Evidence of Immune Modulators in the Secretome of the Equine Tapeworm Anoplocephala perfoliata.

Boontarikaan Wititkornkul,Benjamin J Hulme,Matthew J Hegarty,Martin T Swain,Alan R Cookson,Chelsea N Davis,Helen C Phillips,Nathan R Allen,Sarah D Davey,Russell M Morphew,John J Tomes,Peter M Brophy,Ruth E Wonfor

doi:10.3390/pathogens10070912

Abstract

Anoplocephala perfoliata is a neglected gastro-intestinal tapeworm, commonly infecting horses worldwide. Molecular investigation of A. perfoliata is hampered by a lack of tools to better understand the host–parasite interface. This interface is likely influenced by parasite derived immune modulators released in the secretome as free proteins or components of extracellular vesicles (EVs). Therefore, adult RNA was sequenced and de novo assembled to generate the first A. perfoliata transcriptome. In addition, excretory secretory products (ESP) from adult A. perfoliata were collected and EVs isolated using size exclusion chromatography, prior to proteomic analysis of the EVs, the EV surface and EV depleted ESP. Transcriptome analysis revealed 454 sequences homologous to known helminth immune modulators including two novel Sigma class GSTs, five α-HSP90s, and three α-enolases with isoforms of all three observed within the proteomic analysis of the secretome. Furthermore, secretome proteomics identified common helminth proteins across each sample with known EV markers, such as annexins and tetraspanins, observed in EV fractions. Importantly, 49 of the 454 putative immune modulators were identified across the secretome proteomics contained within and on the surface of EVs in addition to those identified in free ESP. This work provides the molecular tools for A. perfoliata to reveal key players in the host–parasite interaction within the horse host.

Highlights

The gastro-intestinal tapeworm, Anoplocephala perfoliata, is one of the most prevalent tapeworm species that infects horses worldwide, with prevalence estimated between 15.8–44% of horses, yet it remains a neglected parasite with respect to management as low infection rates are often asymptomatic [1,2,3,4,5,6]
High burdens of A. perfoliata are linked to abdominal disturbance or pain, including spasmodic colic, ileal impaction [7], ileocaecal or caeco–caecal intussusception [8,9] and ileal or caecal rupture [10,11] due to the accumulation of adults at the ileocaecal region that attach to the caecal epithelium [2,12,13,14,15]
In such high-level infections, a localised caecal mucosal inflammatory response is activated at the site of the tapeworm attachment [2,16,17,18]

Summary

Introduction

The gastro-intestinal tapeworm, Anoplocephala perfoliata, is one of the most prevalent tapeworm species that infects horses worldwide, with prevalence estimated between 15.8–44% of horses, yet it remains a neglected parasite with respect to management as low infection rates are often asymptomatic [1,2,3,4,5,6]. High burdens of A. perfoliata are linked to abdominal disturbance or pain, including spasmodic colic, ileal impaction [7], ileocaecal or caeco–caecal intussusception [8,9] and ileal or caecal rupture [10,11] due to the accumulation of adults at the ileocaecal region that attach to the caecal epithelium [2,12,13,14,15] In such high-level infections, a localised caecal mucosal inflammatory response is activated at the site of the tapeworm attachment [2,16,17,18]. An increased understanding of the underpinning molecular biology of A. perfoliata is required to delineate parasite–host interactions

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Results

Conclusion