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Rajeev S, Li S, Leon-Coria A, Wang A, Kraemer L, Wang SJ, Boim A, Flannigan K, Shute A, Baggio CH, Callejas BE, MacNaughton WK, Finney CAM, McKay DM. Enteric tuft cells coordinate timely expulsion of the tapeworm Hymenolepis diminuta from the murine host by coordinating local but not systemic immunity. PLoS Pathog 2024; 20:e1012381. [PMID: 39083533 PMCID: PMC11290655 DOI: 10.1371/journal.ppat.1012381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Accepted: 06/28/2024] [Indexed: 08/02/2024] Open
Abstract
Recognizing that enteric tuft cells can signal the presence of nematode parasites, we investigated whether tuft cells are required for the expulsion of the cestode, Hymenolepis diminuta, from the non-permissive mouse host, and in concomitant anti-helminthic responses. BALB/c and C57BL/6 mice infected with H. diminuta expelled the worms by 11 days post-infection (dpi) and displayed DCLK1+ (doublecortin-like kinase 1) tuft cell hyperplasia in the small intestine (not the colon) at 11 dpi. This tuft cell hyperplasia was dependent on IL-4Rα signalling and adaptive immunity, but not the microbiota. Expulsion of H. diminuta was slowed until at least 14 dpi, but not negated, in tuft cell-deficient Pou2f3-/- mice and was accompanied by delayed goblet cell hyperplasia and slowed small bowel transit. Worm antigen and mitogen evoked production of IL-4 and IL-10 by splenocytes from wild-type and Pou2f3-/- mice was not appreciably different, suggesting similar systemic immune reactivity to infection with H. diminuta. Wild-type and Pou2f3-/- mice infected with H. diminuta displayed partial protection against subsequent infection with the nematode Heligmosomoides bakeri. We speculate that, with respect to H. diminuta, enteric tuft cells are important for local immune events driving the rapidity of H. diminuta expulsion but are not critical in initiating or sustaining systemic Th2 responses that provide concomitant immunity against secondary infection with H. bakeri.
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Affiliation(s)
- Sruthi Rajeev
- Gastrointestinal Research Group and Inflammation Research Network, Department of Physiology and Pharmacology, Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Host-Parasite Interactions Program, University of Calgary, Calgary, Alberta, Canada
| | - ShuHua Li
- Gastrointestinal Research Group and Inflammation Research Network, Department of Physiology and Pharmacology, Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Host-Parasite Interactions Program, University of Calgary, Calgary, Alberta, Canada
| | - Aralia Leon-Coria
- Host-Parasite Interactions Program, University of Calgary, Calgary, Alberta, Canada
- Department of Biology, Faculty of Science, University of Calgary, Calgary, Alberta, Canada
| | - Arthur Wang
- Gastrointestinal Research Group and Inflammation Research Network, Department of Physiology and Pharmacology, Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Host-Parasite Interactions Program, University of Calgary, Calgary, Alberta, Canada
| | - Lucas Kraemer
- Gastrointestinal Research Group and Inflammation Research Network, Department of Physiology and Pharmacology, Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Host-Parasite Interactions Program, University of Calgary, Calgary, Alberta, Canada
| | - Susan Joanne Wang
- Gastrointestinal Research Group and Inflammation Research Network, Department of Physiology and Pharmacology, Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Host-Parasite Interactions Program, University of Calgary, Calgary, Alberta, Canada
| | - Annaliese Boim
- Gastrointestinal Research Group and Inflammation Research Network, Department of Physiology and Pharmacology, Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Host-Parasite Interactions Program, University of Calgary, Calgary, Alberta, Canada
| | - Kyle Flannigan
- Gastrointestinal Research Group and Inflammation Research Network, Department of Physiology and Pharmacology, Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Adam Shute
- Gastrointestinal Research Group and Inflammation Research Network, Department of Physiology and Pharmacology, Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Host-Parasite Interactions Program, University of Calgary, Calgary, Alberta, Canada
| | - Cristiane H. Baggio
- Gastrointestinal Research Group and Inflammation Research Network, Department of Physiology and Pharmacology, Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Blanca E. Callejas
- Gastrointestinal Research Group and Inflammation Research Network, Department of Physiology and Pharmacology, Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Wallace K. MacNaughton
- Gastrointestinal Research Group and Inflammation Research Network, Department of Physiology and Pharmacology, Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Constance A. M. Finney
- Host-Parasite Interactions Program, University of Calgary, Calgary, Alberta, Canada
- Department of Biology, Faculty of Science, University of Calgary, Calgary, Alberta, Canada
| | - Derek M. McKay
- Gastrointestinal Research Group and Inflammation Research Network, Department of Physiology and Pharmacology, Calvin, Phoebe and Joan Snyder Institute for Chronic Diseases, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Host-Parasite Interactions Program, University of Calgary, Calgary, Alberta, Canada
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2
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Lekki-Jóźwiak J, Bąska P. The Roles of Various Immune Cell Populations in Immune Response against Helminths. Int J Mol Sci 2023; 25:420. [PMID: 38203591 PMCID: PMC10778651 DOI: 10.3390/ijms25010420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 12/15/2023] [Accepted: 12/22/2023] [Indexed: 01/12/2024] Open
Abstract
Helminths are multicellular parasites that are a substantial problem for both human and veterinary medicine. According to estimates, 1.5 billion people suffer from their infection, resulting in decreased life quality and burdens for healthcare systems. On the other hand, these infections may alleviate autoimmune diseases and allergy symptoms. The immune system is programmed to combat infections; nevertheless, its effector mechanisms may result in immunopathologies and exacerbate clinical symptoms. This review summarizes the role of the immune response against worms, with an emphasis on the Th2 response, which is a hallmark of helminth infections. We characterize non-immune cells (enteric tuft cells-ETCs) responsible for detecting parasites, as well as the role of hematopoietic-derived cells (macrophages, basophils, eosinophils, neutrophils, innate lymphoid cells group 2-ILC2s, mast cells, T cells, and B cells) in initiating and sustaining the immune response, as well as the functions they play in granulomas. The aim of this paper is to review the existing knowledge regarding the immune response against helminths, to attempt to decipher the interactions between cells engaged in the response, and to indicate the gaps in the current knowledge.
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Affiliation(s)
- Janina Lekki-Jóźwiak
- Division of Parasitology and Parasitic Diseases, Department of Preclinical Sciences, Institute of Veterinary Medicine, Warsaw University of Life Sciences, 02-786 Warsaw, Poland;
| | - Piotr Bąska
- Division of Pharmacology and Toxicology, Department of Preclinical Sciences, Institute of Veterinary Medicine, Warsaw University of Life Sciences, 02-786 Warsaw, Poland
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3
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Stevens L, Martínez-Ugalde I, King E, Wagah M, Absolon D, Bancroft R, Gonzalez de la Rosa P, Hall JL, Kieninger M, Kloch A, Pelan S, Robertson E, Pedersen AB, Abreu-Goodger C, Buck AH, Blaxter M. Ancient diversity in host-parasite interaction genes in a model parasitic nematode. Nat Commun 2023; 14:7776. [PMID: 38012132 PMCID: PMC10682056 DOI: 10.1038/s41467-023-43556-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 11/13/2023] [Indexed: 11/29/2023] Open
Abstract
Host-parasite interactions exert strong selection pressures on the genomes of both host and parasite. These interactions can lead to negative frequency-dependent selection, a form of balancing selection that is hypothesised to explain the high levels of polymorphism seen in many host immune and parasite antigen loci. Here, we sequence the genomes of several individuals of Heligmosomoides bakeri, a model parasite of house mice, and Heligmosomoides polygyrus, a closely related parasite of wood mice. Although H. bakeri is commonly referred to as H. polygyrus in the literature, their genomes show levels of divergence that are consistent with at least a million years of independent evolution. The genomes of both species contain hyper-divergent haplotypes that are enriched for proteins that interact with the host immune response. Many of these haplotypes originated prior to the divergence between H. bakeri and H. polygyrus, suggesting that they have been maintained by long-term balancing selection. Together, our results suggest that the selection pressures exerted by the host immune response have played a key role in shaping patterns of genetic diversity in the genomes of parasitic nematodes.
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Affiliation(s)
- Lewis Stevens
- Tree of Life, Wellcome Sanger Institute, Hinxton, UK.
| | - Isaac Martínez-Ugalde
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Erna King
- Tree of Life, Wellcome Sanger Institute, Hinxton, UK
| | - Martin Wagah
- Tree of Life, Wellcome Sanger Institute, Hinxton, UK
| | | | - Rowan Bancroft
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | | | - Jessica L Hall
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | | | | | - Sarah Pelan
- Tree of Life, Wellcome Sanger Institute, Hinxton, UK
| | - Elaine Robertson
- Institute of Immunology & Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Amy B Pedersen
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Cei Abreu-Goodger
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Amy H Buck
- Institute of Immunology & Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Mark Blaxter
- Tree of Life, Wellcome Sanger Institute, Hinxton, UK.
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Rich KD, Srivastava S, Muthye VR, Wasmuth JD. Identification of potential molecular mimicry in pathogen-host interactions. PeerJ 2023; 11:e16339. [PMID: 37953771 PMCID: PMC10637249 DOI: 10.7717/peerj.16339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 10/02/2023] [Indexed: 11/14/2023] Open
Abstract
Pathogens have evolved sophisticated strategies to manipulate host signaling pathways, including the phenomenon of molecular mimicry, where pathogen-derived biomolecules imitate host biomolecules. In this study, we resurrected, updated, and optimized a sequence-based bioinformatics pipeline to identify potential molecular mimicry candidates between humans and 32 pathogenic species whose proteomes' 3D structure predictions were available at the start of this study. We observed considerable variation in the number of mimicry candidates across pathogenic species, with pathogenic bacteria exhibiting fewer candidates compared to fungi and protozoans. Further analysis revealed that the candidate mimicry regions were enriched in solvent-accessible regions, highlighting their potential functional relevance. We identified a total of 1,878 mimicked regions in 1,439 human proteins, and clustering analysis indicated diverse target proteins across pathogen species. The human proteins containing mimicked regions revealed significant associations between these proteins and various biological processes, with an emphasis on host extracellular matrix organization and cytoskeletal processes. However, immune-related proteins were underrepresented as targets of mimicry. Our findings provide insights into the broad range of host-pathogen interactions mediated by molecular mimicry and highlight potential targets for further investigation. This comprehensive analysis contributes to our understanding of the complex mechanisms employed by pathogens to subvert host defenses and we provide a resource to assist researchers in the development of novel therapeutic strategies.
