Excretory/secretory products from in vitro-cultured Echinococcus granulosus protoscoleces

Abstract

Cystic hydatid disease (CHD) is caused by infection with Echinococcus granulosus metacestodes and affects humans and livestock. Proteins secreted or excreted by protoscoleces, pre-adult worms found in the metacestode, are thought to play fundamental roles in the host-parasite relationship. In this work, we performed an LC-MS/MS proteomic analysis of the excretory-secretory products obtained from the first 48 h of an in vitro culture of the protoscoleces. We identified 32 proteins, including 18 that were never detected previously in metacestode proteomic studies. Among the novel identified excretory-secretory products are antigenic proteins, such as EG19 and P-29 and a calpain protease. We also identified other important protoscolex excretory-secretory products, such as thioredoxin peroxidase and 14-3-3 proteins, which are potentially involved in evasion mechanisms adopted by parasites to establish infection. Several intracellular proteins were found in the excretory-secretory products, revealing a set of identified proteins not previously thought to be exposed at the host-parasite interface. Additionally, immunological analyses established the antigenic profiles of the newly identified excretory-secretory products and revealed, for the first time, the in vitro secretion of the B antigen by protoscoleces. Considering that the excretory-secretory products obtained in vitro might reflect the products released and exposed to the host in vivo, our results provide valuable information on parasite survival strategies in adverse host environments and on the molecular mechanisms underpinning CHD immunopathology.

Fructose-bisphosphate aldolase and enolase from Echinococcus granulosus: Genes, expression patterns and protein interactions of two potential moonlighting proteins

“…Both proteins have already been identified by proteomic analyses of E. granulosus hydatid fluid (Aziz et al, 2011;Monteiro et al, 2010) and in vitro ES products of protoscoleces (Virginio et al, 2012). Here, these proteins were detected accordingly, both in the hydatid fluid (containing ES products of the germinal layer and protoscolex) and in the ES products from in vitro cultures of protoscoleces.…”

“…To obtain excretory-secretory (ES) products, protoscoleces were cultivated similarly as described by Virginio et al (2012), with some modifications. Protoscoleces were cultured in 4 ml of RPMI medium for 48 h, at 37°C.…”

Characterization of a Secretory Annexin in Echinococcus granulosus

“…Two proteomic studies on the zoonotic pathogen E. granulosus found that an annexin was present in the ES product and hydatid cyst fluid. 22,23 Therefore, we performed a primary study characterizing the Eg-ANX gene and validated the secretory and calcium ion binding properties of Eg-ANX protein.…”

“…15,21 Recently, proteomic research on E. granulosus has shown that annexin B33 protein (Eg-ANX) could be detected in the excreted/secreted (ES) product and hydatid cyst fluid, which might potentially play important roles in parasite survival mechanisms during infection. 22,23 However, the secretory properties of Eg-ANX in the proteomic research on E. granulosus was not very specific. In this study, we validated the existence of Eg-ANX in hydatid cyst fluid and found that Eg-ANX could be secreted in the host-derived layer (granulation tissue) of host liver.…”

An Echinococcus multilocularis Antigen B3 Proteoform That Shows Specific Antibody Responses to Active-Stage Alveolar Echinococcosis

“…In E. granulosus, EgAgB3 was abundantly transcribed in the protoscolex (38), but secretion into the hydatid fluid was minimal at the protein level (25,39). The differential expression patterns of AgB3 in phylogenetically close neighbors imply that an as-yet-unknown transcriptional regulatory mechanism operates in different manners during the maturation of EmAgB3 and EgAgB3.…”