51
|
Abstract
Soil-transmitted helminths (STHs) collectively infect one fourth of all human beings, and the majority of livestock in the developing world. These gastrointestinal nematodes are the most important parasites on earth with regard to their prevalence in humans and livestock. Current anthelmintic drugs are losing their efficacies due to increasing drug resistance, particularly in STHs of livestock and drug treatment is often followed by rapid reinfection due to failure of the immune system to develop a protective response. Vaccines against STHs offer what drugs cannot accomplish alone. Because such vaccines would have to be produced on such a large scale, and be cost effective, recombinant subunit vaccines that include a minimum number of proteins produced in relatively simple and inexpensive expression systems are required. Here, we summarize all of the previous studies pertaining to recombinant subunit vaccines for STHs of humans and livestock with the goal of both informing the public of just how critical these parasites are, and to help guide future developments. We also discuss several key areas of vaccine development, which we believe to be critical for developing more potent recombinant subunit vaccines with broad-spectrum protection.
Collapse
|
52
|
Niche-specific gene expression in a parasitic nematode; increased expression of immunomodulators in Teladorsagia circumcincta larvae derived from host mucosa. Sci Rep 2017; 7:7214. [PMID: 28775251 PMCID: PMC5543109 DOI: 10.1038/s41598-017-07092-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 06/21/2017] [Indexed: 11/29/2022] Open
Abstract
Metazoan parasites have to survive in many different niches in order to complete their life-cycles. In the absence of reliable methods to manipulate parasite genomes and/or proteomes, identification of the molecules critical for parasite survival within these niches has largely depended on comparative transcriptomic and proteomic analyses of different developmental stages of the parasite; however, changes may reflect differences associated with transition between developmental stages rather than specific adaptations to a particular niche. In this study, we compared the transcriptome of two fourth-stage larval populations of the nematode parasite, Teladorsagia circumcincta, which were of the same developmental stage but differed in their location within the abomasum, being either mucosal-dwelling (MD) or lumen-dwelling (LD). Using RNAseq, we identified 57 transcripts which were significantly differentially expressed between MD and LD larvae. Of these transcripts, the majority (54/57) were up-regulated in MD larvae, one of which encoded for an ShKT-domain containing protein, Tck6, capable of modulating ovine T cell cytokine responses. Other differentially expressed transcripts included homologues of ASP-like proteins, proteases, or excretory-secretory proteins of unknown function. Our study demonstrates the utility of niche- rather than stage-specific analysis of parasite transcriptomes to identify parasite molecules of potential importance for survival within the host.
Collapse
|
53
|
Sotillo J, Toledo R, Mulvenna J, Loukas A. Exploiting Helminth-Host Interactomes through Big Data. Trends Parasitol 2017; 33:875-888. [PMID: 28734897 DOI: 10.1016/j.pt.2017.06.011] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 06/26/2017] [Accepted: 06/28/2017] [Indexed: 12/19/2022]
Abstract
Helminths facilitate their parasitic existence through the production and secretion of different molecules, including proteins. Some helminth proteins can manipulate the host's immune system, a phenomenon that is now being exploited with a view to developing therapeutics for inflammatory diseases. In recent years, hundreds of helminth genomes have been sequenced, but as a community we are still taking baby steps when it comes to identifying proteins that govern host-helminth interactions. The information generated from genomic, immunomic, and proteomic studies, as well as from cutting-edge approaches such as proteogenomics, is leading to a substantial volume of big data that can be utilised to shed light on fundamental biology and provide solutions for the development of bioactive-molecule-based therapeutics.
Collapse
Affiliation(s)
- Javier Sotillo
- Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD, Australia.
| | - Rafael Toledo
- Departament de Farmacia, Tecnologia Farmacéutica y Parasitologia, Facultat de Farmacia, Universitat de Valencia, Spain
| | - Jason Mulvenna
- QIMR-Berghofer Medical Research Institute, Brisbane, QLD, Australia
| | - Alex Loukas
- Centre for Biodiscovery and Molecular Development of Therapeutics, Australian Institute of Tropical Health and Medicine, James Cook University, Cairns, QLD, Australia.
| |
Collapse
|
54
|
Bartley K, Turnbull F, Wright HW, Huntley JF, Palarea-Albaladejo J, Nath M, Nisbet AJ. Field evaluation of poultry red mite (Dermanyssus gallinae) native and recombinant prototype vaccines. Vet Parasitol 2017; 244:25-34. [PMID: 28917313 PMCID: PMC5613835 DOI: 10.1016/j.vetpar.2017.06.020] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 06/20/2017] [Accepted: 06/24/2017] [Indexed: 11/10/2022]
Abstract
Field trial testing of a native and recombinant poultry red mite vaccines. Vaccination with a soluble mite extract (SME) resulted in a 78% reduction in mite numbers. Poor antibody persistence may relate to lack of effect of a recombinant cocktail vaccine. A semi-protective naturally acquired immunity may develop.
Vaccination is a desirable emerging strategy to combat poultry red mite (PRM), Dermanyssus gallinae. We performed trials, in laying hens in a commercial-style cage facility, to test the vaccine efficacy of a native preparation of soluble mite extract (SME) and of a recombinant antigen cocktail vaccine containing bacterially-expressed versions of the immunogenic SME proteins Deg-SRP-1, Deg-VIT-1 and Deg-PUF-1. Hens (n = 384 per group) were injected with either vaccine or adjuvant only (control group) at 12 and 17 weeks of age and then challenged with PRM 10 days later. PRM counts were monitored and, at the termination of the challenge period (17 weeks post challenge), average PRM counts in cages containing birds vaccinated with SME were reduced by 78% (p < 0.001), compared with those in the adjuvant-only control group. When the trial was repeated using the recombinant antigen cocktail vaccine, no statistically significant differences in mean PRM numbers were observed in cages containing vaccinated or adjuvant-only immunised birds. The roles of antigen-specific antibody levels and duration in providing vaccine-induced and exposure-related protective immunity are discussed.