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Affiliation(s)
- Kaylee D. Rich
- Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
- Host-Parasite Interactions Research Training Network, University of Calgary, Calgary, Alberta, Canada
| | - Shruti Srivastava
- Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
- Host-Parasite Interactions Research Training Network, University of Calgary, Calgary, Alberta, Canada
| | - Viraj R. Muthye
- Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
- Host-Parasite Interactions Research Training Network, University of Calgary, Calgary, Alberta, Canada
| | - James D. Wasmuth
- Faculty of Veterinary Medicine, University of Calgary, Calgary, Alberta, Canada
- Host-Parasite Interactions Research Training Network, University of Calgary, Calgary, Alberta, Canada
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Poulin R. Model worms: knowledge gains and risks associated with the use of model species in parasitological research. Parasitology 2023; 150:967-978. [PMID: 37853764 PMCID: PMC10941210 DOI: 10.1017/s0031182023000963] [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: 09/13/2023] [Revised: 10/05/2023] [Accepted: 10/07/2023] [Indexed: 10/20/2023]
Abstract
Model parasite species, whose entire life cycle can be completed in the laboratory and maintained for multiple generations, have played a fundamental role in our understanding of host–parasite interactions. Yet, keeping parasites in laboratory conditions may expose them to unnatural evolutionary pressures, and using laboratory cultures for research is therefore not without limitations. Using 2 widely-used model helminth species, the cestode Hymenolepis diminuta and the nematode Heligmosomoides polygyrus, I illustrate the caution needed when interpreting experimental results on model species. I first review more than 1200 experimental studies published on these species in the past 4 decades, to determine which research areas they have contributed to. This is followed by an examination of the institutional laboratory cultures that have provided the parasites used in these studies. Some of these have persisted for decades and accounted for a substantial proportion of published studies, whereas others have been short-lived. Using information provided by the curators of active cultures, I summarize data on their origins and maintenance conditions. Finally, I discuss how laboratory cultures may have been subject to the influence of evolutionary genetic processes, such as founder effects, genetic drift and inbreeding. I also address the possibility that serial passage through laboratory hosts across multiple generations has exerted artificial selection on several parasite traits, resulting in genetic and phenotypic divergence among laboratory cultures, and between these cultures and natural parasite populations. I conclude with recommendations for the continued usage of laboratory helminth cultures aimed at maximizing their important contribution to parasitological research.
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Affiliation(s)
- Robert Poulin
- Department of Zoology, University of Otago, Dunedin 9054, New Zealand
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6
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Musah-Eroje M, Burton L, Kerr N, Behnke JM. Quantitative assessment of spicule length in Heligmosomoides spp. (Nematoda, Heligmosomidae): distinction between H. bakeri, H. polygyrus and H. glareoli. Parasitology 2023; 150:1022-1030. [PMID: 37705292 PMCID: PMC10941215 DOI: 10.1017/s0031182023000872] [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: 07/07/2023] [Revised: 09/06/2023] [Accepted: 09/06/2023] [Indexed: 09/15/2023]
Abstract
Nematode spicules play a vital role in the reproductive activity of species that possess them. Our primary objective was to compare the lengths of spicules of the laboratory mouse (Mus musculus) – maintained isolate H. bakeri – with those of H. polygyrus from naturally infected wood mice (Apodemus sylvaticus). On a more limited scale, we also included H. glareoli from bank voles (Myodes glareolus), a species reputed to possess longer spicules than either of the 2 former species. In total, we measured 1264 spicules (H. bakeri, n = 614; H. polygyrus n = 582; and H. glareoli, n = 68). There was a highly significant difference between the spicule lengths of the Nottingham-maintained H. bakeri (mean = 0.518 mm) and H. polygyrus (0.598 mm) from 11 different localities across the British Isles. A comparison of the spicules of H. bakeri maintained in 4 different laboratories in 3 continents revealed a range in the mean values from 0.518 to 0.540 mm, while those of worms from Australian wild house mice were shorter (0.480 mm). Mean values for H. polygyrus from wood mice from the British Isles ranged from 0.564 to 0.635 mm, although isolates of this species from Norway had longer spicules (0.670 mm). In agreement with the literature, the spicules of H. glareoli were considerably longer (1.098 mm). Since spicules play a vital role in the reproduction of nematode species that possess them, the difference in spicule lengths between H. bakeri and H. polygyrus adds to the growing evidence that these 2 are quite distinct species and likely reproductively isolated.
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Affiliation(s)
- Mayowa Musah-Eroje
- School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Laura Burton
- School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Nicola Kerr
- School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
| | - Jerzy M. Behnke
- School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
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7
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Pollo SMJ, Leon-Coria A, Liu H, Cruces-Gonzalez D, Finney CAM, Wasmuth JD. Transcriptional patterns of sexual dimorphism and in host developmental programs in the model parasitic nematode Heligmosomoides bakeri. Parasit Vectors 2023; 16:171. [PMID: 37246221 DOI: 10.1186/s13071-023-05785-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 04/24/2023] [Indexed: 05/30/2023] Open
Abstract
BACKGROUND Heligmosomoides bakeri (often mistaken for Heligmosomoides polygyrus) is a promising model for parasitic nematodes with the key advantage of being amenable to study and manipulation within a controlled laboratory environment. While draft genome sequences are available for this worm, which allow for comparative genomic analyses between nematodes, there is a notable lack of information on its gene expression. METHODS We generated biologically replicated RNA-seq datasets from samples taken throughout the parasitic life of H. bakeri. RNA from tissue-dwelling and lumen-dwelling worms, collected under a dissection microscope, was sequenced on an Illumina platform. RESULTS We find extensive transcriptional sexual dimorphism throughout the fourth larval and adult stages of this parasite and identify alternative splicing, glycosylation, and ubiquitination as particularly important processes for establishing and/or maintaining sex-specific gene expression in this species. We find sex-linked differences in transcription related to aging and oxidative and osmotic stress responses. We observe a starvation-like signature among transcripts whose expression is consistently upregulated in males, which may reflect a higher energy expenditure by male worms. We detect evidence of increased importance for anaerobic respiration among the adult worms, which coincides with the parasite's migration into the physiologically hypoxic environment of the intestinal lumen. Furthermore, we hypothesize that oxygen concentration may be an important driver of the worms encysting in the intestinal mucosa as larvae, which not only fully exposes the worms to their host's immune system but also shapes many of the interactions between the host and parasite. We find stage- and sex-specific variation in the expression of immunomodulatory genes and in anthelmintic targets. CONCLUSIONS We examine how different the male and female worms are at the molecular level and describe major developmental events that occur in the worm, which extend our understanding of the interactions between this parasite and its host. In addition to generating new hypotheses for follow-up experiments into the worm's behavior, physiology, and metabolism, our datasets enable future more in-depth comparisons between nematodes to better define the utility of H. bakeri as a model for parasitic nematodes in general.
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Affiliation(s)
- Stephen M J Pollo
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada
- Host-Parasite Interactions Research Training Network, University of Calgary, Calgary, AB, Canada
| | - Aralia Leon-Coria
- Host-Parasite Interactions Research Training Network, University of Calgary, Calgary, AB, Canada
- Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, AB, Canada
| | - Hongrui Liu
- Host-Parasite Interactions Research Training Network, University of Calgary, Calgary, AB, Canada
- Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, AB, Canada
| | - David Cruces-Gonzalez
- Host-Parasite Interactions Research Training Network, University of Calgary, Calgary, AB, Canada
- Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, AB, Canada
| | - Constance A M Finney
- Host-Parasite Interactions Research Training Network, University of Calgary, Calgary, AB, Canada
- Department of Biological Sciences, Faculty of Science, University of Calgary, Calgary, AB, Canada
| | - James D Wasmuth
- Faculty of Veterinary Medicine, University of Calgary, Calgary, AB, Canada.
- Host-Parasite Interactions Research Training Network, University of Calgary, Calgary, AB, Canada.
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Lehnert K, Boyi JO, Siebert U. Potential new species of pseudaliid lung nematode (Metastrongyloidea) from two stranded neonatal orcas ( Orcinus orca) characterized by ITS-2 and COI sequences. Ecol Evol 2023; 13:e10036. [PMID: 37139403 PMCID: PMC10150029 DOI: 10.1002/ece3.10036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 03/24/2023] [Accepted: 04/03/2023] [Indexed: 05/05/2023] Open
Abstract
Knowledge about parasite species of orcas, their prevalence, and impact on the health status is scarce. Only two records of lungworm infections in orca exist from male neonatal orcas stranded in Germany and Norway. The nematodes were identified as Halocercus sp. (Pseudaliidae), which have been described in the respiratory tract of multiple odontocete species, but morphological identification to species level remained impossible due to the fragile structure and ambiguous morphological features. Pseudaliid nematodes (Metastrongyloidea) are specific to the respiratory tract of toothed whales and are hypothesized to have become almost extinct in terrestrial mammals. Severe lungworm infections can cause secondary bacterial infections and bronchopneumonia and are a common cause of mortality in odontocetes. DNA isolations and subsequent sequencing of the rDNA ITS-2 and mtDNA COI revealed nucleotide differences between previously described Halocercus species from common dolphin (H. delphini) and harbor porpoises (H. invaginatus) that were comparatively analyzed, pointing toward a potentially new species of pseudaliid lungworm in orcas. New COI sequences of six additional metastrongyloid lungworms of seals and porpoises were derived to elucidate phylogenetic relationships and differences between nine species of Metastrongyloidea.
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Affiliation(s)
- Kristina Lehnert
- Institute for Terrestrial and Aquatic Wildlife ResearchUniversity of Veterinary Medicine Hannover, FoundationHannoverGermany
| | - Joy Ometere Boyi
- Institute for Terrestrial and Aquatic Wildlife ResearchUniversity of Veterinary Medicine Hannover, FoundationHannoverGermany
| | - Ursula Siebert
- Institute for Terrestrial and Aquatic Wildlife ResearchUniversity of Veterinary Medicine Hannover, FoundationHannoverGermany
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9
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The effect of conventional preservatives on spicule length of Heligmosomoides bakeri (Nematoda, Heligmosomidae). J Helminthol 2021; 95:e69. [PMID: 34802477 DOI: 10.1017/s0022149x21000596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Nematode spicules vary in shape and size even between closely related species and, therefore, constitute key characters in nematode taxonomy for distinguishing between species. Spicules are seldom measured on fresh specimens, but rather at some time after extraction from culled hosts and after a period of preservation of the worms in chemical fixatives or by freezing. We carried out two experiments to assess the effects of freezing in Hanks' balanced salt solution, 70% or 80% ethanol and 10% formalin (both of the latter at room temperature and after storage at -80°C) on spicule length of Heligmosomoides bakeri at two time intervals after extraction from mice (Experiment 1, one and four weeks; Experiment 2, one and four months). In Experiment 1, no significant differences were detected, although there was some variation between treatments and over time. In Experiment 2, spicule length varied significantly between treatments and over time, the greatest shrinkage being in 80% ethanol and the least in 10% formalin. However, overall variation in spicule length was very limited, accounting for no more than 5.03% change in length over time and 4.95% between treatments at any of the periods of assessment. Therefore, while whole nematodes can shrivel and shrink in preservatives, making many measurements unreliable, our data indicated that spicule lengths are very little changed by preservation techniques over time, and so spicule length remains as a reliable taxonomic character.
