNLP-CONICET), Facultad de Ciencias Médicas, Universidad Nacional de La Plata (UNLP), La Plata, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Gisela R. Franchini
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP) (UNLP-CONICET), Facultad de Ciencias Médicas, Universidad Nacional de La Plata (UNLP), La Plata, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Jorge L. Pórfido
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP) (UNLP-CONICET), Facultad de Ciencias Médicas, Universidad Nacional de La Plata (UNLP), La Plata, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
| | - Malcolm W. Kennedy
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - Ana M. Ferreira
- Cátedra de Inmunología, Facultad de Ciencias/Facultad de Química, Universidad de la República (UdelaR), Montevideo, Uruguay
| | - Betina Córsico
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP) (UNLP-CONICET), Facultad de Ciencias Médicas, Universidad Nacional de La Plata (UNLP), La Plata, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Ciudad Autónoma de Buenos Aires, Argentina
- * E-mail:
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Silva-Álvarez V, Folle AM, Ramos AL, Zamarreño F, Costabel MD, García-Zepeda E, Salinas G, Córsico B, Ferreira AM. Echinococcus granulosus antigen B: a Hydrophobic Ligand Binding Protein at the host-parasite interface. Prostaglandins Leukot Essent Fatty Acids 2015; 93:17-23. [PMID: 25451555 DOI: 10.1016/j.plefa.2014.09.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Revised: 09/17/2014] [Accepted: 09/18/2014] [Indexed: 11/25/2022]
Abstract
Lipids are mainly solubilized by various families of lipid binding proteins which participate in their transport between tissues as well as cell compartments. Among these families, Hydrophobic Ligand Binding Proteins (HLBPs) deserve special consideration since they comprise intracellular and extracellular members, are able to bind a variety of fatty acids, retinoids and some sterols, and are present exclusively in cestodes. Since these parasites have lost catabolic and biosynthetic pathways for fatty acids and cholesterol, HLBPs are likely relevant for lipid uptake and transportation between parasite and host cells. Echinococcus granulosus antigen B (EgAgB) is a lipoprotein belonging to the HLBP family, which is very abundant in the larval stage of this parasite. Herein, we review the literature on EgAgB composition, structural organization and biological properties, and propose an integrated scenario in which this parasite HLBP contributes to adaptation to mammalian hosts by meeting both metabolic and immunomodulatory parasite demands.
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Affiliation(s)
- Valeria Silva-Álvarez
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-Universidad Nacional de La Plata (UNLP), La Plata, Argentina; Cátedra de Inmunología, Facultad de Ciencias/Facultad de Química, Universidad de la República (UdelaR), Montevideo, Uruguay
| | - Ana Maite Folle
- Cátedra de Inmunología, Facultad de Ciencias/Facultad de Química, Universidad de la República (UdelaR), Montevideo, Uruguay
| | - Ana Lía Ramos
- Cátedra de Inmunología, Facultad de Ciencias/Facultad de Química, Universidad de la República (UdelaR), Montevideo, Uruguay
| | - Fernando Zamarreño
- Grupo de Biofísica, Departamento de Física, Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina
| | - Marcelo D Costabel
- Grupo de Biofísica, Departamento de Física, Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina
| | - Eduardo García-Zepeda
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México (UNAM), Ciudad de México, Mexico
| | - Gustavo Salinas
- Cátedra de Inmunología, Facultad de Ciencias/Facultad de Química, Universidad de la República (UdelaR), Montevideo, Uruguay
| | - Betina Córsico
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)-Universidad Nacional de La Plata (UNLP), La Plata, Argentina
| | - Ana María Ferreira
- Cátedra de Inmunología, Facultad de Ciencias/Facultad de Química, Universidad de la República (UdelaR), Montevideo, Uruguay.
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Ahn CS, Han X, Bae YA, Ma X, Kim JT, Cai H, Yang HJ, Kang I, Wang H, Kong Y. Alteration of immunoproteome profile of Echinococcus granulosus hydatid fluid with progression of cystic echinococcosis. Parasit Vectors 2015; 8:10. [PMID: 25566682 PMCID: PMC4311513 DOI: 10.1186/s13071-014-0610-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 12/17/2014] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Cystic echinococcosis (CE), caused by Echinococcus granulosus metacestode, invokes a serious public health concern. Early diagnosis has great impacts on reduction of disability-adjusted life years. Several antigen B-related molecules (EgAgB; EgAgB1-5) are known to be immunopotent, but detection of EgAgB is variable in many patients and may not allow reliable interpretation of its immunological relevance. More importantly, the immunoproteome profile of hydatid fluid (HF) has not been addressed. METHODS We conducted a proteome analysis of the HF of a single fertile cyst of CE1 and CE2 stages through two-dimensional electrophoresis (2-DE). Each protein spot was analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). We subsequently determined the immunoproteome profile employing patient sera of entire disease spectrum from CE1 to CE5 stages. RESULTS We identified 40 parasite proteins, of which EgAgB (28 spots) and antigen 5 (EgAg5; 5 molecules) were abundant. EgAgB proteoforms constituted the majority, mostly EgAgB1 (24 spots), followed by EgAgB2 and EgAgB4 (2 spots each). EgAgB3 was detected only by liquid chromatography-MS/MS. EgAgB5 was not recognized. We also detected 38 host proteins, which were largely composed of serum components, antioxidant/xenobiotic enzymes, and enzymes involved in carbohydrate metabolism. CE1 and CE2 HF exhibited comparable spotting patterns, but CE2 HF harbored greater amounts of EgAgB and EgAg5 complexes. CE sera demonstrated complicated immune recognition patterns according to the disease progression; CE2 and CE3 stages exhibited strong antibody responses against diverse EgAgB and EgAg5 proteoforms, while CE1, CE4, and CE5 stages mainly reacted to EgAg5 and cathepsin B. Patient sera of alveolar echinococcosis (AE) cross-reacted with diverse EgAgB isoforms (36%). EgAg5 and cathepsin B also demonstrated cross-reactions with sera from neurocysticercosis and sparganosis. CONCLUSIONS Our results demonstrated that detection of a single defined molecule may not properly diagnose CE, since specific immunodominant epitopes changed as the disease progresses. Immunoproteome analysis combined with imaging studies may be practical in the differential diagnosis of CE from AE and other cystic lesions, as well as for staging CE, which are pertinent to establish appropriate patient management.
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Affiliation(s)
- Chun-Seob Ahn
- Department of Molecular Parasitology, Sungkyunkwan University School of Medicine and Center for Molecular Medicine, Samsung Biomedical Research Institute, Suwon, 440-746, Korea.
| | - Xiumin Han
- Qinghai Province Institute for Endemic Diseases Prevention and Control, Xining, Qinghai, China.
| | - Young-An Bae
- Department of Microbiology, Graduate School of Medicine, Gachon University, Incheon, Korea.
| | - Xiao Ma
- Qinghai Province Institute for Endemic Diseases Prevention and Control, Xining, Qinghai, China.
| | - Jin-Taek Kim
- Department of Molecular Parasitology, Sungkyunkwan University School of Medicine and Center for Molecular Medicine, Samsung Biomedical Research Institute, Suwon, 440-746, Korea.
| | - Huixia Cai
- Department of Molecular Parasitology, Sungkyunkwan University School of Medicine and Center for Molecular Medicine, Samsung Biomedical Research Institute, Suwon, 440-746, Korea.
- Qinghai Province Institute for Endemic Diseases Prevention and Control, Xining, Qinghai, China.
| | - Hyun-Jong Yang
- Department of Parasitology, Ewha Womans University, School of Medicine, Seoul, Korea.
| | - Insug Kang
- Department of Molecular Biology and Biochemistry, School of Medicine, Kyung Hee University, Seoul, Korea.
| | - Hu Wang
- Qinghai Province Institute for Endemic Diseases Prevention and Control, Xining, Qinghai, China.
| | - Yoon Kong
- Department of Molecular Parasitology, Sungkyunkwan University School of Medicine and Center for Molecular Medicine, Samsung Biomedical Research Institute, Suwon, 440-746, Korea.