Collapse
Affiliation(s)
- Kathryn Bartley
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, Midlothian EH26 0PZ, United Kingdom.
| | - Frank Turnbull
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, Midlothian EH26 0PZ, United Kingdom
| | - Harry W Wright
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, Midlothian EH26 0PZ, United Kingdom
| | - John F Huntley
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, Midlothian EH26 0PZ, United Kingdom
| | - Javier Palarea-Albaladejo
- Biomathematics and Statistics Scotland, The King's Buildings, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, United Kingdom
| | - Mintu Nath
- Biomathematics and Statistics Scotland, The King's Buildings, Peter Guthrie Tait Road, Edinburgh, EH9 3FD, United Kingdom
| | - Alasdair J Nisbet
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, Midlothian EH26 0PZ, United Kingdom
| |
Collapse
|
55
|
Kenyon F, Hutchings F, Morgan-Davies C, van Dijk J, Bartley DJ. Worm Control in Livestock: Bringing Science to the Field. Trends Parasitol 2017. [PMID: 28647171 DOI: 10.1016/j.pt.2017.05.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Parasitic roundworm infections are ubiquitous in grazing livestock. Chemical control through the frequent 'blanket' administration of anthelmintics (wormers) has been, and remains, the cornerstone in controlling these infections, but this practice is unsustainable. Alternative strategies are available but, even with the plethora of best practice advice available, have yet to be integrated into routine farming practice. This is probably due to a range of factors, including contradictory advice from different sources, changes to advice following increased scientific understanding, and top-down knowledge exchange patterns. In this article, we discuss the worm control options available, the translation of new best practice advice from science bench to field, and ideas for future work and directions.
Collapse
|
56
|
Joekel D, Hinse P, Raulf MK, Schicht S, Bäumer W, Werling D, Kremmer E, Strube C. Vaccination of calves with yeast- and bacterial-expressed paramyosin from the bovine lungworm Dictyocaulus viviparus. Parasite Immunol 2016; 37:614-23. [PMID: 26408341 DOI: 10.1111/pim.12280] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 09/16/2015] [Indexed: 11/28/2022]
Abstract
Previously, vaccination of cattle with Escherichia coli-expressed bovine lungworm paramyosin (EcPMY) adjuvanted with Quil A resulted in considerable reduction in worm burden and larvae shedding (Strube et al., 2015). To further evaluate the protective potential of PMY, cattle vaccination trials were performed using either E. coli- (EcPMY) or Pichia pastoris-expressed PMY (PpPMY) with different adjuvants (Matrix-Q(™) or Quil A). Combinations EcPMY+Matrix-Q(™) (trial 1), PpPMY+Matrix-Q(™) (trial 2) and PpPMY+Quil A (trial 3) were tested against challenge infections with 2000 Dictyocaulus viviparus larvae. Even though GM worm burden and larvae shedding was lower in almost all vaccinated groups, there were high variations between individuals hampering significant differences. However, in all vaccinated groups, lungworms were significantly shorter compared with those in controls. In vitro stimulation of peripheral blood mononuclear cells (PBMC) with recombinant (r)PMY revealed no significant proliferation following vaccinations or challenge infection. All vaccinated cattle showed a significant rise in specific antibodies, particularly IgG and its subclass IgG1, and detected the native lungworm PMY in immunoblots starting 2 weeks after the first vaccination. The use of a different rPMY-adjuvant combination or combined vaccination with additional recombinant antigens might be a promising future approach towards a new vaccine against lungworms in cattle.
Collapse
Affiliation(s)
- D Joekel
- Institute for Parasitology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - P Hinse
- Institute for Parasitology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - M K Raulf
- Institute for Parasitology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - S Schicht
- Institute for Parasitology, University of Veterinary Medicine Hannover, Hannover, Germany
| | - W Bäumer
- College of Veterinary Medicine, Department of Molecular Biomedical Sciences, North Carolina State University, Raleigh, NC, USA
| | - D Werling
- Molecular Immunology Group, Department of Pathology and Pathogen Biology, Royal Veterinary College, Hatfield, UK
| | - E Kremmer
- Helmholtz Zentrum München, German Research Center for Environmental Health, Institute of Molecular Immunology, Munich, Germany
| | - C Strube
- Institute for Parasitology, University of Veterinary Medicine Hannover, Hannover, Germany
| |
Collapse
|
57
|
The genome ofStrongyloidesspp. gives insights into protein families with a putative role in nematode parasitism. Parasitology 2016; 144:343-358. [DOI: 10.1017/s0031182016001554] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
SUMMARYParasitic nematodes are important and abundant parasites adapted to live a parasitic lifestyle, with these adaptations all aimed at facilitating their survival and reproduction in their hosts. The recently sequenced genomes of fourStrongyloidesspecies, gastrointestinal parasites of humans and other animals, alongside transcriptomic and proteomic analysis of free-living and parasitic stages of their life cycles have revealed a number of protein families with a putative role in their parasitism. Many of these protein families have also been associated with parasitism in other parasitic nematode species, suggesting that these proteins may play a fundamental role in nematode parasitism more generally. Here, we review key protein families that have a putative role inStrongyloides’ parasitism – acetylcholinesterases, astacins, aspartic proteases, prolyl oligopeptidases, proteinase inhibitors (trypsin inhibitors and cystatins), SCP/TAPS and transthyretin-like proteins – and the evidence for their key, yet diverse, roles in the parasitic lifestyle.