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10
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Abstract
The spicules of male parasitic nematodes are key morphological features, which vary between species in shape and length and are used often for species identification. However, little is known about spicules and particularly if/how their length varies during growth. We first assessed the degree of variation in spicule length of male Heligmosomoides bakeri 21 days post infection (PI), and then in two follow-up experiments measured spicule lengths at half daily/daily intervals between days 6 and 14 PI. Mean spicule length in 21-day worms was 0.518 mm with a range of 94 μm, and variation between the two spicules of individual worms from 2 to 32 μm. Spicules were first detectable on day 6-6.5, after which their lengths increased until day 7 PI (mean = 0.61 and 0.59). This was followed by significant contraction, initially relatively quickly over the following 48 h and then more slowly over a longer period, stabilizing by days 10-14, with only minor further reduction in length. We conclude that the length of spicules varies significantly over the first few days after they have formed, and, consequently, the age of worms is an important factor for consideration when spicule lengths are measured for experimental/diagnostic or taxonomical purposes.
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11
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Sweeny AR, Clerc M, Pontifes PA, Venkatesan S, Babayan SA, Pedersen AB. Supplemented nutrition decreases helminth burden and increases drug efficacy in a natural host-helminth system. Proc Biol Sci 2021; 288:20202722. [PMID: 33468010 PMCID: PMC7893286 DOI: 10.1098/rspb.2020.2722] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 12/15/2020] [Indexed: 12/17/2022] Open
Abstract
Gastrointestinal (GI) helminths are common parasites of humans, wildlife, and livestock, causing chronic infections. In humans and wildlife, poor nutrition or limited resources can compromise an individual's immune response, predisposing them to higher helminth burdens. This relationship has been tested in laboratory models by investigating infection outcomes following reductions of specific nutrients. However, much less is known about how diet supplementation can impact susceptibility to infection, acquisition of immunity, and drug efficacy in natural host-helminth systems. We experimentally supplemented the diet of wood mice (Apodemus sylvaticus) with high-quality nutrition and measured resistance to the common GI nematode Heligmosomoides polygyrus. To test whether diet can enhance immunity to reinfection, we also administered anthelmintic treatment in both natural and captive populations. Supplemented wood mice were more resistant to H. polygyrus infection, cleared worms more efficiently after treatment, avoided a post-treatment infection rebound, produced stronger general and parasite-specific antibody responses, and maintained better body condition. In addition, when applied in conjunction with anthelmintic treatment, supplemented nutrition significantly reduced H. polygyrus transmission potential. These results show the rapid and extensive benefits of a well-balanced diet and have important implications for both disease control and wildlife health under changing environmental conditions.
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Affiliation(s)
- Amy R. Sweeny
- Institute of Evolutionary Biology and Centre for Immunity, Infection and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Melanie Clerc
- MRC Centre for Inflammation Research, The Queen's Medical Research Institute, University of Edinburgh, Edinburgh EH16 4TJ, UK
| | - Paulina A. Pontifes
- Departamento de Etología, Fauna Silvestre y Animales de Laboratorio, Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Autónoma de México, Avenida Ciudad Universitaria 3000, CP 04510 Coyoacán, Ciudad de México, México
| | - Saudamini Venkatesan
- Institute of Evolutionary Biology and Centre for Immunity, Infection and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Simon A. Babayan
- Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow, Glasgow G12 8QQ, UK
| | - Amy B. Pedersen
- Institute of Evolutionary Biology and Centre for Immunity, Infection and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
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Hughes MR, Gibson AA, Wolfe ER, Bronson CD, Duffield DA. Phylogenetics and genetic variation of Heligmosomoides thomomyos in Western pocket gophers (Thomomys spp.). J Nematol 2021; 53:e2021-110. [PMID: 35156052 PMCID: PMC8762979 DOI: 10.21307/jofnem-2021-110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Indexed: 11/18/2022] Open
Abstract
The host specificities and systematics of North American Heligmosomoides species remain particularly uncertain. The primary aim of this study was to verify that a species described previously based only on morphology, H. thomomyos, from pocket gopher (Rodentia: Geomyidae) hosts in Oregon represented a monophyletic lineage. In order to address this aspect, as well as to further understand relationships and geographic patterns, we carried out phylogenetic, genetic diversity, and population dynamic analyses using partial 18S rRNA and COI mtDNA sequences of Heligmosomoides specimens. Phylogenetic analyses suggested that there are likely multiple Heligmosomoides species present in these hosts. This was supported by the high degree of divergence and differentiation found among populations, significant population structure between locations, and a modest positive association between geographic and genetic distances. This study serves as the first molecular characterization and first phylogenetic report of H. thomomyos, and documents two new host records for this parasite. The relationship of H. thomomyos among pocket gopher hosts and to other Heligmosomoides species, however, warrants continued study.
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Affiliation(s)
- Malorri R. Hughes
- Department of Biology, Portland State University, 1719 SW 10th Ave, Portland, Oregon 97201
- *E-mail:
| | - Alexandra A. Gibson
- One Health Institute, School of Veterinary Medicine, University of California Davis, 1 Shields Ave, Davis, CA 95616
| | - Emily R. Wolfe
- Department of Biology, Portland State University, 1719 SW 10th Ave, Portland, Oregon 97201
| | - Cecily D. Bronson
- Department of Biology, Portland State University, 1719 SW 10th Ave, Portland, Oregon 97201
| | - Deborah A. Duffield
- Department of Biology, Portland State University, 1719 SW 10th Ave, Portland, Oregon 97201
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Gomez SR, Morgans S, Kristan DM. Rapamycin exposure to host and to adult worms affects life history traits of Heligmosomoides bakeri. Exp Parasitol 2019; 204:107720. [PMID: 31279929 DOI: 10.1016/j.exppara.2019.107720] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 03/26/2019] [Accepted: 07/03/2019] [Indexed: 01/24/2023]
Abstract
Parasite life history can be affected by conditions of the host and of the external environment. Rapamycin, a known immunosuppressant of mammals, was fed to laboratory mice that were then infected with the Trichostrongylid nematode Heligmosomoides bakeri to determine if host rapamycin exposure would affect parasite survival, growth, and reproduction. In addition, adult worms from control fed mice were directly exposed to rapamycin to assess if rapamycin would affect worm viability and ex vivo reproduction. We found that host ingestion of rapamycin did not affect H. bakeri survival or growth for male or female worms, but female worms had increased reproduction both in vivo and when removed from the host and cultured ex vivo. After direct rapamycin exposure, motility of female worms was greater at low levels of rapamycin compared to high levels of rapamycin or high levels of DMSO (the vehicle used to solubilize rapamycin) in control media, but was similar to females in low levels of DMSO in control media. Male motility was not affected by the presence of rapamycin or DMSO in the media. Ex vivo egg deposition was higher when exposed to rapamycin than when cultured in control media that contained DMSO, regardless of DMSO dose. Overall, we conclude that host ingestion of rapamycin or direct exposure to rapamycin was generally favorable or neutral for parasite life history traits.
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Affiliation(s)
- Sarah R Gomez
- Department of Biological Sciences, 333 S. Twin Oaks Valley Rd, California State University San Marcos, San Marcos, CA, 92096, USA
| | - Scott Morgans
- Department of Biological Sciences, 333 S. Twin Oaks Valley Rd, California State University San Marcos, San Marcos, CA, 92096, USA
| | - Deborah M Kristan
- Department of Biological Sciences, 333 S. Twin Oaks Valley Rd, California State University San Marcos, San Marcos, CA, 92096, USA.
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Clerc M, Babayan SA, Fenton A, Pedersen AB. Age affects antibody levels and anthelmintic treatment efficacy in a wild rodent. INTERNATIONAL JOURNAL FOR PARASITOLOGY-PARASITES AND WILDLIFE 2019; 8:240-247. [PMID: 30923672 PMCID: PMC6423487 DOI: 10.1016/j.ijppaw.2019.03.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 02/25/2019] [Accepted: 03/09/2019] [Indexed: 12/22/2022]
Abstract
The role of the host immune system in determining parasite burdens and mediating within-host parasite interactions has traditionally been studied in highly controlled laboratory conditions. This does, however, not reflect the diversity of individuals living in nature, which is often characterised by significant variation in host demography, such as host age, sex, and infection history. Whilst studies using wild hosts and parasites are beginning to give insights into the complex relationships between immunity, parasites and host demography, the cause-and-effect relationships often remain unknown due to a lack of high resolution, longitudinal data. We investigated the infection dynamics of two interacting gastrointestinal parasites of wild wood mice (Apodemus sylvaticus), the nematode Heligmosomoides polygyrus and the coccidian Eimeria hungaryensis, in order to assess the links between infection, coinfection, and the immunological dynamics of two antibodies (IgG1 and IgA). In an anthelmintic treatment experiment, mice were given a single oral dose of an anthelmintic treatment, or control dose, and then subsequently followed longitudinally over a period of 7–15 days to measure parasite burdens and antibody levels. Anthelmintic treatment successfully reduced burdens of H. polygyrus, but had no significant impact on E. hungaryensis. Treatment efficacy was driven by host age, with adult mice showing stronger reductions in burdens compared to younger mice. We also found that the relationship between H. polygyrus-specific IgG1 and nematode burden changed from positive in young mice to negative in adult mice. Our results highlight that a key host demographic factor like age could account for large parts of the variation in nematode burden and nematode-specific antibody levels observed in a naturally infected host population, possibly due to different immune responses in young vs. old animals. Given the variable success in community-wide de-worming programmes in animals and humans, accounting for the age-structure of a population could increase overall efficacy. Anthelmintic treatment reveals strong force of infection for H. polygyrus in wild wood mice. Anthelmintic treatment is more successful in younger compared to older mice. Relationship between IgG1 and H. polygyrus burden reverts with host age.