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Boubaker G, Gottstein B, Hemphill A, Babba H, Spiliotis M. Echinococcus P29 antigen: molecular characterization and implication on post-surgery follow-up of CE patients infected with different species of the Echinococcus granulosus complex. PLoS One 2014; 9:e98357. [PMID: 24851904 PMCID: PMC4031130 DOI: 10.1371/journal.pone.0098357] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Accepted: 05/01/2014] [Indexed: 01/12/2023] Open
Abstract
The protein P29 is a potential serological marker for post-treatment monitoring of cystic echinococcosis (CE) especially in young patients. We now have demonstrated that P29 is encoded in the Echinococcus genus by a single gene consisting of 7 exons spanning 1.2 kb of DNA. Variability of the p29 gene at inter- and intra-species level was assessed with 50 cDNA and 280 genomic DNA clones isolated from different E. granulosus s.l. isolates (E. granulosus sensu stricto (G1), E. equinus (G4), E. ortleppi (G5), E. canadensis (G6), E. canadensis (G7) and E. canadensis (G10)) as well as four E. multilocularis isolates. Scarce interspecies polymorphism at the p29 locus was observed and affected predominantly E. granulosus s.s. (G1), where we identified two alleles (A1 and A2) coding for identical P29 proteins and yielding in three genotypes (A1/A1, A2/A2 and A1/A2). Genotypic frequencies expected under Hardy-Weinberg equilibrium revealed a high rate of heterozygosity (47%) that strongly supports the hypothesis that E. granulosus s.s. (G1) is predominantly outbreeding. Comparative sequence analyses of the complete p29 gene showed that phylogenetic relationships within the genus Echinococcus were in agreement with those of previous nuclear gene studies. At the protein level, the deduced P29 amino acid (AA) sequences exhibited a high level of conservation, ranging from 97.9% AA sequence identity among the whole E. granulosus s.l. group to 99.58% identity among E. multilocularis isolates. We showed that P29 proteins of these two species differ by three AA substitutions without implication for antigenicity. In Western-blot analyses, serum antibodies from a human CE patient infected with E. canadensis (G6) strongly reacted with recombinant P29 from E. granulosus s.s. (G1) (recEg(G1)P29). In the same line, human anti-Eg(G1)P29 antibodies bound to recEcnd(G6)P29. Thus, minor AA sequence variations appear not to impair the prognostic serological use of P29.
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Affiliation(s)
- Ghalia Boubaker
- Institute of Parasitology, University of Berne, Berne, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Berne, Berne, Switzerland
- Department of Clinical Biology B, Laboratory of Parasitology and Mycology, University of Monastir, Monastir, Tunisia
| | - Bruno Gottstein
- Institute of Parasitology, University of Berne, Berne, Switzerland
- * E-mail:
| | - Andrew Hemphill
- Institute of Parasitology, University of Berne, Berne, Switzerland
| | - Hamouda Babba
- Department of Clinical Biology B, Laboratory of Parasitology and Mycology, University of Monastir, Monastir, Tunisia
| | - Markus Spiliotis
- Institute of Parasitology, University of Berne, Berne, Switzerland
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18
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Santos GB, Espínola SM, Ferreira HB, Margis R, Zaha A. Rapid detection of Echinococcus species by a high-resolution melting (HRM) approach. Parasit Vectors 2013; 6:327. [PMID: 24517106 PMCID: PMC4029041 DOI: 10.1186/1756-3305-6-327] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 11/05/2013] [Indexed: 12/27/2022] Open
Abstract
Background High-resolution melting (HRM) provides a low-cost, fast and sensitive scanning method that allows the detection of DNA sequence variations in a single step, which makes it appropriate for application in parasite identification and genotyping. The aim of this work was to implement an HRM-PCR assay targeting part of the mitochondrial cox1 gene to achieve an accurate and fast method for Echinococcus spp. differentiation. Findings For melting analysis, a total of 107 samples from seven species were used in this study. The species analyzed included Echinococcus granulosus (n = 41) and Echinococcus ortleppi (n = 50) from bovine, Echinococcus vogeli (n = 2) from paca, Echinococcus oligarthra (n = 3) from agouti, Echinococcus multilocularis (n = 6) from monkey and Echinococcus canadensis (n = 2) and Taenia hydatigena (n = 3) from pig. DNA extraction was performed, and a 444-bp fragment of the cox1 gene was amplified. Two approaches were used, one based on HRM analysis, and a second using SYBR Green Tm-based. In the HRM analysis, a specific profile for each species was observed. Although some species exhibited almost the same melting temperature (Tm) value, the HRM profiles could be clearly discriminated. The SYBR Green Tm-based analysis showed differences between E. granulosus and E. ortleppi and between E. vogeli and E. oligarthra. Conclusions In this work, we report the implementation of HRM analysis to differentiate species of the genus Echinococcus using part of the mitochondrial gene cox1. This method may be also potentially applied to identify other species belonging to the Taeniidae family.
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Affiliation(s)
| | | | | | | | - Arnaldo Zaha
- Programa de Pós-Graduação em Biologia Celular e Molecular, Universidade Federal do Rio Grande do Sul, Caixa Postal 15005, CEP 91501-970, Porto Alegre, RS, Brazil.
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Balbinotti H, Santos GB, Badaraco J, Arend AC, Graichen DÂS, Haag KL, Zaha A. Echinococcus ortleppi (G5) and Echinococcus granulosus sensu stricto (G1) loads in cattle from Southern Brazil. Vet Parasitol 2012; 188:255-60. [DOI: 10.1016/j.vetpar.2012.04.007] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2011] [Revised: 12/20/2011] [Accepted: 04/04/2012] [Indexed: 11/25/2022]
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Olson PD, Zarowiecki M, Kiss F, Brehm K. Cestode genomics - progress and prospects for advancing basic and applied aspects of flatworm biology. Parasite Immunol 2012; 34:130-50. [PMID: 21793855 DOI: 10.1111/j.1365-3024.2011.01319.x] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Characterization of the first tapeworm genome, Echinococcus multilocularis, is now nearly complete, and genome assemblies of E. granulosus, Taenia solium and Hymenolepis microstoma are in advanced draft versions. These initiatives herald the beginning of a genomic era in cestodology and underpin a diverse set of research agendas targeting both basic and applied aspects of tapeworm biology. We discuss the progress in the genomics of these species, provide insights into the presence and composition of immunologically relevant gene families, including the antigen B- and EG95/45W families, and discuss chemogenomic approaches toward the development of novel chemotherapeutics against cestode diseases. In addition, we discuss the evolution of tapeworm parasites and introduce the research programmes linked to genome initiatives that are aimed at understanding signalling systems involved in basic host-parasite interactions and morphogenesis.
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Affiliation(s)
- P D Olson
- Department of Zoology, The Natural History Museum, London, UK
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Obal G, Ramos AL, Silva V, Lima A, Batthyany C, Bessio MI, Ferreira F, Salinas G, Ferreira AM. Characterisation of the native lipid moiety of Echinococcus granulosus antigen B. PLoS Negl Trop Dis 2012; 6:e1642. [PMID: 22616019 PMCID: PMC3352830 DOI: 10.1371/journal.pntd.0001642] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Accepted: 03/29/2012] [Indexed: 12/21/2022] Open
Abstract
Antigen B (EgAgB) is the most abundant and immunogenic antigen produced by the larval stage (metacestode) of Echinococcus granulosus. It is a lipoprotein, the structure and function of which have not been completely elucidated. EgAgB apolipoprotein components have been well characterised; they share homology with a group of hydrophobic ligand binding proteins (HLBPs) present exclusively in cestode organisms, and consist of different isoforms of 8-kDa proteins encoded by a polymorphic multigene family comprising five subfamilies (EgAgB1 to EgAgB5). In vitro studies have shown that EgAgB apolipoproteins are capable of binding fatty acids. However, the identity of the native lipid components of EgAgB remains unknown. The present work was aimed at characterising the lipid ligands bound to EgAgB in vivo. EgAgB was purified to homogeneity from hydatid cyst fluid and its lipid fraction was extracted using chloroform∶methanol mixtures. This fraction constituted approximately 40-50% of EgAgB total mass. High-performance thin layer chromatography revealed that the native lipid moiety of EgAgB consists of a variety of neutral (mainly triacylglycerides, sterols and sterol esters) and polar (mainly phosphatidylcholine) lipids. Gas-liquid chromatography analysis showed that 16∶0, 18∶0 and 18∶1(n-9) are the most abundant fatty acids in EgAgB. Furthermore, size exclusion chromatography coupled to light scattering demonstrated that EgAgB comprises a population of particles heterogeneous in size, with an average molecular mass of 229 kDa. Our results provide the first direct evidence of the nature of the hydrophobic ligands bound to EgAgB in vivo and indicate that the structure and composition of EgAgB lipoprotein particles are more complex than previously thought, resembling high density plasma lipoproteins. Results are discussed considering what is known on lipid metabolism in cestodes, and taken into account the Echinococcus spp. genomic information regarding both lipid metabolism and the EgAgB gene family.