Collapse
|
58
|
Protection of ewes against Teladorsagia circumcincta infection in the periparturient period by vaccination with recombinant antigens. Vet Parasitol 2016; 228:130-136. [PMID: 27692315 DOI: 10.1016/j.vetpar.2016.09.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 09/01/2016] [Accepted: 09/03/2016] [Indexed: 11/21/2022]
Abstract
Teladorsagiosis is a major production-limiting disease in ruminants in temperate regions throughout the world and one of the key interventions in the management of the disease is the prevention of pasture contamination with Teladorsagia circumcincta eggs by ewes during the periparturient relaxation in immunity which occurs in the period around lambing. Here, we describe the immunisation of twin-bearing ewes with a T. circumcincta recombinant subunit vaccine and the impact that vaccination has on their immune responses and shedding of parasite eggs during a continuous T. circumcincta challenge period spanning late gestation and lactation. In ewes which displayed a clear periparturient relaxation in immunity, vaccination resulted in a 45% reduction in mean cumulative faecal egg count (cFEC, p=0.027) compared to control (immunised with adjuvant only) ewes. Recombinant antigen-specific IgG and IgA, which bound each of the vaccine antigens, were detected in the serum of vaccinated ewes following each immunisation and in colostrum taken from vaccinated ewes post-partum whereas low levels of antigen-specific IgG were detected in serum and colostrum from control ewes. Antigen-specific IgG and IgA levels in blood collected within 48h of birth from lambs largely reflected those in the colostrum of their ewes.
Collapse
|
59
|
Host protective ASP-based vaccine against the parasitic nematode Ostertagia ostertagi triggers NK cell activation and mixed IgG1-IgG2 response. Sci Rep 2016; 6:29496. [PMID: 27403891 PMCID: PMC4941725 DOI: 10.1038/srep29496] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Accepted: 06/20/2016] [Indexed: 12/20/2022] Open
Abstract
The mucus-dwelling parasite Ostertagia ostertagi is one of the most important gastrointestinal nematodes in cattle. Our group has previously demonstrated the protective capacity of a vaccine against this parasite based on a native activation-associated secreted protein ASP1 (nASP) in combination with the saponin adjuvant QuilA. The aim of the current study was to analyse the effect of both antigen and adjuvant on the cellular and humoral vaccine-induced immune responses by comparing the native ASP to a recombinant version expressed in Pichia pastoris (pASP) and replacing QuilA by Al(OH)3. Immunization of cattle with the protective nASP+QuilA vaccine was associated with antigen-induced proliferation of natural killer (NK) cells combined with IFN-γ secretion and the induction of a mixed IgG1/IgG2 antibody response. ASP-specific activation and proliferation of NK cells was also observed in mice following the same vaccination regime. Replacing QuilA by Al(OH)3 or nASP by pASP significantly decreased the capacity of the vaccines to trigger both NK cell activation and antibody responses and failed to induce protection against a challenge infection. Reduction of the structurally anchoring disulphide bonds of the nASP completely abolished its ability to induce NK cell activation and antibody responses, highlighting the importance of protein conformation for the immunostimulatory activity.
Collapse
|
60
|
Abstract
Sheep are capable of developing protective immunity to Haemonchus contortus through repeated exposure to this parasite, although this immune protection is the result of a complex interaction among age, gender, physiological status, pregnancy, lactation, nutrition and innate and adaptive immunity in the host animal. There are multiple effectors of the protective immune response, which differ depending on the developmental stage of the parasite being targeted, and our understanding of the effector mechanisms has developed considerably in the 2000s. The rational design of vaccines based on 'natural' or 'exposed' antigens depends on an understanding of this exposure-induced immunity. However, the most effective current vaccines rely on protection via the induction of high circulating antibody levels to 'hidden' gut antigens of H. contortus. The success of this latter strategy has resulted in the launch of a vaccine, which is based on extracts of the parasite's gut, to aid in the control of Haemonchus in Australia. The development of recombinant subunit vaccines based on the components of the successful native vaccine has not yet been achieved and most of the recent successes with recombinant subunit vaccines have focussed on antigens unrelated to the gut antigens. The future integration of an understanding of the immunobiology of this parasite with advances in antigen identification, expression (or synthesis) and presentation is likely to be pivotal to the further development of these recombinant subunit vaccines. Recent progress in each of the components underpinning this integrated approach is summarized in this review.
Collapse
|
61
|
Gasser RB, Schwarz EM, Korhonen PK, Young ND. Understanding Haemonchus contortus Better Through Genomics and Transcriptomics. ADVANCES IN PARASITOLOGY 2016; 93:519-67. [PMID: 27238012 DOI: 10.1016/bs.apar.2016.02.015] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Parasitic roundworms (nematodes) cause substantial mortality and morbidity in animals globally. The barber's pole worm, Haemonchus contortus, is one of the most economically significant parasitic nematodes of small ruminants worldwide. Although this and related nematodes can be controlled relatively well using anthelmintics, resistance against most drugs in common use has become a major problem. Until recently, almost nothing was known about the molecular biology of H. contortus on a global scale. This chapter gives a brief background on H. contortus and haemonchosis, immune responses, vaccine research, chemotherapeutics and current problems associated with drug resistance. It also describes progress in transcriptomics before the availability of H. contortus genomes and the challenges associated with such work. It then reviews major progress on the two draft genomes and developmental transcriptomes of H. contortus, and summarizes their implications for the molecular biology of this worm in both the free-living and the parasitic stages of its life cycle. The chapter concludes by considering how genomics and transcriptomics can accelerate research on Haemonchus and related parasites, and can enable the development of new interventions against haemonchosis.