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Affiliation(s)
- Melanie Clerc
- Institute of Evolutionary Biology and Centre for Immunity, Infection and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FL, UK.,MRC Centre for Inflammation Research, Queen´s Medical Research Institute, University of Edinburgh UK, EH16 4TJ, UK
| | - Simon A Babayan
- Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, G12 8QQ, UK
| | - Andy Fenton
- Institute of Integrative Biology, University of Liverpool, Liverpool, L69 7ZB, UK
| | - Amy B Pedersen
- Institute of Evolutionary Biology and Centre for Immunity, Infection and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, EH9 3FL, UK
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Babayan SA, Liu W, Hamilton G, Kilbride E, Rynkiewicz EC, Clerc M, Pedersen AB. The Immune and Non-Immune Pathways That Drive Chronic Gastrointestinal Helminth Burdens in the Wild. Front Immunol 2018; 9:56. [PMID: 29459856 PMCID: PMC5807686 DOI: 10.3389/fimmu.2018.00056] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2017] [Accepted: 01/09/2018] [Indexed: 01/09/2023] Open
Abstract
Parasitic helminths are extremely resilient in their ability to maintain chronic infection burdens despite (or maybe because of) their hosts’ immune response. Explaining how parasites maintain these lifelong infections, identifying the protective immune mechanisms that regulate helminth infection burdens, and designing prophylactics and therapeutics that combat helminth infection, while preserving host health requires a far better understanding of how the immune system functions in natural habitats than we have at present. It is, therefore, necessary to complement mechanistic laboratory-based studies with studies on wild populations and their natural parasite communities. Unfortunately, the relative paucity of immunological tools for non-model species has held these types of studies back. Thankfully, recent progress in high-throughput ‘omics platforms provide powerful and increasingly practical means for immunologists to move beyond traditional lab-based model organisms. Yet, assigning both metabolic and immune function to genes, transcripts, and proteins in novel species and assessing how they interact with other physiological and environmental factors requires identifying quantitative relationships between their expression and infection. Here, we used supervised machine learning to identify gene networks robustly associated with burdens of the gastrointestinal nematode Heligmosomoides polygyrus in its natural host, the wild wood mice Apodemus sylvaticus. Across 34 mice spanning two wild populations and across two different seasons, we found 17,639 transcripts that clustered in 131 weighted gene networks. These clusters robustly predicted H. polygyrus burden and included well-known effector and regulatory immune genes, but also revealed a number of genes associated with the maintenance of tissue homeostasis and hematopoiesis that have so far received little attention. We then tested the effect of experimentally reducing helminth burdens through drug treatment on those putatively protective immune factors. Despite the near elimination of H. polygyrus worms, the treatment had surprisingly little effect on gene expression. Taken together, these results suggest that hosts balance tissue homeostasis and protective immunity, resulting in relatively stable immune and, consequently, parasitological profiles. In the future, applying our approach to larger numbers of samples from additional populations will help further increase our ability to detect the immune pathways that determine chronic gastrointestinal helminth burdens in the wild.
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Affiliation(s)
- Simon A Babayan
- Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Wei Liu
- Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | | | - Elizabeth Kilbride
- Institute of Biodiversity, Animal Health & Comparative Medicine, University of Glasgow, Glasgow, United Kingdom
| | - Evelyn C Rynkiewicz
- Institute of Evolutionary Biology and Centre for Immunity, Infection and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Melanie Clerc
- Institute of Evolutionary Biology and Centre for Immunity, Infection and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
| | - Amy B Pedersen
- Institute of Evolutionary Biology and Centre for Immunity, Infection and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh, United Kingdom
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An appreciation of Professor John Lewis. J Helminthol 2017; 92:2-11. [PMID: 29283082 DOI: 10.1017/s0022149x17001043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Parasitic nematodes of the genus Syphacia Seurat, 1916 infecting Muridae in the British Isles, and the peculiar case of Syphacia frederici. Parasitology 2017; 145:269-280. [PMID: 28831960 DOI: 10.1017/s0031182017001470] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Syphacia stroma (von Linstow, 1884) Morgan, 1932 and Syphacia frederici Roman, 1945 are oxyurid nematodes that parasitize two murid rodents, Apodemus sylvaticus and Apodemus flavicollis, on the European mainland. Only S. stroma has been recorded previously in Apodemus spp. from the British Isles. Despite the paucity of earlier reports, we identified S. frederici in four disparate British sites, two in Nottinghamshire, one each in Berkshire and Anglesey, Wales. Identification was based on their site in the host (caecum and not small intestine), on key morphological criteria that differentiate this species from S. stroma (in particular the tail of female worms) and by sequencing two genetic loci (cytochrome C oxidase 1 gene and a section of ribosomal DNA). Sequences derived from both genetic loci of putative British S. frederici isolates formed a tight clade with sequences from continental worms known to be S. frederici, clearly distinguishing these isolates from S. stroma which formed a tight clade of its own, distinct from clades representative of Syphacia obvelata from Mus and S. muris from Rattus. The data in this paper therefore constitute the first record of S. frederici from British wood mice, and confirm the status of this species as distinct from both S. obvelata and S. stroma.
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Budischak SA, Sakamoto K, Megow LC, Cummings KR, Urban JF, Ezenwa VO. Resource limitation alters the consequences of co-infection for both hosts and parasites. Int J Parasitol 2015; 45:455-63. [DOI: 10.1016/j.ijpara.2015.02.005] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 02/03/2015] [Accepted: 02/08/2015] [Indexed: 12/21/2022]
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Luoga W, Mansur F, Lowe A, Duce IR, Buttle DJ, Behnke JM. Factors affecting the anthelmintic efficacy of papaya latex in vivo: host sex and intensity of infection. Parasitol Res 2015; 114:2535-41. [PMID: 25855350 DOI: 10.1007/s00436-015-4456-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 03/24/2015] [Indexed: 01/09/2023]
Abstract
The development of plant-derived cysteine proteinases, such as those in papaya latex, as novel anthelmintics requires that the variables affecting efficacy be fully evaluated. Here, we conducted two experiments, the first to test for any effect of host sex and the second to determine whether the intensity of the worm burden carried by mice would influence efficacy. In both experiments, we used the standard C3H mouse reference strain in which papaya latex supernatant (PLS) consistently shows >80 % reduction in Heligmosomoides bakeri worm burdens, but to broaden the perspective, we also included for comparison mice of other strains that are known to respond more poorly to treatment with papaya latex. Our results confirmed that there is a strong genetic influence affecting efficacy of PLS in removing adult worm burdens. However, there was no effect of host sex on efficacy (C3H and NIH) and no effect of infection intensity (C3H and BALB/c). These results offer optimism that plant-derived cysteine proteinases (CPs), such as these from papaya latex, can function as effective anthelmintics, with neither host sex nor infection intensity presenting further hurdles to impede their development for future medicinal and veterinary usage.
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Affiliation(s)
- Wenceslaus Luoga
- School of Life Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK
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20
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Host genetic influences on the anthelmintic efficacy of papaya-derived cysteine proteinases in mice. Parasitology 2015; 142:989-98. [PMID: 25736575 DOI: 10.1017/s003118201500013x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Eight strains of mice, of contrasting genotypes, infected with Heligmosomoides bakeri were studied to determine whether the anthelmintic efficacy of papaya latex varied between inbred mouse strains and therefore whether there is an underlying genetic influence on the effectiveness of removing the intestinal nematode. Infected mice were treated with 330 nmol of crude papaya latex or with 240 nmol of papaya latex supernatant (PLS). Wide variation of response between different mouse strains was detected. Treatment was most effective in C3H (90·5-99·3% reduction in worm counts) and least effective in CD1 and BALB/c strains (36·0 and 40·5%, respectively). Cimetidine treatment did not improve anthelmintic efficacy of PLS in a poor drug responder mouse strain. Trypsin activity, pH and PLS activity did not differ significantly along the length of the gastro-intestinal (GI) tract between poor (BALB/c) and high (C3H) drug responder mouse strains. Our data indicate that there is a genetic component explaining between-mouse variation in the efficacy of a standard dose of PLS in removing worms, and therefore warrant some caution in developing this therapy for wider scale use in the livestock industry, and even in human medicine.
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Athanasiadou S, Tolossa K, Debela E, Tolera A, Houdijk JGM. Tolerance and resistance to a nematode challenge are not always mutually exclusive. Int J Parasitol 2015; 45:277-82. [PMID: 25659496 DOI: 10.1016/j.ijpara.2014.12.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2014] [Revised: 12/10/2014] [Accepted: 12/23/2014] [Indexed: 11/15/2022]
Abstract
The relationship between the manifestations of tolerance (a host's ability to reduce the impact of a given level of pathogens) and resistance (a host's ability to clear pathogens) has been assumed to be an antagonistic one. Here we tested the hypothesis that mice from strains more resistant to intestinal nematodes will experience reduced tolerance compared with less resistant mice. Three inbred strains of mice were used: C57BL/6 mice have been characterised as susceptible, whereas BALB/c and NIH mice have been characterised as resistant to Heligmosomoides bakeri infection. Mice of each strain were either parasitised with a single dose of 250 L3H. bakeri (n=10) in water or were sham-infected with water (n=10). Body weight, food intake and worm egg output were recorded regularly throughout the experiment. Forty-two days p.i. mice were euthanised and organ weights, eggs in colon and worm counts were determined. C57BL/6 mice showed significantly greater worm egg output (P<0.001), eggs in colon (P<0.05) and female worm fecundity (P<0.05) compared with NIH and BALB/c mice. Parasitised BALB/c mice grew more whilst parasitised C57BL/6 mice grew less than their sham-infected counterparts during the first 2 weeks post-challenge (P=0.05). Parasitism significantly increased liver, spleen, small intestine and caecum weights (P<0.001) but reduced carcass weight (P<0.01). Average daily weight gain and worm numbers were positively correlated in NIH mice (P=0.05); however, the relationship was reversed when carcass weight was used as a measure for tolerance. BALB/c mice did not appear to suffer from the consequences of parasitism, with carcass weight similar in all animals. Our hypothesis that strains more resistant to the H. bakeri infection are less tolerant compared with less resistant strains is rejected, as the two resistant strains showed variable tolerance. Thus, tolerance and resistance to an intestinal nematode infection are not always mutually exclusive.