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Affiliation(s)
- Gonzalo Obal
- Cátedra de Inmunología, Facultad de Ciencias/Facultad de Química, Universidad de la República (UdelaR), Montevideo, Uruguay
- Unidad de Biofísica de Proteínas, Instituto Pasteur de Montevideo, Montevideo, Uruguay
| | - Ana Lía Ramos
- Cátedra de Inmunología, Facultad de Ciencias/Facultad de Química, Universidad de la República (UdelaR), Montevideo, Uruguay
| | - Valeria Silva
- Cátedra de Inmunología, Facultad de Ciencias/Facultad de Química, Universidad de la República (UdelaR), Montevideo, Uruguay
| | - Analía Lima
- Unidad de Bioquímica y Proteómica Analíticas, Instituto Pasteur de Montevideo, Montevideo, Uruguay
| | - Carlos Batthyany
- Unidad de Bioquímica y Proteómica Analíticas, Instituto Pasteur de Montevideo, Montevideo, Uruguay
| | - María Inés Bessio
- Laboratorio de Carbohidratos y Glicoconjugados, Departamento de Química Orgánica/Departamento de Desarrollo Biotecnológico, Facultad de Química/Facultad de Medicina, Universidad de la República (UdelaR), Montevideo, Uruguay
| | - Fernando Ferreira
- Laboratorio de Carbohidratos y Glicoconjugados, Departamento de Química Orgánica/Departamento de Desarrollo Biotecnológico, Facultad de Química/Facultad de Medicina, Universidad de la República (UdelaR), Montevideo, Uruguay
| | - Gustavo Salinas
- Cátedra de Inmunología, Facultad de Ciencias/Facultad de Química, Universidad de la República (UdelaR), Montevideo, Uruguay
| | - Ana María Ferreira
- Cátedra de Inmunología, Facultad de Ciencias/Facultad de Química, Universidad de la República (UdelaR), Montevideo, Uruguay
- * E-mail:
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Jiang L, Zhang YG, Liu MX, Feng Z. Analysis on the reactivity of five subunits of antigen B family in serodiagnosis of echinococcosis. Exp Parasitol 2012; 131:85-91. [PMID: 22446351 DOI: 10.1016/j.exppara.2012.03.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Revised: 03/02/2012] [Accepted: 03/04/2012] [Indexed: 12/23/2022]
Abstract
In this study, the reactivity and differences of five subunits of echinococcus antigen B (AgB) family, recognizing specific antibodies in echinococcosis patient serum, were analyzed. Eight recombinant subunit antigens from Echinococcus granulosus (EgAgB1-EgAgB4) and Echinococcus multilocularis (EmAgB1-EmAgB3 and EmAgB5) were tested by ELISA using a panel of 243 serum samples collected from cystic echinococcosis (CE), alveolar echinococcosis (AE), cysticercosis (CC) patients and clinically normal individuals (NH). The results showed that the diagnostic sensitivity of the subunits for CE sera were 83.06%, 62.90%, 29.03%, 75.81% and 41.13%, and the specificities were 73.95%, 72.27%, 76.47%, 73.11% and 85.71%, respectively. The reactivity of three paralogous subunits, EgAgB1, EgAgB2 and EgAgB3 from E. granulosus and EmAgB1, EmAgB2 and EmAgB3 from E. multilocularis were compared by serological assay. All of the orthologous subunits showed no statistical difference (P>0.05) in detecting CE and AE sera; it revealed that the reactive epitopes may be similar between the orthologous subunits. In a total of 124 CE sera, the positive recognition rate by EgAgB1 was the highest (103/124), yet cocktail subunit antigens may detect even more positives from 100/124 to 112/124 using different subunit combinations. IgG4 subclass was the predominant antibody in reacting with subunit antigens. To conclude, the epitopes of orthologous AgB subunits from E. granulosus and E. multilocularis that recognize specific antibodies may be similar. The paralogous subunits EgAgB1, EgAgB2 and EgAgB4 were the main reactive subunit in sera detection and may have utility as echinococcosis diagnostics, with EgAgB1 possessing the greatest potential. Cocktail subunits may improve the positive detection rate.
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Affiliation(s)
- Li Jiang
- Shanghai Municipal Center for Disease Control and Prevention/Shanghai Institutes of Preventive Medicine, Shanghai 200336, China.
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Monteiro KM, Cardoso MB, Follmer C, da Silveira NP, Vargas DM, Kitajima EW, Zaha A, Ferreira HB. Echinococcus granulosus antigen B structure: subunit composition and oligomeric states. PLoS Negl Trop Dis 2012; 6:e1551. [PMID: 22413028 PMCID: PMC3295803 DOI: 10.1371/journal.pntd.0001551] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Accepted: 01/12/2012] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND Antigen B (AgB) is the major protein secreted by the Echinococcus granulosus metacestode and is involved in key host-parasite interactions during infection. The full comprehension of AgB functions depends on the elucidation of several structural aspects that remain unknown, such as its subunit composition and oligomeric states. METHODOLOGY/PRINCIPAL FINDINGS The subunit composition of E. granulosus AgB oligomers from individual bovine and human cysts was assessed by mass spectrometry associated with electrophoretic analysis. AgB8/1, AgB8/2, AgB8/3 and AgB8/4 subunits were identified in all samples analyzed, and an AgB8/2 variant (AgB8/2v8) was found in one bovine sample. The exponentially modified protein abundance index (emPAI) was used to estimate the relative abundance of the AgB subunits, revealing that AgB8/1 subunit was relatively overrepresented in all samples. The abundance of AgB8/3 subunit varied between bovine and human cysts. The oligomeric states formed by E. granulosus AgB and recombinant subunits available, rAgB8/1, rAgB8/2 and rAgB8/3, were characterized by native PAGE, light scattering and microscopy. Recombinant subunits showed markedly distinct oligomerization behaviors, forming oligomers with a maximum size relation of rAgB8/3>rAgB8/2>rAgB8/1. Moreover, the oligomeric states formed by rAgB8/3 subunit were more similar to those observed for AgB purified from hydatid fluid. Pressure-induced dissociation experiments demonstrated that the molecular assemblies formed by the more aggregative subunits, rAgB8/2 and rAgB8/3, also display higher structural stability. CONCLUSIONS/SIGNIFICANCE For the first time, AgB subunit composition was analyzed in samples from single hydatid cysts, revealing qualitative and quantitative differences between samples. We showed that AgB oligomers are formed by different subunits, which have distinct abundances and oligomerization properties. Overall, our findings have significantly contributed to increase the current knowledge on AgB expression and structure, highlighting issues that may help to understand the parasite adaptive response during chronic infection.