Collapse
Affiliation(s)
- R B Gasser
- The University of Melbourne, Parkville, VIC, Australia
| | - E M Schwarz
- The University of Melbourne, Parkville, VIC, Australia; Cornell University, Ithaca, NY, United States
| | - P K Korhonen
- The University of Melbourne, Parkville, VIC, Australia
| | - N D Young
- The University of Melbourne, Parkville, VIC, Australia
| |
Collapse
|
62
|
Tzelos T, Matthews JB, Buck AH, Simbari F, Frew D, Inglis NF, McLean K, Nisbet AJ, Whitelaw CBA, Knox DP, McNeilly TN. A preliminary proteomic characterisation of extracellular vesicles released by the ovine parasitic nematode, Teladorsagia circumcincta. Vet Parasitol 2016; 221:84-92. [PMID: 27084478 PMCID: PMC4867787 DOI: 10.1016/j.vetpar.2016.03.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 03/14/2016] [Accepted: 03/15/2016] [Indexed: 12/21/2022]
Abstract
Teladorsagia circumcincta is a major cause of ovine parasitic gastroenteritis in temperate climatic regions. The development of high levels of anthelmintic resistance in this nematode species challenges its future control. Recent research indicates that many parasite species release extracellular vesicles into their environment, many of which have been classified as endocytic in origin, termed exosomes. These vesicles are considered to play important roles in the intercellular communication between parasites and their hosts, and thus represent potentially useful targets for novel control strategies. Here, we demonstrate that exosome-like extracellular vesicles can be isolated from excretory-secretory (ES) products released by T. circumcincta fourth stage larvae (Tci-L4ES). Furthermore, we perform a comparative proteomic analysis of vesicle-enriched and vesicle-free Tci-L4ES. Approximately 73% of the proteins identified in the vesicle-enriched fraction were unique to this fraction, whilst the remaining 27% were present in both vesicle-enriched and vesicle-free fraction. These unique proteins included structural proteins, nuclear proteins, metabolic proteins, proteolytic enzymes and activation-associated secreted proteins. Finally, we demonstrate that molecules present within the vesicles-enriched material are targets of the IgA and IgG response in T. circumcincta infected sheep, and could potentially represent useful targets for future vaccine intervention studies.
Collapse
Affiliation(s)
- Thomas Tzelos
- Moredun Research Institute, Pentlands Science Park, Bush Loan, EH26 0PZ, Edinburgh, UK.
| | - Jacqueline B Matthews
- Moredun Research Institute, Pentlands Science Park, Bush Loan, EH26 0PZ, Edinburgh, UK
| | - Amy H Buck
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, King's Buildings, EH9 3JL, Edinburgh, UK
| | - Fabio Simbari
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, King's Buildings, EH9 3JL, Edinburgh, UK
| | - David Frew
- Moredun Research Institute, Pentlands Science Park, Bush Loan, EH26 0PZ, Edinburgh, UK
| | - Neil F Inglis
- Moredun Research Institute, Pentlands Science Park, Bush Loan, EH26 0PZ, Edinburgh, UK
| | - Kevin McLean
- Moredun Research Institute, Pentlands Science Park, Bush Loan, EH26 0PZ, Edinburgh, UK
| | - Alasdair J Nisbet
- Moredun Research Institute, Pentlands Science Park, Bush Loan, EH26 0PZ, Edinburgh, UK
| | - C Bruce A Whitelaw
- The Roslin Institute, University of Edinburgh, Easter Bush, Midlothian,EH25 9RG, Edinburgh, UK
| | - David P Knox
- Moredun Research Institute, Pentlands Science Park, Bush Loan, EH26 0PZ, Edinburgh, UK
| | - Tom N McNeilly
- Moredun Research Institute, Pentlands Science Park, Bush Loan, EH26 0PZ, Edinburgh, UK
| |
Collapse
|
63
|
Burgess STG, Nunn F, Nath M, Frew D, Wells B, Marr EJ, Huntley JF, McNeilly TN, Nisbet AJ. A recombinant subunit vaccine for the control of ovine psoroptic mange (sheep scab). Vet Res 2016; 47:26. [PMID: 26861998 PMCID: PMC4748516 DOI: 10.1186/s13567-016-0315-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Accepted: 01/28/2016] [Indexed: 01/14/2023] Open
Abstract
Sheep scab, caused by infestation with the mite Psoroptes ovis, is highly contagious, causing intense pruritus and represents a major welfare and economic concern. Disease control strategies rely upon chemotherapy, however, sustainability is questionable due to issues of chemical residues, eco-toxicity and acaricide resistance. Control by vaccination is supported by demonstration of protective immunity in sheep previously infested with P. ovis. We identified vaccine candidates for P. ovis based on: (1) antigens selected by their interaction with host signalling pathways and the host immune-response; and (2) those shown to be either immunogenic or involved in mite feeding. This resulted in the development and validation, in repeated immunisation and challenge trials, of a seven recombinant protein sub-unit cocktail vaccine. Sheep were inoculated on three occasions, 2 weeks apart, along with QuilA adjuvant. Vaccination resulted in highly significant reductions in both lesion size (up to 63%) and mite numbers (up to 56%) following challenge. Mean lesion size in vaccinates was significantly smaller than controls from 1 week post infestation (wpi) until the end of the experiment at 6 wpi. All antigens elicited serum IgG responses following immunisation and prior to infestation, whereas controls did not produce antigen-specific IgG during the pre-infestation period. Vaccinated animals showed an amnestic response, with levels of antigen-specific IgG against muGST, Pso o 1 and Pso o 2 increasing following infestation. This vaccine represents the greatest reduction in lesion size to date with a sheep scab vaccine, providing encouragement for future production of a commercially-viable means of immunoprophylaxis.
Collapse
Affiliation(s)
- Stewart T G Burgess
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, Midlothian, Scotland, EH26 0PZ, UK.
| | - Francesca Nunn
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, Midlothian, Scotland, EH26 0PZ, UK.
| | - Mintu Nath
- Biomathematics & Statistics Scotland, JCMB, King's Buildings, Peter Guthrie Tait Road, Edinburgh, Scotland, EH9 3FD, UK.
| | - David Frew
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, Midlothian, Scotland, EH26 0PZ, UK.
| | - Beth Wells
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, Midlothian, Scotland, EH26 0PZ, UK.
| | - Edward J Marr
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, Midlothian, Scotland, EH26 0PZ, UK.
| | - John F Huntley
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, Midlothian, Scotland, EH26 0PZ, UK.
| | - Tom N McNeilly
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, Midlothian, Scotland, EH26 0PZ, UK.
| | - Alasdair J Nisbet
- Moredun Research Institute, Pentlands Science Park, Bush Loan, Edinburgh, Midlothian, Scotland, EH26 0PZ, UK.
