Infection with the sheep gastrointestinal nematode Teladorsagia circumcincta increases luminal pathobionts


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Authors
Cortés, Alba 
Wills, John 
Su, Xiaopei 
Hewitt, Rachel E. 
Robertson, Jack 
Abstract

Abstract: Background: The multifaceted interactions between gastrointestinal (GI) helminth parasites, host gut microbiota and immune system are emerging as a key area of research within the field of host-parasite relationships. In spite of the plethora of data available on the impact that GI helminths exert on the composition of the gut microflora, whether alterations of microbial profiles are caused by direct parasite-bacteria interactions or, indirectly, by alterations of the GI environment (e.g. mucosal immunity) remains to be determined. Furthermore, no data is thus far available on the downstream roles that qualitative and quantitative changes in gut microbial composition play in the overall pathophysiology of parasite infection and disease. Results: In this study, we investigated the fluctuations in microbiota composition and local immune microenvironment of sheep vaccinated against, and experimentally infected with, the ‘brown stomach worm’ Teladorsagia circumcincta, a parasite of worldwide socio-economic significance. We compared the faecal microbial profiles of vaccinated and subsequently infected sheep with those obtained from groups of unvaccinated/infected and unvaccinated/uninfected animals. We show that alterations of gut microbial composition are associated mainly with parasite infection, and that this involves the expansion of populations of bacteria with known pro-inflammatory properties that may contribute to the immunopathology of helminth disease. Using novel quantitative approaches for the analysis of confocal microscopy-derived images, we also show that gastric tissue infiltration of T cells is driven by parasitic infection rather than anti-helminth vaccination. Conclusions: Teladorsagia circumcincta infection leads to an expansion of potentially pro-inflammatory gut microbial species and abomasal T cells. This data paves the way for future experiments aimed to determine the contribution of the gut flora to the pathophysiology of parasitic disease, with the ultimate aim to design and develop novel treatment/control strategies focused on preventing and/or restricting bacterial-mediated inflammation upon infection by GI helminths. DCvTgHLrMa4pPTvhPWGjhoVideo Abstract

Description
Keywords
Research, Gastrointestinal helminth, Teladorsagia circumcincta, Parasite gastroenteritis, Gut microbiota, Bacterial 16S rRNA gene sequencing, Vaccine, Pathobiont, T cell, Automated in situ cell counting
Journal Title
Microbiome
Conference Name
Journal ISSN
2049-2618
Volume Title
8
Publisher
BioMed Central
Sponsorship
Fundación Alfonso Martín Escudero (N/A)
Isaac Newton Trust (N/A)
Rural and Environment Science and Analytical Services Division (N/A)
Horizon 2020 Framework Programme (635408)
Medical Research Council (MR/R005699/1)