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17 results on '"Larcombe, Stephen D."'

3. Susceptibility to disease (tropical theileriosis) is associated with differential expression of host genes that possess motifs recognised by a pathogen DNA binding protein

Author

Larcombe, Stephen D., Capewell, Paul, Jensen, Kirsty, Weir, William, Kinnaird, Jane, Glass, Elizabeth J., and Shiels, Brian R.

Subjects
Carcinogenesis, Science, Immunology, Cattle Diseases, Gene Expression, Gastroenterology and Hepatology, Cell Line, Medical Conditions, Gene Types, Gastrointestinal Cancers, Genetics, Medicine and Health Sciences, Parasitic Diseases, Animals, Cluster Analysis, Gene Regulation, Immune Response, Principal Component Analysis, Multidisciplinary, Base Sequence, Biology and Life Sciences, Helminth Proteins, Genomics, Theileria annulata, Immunity, Innate, Theileriasis, DNA-Binding Proteins, Veterinary Diseases, Interferon Type I, Regulator Genes, Medicine, Cattle, Veterinary Science, Disease Susceptibility, Transcriptome, Research Article
Abstract

Background Knowledge of factors that influence the outcome of infection are crucial for determining the risk of severe disease and requires the characterisation of pathogen-host interactions that have evolved to confer variable susceptibility to infection. Cattle infected by Theileria annulata show a wide range in disease severity. Native (Bos indicus) Sahiwal cattle are tolerant to infection, whereas exotic (Bos taurus) Holstein cattle are susceptible to acute disease. Methodology/Principal findings We used RNA-seq to assess whether Theileria infected cell lines from Sahiwal cattle display a different transcriptome profile compared to Holstein and screened for altered expression of parasite factors that could generate differences in host cell gene expression. Significant differences (B. indicus vs. B. taurus, and divergent motif patterns were identified in infection-associated genes differentially expressed between Sahiwal and Holstein infected cells. Conclusions/Significance We conclude that divergent pathogen-host molecular interactions that influence chromatin architecture of the infected cell are a major determinant in the generation of gene expression differences linked to disease susceptibility.

Published
2022

8. Identification of candidate transmission-blocking antigen genes in Theileria annulata and related vector-borne apicomplexan parasites

Author

Lempereur, Laetitia, primary, Larcombe, Stephen D., additional, Durrani, Zeeshan, additional, Karagenc, Tulin, additional, Bilgic, Huseyin Bilgin, additional, Bakirci, Serkan, additional, Hacilarlioglu, Selin, additional, Kinnaird, Jane, additional, Thompson, Joanne, additional, Weir, William, additional, and Shiels, Brian, additional

Published
2017
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12. Identification of candidate transmissionblocking antigen genes in Theileria annulata and related vector-borne apicomplexan parasites.

Author

Lempereur, Laetitia, Larcombe, Stephen D., Durrani, Zeeshan, Karagenc, Tulin, Bilgic, Huseyin Bilgin, Bakirci, Serkan, Hacilarlioglu, Selin, Kinnaird, Jane, Thompson, Joanne, Weir, William, and Shiels, Brian

Subjects
*THEILERIA, *CELL surface antigens, *APICOMPLEXA, *DISEASE vectors, *TRANSMISSION of protozoan diseases, *PLASMODIUM
Abstract

Background: Vector-borne apicomplexan parasites are a major cause of mortality and morbidity to humans and livestock globally. The most important disease syndromes caused by these parasites are malaria, babesiosis and theileriosis. Strategies for control often target parasite stages in the mammalian host that cause disease, but this can result in reservoir infections that promote pathogen transmission and generate economic loss. Optimal control strategies should protect against clinical disease, block transmission and be applicable across related genera of parasites. We have used bioinformatics and transcriptomics to screen for transmission-blocking candidate antigens in the tick-borne apicomplexan parasite, Theileria annulata. Results: A number of candidate antigen genes were identified which encoded amino acid domains that are conserved across vector-borne Apicomplexa (Babesia, Plasmodium and Theileria), including the Pfs48/45 6-cys domain and a novel cysteine-rich domain. Expression profiling confirmed that selected candidate genes are expressed by life cycle stages within infected ticks. Additionally, putative B cell epitopes were identified in the T. annulata gene sequences encoding the 6-cys and cysteine rich domains, in a gene encoding a putative papain-family cysteine peptidase, with similarity to the Plasmodium SERA family, and the gene encoding the T. annulata major merozoite/piroplasm surface antigen, Tams1. Conclusions: Candidate genes were identified that encode proteins with similarity to known transmission blocking candidates in related parasites, while one is a novel candidate conserved across vector-borne apicomplexans and has a potential role in the sexual phase of the life cycle. The results indicate that a 'One Health' approach could be utilised to develop a transmission-blocking strategy effective against vector-borne apicomplexan parasites of animals and humans. [ABSTRACT FROM AUTHOR]

Published
2017
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13. Social interactions modulate the virulence of avian malaria infection

Author

Conseil Régional de Bourgogne, Centre National de la Recherche Scientifique (France), Larcombe, Stephen D., Bedhomme, Stéphanie, Garnier, Stéphane, Cellier-Holzem, Elise, Faivre, Bruno, Sorci, Gabriele, Conseil Régional de Bourgogne, Centre National de la Recherche Scientifique (France), Larcombe, Stephen D., Bedhomme, Stéphanie, Garnier, Stéphane, Cellier-Holzem, Elise, Faivre, Bruno, and Sorci, Gabriele

Abstract

There is an increasing understanding of the context-dependent nature of parasite virulence. Variation in parasite virulence can occur when infected individuals compete with conspecifics that vary in infection status; virulence may be higher when competing with uninfected competitors. In vertebrates with social hierarchies, we propose that these competition-mediated costs of infection may also vary with social status. Dominant individuals have greater competitive ability than competing subordinates, and consequently may pay a lower prevalence-mediated cost of infection. In this study we investigated whether costs of malarial infection were affected by the occurrence of the parasite in competitors and social status in domestic canaries (Serinus canaria). We predicted that infected subordinates competing with non-infected dominants would pay higher costs than infected subordinates competing with infected dominants. We also predicted that these occurrence-mediated costs of infection would be ameliorated in infected dominant birds. We found that social status and the occurrence of parasites in competitors significantly interacted to change haematocrit in infected birds. Namely, subordinate and dominant infected birds differed in haematocrit depending on the infection status of their competitors. However, in contrast to our prediction, dominants fared better with infected subordinates, whereas subordinates fared better with uninfected dominants. Moreover, we found additional effects of parasite occurrence on mortality in canaries. Ultimately, we provide evidence for costs of parasitism mediated by social rank and the occurrence of parasites in competitors in a vertebrate species. This has important implications for our understanding of the evolutionary processes that shape parasite virulence and group living. © 2013 Australian Society for Parasitology Inc.

Published
2013

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