| |
Collapse
|
64
|
Mohandas N, Young ND, Jabbar A, Korhonen PK, Koehler AV, Hall RS, Hu M, Hofmann A, Gasser RB. The complement of family M1 aminopeptidases of Haemonchus contortus--Biotechnological implications. Biotechnol Adv 2015; 34:65-76. [PMID: 26597954 DOI: 10.1016/j.biotechadv.2015.10.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2015] [Revised: 10/04/2015] [Accepted: 10/10/2015] [Indexed: 01/03/2023]
Abstract
Although substantial research has been focused on the 'hidden antigen' H11 of Haemonchus contortus as a vaccine against haemonchosis in small ruminants, little is know about this and related aminopeptidases. In the present article, we reviewed genomic and transcriptomic data sets to define, for the first time, the complement of aminopeptidases (designated Hc-AP-1 to Hc-AP-13) of the family M1 with homologues in Caenorhabditis elegans, characterised by zinc-binding (HEXXH) and exo-peptidase (GAMEN) motifs. The three previously published H11 isoforms (accession nos. X94187, FJ481146 and AJ249941) had most sequence similarity to Hc-AP-2 and Hc-AP-8, whereas unpublished isoforms (accession nos. AJ249942 and AJ311316) were both most similar to Hc-AP-3. The aminopeptidases characterised here had homologues in C. elegans. Hc-AP-1 to Hc-AP-8 were most similar in amino acid sequence (28-41%) to C. elegans T07F10.1; Hc-AP-9 and Hc-AP-10 to C. elegans PAM-1 (isoform b) (53-54% similar); Hc-AP-11 and Hc-AP-12 to C. elegans AC3.5 and Y67D8C.9 (26% and 50% similar, respectively); and Hc-AP-13 to C. elegans C42C1.11 and ZC416.6 (50-58% similar). Comparative analysis suggested that Hc-AP-1 to Hc-AP-8 play roles in digestion, metabolite excretion, neuropeptide processing and/or osmotic regulation, with Hc-AP-4 and Hc-AP-7 having male-specific functional roles. The analysis also indicated that Hc-AP-9 and Hc-AP-10 might be involved in the degradation of cyclin (B3) and required to complete meiosis. Hc-AP-11 represents a leucyl/cystinyl aminopeptidase, predicted to have metallopeptidase and zinc ion binding activity, whereas Hc-AP-12 likely encodes an aminopeptidase Q homologue also with these activities and a possible role in gonad function. Finally, Hc-AP-13 is predicted to encode an aminopeptidase AP-1 homologue of C. elegans with hydrolase activity, suggested to operate, possibly synergistically with a PEPT-1 ortholog, as an oligopeptide transporter in the gut for protein uptake and normal development and/or reproduction of the worm. An appraisal of structure-based amino acid sequence alignments revealed that all conceptually translated Hc-AP proteins, with the exception of Hc-AP-12, adopt a topology similar to those observed for the two subgroups of mammalian M1 aminopeptidases, which possess either three (I, II and IV) or four (I-IV) domains. In contrast, Hc-AP-12 lacks the N-terminal domain (I), but possesses a substantially expanded domain III. Although further work needs to be done to assess amino acid sequence conservation of the different aminopeptidases among individual worms within and among H. contortus populations, we hope that these insights will support future localisation, structural and functional studies of these molecules in H. contortus as well as facilitate future assessments of a recombinant subunit or cocktail vaccine against haemonchosis.
Collapse
Affiliation(s)
- Namitha Mohandas
- The University of Melbourne, Faculty of Veterinary and Agricultural Sciences, Parkville, Victoria 3010, Australia
| | - Neil D Young
- The University of Melbourne, Faculty of Veterinary and Agricultural Sciences, Parkville, Victoria 3010, Australia
| | - Abdul Jabbar
- The University of Melbourne, Faculty of Veterinary and Agricultural Sciences, Parkville, Victoria 3010, Australia
| | - Pasi K Korhonen
- The University of Melbourne, Faculty of Veterinary and Agricultural Sciences, Parkville, Victoria 3010, Australia
| | - Anson V Koehler
- The University of Melbourne, Faculty of Veterinary and Agricultural Sciences, Parkville, Victoria 3010, Australia
| | - Ross S Hall
- The University of Melbourne, Faculty of Veterinary and Agricultural Sciences, Parkville, Victoria 3010, Australia
| | - Min Hu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, Hubei, China
| | - Andreas Hofmann
- The University of Melbourne, Faculty of Veterinary and Agricultural Sciences, Parkville, Victoria 3010, Australia; Structural Chemistry Program, Eskitis Institute for Drug Discovery, Griffith University, Brisbane, Queensland 4111, Australia.
| | - Robin B Gasser
- The University of Melbourne, Faculty of Veterinary and Agricultural Sciences, Parkville, Victoria 3010, Australia; State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan 430070, Hubei, China.
| |
Collapse
|
65
|
Abstract
Gastrointestinal nematodes represent important sources of economic losses in farmed ruminants, and the increasing frequency of anthelmintic resistance requires an increased ability to explore alternative strategies. Theoretical approaches at the crossroads of immunology and epidemiology are valuable tools in that context. In the case of Teladorsagia circumcincta in sheep, the immunological mechanisms important for resistance are increasingly well-characterized. However, despite the existence of a wide range of theoretical models, there is no framework integrating the characteristic features of this immune response into a tractable phenomenological model. Here, we propose to bridge that gap by developing a flexible modelling framework that allows for variability in nematode larval intake which can be used to track the variations in worm burdens. We parameterize this model using data from trickle infection of sheep and show that using simple immunological assumptions, our model can capture the dynamics of both adult worm burdens and nematode fecal egg counts. In addition, our analysis reveals interesting dose-dependent effects on the immune response. Finally, we discuss potential developments of this model and highlight how an improved cross-talk between empiricists and theoreticians would facilitate important advances in the study of infectious diseases.