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Affiliation(s)
- Karina M. Monteiro
- Laboratório de Biologia Molecular de Cestódeos and Laboratório de Genômica Estrutural e Funcional, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Mateus B. Cardoso
- Laboratório Nacional de Luz Síncrotron (LNLS), Campinas, São Paulo, Brazil
| | - Cristian Follmer
- Departamento de Físico-Química, Instituto de Química, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Rio de Janeiro, Brazil
| | - Nádya P. da Silveira
- Instituto de Química, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Daiani M. Vargas
- Laboratório de Biologia Molecular de Cestódeos and Laboratório de Genômica Estrutural e Funcional, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Elliot W. Kitajima
- Departamento de Entomologia, Fitopatologia e Zoologia Agrícola, Escola Superior de Agricultura Luiz de Queiroz (ESALQ), Universidade de São Paulo, Piracicaba, São Paulo, Brazil
| | - Arnaldo Zaha
- Laboratório de Biologia Molecular de Cestódeos and Laboratório de Genômica Estrutural e Funcional, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
| | - Henrique B. Ferreira
- Laboratório de Biologia Molecular de Cestódeos and Laboratório de Genômica Estrutural e Funcional, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
- * E-mail:
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Siracusano A, Delunardo F, Teggi A, Ortona E. Host-parasite relationship in cystic echinococcosis: an evolving story. Clin Dev Immunol 2011; 2012:639362. [PMID: 22110535 PMCID: PMC3206507 DOI: 10.1155/2012/639362] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Accepted: 09/27/2011] [Indexed: 01/29/2023]
Abstract
The larval stage of Echinococcus granulosus causes cystic echinococcosis, a neglected infectious disease that constitutes a major public health problem in developing countries. Despite being under constant barrage by the immune system, E. granulosus modulates antiparasite immune responses and persists in the human hosts with detectable humoral and cellular responses against the parasite. In vitro and in vivo immunological approaches, together with molecular biology and immunoproteomic technologies, provided us exciting insights into the mechanisms involved in the initiation of E. granulosus infection and the consequent induction and regulation of the immune response. Although the last decade has clarified many aspects of host-parasite relationship in human cystic echinococcosis, establishing the full mechanisms that cause the disease requires more studies. Here, we review some of the recent developments and discuss new avenues in this evolving story of E. granulosus infection in man.
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Affiliation(s)
- Alessandra Siracusano
- Dipartimento di Malattie Infettive, Parassitarie e Immunomediate, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Roma, Italy.
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Simsek S, Ozcetin C, Balkaya I. Detection of polymorphism in AgB1 gene from sheep, cattle and human isolates of echinococcus granulosus by SSCP. Vet Parasitol 2011; 184:352-5. [PMID: 21978743 DOI: 10.1016/j.vetpar.2011.09.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2011] [Revised: 09/02/2011] [Accepted: 09/06/2011] [Indexed: 11/27/2022]
Abstract
Antigen B (AgB) is a major protein produced by the metacestode cyst of Echinococcus granulosus, the causative agent of cystic hydatid disease. E. granulosus AgB is a gene family of at least five gene loci (B1-B5), each one consisting of several minor variants. We used PCR-SSCP followed by DNA sequencing to evaluate sequence variation and polymorphism of AgB1 in 99 isolates which the 43 were from cattle, 25 of sheep and 31 of human. All samples were analyzed with 12S rRNA-PCR for the strain detection and all of were identified as G1-G3 cluster (E. granulosus sensu stricto). The 16 human, 35 cattle and 25 sheep isolates were yielded the 102 bp band by PCR and these samples were tested by SSCP. As results of the SSCP, different band profiles were detected one each of cattle and human isolates while the other 74 isolates showed same band patterns. The DNA sequence analysis was performed for these two isolates and the other selected 4 isolates and polymorphism was confirmed.
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Affiliation(s)
- Sami Simsek
- Department of Parasitology, Faculty of Veterinary Medicine University of Firat, 23119 Elazig, Turkey.
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Comparative analysis of the diagnostic performance of crude sheep hydatid cyst fluid, purified antigen B and its subunit (12 Kda), assessed by ELISA, in the diagnosis of human cystic echinococcosis. Parasitol Res 2010; 108:371-6. [PMID: 20922427 DOI: 10.1007/s00436-010-2074-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2010] [Accepted: 09/08/2010] [Indexed: 12/28/2022]
Abstract
The diagnosis of patients with cystic echinococcosis (CE) by means of serology has a limited support in clinical practice due to cross-reactivity with other helminthes leading to overestimation of the parasite's true prevalence. A wealth of reports on the diagnostic performance of antigen B (AgB) has been produced. This study was designed to comparatively assess the diagnostic efficacy of crude sheep hydatid cyst fluid (HCF), AgB and its subunit (12 KDa) to detect IgG or IgG4 antibodies in CE patients' sera using enzyme-linked immunosorbent assay (ELISA).The best diagnostic performance was obtained with anti-HCF IgG ELISA which gave 92.4% sensitivity and 92.6% specificity. Despite the low sensitivity of anti AgB IgG ELISA (84%), it gave the best specificity (94.4%) with less cross-reaction with sera of subjects infected with other parasites. In conclusion, it is recommended to use anti-HCF IgG ELISA for initial screening in large seroprevalence studies. Further analysis of positive serum samples with anti AgB IgG ELISA would allow the confirmation of true positives. Specific IgG4 ELISA may represent a complementary assay, useful as secondary confirmatory tests for patients with suspected CE and negative for total IgG ELISA.
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Pan D, Bera AK, Bandyopadhyay S, Das S, Rana T, Das SK, Bandyopadhyay S, Manna B, Bhattacharya D. Molecular characterization of antigen B2 subunit in two genotypes of Echinococcus granulosus from Indian bubaline isolates, its stage specific expression and serological evaluation. Mol Biol Rep 2010; 38:2067-73. [PMID: 20852940 DOI: 10.1007/s11033-010-0332-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Accepted: 09/03/2010] [Indexed: 03/08/2023]
Abstract
Echinococcus granulosus is a parasitic helminth which affects both man and animals. During infection with larval stage of the organism secretory and membrane-bound (S/M) proteins play a meaningful role for evasion of immune system. Antigen B (AgB) is one of them. Present investigation has defined sequence diversity of AgB2 subunit of cattle and buffalo isolates of the organism. A total of 55 isolates were screened by polymerase chain reaction based single stranded conformation polymorphism (PCR-SSCP). Subsequently, six conformers could be detected. Based on predicted amino acid sequences of 90 amino acid residues, three clusters could be deduced. Sequence information of two buffalo isolates was homologous to AgB4 indicating gene switching phenomenon in between closely related isoforms. Numerical value of Tajima's D test proved negative selection pressure. Using artificial neural network (ANN), B cell linear epitope and stretches of agretope were predicted. Three clusters could be defined on the basis of B cell linear epitope. Out of three clusters, two showed more than 50% binding propensity with same MHCII alleles whereas, cluster 3 exhibited binding propensity with other MHCII alleles (DRB1_1501, DRB1_1502). Relative expression of AgB2 was more in active cysts (1.636 ± 0.092) followed by degenerating (0.449 ± 0.037) and calcified (0.255 ± 0.008). This result suggested that relative expression of AgB2 declines with progression of the disease. Using recombinant AgB2 sensitivity, specificity and accuracy of the ELISA test was 96.7, 94.7 and 95.9%, respectively. No cross reactivity was found with common cestode and trematode infected cattle and buffalo because cross reactive antigen was expressed intracellularly. Finally, this was concluded that AgB2 is the suitable immunological marker for detection, diagnosis and progression of the disease.
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Affiliation(s)
- D Pan
- Indian Veterinary Research Institute, Eastern Regional Station, 37-Belgachia Road, 700037 WestBengal, Kolkata, India.