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Affiliation(s)
- Spiridoula Athanasiadou
- Disease Systems, Scotland's Rural College (SRUC), Easter Bush, Midlothian EH25 9RG, United Kingdom.
| | - Ketema Tolossa
- Disease Systems, Scotland's Rural College (SRUC), Easter Bush, Midlothian EH25 9RG, United Kingdom; Department of Chemistry, College of Natural and Computational Science, Hawassa University, P.O. Box 05, Hawassa, Ethiopia
| | - Etana Debela
- School of Veterinary Medicine, Hawassa University, P.O. Box 05, Hawassa, Ethiopia
| | - Adugna Tolera
- School of Animal and Range Science, College of Agriculture, Hawassa University, P.O. Box 222, Hawassa, Ethiopia
| | - Jos G M Houdijk
- Disease Systems, Scotland's Rural College (SRUC), Easter Bush, Midlothian EH25 9RG, United Kingdom
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Harris PD, Zaleśny G, Hildebrand J, Paziewska-Harris A, Behnke JM, Tkach V, Hwang YT, Kinsella JM. The Status of Heligmosomoides americanus, Representative of an American Clade of Vole-Infecting Nematodes. J Parasitol 2015; 101:382-5. [PMID: 25574753 DOI: 10.1645/13-455.1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Heligmosomoides americanus is shown by molecular phylogenetic analysis of 3 nuclear (28S, ITS1, and ITS2) and 2 mitochondrial (cytochrome oxidase 1 and cytochrome b) loci to be a distinct species of heligmosomid nematode with a long-independent evolutionary history, and not a subspecies of Heligmosomoides polygyrus . Rather than being a recent arrival in North America, the species probably originated as a Beringian immigrant with the host vole Phenacomys, approximately 2 million years ago (MYA).
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Affiliation(s)
| | - G Zaleśny
- Department of Invertebrate Systematics and Ecology, Institute of Biology, Wrocław University of Environmental and Life Sciences, ul. Kożuchowska 5b, 51-631 Wrocław, Poland
| | - J Hildebrand
- Department of Parasitology, Institute of Genetics and Microbiology, University of Wrocław, ul. Przybyszewskiego 63, 51-148 Wrocław, Poland
| | - A Paziewska-Harris
- KIT Biomedical Research, Royal Tropical Institute, Meibergdreef 39, 1105 AZ Amsterdam, The Netherlands
| | - J M Behnke
- School of Life Sciences, University of Nottingham, Nottingham NG2 7RD
| | - V Tkach
- Department of Biology, University of North Dakota, Grand Forks, North Dakota 58202-9019
| | - Y-T Hwang
- Department of Veterinary Pathology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5B4, Canada
| | - J M Kinsella
- HelmWest Laboratory, 2108 Hilda Avenue, Missoula, Montana 59801. Correspondence should be sent to:
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Evidence for genes controlling resistance to Heligmosomoides bakeri on mouse chromosome 1. Parasitology 2014; 142:566-75. [PMID: 25377239 DOI: 10.1017/s0031182014001644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Resistance to infections with Heligmosomoides bakeri is associated with a significant quantitative trait locus (QTL-Hbnr1) on mouse chromosome 1 (MMU1). We exploited recombinant mice, with a segment of MMU1 from susceptible C57Bl/10 mice introgressed onto MMU1 in intermediate responder NOD mice (strains 1094 and 6109). BALB/c (intermediate responder) and C57Bl/6 mice (poor responder) were included as control strains and strain 1098 (B10 alleles on MMU3) as NOD controls. BALB/c mice resisted infection rapidly and C57Bl/6 accumulated heavy worm burdens. Fecal egg counts dropped by weeks 10-11 in strain 1098, but strains 1094 and 6109 continued to produce eggs, harbouring more worms when autopsied (day 77). PubMed search identified 3 genes (Ctla4, Cd28, Icos) as associated with 'Heligmosomoides' in the B10 insert. Single nucleotide polymorphism (SNP) differences in Ctla4 could be responsible for regulatory changes in gene function, and a SNP within a splice site in Cd28 could have an impact on function, but no polymorphisms with predicted effects on function were found in Icos. Therefore, one or more genes encoded in the B10 insert into NOD mice contribute to the response phenotype, narrowing down the search for genes underlying the H. bakeri resistance QTL, and suggest Cd28 and Ctla4 as candidate genes.
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Zaleśny G, Hildebrand J, Paziewska-Harris A, Behnke JM, Harris PD. Heligmosomoides neopolygyrus Asakawa & Ohbayashi, 1986, a cryptic Asian nematode infecting the striped field mouse Apodemus agrarius in Central Europe. Parasit Vectors 2014; 7:457. [PMID: 25303901 PMCID: PMC4198666 DOI: 10.1186/s13071-014-0457-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 09/20/2014] [Indexed: 12/31/2022] Open
Abstract
Background Heligmosomoides polygyrus is a widespread gastro-intestinal nematode infecting wild Apodemus (wood mice) throughout Europe. Using molecular and morphological evidence, we review the status of Heligmosomoides from Apodemus agrarius in Poland previously considered to be an outlying clade of H. polygyrus, to further resolve the status of the laboratory model species, H. bakeri. Methods Morphological analysis of the male bursa and the synlophe, and molecular analyses of concatenated nuclear (28S rDNA, ITS1 and ITS2) and mitochondrial (CO1 and cytb) genes, of Heligmosomoides collected from Apodemus agrarius from two sites in Poland and comparison with related heligmosomids from voles and mice in Eurasia. Results Heligmosomoides neopolygyrus, a heligmosomid nematode from Apodemus species from China and Japan, is recognised for the first time in western Europe infecting Apodemus agrarius in Poland. It can be distinguished from H. polygyrus by the filiform externo-dorsal rays of the male copulatory bursa and the small, equally distributed longitudinal crêtes on the body. Specimens from A. agrarius are 20% different at ribosomal (ITS1 and ITS2) nuclear loci, and 10% different at the mitochondrial cytb locus from H. polygyrus, and in phylogenetic analyses group with the vole-infecting genus Heligmosomum. Conclusions Despite morphological similarity, H. neopolygyrus is only distantly related to H. polygyrus from western European Apodemus, and may be more closely related to vole-infecting taxa. It was brought into Europe by the recent rapid migration of the host mice. Inclusion of H. neopolygyrus in phylogenies makes it clear that Heligmosomoides is paraphyletic, with the pika-infecting Ohbayashinema and the vole-infecting Heligmosomum nesting within it. Clarification of the European status of H. neopolygyrus also allows H. bakeri, the laboratory model species, to be seen as a terminal sister clade to H. polygyrus, rather than as an internal clade of the latter taxon. Electronic supplementary material The online version of this article (doi:10.1186/s13071-014-0457-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Grzegorz Zaleśny
- Department of Invertebrate Systematics and Ecology, Institute of Biology, Wrocław University of Environmental and Life Sciences, ul. Kożuchowska 5b, 51-631, Wrocław, Poland.
| | - Joanna Hildebrand
- Department of Parasitology, Institute of Genetics and Microbiology, University of Wrocław, ul. Przybyszewskiego 63, 51-148, Wrocław, Poland.
| | - Anna Paziewska-Harris
- KIT Biomedical Research, Royal Tropical Institute, Meibergdreef 39, 1105 AZ, Amsterdam, the Netherlands.
| | - Jerzy M Behnke
- School of Life Sciences, University of Nottingham, NG2 7RD, Nottingham, UK.
| | - Philip D Harris
- Natural History Museum, University of Oslo, P.O. Box 1172, N-0562, Oslo, Norway.
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Clough D, Råberg L. Contrasting patterns of structural host specificity of two species of Heligmosomoides nematodes in sympatric rodents. Parasitol Res 2014; 113:4633-9. [PMID: 25273630 DOI: 10.1007/s00436-014-4154-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2014] [Accepted: 09/23/2014] [Indexed: 11/28/2022]
Abstract
Host specificity is a fundamental property of parasites. Whereas most studies focus on measures of specificity on host range, only few studies have considered quantitative aspects such as infection intensity or prevalence. The relative importance of these quantitative aspects is still unclear, mainly because of methodological constraints, yet central to a precise assessment of host specificity. Here, we assessed simultaneously two quantitative measures of host specificity of Heligmosomoides glareoli and Heligmosomoides polygyrus polygyrus infections in sympatric rodent hosts. We used standard morphological techniques as well as real-time quantitative PCR and sequencing of the rDNA ITS2 fragment to analyse parasite infection via faecal sample remains. Although both parasite species are thought to be strictly species-specific, we found morphologically and molecularly validated co- and cross-infections. We also detected contrasting patterns within and between host species with regard to specificity for prevalence and intensity of infection. H. glareoli intensities were twofold higher in bank voles than in yellow-necked mice, but prevalence did not differ significantly between species (33 vs. 18%). We found the opposite pattern in H. polygyrus infections with similar intensity levels between host species but significantly higher prevalence in mouse hosts (56 vs. 10%). Detection rates were higher with molecular tools than morphological methods. Our results emphasize the necessity to consider quantitative aspects of specificity for a full view of a parasites' capacity to replicate and transmit in hosts and present a worked example of how modern molecular tools help to advance our understanding of selective forces in host-parasite ecology and evolution.
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Affiliation(s)
- Dagmar Clough
- Molecular Ecology and Evolution Laboratory, Department of Biology, Lund University, Sölvegatan 37, SE-223 62, Lund, Sweden,
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Harris NL, Pleass R, Behnke JM. Understanding the role of antibodies in murine infections with Heligmosomoides (polygyrus) bakeri: 35 years ago, now and 35 years ahead. Parasite Immunol 2014; 36:115-24. [PMID: 23889357 DOI: 10.1111/pim.12057] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 07/24/2013] [Indexed: 12/14/2022]
Abstract
The rodent intestinal nematode H.p.bakeri has played an important role in the exploration of the host-parasite relationship of chronic nematode infections for over six decades, since the parasite was first isolated in the 1950s by Ehrenford. It soon became a popular laboratory model providing a tractable experimental system that is easy to maintain in the laboratory and far more cost-effective than other laboratory nematode-rodent model systems. Immunity to this parasite is complex, dependent on antibodies, but confounded by the parasite's potent immunosuppressive secretions that facilitate chronic survival in murine hosts. In this review, we remind readers of the state of knowledge in the 1970s, when the first volume of Parasite Immunology was published, focusing on the role of antibodies in protective immunity. We show how our understanding of the host-parasite relationship then developed over the following 35 years to date, we propose testable hypotheses for future researchers to tackle, and we speculate on how the new technologies will be applied to enable an increasingly refined understanding of the role of antibodies in host-protective immunity, and its evasion, to be achieved in the longer term.