Collapse
|
66
|
Sharma N, Singh V, Shyma KP. Role of parasitic vaccines in integrated control of parasitic diseases in livestock. Vet World 2015; 8:590-8. [PMID: 27047140 PMCID: PMC4774718 DOI: 10.14202/vetworld.2015.590-598] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Revised: 03/26/2015] [Accepted: 03/31/2015] [Indexed: 11/18/2022] Open
Abstract
Parasitic infections adversely affect animal’s health and threaten profitable animal production, thus affecting the economy of our country. These infections also play a major role in the spread of zoonotic diseases. Parasitic infections cause severe morbidity and mortality in animals especially those affecting the gastrointestinal system and thus affect the economy of livestock owner by decreasing the ability of the farmer to produce economically useful animal products. Due to all these reasons proper control of parasitic infection is critically important for sustained animal production. The most common and regularly used method to control parasitic infection is chemotherapy, which is very effective but has several disadvantages like drug resistance and drug residues. Integrated approaches to control parasitic infections should be formulated including grazing management, biological control, genetic resistance of hosts, and parasitic vaccines. India ranks first in cattle and buffalo population, but the majority of livestock owners have fewer herds, so other measures like grazing management, biological control, genetic resistance of hosts are not much practical to use. The most sustainable and economical approach to control parasitic infection in our country is to vaccinate animals, although vaccines increase the initial cost, but the immunity offered by the vaccine are long lived. Thus, vaccination of animals for various clinical, chronic, subclinical parasitic infections will be a cheaper and effective alternative to control parasitic infection for long time and improve animal production.
Collapse
Affiliation(s)
- Neelu Sharma
- Department of Veterinary Parasitology, College of Veterinary Science and Animal Husbandry, Sardarkrushinagar Dantiwada Agricultural University, Sardarkrushinagar - 385 506, Gujarat, India
| | - Veer Singh
- Department of Veterinary Parasitology, College of Veterinary Science and Animal Husbandry, Sardarkrushinagar Dantiwada Agricultural University, Sardarkrushinagar - 385 506, Gujarat, India
| | - K P Shyma
- Department of Veterinary Parasitology, College of Veterinary Science and Animal Husbandry, Sardarkrushinagar Dantiwada Agricultural University, Sardarkrushinagar - 385 506, Gujarat, India
| |
Collapse
|
67
|
Abstract
Vaccines against gastrointestinal nematodes are one potential option for the control of parasitic gastroenteritis in ruminants. Excretory/secretory (E/S) and hidden antigens are being studied as candidates for vaccines against Haemonchus spp., which is a major parasite in cattle and small ruminants that are raised in warm climates. Protection has been observed after vaccination with some E/S proteases, particularly cysteine proteases and with some glycans that are abundant on the surfaces and in the secretory products of helminths. However, the most promising results are being obtained with glycoprotein antigens extracted from the microvillar surfaces of the Haemonchus contortus intestinal cells. These antigens are called 'hidden' because they are not exposed to the host's immune system during infection. Thus far, recombinant forms of these antigens have not been usefully protective. However, because only 5 μg of antigen is required per dose, production of a native antigen vaccine from adult parasites has been found to be practical and commercially viable. Trials indicate that a vaccine made from one particular isolate will cross-protect against geographically distant isolates.
Collapse
|
68
|
McNair CM. Ectoparasites of medical and veterinary importance: drug resistance and the need for alternative control methods. ACTA ACUST UNITED AC 2015; 67:351-63. [PMID: 25644683 DOI: 10.1111/jphp.12368] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2014] [Accepted: 11/02/2014] [Indexed: 11/28/2022]
Abstract
OBJECTIVES Despite multiple attempts at eradication, many ectoparasites of humans and domestic livestock remain a persistent problem in the modern world. For many years, a range of pesticide drugs including organophosphates, organochlorides and synthetic pyrethroids provided effective control of these parasites; but intensive use of these drugs has led to the evolution of resistance in many target species. This paper aims to review the effectiveness of current control methods and discuss potential alternatives for the long term sustainable control of ectoparasites. KEY FINDINGS Important medical ectoparasites such as scabies mites, head lice and bed bugs present a significant public health problem, and so adequate control methods are essential. Ectoparasites of domestic livestock and farmed fish (for example sheep scab mites, poultry mites and sea lice) are also of concern given the increasing strain on the world's food supply. These parasites have become resistant to several classes of pesticide, making control very difficult. Recently, an increasing amount of research has focussed on alternative control methods such as insect growth regulators, biological control using essential oils or fungi, as well as vaccine development against some ectoparasites of medical and veterinary importance. SUMMARY Drug resistance is prevalent in all of the ectoparasites discussed in this review. A wide variety of alternative control methods have been identified, however further research is necessary in order for these to be used to successfully control ectoparasitic diseases in the future.
Collapse
Affiliation(s)
- Carol M McNair
- Institute of Aquaculture, University of Stirling, Stirling, UK
| |
Collapse
|
69
|
Molina-Hernández V, Mulcahy G, Pérez J, Martínez-Moreno Á, Donnelly S, O'Neill SM, Dalton JP, Cwiklinski K. Fasciola hepatica vaccine: we may not be there yet but we're on the right road. Vet Parasitol 2015; 208:101-11. [PMID: 25657086 PMCID: PMC4366043 DOI: 10.1016/j.vetpar.2015.01.004] [Citation(s) in RCA: 121] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Major advances have been made in identifying potential vaccine molecules for the control of fasciolosis in livestock but we have yet to reach the level of efficacy required for commercialisation. The pathogenesis of fasciolosis is associated with liver damage that is inflicted by migrating and feeding immature flukes as well as host inflammatory immune responses to parasite-secreted molecules and tissue damage alarm signals. Immune suppression/modulation by the parasites prevents the development of protective immune responses as evidenced by the lack of immunity observed in naturally and experimentally infected animals. In our opinion, future efforts need to focus on understanding how parasites invade and penetrate the tissues of their hosts and how they potentiate and control the ensuing immune responses, particularly in the first days of infection. Emerging 'omics' data employed in an unbiased approach are helping us understand liver fluke biology and, in parallel with new immunological data, to identify molecules that are essential to parasite development and accessible to vaccine-induced immune responses.