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Zhang W, Li J, Jones MK, Zhang Z, Zhao L, Blair D, McManus DP. The Echinococcus granulosus antigen B gene family comprises at least 10 unique genes in five subclasses which are differentially expressed. PLoS Negl Trop Dis 2010; 4:e784. [PMID: 20706625 PMCID: PMC2919375 DOI: 10.1371/journal.pntd.0000784] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2010] [Accepted: 07/07/2010] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Antigen B (EgAgB) is a major protein produced by the metacestode cyst of Echinococcus granulosus, the causative agent of cystic hydatid disease. This protein has been shown to play an important role in modulating host immune responses, although its precise biological function still remains unknown. It is generally accepted that EgAgB is comprised of a gene family of five subfamilies which are highly polymorphic, but the actual number of genes present is unknown. METHODOLOGY/PRINCIPAL FINDINGS Based on published sequences for the family, we designed specific primers for each subfamily and used PCR to amplify them from genomic DNA isolated from individual mature adult worms (MAW) taken from an experimentally infected dog in China and individual larval protoscoleces (PSC) excised from a single hydatid cyst taken from an Australian kangaroo. We then used real-time PCR to measure expression of each of the genes comprising the five EgAgB subfamilies in all life-cycle stages including the oncosphere (ONC). CONCLUSIONS/SIGNIFICANCE Based on sequence alignment analysis, we found that the EgAgB gene family comprises at least ten unique genes. Each of the genes was identical in both larval and adult E. granulosus isolates collected from two geographical areas (different continents). DNA alignment comparisons with EgAgB sequences deposited in GenBank databases showed that each gene in the gene family is highly conserved within E. granulosus, which contradicts previous studies claiming significant variation and polymorphism in EgAgB. Quantitative PCR analysis revealed that the genes were differentially expressed in different life-cycle stages of E. granulosus with EgAgB3 expressed predominantly in all stages. These findings are fundamental for determining the expression and the biological function of antigen B.
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Affiliation(s)
- Wenbao Zhang
- Molecular Parasitology Laboratory, Infectious Diseases Division, Queensland Institute of Medical Research, Brisbane, Queensland, Australia.
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Echinococcus multilocularis as an experimental model in stem cell research and molecular host-parasite interaction. Parasitology 2009; 137:537-55. [PMID: 19961652 DOI: 10.1017/s0031182009991727] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Totipotent somatic stem cells (neoblasts) are key players in the biology of flatworms and account for their amazing regenerative capability and developmental plasticity. During recent years, considerable progress has been made in elucidating molecular features of neoblasts from free-living flatworms, whereas their role in parasitic species has so far merely been addressed by descriptive studies. Very recently, however, significant advances have been made in the in vitro culture of neoblasts from the cestode Echinococcus multilocularis. The isolated cells proved capable of generating mature metacestode vesicles under laboratory conditions in a manner that closely resembles the oncosphere-metacestode transition during natural infections. Using the established neoblast cultivation protocols, combined with targeted manipulation of Echinococcus genes by RNA-interference, several fundamental questions of host-dependent parasite development can now be addressed. Here, I give an overview of current cultivation techniques for E. multilocularis neoblasts and present experimental approaches to study their function. Furthermore, I introduce the E. multilocularis genome sequencing project that is presently in an advanced stage. The combined input of data from the E. multilocularis sequencing project, stem cell cultivation, and recently initiated attempts to genetically manipulate Echinococcus will provide an ideal platform for hypothesis-driven research into cestode development in the next years.
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Arikoglu H, Arslan A, Hepdogru MA, Turhan AB. Expression profile and polymorphisms of actin genes in protoscoleces of Echinococcus granulosus from sheep in central Turkey. Vet Parasitol 2009; 166:80-5. [DOI: 10.1016/j.vetpar.2009.08.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Revised: 07/24/2009] [Accepted: 08/03/2009] [Indexed: 11/17/2022]
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Relative expression of antigen B coding gene of bubaline isolates of Echinococcus granulosus in fertile and sterile cysts. J Helminthol 2009; 84:241-4. [PMID: 19781130 DOI: 10.1017/s0022149x09990605] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
This article communicates the relative quantification of five isoforms of antigen B (AgB) of Echinococcus granulosus. Relative expression of the AgB was quantified in active and inactive cysts. Cysts with germinal membrane, clear cyst fluid and protoscoleces showed uniform expression of the five isoforms and were utilized as control. Relative expression of AgB1 was the highest in cysts, where calcification has initiated. AgB2 and AgB4 were expressed more in fertile cysts irrespective of the condition of germinal membrane. The lowest expression of AgB3 was seen in calcified cysts. The relative expression of AgB5 could not be correlated with respect to the condition of the cyst because AgB5 is typically expressed by the adult stage of the parasite.
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Tawfeek GM, Elwakil HS, Awad NS, El-Hoseiny L, Thabet HS, Sarhan RM, Darweesh SK, Anwar WA. Genetic variability of antigen B among Echinococcus granulosus Egyptian isolates. THE KOREAN JOURNAL OF PARASITOLOGY 2009; 47:259-64. [PMID: 19724699 DOI: 10.3347/kjp.2009.47.3.259] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2008] [Revised: 04/12/2009] [Accepted: 04/17/2009] [Indexed: 11/23/2022]
Abstract
Genetic polymorphisms of encoding antigen B2 gene (AgB2) in Echinococcus granulosus were studied using PCR-RFLP and DNA sequencing among 20 Egyptian isolates. Five isolates from different host origins (humans, camels, pigs, and sheep) were collected and used. All examined isolates of each host group gave very similar patterns of PCR-RFLP after restriction enzyme digestion with AluI, with the gene size of approximately 140 bp and 240 bp for sheep and human isolates, and approximately 150 bp and 250 bp for pig and camel isolates. No digestion pattern was obtained after incubation of all studied isolates with EcoRI. These results reveal high intra-group homogeneity. DNA sequence analysis highlighted that human infecting strain showed 100% identity with respect to sheep infecting isolate, 96% and 99% with pig and camel infecting isolates, respectively.
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Affiliation(s)
- Gihan M Tawfeek
- Department of Parasitology, Faculty of Medicine, Ain Shams University, Cairo, Egypt
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Pan D, Bera AK, Das SK, Bandyopadhyay S, Manna B, Bhattacharya D. Polymorphism and natural selection of antigen B1 of Echinococcus granulosus isolated from different host assemblages in India. Mol Biol Rep 2009; 37:1477-82. [PMID: 19430958 DOI: 10.1007/s11033-009-9542-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2008] [Accepted: 04/29/2009] [Indexed: 11/25/2022]
Abstract
Antigen B (AgB) is an excretory-secretory product of larval stage of Echinococcus granulosus. This antigen is abundantly secreted by larval stage of the worm. AgB is encoded by a multigene family and is suggested to be involved in evasion of host immune system. During the present study a total of 110 animal isolates of E. granulosus has been screened by mutation scan screening. A total of 14 conformers were detected on the basis of single strand banding profile of 129 bp fragment of AgB1 subunit. Analysis of sequence information of 14 conformers could cluster the isolates into two different group viz. buffalo-cattle and sheep-goat cluster. Conceptual amino acid sequence information of two clusters could be differentiated in terms of MHCII binding propensity of agretope and B-cell epitope region. This type of analysis of clustering of animal isolates on the basis of binding propensity towards different MHC antigens and B-cell linear epitope is the example of its own kind. Positive Tajima's D value indicated that, AgB1 is under balancing selection pressure which might be considered as heterogeneous selection pressure exerted by the host.