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Affiliation(s)
- N L Harris
- Global Health Institute and Swiss Vaccine Research Institute, École Polytechnique Fédèrale de Lausanne (EPFL), Switzerland
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Protein deficiency alters impact of intestinal nematode infection on intestinal, visceral and lymphoid organ histopathology in lactating mice. Parasitology 2014; 141:801-13. [DOI: 10.1017/s0031182013002308] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
SUMMARYProtein deficiency impairs local and systemic immune responses toHeligmosomoides bakeriinfection but little is known about their individual and interactive impacts on tissue architecture of maternal lymphoid (thymus, spleen) and visceral (small intestine, kidney, liver, pancreas) organs during the demanding period of lactation. Using a 2×2 factorial design, pregnant CD1 mice were fed a 24% protein sufficient (PS) or a 6% protein deficient (PD) isoenergetic diet beginning on day 14 of pregnancy and were infected with 100H. bakerilarvae four times or exposed to four sham infections. On day 20 of lactation, maternal organs were examined histologically and serum analytes were assayed as indicators of organ function. The absence of villus atrophy in response to infection was associated with increased crypt depth and infiltration of mast cells and eosinophils but only in lactating dams fed adequate protein. Infection-induced lobular liver inflammation was reduced in PD dams, however, abnormalities in the kidney caused by protein deficiency were absent in infected dams. Bilirubin and creatinine were highest in PD infected mice. Infection-induced splenomegaly was not due to an increase in the lymphoid compartment of the spleen. During lactation, infection and protein deficiency have interactive effects on extra-intestinal pathologies.
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Order of Inoculation during Heligmosomoides bakeri and Hymenolepis microstoma Coinfection Alters Parasite Life History and Host Responses. Pathogens 2013; 2:130-52. [PMID: 25436885 PMCID: PMC4235709 DOI: 10.3390/pathogens2010130] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 02/02/2013] [Accepted: 02/21/2013] [Indexed: 11/24/2022] Open
Abstract
Parasite life history may differ during coinfection compared to single infections, and the order of infection may be an important predictor of life history traits. We subjected laboratory mice (Mus musculus) to single and coinfections with Heligmosomoides bakeri and Hymenolepis microstoma and measured life history traits of worms and also hepatobiliary and morphological responses by the host. We found that fewer H. bakeri larvae established, and adult worms were shorter and produced fewer eggs during a coinfection where H. microstoma occurred first. H. microstoma grew more and released more eggs after simultaneous inoculation of both parasites compared to a single H. microstoma infection, despite similar worm numbers. Mouse small intestine mass, but not length, varied with coinfection and bile duct mass was largest when H. microstoma was given alone or first. Mouse serum alkaline phosphatase levels were greatest for mice infected with H. microstoma only but did not vary with number of scolices; no change in mouse serum alanine transaminase levels was observed. Overall, the order of coinfection influenced life history traits of both H. bakeri and H. microstoma, but changes in survival, growth, and reproduction with order of inoculation were not consistent between the two parasites.
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Odiere MR, Scott ME, Leroux LP, Dzierszinski FS, Koski KG. Maternal protein deficiency during a gastrointestinal nematode infection alters developmental profile of lymphocyte populations and selected cytokines in neonatal mice. J Nutr 2013; 143:100-7. [PMID: 23190758 DOI: 10.3945/jn.112.160457] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Neonatal immune development begins in pregnancy and continues into lactation and may be affected by maternal diet. We investigated the possibility that maternal protein deficiency (PD) during a chronic gastrointestinal (GI) nematode infection could impair neonatal immune development. Beginning on d 14 of pregnancy, mice were fed protein-sufficient (PS; 24%) or protein-deficient (PD; 6%) isoenergetic diets and were infected weekly with either 0 (sham) or 100 Heligmosomoides bakeri larvae. Pups were killed on d 2, 7, 14, and d 21 and dams on d 20 of lactation. Lymphoid organs were weighed. Cytokine concentration in maternal and pup serum and in milk from pup stomachs and lymphoid cell populations in pup spleen and thymus were determined using luminex and flow cytometry, respectively. GI nematode infection increased Th2 cytokines (IL-4, IL-5, IL-13), IL-2, IL-10, and eotaxin in serum of dams whereas PD reduced IL-4 and IL-13. The lower IL-13 in PD dams was associated with increased fecal egg output and worm burdens. Maternal PD increased vascular endothelial growth factor in pup milk and eotaxin in pup serum. Maternal infection increased eotaxin in pup serum. Evidence of impaired neonatal immune development included reduced lymphoid organ mass in pups associated with both maternal infection and PD and increased percentage of T cells and T:B cell ratio in the spleen associated with maternal PD. Findings suggest that increases in specific proinflammatory cytokines as a result of the combination of infection and dietary PD in dams can impair splenic immune development in offspring.
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Affiliation(s)
- Maurice R Odiere
- Institute of Parasitology, McGill University (Macdonald Campus), Ste-Anne de Bellevue, Quebec, Canada
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30
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Massoni J, Durette-Desset MC, Quéré JP, Audebert F. Redescription of Heligmosomoides neopolygyrus, Asakawa and Ohbayashi, 1986 (Nematoda: Heligmosomidae) from a Chinese rodent, Apodemus peninsulae (Rodentia: Muridae); with comments on Heligmosomoides polygyrus polygyrus (Dujardin, 1845) and related species in China and Japan. Parasite 2012. [PMID: 23193521 PMCID: PMC3671467 DOI: 10.1051/parasite/2012194367] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Heligmosomoides neopolygyrus, Asakawa and Ohbayashi, 1986 (Nematoda, Heligmosomoidea) is redescribed from Apodemus peninsulae from Rangtang, Sichuan, China. A morphological review of the Heligmosomoides spp. belonging to the "polygyrus line" proposed by Asakawa (1988) is made using new characters. This enabled us to distinguish two subspecies in Mus musculus (Heligmosomoides polygyrus bakeri from Japan and H. p. polygyrus from China) and two valid species in Apodemus spp. (H. neopolygyrus from Japan (in A. peninsulae) and from China (in A. agrarius) and H. asakawae from China (in A. uralensis)). Three parasite species of A. agrarius and A. peninsulae, previously identified by Asakawa et al. (1993) as H. neopolygyrus, are considered to be Heligmosomoides incertae sedis. This is the first report of H. neopolygyrus in A. peninsulae from China.
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Affiliation(s)
- J Massoni
- Université Pierre et Marie Curie, Paris, UMR 7207 CNRS-MNHN-UPMC "Centre de recherche sur la Paléobiodiversité et les Paléoenvironnements - CR2P". MNHN, Paris Cedex, France
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Reynolds LA, Filbey KJ, Maizels RM. Immunity to the model intestinal helminth parasite Heligmosomoides polygyrus. Semin Immunopathol 2012; 34:829-46. [PMID: 23053394 PMCID: PMC3496515 DOI: 10.1007/s00281-012-0347-3] [Citation(s) in RCA: 150] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2012] [Accepted: 09/13/2012] [Indexed: 02/07/2023]
Abstract
Heligmosomoides polygyrus is a natural intestinal parasite of mice, which offers an excellent model of the immunology of gastrointestinal helminth infections of humans and livestock. It is able to establish long-term chronic infections in many strains of mice, exerting potent immunomodulatory effects that dampen both protective immunity and bystander reactions to allergens and autoantigens. Immunity to the parasite develops naturally in some mouse strains and can be induced in others through immunization; while the mechanisms of protective immunity are not yet fully defined, both antibodies and a host cellular component are required, with strongest evidence for a role of alternatively activated macrophages. We discuss the balance between resistance and susceptibility in this model system and highlight new themes in innate and adaptive immunity, immunomodulation, and regulation of responsiveness in helminth infection.
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Affiliation(s)
- Lisa A. Reynolds
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, EH9 3JT UK
| | - Kara J. Filbey
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, EH9 3JT UK
| | - Rick M. Maizels
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, EH9 3JT UK
- Institute of Immunology and Infection Research, University of Edinburgh, West Mains Road, Edinburgh, EH9 3JT UK
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Maizels RM, Hewitson JP, Murray J, Harcus YM, Dayer B, Filbey KJ, Grainger JR, McSorley HJ, Reynolds LA, Smith KA. Immune modulation and modulators in Heligmosomoides polygyrus infection. Exp Parasitol 2012; 132:76-89. [PMID: 21875581 PMCID: PMC6485391 DOI: 10.1016/j.exppara.2011.08.011] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2011] [Revised: 08/09/2011] [Accepted: 08/15/2011] [Indexed: 01/12/2023]
Abstract
The intestinal nematode parasite Heligmosomoides polygyrus bakeri exerts widespread immunomodulatory effects on both the innate and adaptive immune system of the host. Infected mice adopt an immunoregulated phenotype, with abated allergic and autoimmune reactions. At the cellular level, infection is accompanied by expanded regulatory T cell populations, skewed dendritic cell and macrophage phenotypes, B cell hyperstimulation and multiple localised changes within the intestinal environment. In most mouse strains, these act to block protective Th2 immunity. The molecular basis of parasite interactions with the host immune system centres upon secreted products termed HES (H. polygyrus excretory-secretory antigen), which include a TGF-β-like ligand that induces de novo regulatory T cells, factors that modify innate inflammatory responses, and molecules that block allergy in vivo. Proteomic and transcriptomic definition of parasite proteins, combined with biochemical identification of immunogenic molecules in resistant mice, will provide new candidate immunomodulators and vaccine antigens for future research.
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Affiliation(s)
- Rick M Maizels
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh EH9 3JT, UK.
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The anthelmintic efficacy of papaya latex in a rodent–nematode model is not dependent on fasting before treatment. J Helminthol 2011; 86:311-6. [DOI: 10.1017/s0022149x11000368] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
AbstractIn earlier studies of the anthelmintic activity of plant cysteine proteinases (CPs), a period of food deprivation was routinely employed before administration of CPs, but there has been no systematic evaluation as to whether this does actually benefit the anthelmintic efficacy. Therefore, we assessed the effect of fasting on the efficacy of CPs from papaya latex (PL) against Heligmosomoides bakeri in C3H mice. We used a refined, supernatant extract of papaya latex (PLS) with known active enzyme content. The animals were divided into three groups (fasted prior to treatment with PLS, not fasted but treated with PLS and fasted but given only water). The study demonstrated clearly that although food deprivation had been routinely employed in much of the earlier work on CPs in mice infected with nematodes, fasting has no beneficial effect on the efficacy of PLS against H. bakeri infections. Administration of CPs to fed animals will also reduce the stress associated with fasting.