Collapse
Affiliation(s)
| | - Grace Mulcahy
- Veterinary Science Centre, University College Dublin, Belfield, Dublin, Ireland
| | - Jose Pérez
- School of Veterinary Medicine, University of Cordoba, Córdoba, Spain
| | | | - Sheila Donnelly
- The i3 Institute & School of Medical and Molecular Biosciences, University of Technology, Sydney, Australia
| | | | - John P Dalton
- School of Biological Sciences, Queen's University Belfast, Belfast, UK
| | | |
Collapse
|
70
|
Abstract
Helminth parasites infect over one fourth of the human population and are highly prevalent in livestock worldwide. In model systems, parasites are strongly immunomodulatory, but the immune system can be driven to expel them by prior vaccination. However, no vaccines are currently available for human use. Recent advances in vaccination with recombinant helminth antigens have been successful against cestode infections of livestock and new vaccines are being tested against nematode parasites of animals. Numerous vaccine antigens are being defined for a wide range of helminth parasite species, but greater understanding is needed to define the mechanisms of vaccine-induced immunity, to lay a rational platform for new vaccines and their optimal design. With human trials underway for hookworm and schistosomiasis vaccines, a greater integration between veterinary and human studies will highlight the common molecular and mechanistic pathways, and accelerate progress towards reducing the global health burden of helminth infection.
Collapse
|
71
|
McNeilly TN, Nisbet AJ. Immune modulation by helminth parasites of ruminants: implications for vaccine development and host immune competence. ACTA ACUST UNITED AC 2014; 21:51. [PMID: 25292481 PMCID: PMC4189095 DOI: 10.1051/parasite/2014051] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Accepted: 09/21/2014] [Indexed: 12/20/2022]
Abstract
Parasitic helminths reside in immunologically-exposed extracellular locations within their hosts, yet they are capable of surviving for extended periods. To enable this survival, these parasites have developed complex and multifaceted mechanisms to subvert or suppress host immunity. This review summarises current knowledge of immune modulation by helminth parasites of ruminants and the parasite-derived molecules involved in driving this modulation. Such immunomodulatory molecules have considerable promise as vaccine targets, as neutralisation of their function is predicted to enhance anti-parasite immunity and, as such, current knowledge in this area is presented herein. Furthermore, we summarise current evidence that, as well as affecting parasite-specific immunity, immune modulation by these parasites may also affect the ability of ruminant hosts to control concurrent diseases or mount effective responses to vaccination.
Collapse
Affiliation(s)
- Tom N McNeilly
- Disease Control, Moredun Research Institute, Pentlands Science Park, EH26 OPZ, UK
| | - Alasdair J Nisbet
- Vaccines and Diagnostics, Moredun Research Institute, Pentlands Science Park, EH26 OPZ, UK
| |
Collapse
|
72
|
Ovine IgA-reactive proteins from Teladorsagia circumcincta infective larvae. Int J Parasitol 2014; 44:743-50. [DOI: 10.1016/j.ijpara.2014.05.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 05/14/2014] [Accepted: 05/15/2014] [Indexed: 01/27/2023]
|
73
|
Hayward AD, Garnier R, Watt KA, Pilkington JG, Grenfell BT, Matthews JB, Pemberton JM, Nussey DH, Graham AL. Heritable, Heterogeneous, and Costly Resistance of Sheep against Nematodes and Potential Feedbacks to Epidemiological Dynamics. Am Nat 2014; 184 Suppl 1:S58-76. [DOI: 10.1086/676929] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
74
|
Garnier R, Graham AL. Insights from parasite-specific serological tools in eco-immunology. Integr Comp Biol 2014; 54:363-76. [PMID: 24760794 PMCID: PMC7537858 DOI: 10.1093/icb/icu022] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Eco-immunology seeks evolutionary explanations for the tremendous variation in immune defense observed in nature. Assays to quantify immune phenotypes often are crucial to this endeavor. To this end, we suggest that more use could (and arguably should) be made of the veterinary and clinical serological toolbox. For example, measuring the magnitude and half-life of parasite-specific antibodies across a range of host taxa may provide new ways of testing theories in eco-immunology. Here, we suggest that antibody assays developed in veterinary and clinical immunology and epidemiology provide excellent tools--or at least excellent starting points for development of tools--for tests of such hypotheses. We review how such assays work and how they may be optimized for new questions and new systems in eco-immunology. We provide examples of the application of such tools to eco-immunological studies of seabirds and mammals, and suggest a decision-tree to aid development of assays. We expect that addition of such tools to the eco-immunological toolbox will promote progress in the field and help elucidate how immune systems function and why they vary in nature.
Collapse
Affiliation(s)
- Romain Garnier
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
| | - Andrea L Graham
- Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544, USA
| |
Collapse
|
75
|
Qu G, Fetterer R, Leng L, Du X, Zarlenga D, Shen Z, Han W, Bucala R, Tuo W. Ostertagia ostertagi macrophage migration inhibitory factor is present in all developmental stages and may cross-regulate host functions through interaction with the host receptor. Int J Parasitol 2014; 44:355-67. [PMID: 24583184 DOI: 10.1016/j.ijpara.2014.01.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Revised: 12/31/2013] [Accepted: 01/06/2014] [Indexed: 01/04/2023]
Abstract
Macrophage migration inhibitory factor (MIF) of Ostertagia ostertagi, an abomasal parasite of cattle, was characterised in the present study. Phylogenetic analysis identified at least three O. ostertagi MIFs (Oos-MIFs), each encoded by a distinct transcript: Oos-MIF-1.1, Oos-MIF-1.2 and Oos-MIF-2. Oos-MIF-2 is only distantly related to Oos-MIF-1s, but has higher sequence similarity with the Caenorhabditis elegans MIF2. Oos-MIF-1.1 and Oos-MIF-1.2 are similar (93%) and thus collectively referred to as Oos-MIF-1 when characterised with immunoassays. Recombinant Oos-MIF-1.1 (rOos-MIF-1.1) is catalytically active as a tautomerase. A mutation (rOos-MIF-1.1P1G) or duplication of Pro1 residue (rOos-MIF-1.1P1+P) resulted in reduced oligomerisation and loss of tautomerase activity. The tautomerase activity of rOos-MIF-1.1 was only partially inhibited by ISO-1 but was abrogated by a rOos-MIF-1.1-specific antibody. Oos-MIF-1 was detected in all developmental stages of O. ostertagi, with higher levels in the adult stage; it was also detected in adult worm excretory/secretory product. Oos-MIF-1 was localised to the hypodermis/muscle, reproductive tract and intestine, but not to the cuticle. rOos-MIF-1.1, but not rOos-MIF-1.1P1G, was able to specifically bind to human CD74, a MIF cell surface receptor, with an affinity comparable with human MIF. Immunostaining indicated that macrophages were able to internalise rOos-MIF-1.1, further supporting receptor-mediated transportation. Herein we also show that rOos-MIF-1.1 inhibited migration of bovine macrophages and restored glucocorticoid-suppressed, lipopolysaccharide-induced TNF-α and IL-8 in human and/or bovine macrophages. Given its dual role in self-regulation and molecular mimicry, this secreted parasite protein warrants investigation as a vaccine candidate against O. ostertagi infections in cattle.