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Affiliation(s)
- D Pan
- Indian Veterinary Research Institute, Eastern Regional Station, Kolkata, India
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An evaluation of antigen B family of Echinococcus granulosus, its conformational propensity and elucidation of the agretope. J Helminthol 2008; 83:219-24. [PMID: 19102812 DOI: 10.1017/s0022149x0814740x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The present communication evaluates the antigen B (AgB) family of bubaline isolates of Echinococcus granulosus with respect to their conformational propensity and also discusses the stretches of agretope. AgB, which is abundantly present in hydatid cyst fluid, is encoded by a gene family, AgB1-AgB5. Hydatidosis is of zoonotic and economic importance in India. Buffaloes serve as the intermediate host. However, to date the AgB family has not been fully analysed. During the present study two different primers used for amplification of AgB1 revealed homology to Echinococcus canadensis (G8) as well as E. granulosus sensu stricto (G1/G2). The sequence of AgB3 is homologous to that of the well-defined species, Echinococcus ortleppi (G5), and the predicted amino acid sequence of AgB4 is homologous to bovine isolates identified earlier. alpha- and beta-amphipathic structures were recorded in all the antigens designated as T-cell receptor sites. The antigenic index of different stretches correlated with hydrophilicity because the hydrophobic residues are not accessible to the cells. In this study, we investigated the binding propensity of AgB to MHC II in order to determine stretches of agretope. Agretopes began with four hydrophilic residues. Two to three additional hydrophilic residues were present in the internal motif. This comparison of AgB and its family of bubaline isolates, with respect to their sequence information, alpha- and beta- amphipathic regions, antigenic index and stretches of agretope is the first such report from India.
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Monteiro KM, Zaha A, Ferreira HB. Recombinant subunits as tools for the structural and functional characterization of Echinococcus granulosus antigen B. Exp Parasitol 2008; 119:490-498. [DOI: 10.1016/j.exppara.2008.04.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2007] [Revised: 04/15/2008] [Accepted: 04/17/2008] [Indexed: 10/22/2022]
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Siracusano A, Margutti P, Delunardo F, Profumo E, Riganò R, Buttari B, Teggi A, Ortona E. Molecular cross-talk in host-parasite relationships: the intriguing immunomodulatory role of Echinococcus antigen B in cystic echinococcosis. Int J Parasitol 2008; 38:1371-6. [PMID: 18692060 DOI: 10.1016/j.ijpara.2008.06.003] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Accepted: 06/26/2008] [Indexed: 12/17/2022]
Abstract
Cystic echinococcosis (CE), a zoonosis caused by the development of Echinococcus granulosus tapeworm larvae in the internal organs of ungulates and humans, continues to pose a major public health burden in underdeveloped and industrialised areas worldwide. Research designed to improve parasitic disease control and find out more about parasite biology has already identified a number of E. granulosus antigenic molecules. The major E. granulosus immunomodulant antigen isolated from hydatid fluid is antigen B, a 120 kDa polymeric lipoprotein consisting of various 8 kDa subunits. By inhibiting elastase activity and neutrophil chemotaxis and eliciting a non-protective Th2 cell response, antigen B helps the parasite evade the human response. In this review, we briefly discuss current information on the molecular characteristics and immunomodulatory properties of E. granulosus antigen B. Besides focusing on findings that provide intriguing insights into the complex interplay between host and parasite, we suggest how this information could extend the current therapeutic options in inflammatory diseases.
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Affiliation(s)
- Alessandra Siracusano
- Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Rome, Italy.
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Mutation scan screening of Echinococcus granulosus isolates of Indian origin. Vet Res Commun 2008; 32:427-32. [PMID: 18283553 DOI: 10.1007/s11259-008-9039-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Accepted: 01/22/2008] [Indexed: 10/22/2022]
Abstract
During the present investigation a total of forty Indian animal isolates were screened by single strand conformation polymorphism (SSCP) collected from sheep, goat, cattle and buffalo. The result of the study indicated that nuclear variants of Echinococcus granulosus were present in both small and large ruminants. SSCP phenotypes of AgB, intron of actin II and Hbx-2 have been deduced. Presence of nuclear variants due to mutation of E. granulosus has been discussed depending on hypotheses imparted earlier in literature. High polymophism of AgB demands further investigation because the gene is related with immune evasion and infectivity. This communication reports for the first time the comparative profile of Indian goat, sheep, cattle and buffalo isolates of E. granulosus complex.
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Siracusano A, Riganò R, Ortona E, Profumo E, Margutti P, Buttari B, Delunardo F, Teggi A. Immunomodulatory mechanisms during Echinococcus granulosus infection. Exp Parasitol 2008; 119:483-489. [PMID: 18329023 DOI: 10.1016/j.exppara.2008.01.016] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2007] [Revised: 01/22/2008] [Accepted: 01/28/2008] [Indexed: 12/15/2022]
Abstract
The pathologic events that ensue after humans ingest the eggs of Echinococcus granulosus and continue while cystic echinococcosis develops, provide an excellent example illustrating the evasive strategies helminth parasites use to develop, progress and cause chronic disease. The hydatid cyst secretes and exposes numerous immunomodulatory molecules to the host's immune system. By characterizing these molecules we can understand the mechanisms that E. granulosus uses for increasing the efficiency and persistency of infection in the host. These molecules modulate both the innate and adaptive arms of the immune response and appear to target cellular and humoral responses. In this review, we discuss recent advances in the immunobiology of host-E. granulosus interactions that provide intriguing insights into the complex interplay between host and parasite that ultimately facilitates parasite survival.
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Affiliation(s)
- Alessandra Siracusano
- Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate, Istituto Superiore di Sanità, Viale Regina Elena 299, 00161 Roma, Italy.
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Muzulin PM, Kamenetzky L, Gutierrez AM, Guarnera EA, Rosenzvit MC. Echinococcus granulosus antigen B gene family: Further studies of strain polymorphism at the genomic and transcriptional levels. Exp Parasitol 2008; 118:156-64. [PMID: 17825293 DOI: 10.1016/j.exppara.2007.07.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2007] [Revised: 07/03/2007] [Accepted: 07/16/2007] [Indexed: 11/18/2022]
Abstract
Echinococcus granulosus AgB gene family is constituted by five gene loci. In a previous study, we analyzed the strain variation of EgAgB2/B4 sequences. Here, we have analyzed, by SSCP and sequencing, 250 genomic clones of EgAgB1/B3/B5 gene cluster from five E. granulosus strains. Several new EgAgB genomic variants were found. EgAgB1 and EgAgB3 genomic sequences grouped E. granulosus strains by phylogenetic tools in two clusters: one formed by G1/G2 and the other by G5, G6/G7 strains, in accordance with other molecular markers. EgAgB5 genomic and cDNA sequences were only found in G1/G2 cluster. Reverse transcription-PCR analysis using subunit specific primers revealed that all the EgAgB genes were transcribed in G1 and G7 strains with the exception of EgAgB5 transcripts that were not detected in G7 strain. Interestingly, AgB2 transcripts that were probably processed by an aberrant splicing mechanism leading to a non-functional B2 protein were found in G7 strain.
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Affiliation(s)
- Patricia Marcela Muzulin
- Departamento de Parasitología, Instituto Nacional de Enfermedades Infecciosas ANLIS Dr. Carlos G. Malbrán, Av. Vélez Sarsfield 563, Buenos Aires (1281), Argentina
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Haag KL, Gottstein B, Ayala FJ. Taeniid history, natural selection and antigenic diversity: evolutionary theory meets helminthology. Trends Parasitol 2008; 24:96-102. [PMID: 18182327 DOI: 10.1016/j.pt.2007.11.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2007] [Revised: 10/31/2007] [Accepted: 11/05/2007] [Indexed: 10/22/2022]
Abstract
Large sets of nucleotide sequence data of parasitic helminths have been accumulated in the past two decades. Our ability to improve the health of people and animals using this knowledge has not increased proportionally, however. Evolutionary biology provides the background to understand how parasites adapt to their hosts, and computational molecular biology offers the tools to infer the mechanisms involved. The study of antigenic diversity, a way for parasites to overcome host defenses against parasites, has been neglected in helminths, yet such a study could contribute to the development of more efficient drugs, diagnostic tests and vaccines. This review focuses on the study of adaptive evolution as the cause of antigenic diversity in tapeworms and its potential applications.
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Affiliation(s)
- Karen L Haag
- Departamento de Genética, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Porto Alegre, 91501-970 RS, Brazil.