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Wabo Poné J, Fossi Tankoua O, Yondo J, Komtangi MC, Mbida M, Bilong Bilong CF. The In Vitro Effects of Aqueous and Ethanolic Extracts of the Leaves of Ageratum conyzoides (Asteraceae) on Three Life Cycle Stages of the Parasitic Nematode Heligmosomoides bakeri (Nematoda: Heligmosomatidae). Vet Med Int 2011; 2011:140293. [PMID: 21772960 PMCID: PMC3134952 DOI: 10.4061/2011/140293] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2010] [Revised: 03/27/2011] [Accepted: 05/16/2011] [Indexed: 11/20/2022] Open
Abstract
A comparative in vitro study was carried out to determine the ovicidal and larvicidal activity of aqueous and ethanolic extracts of Ageratum conyzoides (Asteraceae) leaves on the eggs (unembryonated and embryonated), first and second larval stages of Heligmosomoides bakeri. Four different concentrations (0.625, 1.25, 2.5, and 3.75 mg·mL(-1)) of both aqueous and ethanolic extracts were tested. Distilled water and 5% tween were used as negative controls in the bioassay. In fact, they did not affect development of eggs, hatching, and larval survival. The extract activities were dose dependent. The ethanolic extract was more potent against embryonation (39.6 ± 2.9%) than the aqueous extract (53.3 ± 10.9%) at the highest concentration (3.75 mg·ml(-1)). Both types of extracts killed larvae. Mebendazole proved more lethal (EC(50) of 0.745 and 0.323 mg·mL(-1), resp., for L(1) and L(2) larvae). The aqueous extracts were the least lethal (EC(50) of 4.76 and 2.29 mg·mL(-1), resp., for L(1) and L(2) larvae). The ethanolic extracts showed intermediate activity (EC(50) of 1.323 and 1.511 mg·mL(-1), resp., for L(1) and L(2) larvae). It is concluded that the ovicidal and larvicidal properties of aqueous and ethanolic extracts of Ageratum conyzoides leaves are demonstrated in this work.
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Affiliation(s)
- J Wabo Poné
- Department of Animal Biology, Faculty of Science, University of Dschang, P.O. Box 067, Dschang, Cameroon
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Harris NL. Advances in helminth immunology: optimism for future vaccine design? Trends Parasitol 2011; 27:288-93. [PMID: 21531626 DOI: 10.1016/j.pt.2011.03.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Revised: 03/30/2011] [Accepted: 03/30/2011] [Indexed: 11/26/2022]
Abstract
Intestinal helminths infect approximately 2 billion people worldwide. Worm burdens correlate with disease morbidity and children generally harbor the largest numbers. The majority of intestinal helminths do not replicate within their host, and worm burdens increase through constant reinfection. Current strategies of worm control involve drug administration to school-aged children. Yet the rapid rate of reinfection and the appearance of drug resistant strains in livestock raise concerns over the sustainable nature of this strategy. A combined strategy of drug treatment for the expulsion of adult worms and vaccination designed to halt reinfection would offer the most effective means of control. Before successful vaccines can be developed our knowledge of the initiation and implementation of host immunity must be improved.
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Affiliation(s)
- Nicola L Harris
- Swiss Vaccine Research Institute and Global Health Institute, Ecole Polytechnique Fédérale, Lausanne, Switzerland.
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36
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Doligalska M, Jóźwicka K, Kiersnowska M, Mroczek A, Pączkowski C, Janiszowska W. Triterpenoid saponins affect the function of P-glycoprotein and reduce the survival of the free-living stages of Heligmosomoides bakeri. Vet Parasitol 2011; 179:144-51. [PMID: 21376470 DOI: 10.1016/j.vetpar.2011.01.053] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2010] [Revised: 01/23/2011] [Accepted: 01/27/2011] [Indexed: 11/25/2022]
Abstract
We studied the effect of triterpenoid saponins on the development of free-living stages of Heligmosomoides bakeri, a parasitic nematode of the mouse intestine. We evaluated the effectiveness of oleane-type glucuronides (GlcUAOA) isolated from Calendula officinalis and Beta vulgaris. The rhodamine 123 retention assay was used to detect dysfunctions of the major membrane transporter for xenobiotics, P-glycoprotein (Pgp). Both C. officinals and B. vulgaris GlcUAOA affect the development of the free living stages and function of Pgp in H. bakeri. The GlcUAOA inhibits egg hatching and moulting of larvae and also changes their morphology. These saponin fractions reversed the toxic effect of thiabendazole on the nematode; the function of Pgp was also inhibited.
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Affiliation(s)
- M Doligalska
- Institute of Zoology, University of Warsaw, Warsaw, Poland.
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37
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Maizels RM, Hewitson JP, Gause WC. Heligmosomoides polygyrus: one species still. Trends Parasitol 2010; 27:100-1. [PMID: 21159557 DOI: 10.1016/j.pt.2010.11.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Revised: 11/15/2010] [Accepted: 11/16/2010] [Indexed: 10/18/2022]
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Harris N, Gause WC. To B or not to B: B cells and the Th2-type immune response to helminths. Trends Immunol 2010; 32:80-8. [PMID: 21159556 DOI: 10.1016/j.it.2010.11.005] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Revised: 11/01/2010] [Accepted: 11/15/2010] [Indexed: 10/18/2022]
Abstract
Similar T helper (Th)2-type immune responses are generated against different helminth parasites, but the mechanisms that initiate Th2 immunity, and the specific immune components that mediate protection against these parasites, can vary greatly. B cells are increasingly recognized as important during the Th2-type immune response to helminths, and B cell activation might be a target for effective vaccine development. Antibody production is a function of B cells during helminth infection and understanding how polyclonal and antigen-specific antibodies contribute should provide important insights into how protective immunity develops. In addition, B cells might also contribute to the host response against helminths through antibody-independent functions including, antigen presentation, as well as regulatory and effector activity. In this review, we examine the role of B cells during Th2-type immune response to these multicellular parasites.
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Affiliation(s)
- Nicola Harris
- Swiss Vaccine Research Institute and Global Health Institute, Ecole Polytechnique Fédérale, Lausanne, Switzerland
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39
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Heligmosomoides bakeri: a new name for an old worm? Trends Parasitol 2010; 26:524-9. [DOI: 10.1016/j.pt.2010.07.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Revised: 06/30/2010] [Accepted: 07/01/2010] [Indexed: 11/21/2022]
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40
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Odiere MR, Scott ME, Weiler HA, Koski KG. Protein deficiency and nematode infection during pregnancy and lactation reduce maternal bone mineralization and neonatal linear growth in mice. J Nutr 2010; 140:1638-45. [PMID: 20660285 DOI: 10.3945/jn.110.125013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Using a 2 x 2 factorial design, we investigated the combined impact of protein deficiency (PD) and gastrointestinal nematode infection during late pregnancy and lactation on resting metabolic rate (RMR), body composition and bone mineralization, neonatal growth, and the regulatory hormones [corticosterone, leptin, and insulin-like growth factor-1 (IGF-1)] and proinflammatory cytokines [interleukin (IL)-1 beta and IL-6] that may drive these processes. Pregnant CD1 mice, fed either a protein-sufficient (PS; 24%) or protein-deficient (PD; 6%) isocaloric diet, were infected 4 times with either 0 (sham) or 100 Heligmosomoides bakeri larvae beginning on d 14 of pregnancy. Dams were killed on d 20 postpartum and pups on d 2, 7, 14, and 21. Diet and infection had largely independent effects. The PD diet elevated corticosterone and upregulated leptin concentration in maternal serum, which was associated with reduced food intake leading to lower body mass, RMR, and body temperature. Infection reduced food intake but elevated maternal serum IL-1 beta and IL-6 and did not affect corticosterone, leptin, RMR, or body temperature. The PD diet decreased maternal bone area and bone mineral content. Infection lowered maternal bone mineral density, consistent with elevated IL-1 beta and IL-6. The elevated serum IL-1 beta and lower IGF-1 in pups of PD dams and lower serum leptin and IGF-1 in pups of infected dams were both consistent with the lower pup body mass and shorter crown-rump length. This mouse model provides a novel framework to study the impact of diet and nematode infection on bone.
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Affiliation(s)
- Maurice R Odiere
- Institute of Parasitology, McGill University, Ste-Anne de Bellevue, QC, Canada
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41
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Concurrent nematode infection and pregnancy induce physiological responses that impair linear growth in the murine foetus. Parasitology 2009; 137:991-1002. [DOI: 10.1017/s0031182009991764] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
SUMMARYThis study examined concurrent stresses of nematode infection and pregnancy using pregnant and non-pregnant CD1 mice infected 3 times with 0, 50 or 100 Heligmosomoides bakeri larvae. Physiological, energetic, immunological and skeletal responses were measured in maternal and foetal compartments. Resting metabolic rate (RMR) was elevated by pregnancy, but not by the trickle infection. Energy demands during pregnancy were met through increased food intake and fat utilization whereas mice lowered their body temperature during infection. Both infection and pregnancy increased visceral organ mass and both altered regional bone area and mineralization. During pregnancy, lumbar mineralization was lower but femur area and mineralization were higher. On the other hand, infection lowered maternal femur bone area and this was associated with higher IFN-γ in maternal serum of heavily infected pregnant mice. Infection also reduced foetal crown-rump length which was associated with higher amniotic fluid IL-1β.
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Quantitative trait loci for resistance to Heligmosomoides bakeri and associated immunological and pathological traits in mice: comparison of loci on chromosomes 5, 8 and 11 in F2 and F6/7 inter-cross lines of mice. Parasitology 2009; 137:311-20. [PMID: 19925689 DOI: 10.1017/s0031182009991028] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
A comparison of F2 and F6/7 inter-cross lines of mice, derived from CBA and SWR parental strains, has provided strong evidence for several previously undetected quantitative trait loci (QTL) for resistance to Heligmosomoides bakeri. Five QTL affecting average faecal egg counts and/or worm burdens in week 6 were detected on mouse chromosomes 5 (Hbnr9 and Hbnr10), 8 (Hbnr11) and 11 (Hbnr13 and Hbnr14). Three QTL for faecal egg counts in weeks 4 and 6 were found on both chromosomes 5 (Hbnr9) and 11 (Hbnr13 and Hbnr14). Two QTL for the mucosal mast cell protease 1 (MCPT1) response were located on chromosomes 8 (Hbnr11) and 11 (Hbnr13), two for the IgG1 antibody response to adult worms on chromosomes 5 (Hbnr10) and 8 (Hbnr11), two for PCV in week 6 on chromosomes 5 (Hbnr9) and 11 (Hbnr13), and two for the granulomatous response on chromosome 8 (Hbnr12) and 11 (Hbnr15). Our data emphasize that the control of resistance to H. bakeri is multigenic, and regulated by genes within QTL regions that have a complex range of hierarchical relationships.
