Alteration of immunoproteome profile of Echinococcus granulosus hydatid fluid with progression of cystic echinococcosis

Abstract

BackgroundCystic echinococcosis (CE), caused by Echinococcus granulosus metacestode, invokes a serious public health concern. Early diagnosis has great impacts on reduction of disability-adjusted life years. Several antigen B-related molecules (EgAgB; EgAgB1-5) are known to be immunopotent, but detection of EgAgB is variable in many patients and may not allow reliable interpretation of its immunological relevance. More importantly, the immunoproteome profile of hydatid fluid (HF) has not been addressed.MethodsWe conducted a proteome analysis of the HF of a single fertile cyst of CE1 and CE2 stages through two-dimensional electrophoresis (2-DE). Each protein spot was analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). We subsequently determined the immunoproteome profile employing patient sera of entire disease spectrum from CE1 to CE5 stages.ResultsWe identified 40 parasite proteins, of which EgAgB (28 spots) and antigen 5 (EgAg5; 5 molecules) were abundant. EgAgB proteoforms constituted the majority, mostly EgAgB1 (24 spots), followed by EgAgB2 and EgAgB4 (2 spots each). EgAgB3 was detected only by liquid chromatography-MS/MS. EgAgB5 was not recognized. We also detected 38 host proteins, which were largely composed of serum components, antioxidant/xenobiotic enzymes, and enzymes involved in carbohydrate metabolism. CE1 and CE2 HF exhibited comparable spotting patterns, but CE2 HF harbored greater amounts of EgAgB and EgAg5 complexes. CE sera demonstrated complicated immune recognition patterns according to the disease progression; CE2 and CE3 stages exhibited strong antibody responses against diverse EgAgB and EgAg5 proteoforms, while CE1, CE4, and CE5 stages mainly reacted to EgAg5 and cathepsin B. Patient sera of alveolar echinococcosis (AE) cross-reacted with diverse EgAgB isoforms (36%). EgAg5 and cathepsin B also demonstrated cross-reactions with sera from neurocysticercosis and sparganosis.ConclusionsOur results demonstrated that detection of a single defined molecule may not properly diagnose CE, since specific immunodominant epitopes changed as the disease progresses. Immunoproteome analysis combined with imaging studies may be practical in the differential diagnosis of CE from AE and other cystic lesions, as well as for staging CE, which are pertinent to establish appropriate patient management.Electronic supplementary materialThe online version of this article (doi:10.1186/s13071-014-0610-7) contains supplementary material, which is available to authorized users.

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.…”

“…Seronegative patients in this study might have had disease in the very early and far-advanced stages. In cases of CE that lead to false-positive results, simultaneous monitoring of immunoproteome profiles and imaging diagnostics might be helpful to properly diagnose AE patients (25).…”

“…It is noteworthy that EgAgB3, an ortholog of EmAgB3, showed high sequence identity with EmAgB3 at both the amino acid level (94.2%) and the nucleotide level (96.2%) and yet exhibits negligible antibody responses to CE patient sera (25). 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).…”

“…EmHF was centrifuged at 20,000 ϫ g for 1 h at 4°C, concentrated by lyophilization, and stored at Ϫ80°C until use. Echinococcus granulosus HF (EgHF) was collected from a single fertile ovine CE2 cyst at a local abattoir in Xining, Qinghai Province, China (25).…”

Spatiotemporal Expression Patterns and Antibody Reactivity of Taeniidae Endophilin B1

“…The species were identified by observing specific bands for T. solium (474 bp), T. saginata (629 bp), and T. asiatica (706 bp) by multiplex PCR (18). CE2 cysts and AE masses were collected from naturally infected sheep and experimentally infected mice in Xining (Qinghai Province, China) (19,20). E. granulosus and E. multilocularis adults were collected during necropsies of stray dogs (Chengdu, Qinghai Province, China).…”