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41
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Ito A, Nakao M, Sako Y. Echinococcosis: serological detection of patients and molecular identification of parasites. Future Microbiol 2007; 2:439-49. [PMID: 17683279 DOI: 10.2217/17460913.2.4.439] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Alveolar (AE) and cystic echinococcosis (CE) are two of the most dangerous helminthic zoonoses worldwide, representing chronic hepatic diseases, often with lethal outcome. Since early diagnosis of echinococcosis is essential for effective treatment, an overview of serological methods for the detection of echinococcosis and differentiation between AE and CE is given. Recombinant antigens Em18 and Antigen B8/1 are highly recommended for patient screening and identification of AE and CE, respectively, in combination with imaging techniques. Novel aspects of molecular phylogenetic studies on the genus Echinococcus will also be addressed, including the description of Echinococcus shiquicus as a new sister-species of Echinococcus multilocularis. Both the serological detection of the disease and molecular phylogeny will be discussed in perspective.
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Affiliation(s)
- Akira Ito
- Asahikawa Medical College, Department of Parasitology, Midorigaoka, Higashi, Asahikawa, Hokkaido, Japan.
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42
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Mamuti W, Sako Y, Bart JM, Nakao M, Ma X, Wen H, Ito A. Molecular characterization of a novel gene encoding an 8-kDa-subunit of antigen B from Echinococcus granulosus genotypes 1 and 6. Parasitol Int 2007; 56:313-6. [PMID: 17618826 DOI: 10.1016/j.parint.2007.06.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2007] [Revised: 06/04/2007] [Accepted: 06/05/2007] [Indexed: 10/23/2022]
Abstract
Antigen B in hydatid cyst fluid of Echinococcus granulosus is a polymeric lipoprotein of 160 kDa, and is an aggregate of several different but homologous small proteins with approximately 8 kDa which are encoded by a multigene family. Four genes encoding 8-kDa-subunit monomers of the antigen B have been identified from E. granulosus. Recently, we have isolated another novel gene from Echinococcus multilocularis encoding a fifth 8-kDa-subunit of AgB (named EmAgB8/5), predominantly transcribed in the adult worm, but not in vesicles of metacestodes. In this study, we cloned and characterized two EmAgB8/5 homologue genes from E. granulosus genotypes 1 and 6 by PCR, and named as EgG1AgB8/5 and EgG6AgB8/5, respectively. The phylogenetic relationship of these genes with other genes encoding the antigen B 8-kDa-subunit monomers was also discussed.
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Affiliation(s)
- Wulamu Mamuti
- Department of Parasitology, Asahikawa Medical College, Midorigaoka Higashi 2-1-1-1, Asahikawa 078-8510, Japan
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43
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Carmena D, Benito A, Eraso E. [Recent advances in the immunodiagnosis of human cystic echinococcosis]. Enferm Infecc Microbiol Clin 2007; 25:263-9. [PMID: 17386222 DOI: 10.1157/13100468] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Human cystic echinococcosis is a severe zoonotic infection caused by the larval stage of the taeniid tapeworm Echinococcus granulosus. The infection may be fatal if proper treatment is not provided; hence, early diagnosis is very important. Currently, ELISA and immunoblotting are the most reliable tests for serodiagnostic purposes, although their accuracy is largely dependent on the quality of the antigenic source used. Hydatid cyst fluid has been the antigenic extract of choice for primary immunodiagnosis of the disease, which is mainly based on the detection of antigens B and 5. Several problems are associated with this extract, however, including a lack of sensitivity and specificity, and difficulties with standardization of its use. This paper reviews recent advances in the identification and characterization of novel antigens that may be useful for the immunodiagnosing of human cystic echinococcosis, with emphasis on progress in recombinant technologies and synthetic peptides. Novel approaches are discussed, such as the design of antigenic extracts from other developmental stages of the parasite, as well as the usefulness of serum cytokine detection in the clinical follow-up of affected patients after surgical or pharmacological treatment.
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Affiliation(s)
- David Carmena
- MRC Clinical Sciences Centre, Membrane Transport Biology Group, Faculty of Medicine. Imperial College, Hammersmith Hospital Campus, London, UK.
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44
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Jackson AP. Tandem gene arrays in Trypanosoma brucei: comparative phylogenomic analysis of duplicate sequence variation. BMC Evol Biol 2007; 7:54. [PMID: 17408475 PMCID: PMC1855330 DOI: 10.1186/1471-2148-7-54] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2006] [Accepted: 04/04/2007] [Indexed: 11/23/2022] Open
Abstract
Background The genome sequence of the protistan parasite Trypanosoma brucei contains many tandem gene arrays. Gene duplicates are created through tandem duplication and are expressed through polycistronic transcription, suggesting that the primary purpose of long, tandem arrays is to increase gene dosage in an environment where individual gene promoters are absent. This report presents the first account of the tandem gene arrays in the T. brucei genome, employing several related genome sequences to establish how variation is created and removed. Results A systematic survey of tandem gene arrays showed that substantial sequence variation existed across the genome; variation from different regions of an array often produced inconsistent phylogenetic affinities. Phylogenetic relationships of gene duplicates were consistent with concerted evolution being a widespread homogenising force. However, tandem duplicates were not usually identical; therefore, any homogenising effect was coincident with divergence among duplicates. Allelic gene conversion was detected using various criteria and was apparently able to both remove and introduce sequence variation. Tandem arrays containing structural heterogeneity demonstrated how sequence homogenisation and differentiation can occur within a single locus. Conclusion The use of multiple genome sequences in a comparative analysis of tandem gene arrays identified substantial sequence variation among gene duplicates. The distribution of sequence variation is determined by a dynamic balance of conservative and innovative evolutionary forces. Gene trees from various species showed that intraspecific duplicates evolve in concert, perhaps through frequent gene conversion, although this does not prevent sequence divergence, especially where structural heterogeneity physically separates a duplicate from its neighbours. In describing dynamics of sequence variation that have consequences beyond gene dosage, this survey provides a basis for uncovering the hidden functionality within tandem gene arrays in trypanosomatids.
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Affiliation(s)
- Andrew P Jackson
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridgeshire, UK.
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Monteiro KM, Scapin SMN, Navarro MVAS, Zanchin NIT, Cardoso MB, da Silveira NP, Gonçalves PFB, Stassen HK, Zaha A, Ferreira HB. Self-assembly and structural characterization of Echinococcus granulosus antigen B recombinant subunit oligomers. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2007; 1774:278-85. [PMID: 17188949 DOI: 10.1016/j.bbapap.2006.11.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/16/2006] [Revised: 11/07/2006] [Accepted: 11/08/2006] [Indexed: 11/25/2022]
Abstract
Echinococcus granulosus antigen B is an oligomeric protein of 120-160 kDa composed by 8-kDa (AgB8) subunits. Here, we demonstrated that the AgB8 recombinant subunits AgB8/1, AgB8/2 and AgB8/3 are able to self-associate into high order homo-oligomers, showing similar properties to that of parasite-produced AgB, making them valuable tools to study AgB structure. Dynamic light scattering, size exclusion chromatography and cross-linking assays revealed approximately 120- to 160-kDa recombinant oligomers, with a tendency to form populations with different aggregation states. Recombinant oligomers showed helical circular dichroism spectra and thermostability similar to those of purified AgB. Cross-linking and limited proteolysis experiments indicated different degrees of stability and compactness between the recombinant oligomers, with the AgB8/3 one showing a more stable and compact structure. We have also built AgB8 subunit structural models in order to predict the surfaces possibly involved in electrostatic and hydrophobic interactions during oligomerization.