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Knott ML, Matthaei KI, Foster PS, Dent LA. The roles of eotaxin and the STAT6 signalling pathway in eosinophil recruitment and host resistance to the nematodes Nippostrongylus brasiliensis and Heligmosomoides bakeri. Mol Immunol 2009; 46:2714-22. [PMID: 19535141 DOI: 10.1016/j.molimm.2009.05.016] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2009] [Accepted: 05/14/2009] [Indexed: 01/21/2023]
Abstract
Expulsion of adult Nippostrongylus brasiliensis worms from the small intestine is profoundly impaired in signal transducer and activator of transcription (STAT)6-deficient mice. IL-5 transgenic (Tg) mice with constitutive eosinophilia show profound early resistance in the skin and/or later pre-lung phase of primary infections with N. brasiliensis. This study was designed to assess the importance of the eosinophil chemokine eotaxin and the STAT6/interleukin (IL)-4/IL-13 signalling pathway in early resistance to N. brasiliensis. Eosinophil recruitment into the skin following injection of N. brasiliensis larvae was reduced in STAT6- or eotaxin-deficient/IL-5 Tg double mutant mice. While ablation of eotaxin did not impair resistance in the pre-lung phase of N. brasiliensis infections in IL-5 Tg mice, elimination of STAT6 caused a modest reduction in resistance in both primary and secondary infections on this genetic background. STAT6(-/-)-, IL-13(-/-)- and IL-4Ralpha(-/-)-deficient single mutant and IL-13(-/-)/IL-4Ralpha(-/-) double mutant mice were more susceptible than WT mice during the pre-lung phase of secondary N. brasiliensis infections. In contrast, primary or secondary resistance were unaffected at either the pre-lung or gut stages of infection in eotaxin(-/-) single mutant mice. STAT6(-/-) and eotaxin(-/-) mice with or without the IL-5 transgene, were no more susceptible than WT or IL-5 Tg mice to protracted primary infections with Heligmosomoides bakeri, a parasitic nematode that is restricted to the gut. Our data suggest that parasitic nematodes that transit through the skin and lungs en route to the gut may be susceptible to early (pre-lung) innate and adaptive immune mechanisms that are dependent on the STAT6/IL-4/IL-13 signalling pathway, and this may be important for the development of effective therapies and vaccines.
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Genetic growth potential interacts with nutrition on the ability of mice to cope with Heligmosomoides bakeri infection. Parasitology 2009; 136:1043-55. [PMID: 19523257 DOI: 10.1017/s0031182009006428] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Artificial selection for improved productivity may reduce an animal's ability to cope with pathogens. Here, we used Roslin mice, uniquely divergently selected for high (ROH) and low (ROL) body weight, to assess interactive effects of differing growth potential and protein nutrition on host resilience and resistance. In a 2 x 2 x 6 factorial design, ROH and ROL mice were either sham-infected or infected with 250 L(3)Heligmosomoides bakeri and fed diets with 30, 80, 130, 180, 230 and 280 g crude protein per kg. The infected ROL-30 treatment resulted in clinical disease and was discontinued. In the remaining ROL mice, infection and feeding treatments did not affect growth but infection reduced weight gain in ROH-30, ROH-80 and ROH-130 mice. Although infection resulted in temporarily reduced food intake (anorexia) in both mouse lines, mean food intake over the whole experiment was reduced in ROH mice only. ROH mice excreted more worm eggs and had higher worm burdens, with relatively fewer female worms, than ROL mice. However, these resistance traits were not sensitive to dietary protein. These results support the view that selection for high growth may reduce the ability to cope with pathogens, and that improved protein nutrition may to some extent ameliorate this penalty.
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Heligmosomoides bakeri: a model for exploring the biology and genetics of resistance to chronic gastrointestinal nematode infections. Parasitology 2009; 136:1565-80. [PMID: 19450375 DOI: 10.1017/s0031182009006003] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The intestinal nematode Heligmosomoides bakeri has undergone 2 name changes during the last 4 decades. Originally, the name conferred on the organism in the early 20th century was Nematospiroides dubius, but this was dropped in favour of Heligmosomoides polygyrus, and then more recently H. bakeri, to distinguish it from a closely related parasite commonly found in wood mice in Europe. H. bakeri typically causes long-lasting infections in mice and in this respect it has been an invaluable laboratory model of chronic intestinal nematode infections. Resistance to H. bakeri is a dominant trait and is controlled by genes both within and outside the MHC. More recently, a significant QTL has been identified on chromosome 1, although the identity of the underlying genes is not yet known. Other QTL for resistance traits and for the accompanying immune responses were also defined, indicating that resistance to H. bakeri is a highly polygenic phenomenon. Hence marker-assisted breeding programmes aiming to improve resistance to GI nematodes in breeds of domestic livestock will need to be highly selective, focussing on genes that confer the greatest proportion of overall genetic resistance, whilst leaving livestock well-equipped genetically to cope with other types of pathogens and preserving important production traits.
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FVB/N mice are highly resistant to primary infection with Nippostrongylus brasiliensis. Parasitology 2009; 136:93-106. [PMID: 19126273 DOI: 10.1017/s0031182008005192] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Nippostrongylus brasiliensis larvae are particularly susceptible to immunological attack during the pre-lung stage of primary and secondary infections in mice. Whilst most of the common laboratory strains of mice are permissive hosts for the parasite, in this study we report for the first time, the strong resistance of naive FVB/N mice to N. brasiliensis. Damage to larvae is evident within the first 24 h of infection and this may be critical to later larval development and reproductive success. Inflammatory responses in the skin, and larval escape from this tissue were comparable in susceptible CBA/Ca and resistant FVB/N mice, with most larvae exiting within 4 h of a primary infection. Lung larval burdens were also similar between strains, but larvae recovered from FVB/N mice were smaller and less motile. In FVB/N mice, larval colonization of the gut was impaired and worms produced very few eggs. However FVB/N mice did not show enhanced resistance to Heligmosomoides bakeri (also known as Heligmosomoides polygyrus), a nematode largely restricted to the gut. Damage done in the pre-lung or lung stages of infection with N. brasiliensis is likely to contribute to ongoing developmental and functional abnormalities, which are profoundly evident in the gut phase of infection.
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Heligmosomoides polygyrusreduces infestation ofIxodes ricinusin free-living yellow-necked mice,Apodemus flavicollis. Parasitology 2009; 136:305-16. [DOI: 10.1017/s0031182008005404] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
SUMMARYFree-living animals are usually inhabited by a community of parasitic species that can interact with each other and alter both host susceptibility and parasite transmission. In this study we tested the prediction that an increase in the gastrointestinal nematodeHeligmosomoides polygyruswould increase the infestation of the tickIxodes ricinus, in free-living yellow-necked mice,Apodemus flavicollis. An extensive cross-sectional trapping survey identified a negative relationship betweenH. polygyrusandI. ricinuscounter to the prediction. An experimental reduction of the nematode infection through anthelmintic treatment resulted in an increase in tick infestation, suggesting that this negative association was one of cause and effect. Host characteristics (breeding condition and age) and habitat variables also contributed to affect tick infestation. While these results were counter to the prediction, they still support the hypothesis that interactions between parasite species can shape parasite community dynamics in natural systems. Laboratory models may act differently from natural populations and the mechanism generating the negative association is discussed.
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Kristan DM. Calorie restriction and susceptibility to intact pathogens. AGE (DORDRECHT, NETHERLANDS) 2008; 30:147-56. [PMID: 19424864 PMCID: PMC2527633 DOI: 10.1007/s11357-008-9056-1] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2008] [Accepted: 04/14/2008] [Indexed: 04/17/2023]
Abstract
Long-term calorie restriction (CR) causes numerous physiological changes that ultimately increase mean and maximum lifespan of most species examined to date. One physiological change that occurs with CR is enhanced immune function, as tested using antigens and mitogens to stimulate an immune response. Fewer studies have used intact pathogen exposure to test whether the enhanced capacity of the immune response during CR actually decreases susceptibility of hosts to their pathogens. So far, studies using intact bacteria, virus, and helminth worm exposure indicate that, despite similar or enhanced immune system function, CR hosts are more susceptible to infection by intact pathogens than their fully fed counterparts. Long-term CR studies that examine susceptibility to a variety of parasite taxa will help determine if direct CR or CR mimetics will be beneficial to people living in pathogen-rich environments.
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Affiliation(s)
- Deborah M Kristan
- Department of Biological Sciences, California State University San Marcos, 333 S. Twin Oaks Valley Road, San Marcos, CA 92096, USA.
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Bednarska M, Bajer A, Sinski E. Cryptosporidium parvum: The course of Cryptosporidium parvum infection in C57BL/6 mice co-infected with the nematode Heligmosomoides bakeri. Exp Parasitol 2008; 120:21-8. [DOI: 10.1016/j.exppara.2008.04.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2008] [Revised: 04/07/2008] [Accepted: 04/08/2008] [Indexed: 10/22/2022]
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Behnke JM, Buttle DJ, Stepek G, Lowe A, Duce IR. Developing novel anthelmintics from plant cysteine proteinases. Parasit Vectors 2008; 1:29. [PMID: 18761736 PMCID: PMC2559997 DOI: 10.1186/1756-3305-1-29] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2008] [Accepted: 09/01/2008] [Indexed: 11/11/2022] Open
Abstract
Intestinal helminth infections of livestock and humans are predominantly controlled by treatment with three classes of synthetic drugs, but some livestock nematodes have now developed resistance to all three classes and there are signs that human hookworms are becoming less responsive to the two classes (benzimidazoles and the nicotinic acetylcholine agonists) that are licensed for treatment of humans. New anthelmintics are urgently needed, and whilst development of new synthetic drugs is ongoing, it is slow and there are no signs yet that novel compounds operating through different modes of action, will be available on the market in the current decade. The development of naturally-occurring compounds as medicines for human use and for treatment of animals is fraught with problems. In this paper we review the current status of cysteine proteinases from fruits and protective plant latices as novel anthelmintics, we consider some of the problems inherent in taking laboratory findings and those derived from folk-medicine to the market and we suggest that there is a wealth of new compounds still to be discovered that could be harvested to benefit humans and livestock.
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Affiliation(s)
- Jerzy M Behnke
- School of Biology, University of Nottingham, University Park, Nottingham, NG7 2RD, UK.
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