Collapse
Affiliation(s)
- Guanggang Qu
- Animal Parasitic Diseases Laboratory, Agricultural Research Service, USDA, Beltsville, MD 20705, USA; Shangdong Binzhou Academy of Animal Science and Veterinary Medicine, Binzhou City, Shandong 256600, China
| | - Raymond Fetterer
- Animal Parasitic Diseases Laboratory, Agricultural Research Service, USDA, Beltsville, MD 20705, USA
| | - Lin Leng
- Department of Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Xin Du
- Department of Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Dante Zarlenga
- Animal Parasitic Diseases Laboratory, Agricultural Research Service, USDA, Beltsville, MD 20705, USA
| | - Zhiqiang Shen
- Shangdong Binzhou Academy of Animal Science and Veterinary Medicine, Binzhou City, Shandong 256600, China
| | - Wenyu Han
- College of Veterinary Medicine and Animal Science, Jilin University, Changchun, China
| | - Richard Bucala
- Department of Medicine, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Wenbin Tuo
- Animal Parasitic Diseases Laboratory, Agricultural Research Service, USDA, Beltsville, MD 20705, USA.
| |
Collapse
|
76
|
Marker genes for activation of the RNA interference (RNAi) pathway in the free-living nematode Caenorhabditis elegans and RNAi development in the ovine nematode Teladorsagia circumcincta. J Helminthol 2013; 89:208-16. [PMID: 24345514 DOI: 10.1017/s0022149x13000801] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The nematode Teladorsagia circumcincta is a major cause of parasitic gastroenteritis in sheep in temperate regions. The development of resistance to the major anthelmintic classes used for its control is a threat to small ruminant farming sustainability. Vaccination is a potential alternative control method for this nematode. Gene datasets can be exploited to identify potential vaccine candidates and these validated further by methods such as RNA interference (RNAi) prior to vaccine trials. Previous reports indicate that RNAi in parasitic nematodes is inconsistent and, to date, there are no internal controls that indicate activation of the RNAi pathway in response to double-stranded RNA (dsRNA). The present aims were to determine whether or not the transcription levels of potential marker genes in the RNAi pathway could indicate activation of the pathway in Caenorhabditis elegans and to develop an RNAi platform in T. circumcincta. In C. elegans, transcript levels of three candidate marker genes, Ce-dcr-1 (Dicer), Ce-ego-1 (Enhancer of Glp-One family member) and Ce-rsd-3 (RNAi Spreading Defective), were analysed and results indicated that activation of the pathway had no effect on transcript levels of these genes. In T. circumcincta, two vaccine candidate genes from the Activation-associated Secreted Protein (ASP) family were targets for knockdown. RNAi experiments showed successful silencing of both targets, although inconsistencies in efficacy were observed. After testing a number of parameters that might affect variability, it was found that the length of the storage period of the larvae plays an important role in the consistency of the RNAi results.
Collapse
|
77
|
Roberts B, Antonopoulos A, Haslam SM, Dicker AJ, McNeilly TN, Johnston SL, Dell A, Knox DP, Britton C. Novel expression of Haemonchus contortus vaccine candidate aminopeptidase H11 using the free-living nematode Caenorhabditis elegans. Vet Res 2013; 44:111. [PMID: 24289031 PMCID: PMC4176091 DOI: 10.1186/1297-9716-44-111] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 11/19/2013] [Indexed: 11/28/2022] Open
Abstract
With the problem of parasitic nematode drug resistance increasing, vaccine development offers an alternative sustainable control approach. For some parasitic nematodes, native extracts enriched for specific proteins are highly protective. However, recombinant forms of these proteins have failed to replicate this protection. This is thought to be due to differences in glycosylation and/or conformation between native and recombinant proteins. We have exploited the free-living nematode Caenorhabditis elegans to examine its suitability as an alternative system for recombinant expression of parasitic nematode vaccine candidates. We focussed on Haemonchus contortus aminopeptidase H11 glycoprotein, which is enriched in a gut membrane fraction capable of inducing significant protection against this important ovine gastrointestinal nematode. We show that H. contortus H11 expressed in C. elegans is enzymatically active and MALDI mass spectrometry identifies similar di- and tri-fucosylated structures to those on native H11, with fucose at the 3- and/or 6-positions of the proximal GlcNAc. Some glycan structural differences were observed, such as lack of LDNF. Serum antibody to native H11 binds to C. elegans recombinant H11 and most of the antibody to rH11 or native H11 is directed to glycan moieties. Despite these similarities, no reduction in worm burden or faecal egg count was observed following immunisation of sheep with C. elegans-expressed recombinant H11 protein. The findings suggest that the di- and tri-fucosylated N-glycans expressed on rH11 do not contribute to the protective effect of H11 and that additional components present in native H11-enriched extract are likely required for enhancing the antibody response necessary for protection.
Collapse
Affiliation(s)
- Brett Roberts
- Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Bearsden Road, Glasgow G61 1QH, UK.
| | | | | | | | | | | | | | | | | |
Collapse
|