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Affiliation(s)
- Karina M Monteiro
- Laboratório de Biologia Molecular de Cestódeos, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Cx. Postal 15005, 91501-970, Porto Alegre, RS, Brazil
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Graichen DAS, Gottstein B, Matsumoto J, Müller N, Zanotto PMA, Ayala FJ, Haag KL. Expression and diversity of Echinococcus multilocularis AgB genes in secondarily infected mice: evaluating the influence of T-cell immune selection on antigenic variation. Gene 2006; 392:98-105. [PMID: 17208391 DOI: 10.1016/j.gene.2006.11.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2006] [Revised: 11/15/2006] [Accepted: 11/20/2006] [Indexed: 11/27/2022]
Abstract
The T-cell-mediated immune response exhibits a crucial function in the control of the intrahepatic proliferation of Echinococcus multilocularis larvae in mice and humans, both being natural intermediate hosts of the parasite. Antigen B (AgB), a metabolized Echinococcus spp. lipoprotein, contributes to the modulation of the T-cell immune response, and distinct sites of the corresponding AgB1, AgB3 and AgB4 genes were shown to be under positive selection pressure. Since several AgB gene variants are present in a single Echinococcus metacestode, we used secondary E. multilocularis infections in BALB/c and in athymic nude mice (devoid of T-cell responses) to analyze the effect of the cellular immune response on the expression and diversity of EmAgB1-EmAgB4 genes. We demonstrated hereby that EmAgB transcripts were less abundant in nude mice during the early phase of infection (at one month post-infection), and that EmAgB2 is simultaneously down-regulated when compared to the other three genes. A negative relationship exists between the level of transcription and diversity of EmAgB genes. Moreover, no excess of non-synonymous substitutions was found among the distinct EmAgB alleles from a single host. Together, these results pointed to the effect of purifying selection, which seemed to eliminate the detrimental AgB variants generated during the development of the metacestode within the peritoneal cavity of its intermediate host.
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Affiliation(s)
- D A S Graichen
- Programa de Pós Graduação em Genética e Biologia Molecular, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil
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Virginio VG, Taroco L, Ramos AL, Ferreira AM, Zaha A, Ferreira HB, Hernández A. Effects of protoscoleces and AgB from Echinococcus granulosus on human neutrophils: possible implications on the parasite's immune evasion mechanisms. Parasitol Res 2006; 100:935-42. [PMID: 17111175 DOI: 10.1007/s00436-006-0366-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2006] [Accepted: 10/19/2006] [Indexed: 01/04/2023]
Abstract
The factors affecting the innate susceptibility to Echinococcus granulosus infections are largely unknown. We assessed the interaction of healthy human neutrophils with protoscoleces (PSC) and antigen B (AgB) of E. granulosus by analysis of CD11b upregulation and H(2)O(2) production by flow cytometry. PSC induced neutrophil activation, but their viability was not affected. In contrast, no effects were observed with AgB in both assays. Neutrophil-enriched fractions were also incubated with PSC or AgB, and interleukin 8 (IL-8) production was measured by ELISA. Significant increment in IL-8 production was detected only in supernatants from neutrophil-enriched fractions cultured with PSC. The possible effect of a prior incubation with AgB on the phorbol myristate acetate-induced activation was also evaluated. No changes were observed in CD11b expression, but the H(2)O(2) production was significantly reduced in platelet-activating factor (PAF)-primed neutrophils. These results suggest a possible AgB-mediated mechanism of evasion of the host immune response, which would operate upon events of spillage of the fertile hydatid cyst content.
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Affiliation(s)
- Veridiana Gomes Virginio
- Laboratório de Biologia Molecular de Cestódeos, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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Haag KL, Gottstein B, Müller N, Schnorr A, Ayala FJ. Redundancy and recombination in the Echinococcus AgB multigene family: is there any similarity with protozoan contingency genes? Parasitology 2006; 133:411-9. [PMID: 16817991 DOI: 10.1017/s0031182006000564] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2006] [Revised: 04/24/2006] [Accepted: 04/25/2006] [Indexed: 11/06/2022]
Abstract
Numerous genetic variants of the Echinococcus antigen B (AgB) are encountered within a single metacestode. This could be a reflection of gene redundancy or the result of a somatic hypermutation process. We evaluate the complexity of the AgB multigene family by characterizing the upstream promoter regions of the 4 already known genes (EgAgB1-EgAgB4) and evaluating their redundancy in the genome of 3 Echinococcus species (E. granulosus, E. ortleppi and E. multilocularis) using PCR-based approaches. We have ascertained that the number of AgB gene copies is quite variable, both within and between species. The most repetitive gene seems to be AgB3, of which there are more than 110 copies in E. ortleppi. For E. granulosus, we have cloned and characterized 10 distinct upstream promoter regions of AgB3 from a single metacestode. Our sequences suggest that AgB1 and AgB3 are involved in gene conversion. These results are discussed in light of the role of gene redundancy and recombination in parasite evasion mechanisms of host immunity, which at present are known for protozoan organisms, but virtually unknown for multicellular parasites.
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Affiliation(s)
- K L Haag
- Department of Genetics, Institute of Biological Sciences, UFRGS, Porto Alegre, 91501-970 RS, Brazil.
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49
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Haag KL, Zanotto PMA, Alves-Junior L, Gasser RB, Zaha A, Ayala FJ. Searching for antigen B genes and their adaptive sites in distinct strains and species of the helminth Echinococcus. INFECTION GENETICS AND EVOLUTION 2006; 6:251-61. [PMID: 16207536 DOI: 10.1016/j.meegid.2005.07.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2005] [Revised: 07/20/2005] [Accepted: 07/26/2005] [Indexed: 11/30/2022]
Abstract
Twenty-seven PCR-derived antigen B (AgB) nucleotide sequences from four Echinococcus species (Echinococcus granulosus, Echinococcus multilocularis, Echinococcus oligarthrus and Echinococcus vogeli) were aligned with 78 already published sequences, to generate a maximum likelihood phylogeny of the AgB multigene family. The phylogenetic analysis confirms that the family is constituted by four groups of genes present in each one of the four species (AgB1, AgB2, AgB3 and AgB4), and suggests that it originated by ancient duplication events preceding speciation within the genus. AgB5 sequences, which had been formerly suggested to correspond to a putatively new AgB subunit, cluster with AgB3. Likelihood tests suggest that AgB gene evolution may have been driven by heterogeneous selection pressures acting on particular AgB1, AgB3 and AgB4 codons. No selection is detected in AgB2. We discuss implications of our findings in terms of AgB biology and its use as a diagnostic tool.
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Affiliation(s)
- K L Haag
- Departamento de Genética, Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, 9500 Prédio 43323, Caixa Postal 15053, Porto Alegre, RS, CEP 91501-970, Brazil.
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Carmena D, Benito A, Eraso E. Antigens for the immunodiagnosis of Echinococcus granulosus infection: An update. Acta Trop 2006; 98:74-86. [PMID: 16527225 DOI: 10.1016/j.actatropica.2006.02.002] [Citation(s) in RCA: 99] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2005] [Revised: 01/12/2006] [Accepted: 02/07/2006] [Indexed: 12/21/2022]
Abstract
The taeniid tapeworm Echinococcus granulosus is the causative agent of the echinococcal disease, an important zoonosis with worldwide distribution. Accurate immunodiagnosis of the infection requires highly specific and sensitive antigens to be used in immunodiagnostic assays. The choice of an appropriate source of antigenic material is a crucial point in the improvement of the diagnostic features of tests, and must be based on the developmental stage of the parasite and the host. The most common antigenic sources used for the immunodiagnosis of echinococcal disease are hydatid cyst fluid, somatic extracts and excretory-secretory products from protoscoleces or adults of E. granulosus. Hydatid cyst fluid is the antigenic source of reference for immunodiagnosis of human hydatidosis, which is mainly based on the detection of antigens B and 5. Somatic extracts have been widely used in the serodiagnosis for E. granulosus infection in dogs and ruminant intermediate hosts, although in the last few years the detection of excretory-secretory products of the worm in faeces (coproantigens) have become the most reliable method for the detection of the parasite in the definitive host. This review emphasizes recent advances in the identification and characterization of novel antigens with potential for the immunodiagnosis of echinococcal disease. Progress in recombinant technologies and synthetic peptides are also discussed. The paper highlights the need to search for new antigenic components with high diagnostic sensitivity and specificity, a fact that remains a crucial task in the improvement of the immunodiagnosis of the disease.
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Affiliation(s)
- David Carmena
- Department of Immunology, Microbiology and Parasitology, Faculty of Pharmacy, University of the Basque Country, Vitoria, Spain.
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