Expression, immunolocalization and serodiagnostic value of a myophilin-like protein from Schistosoma japonicum

Preparation of polyclonal anti-Schistosoma mansoni cysteine protease antibodies for early diagnosis

In many parts of the tropics, schistosomiasis is a major parasitic disease second only to malaria as a cause of morbidity and mortality. Diagnostic approaches include microscopic sampling of excreta such as the Kato-Katz method, radiography, and serology. Due to their vital role in many stages of the parasitic life cycle, proteases have been under investigation as targets of immunological or chemotherapeutic anti-Schistosoma agents. Five major classes of protease have been identified on the basis of the peptide hydrolysis mechanism: serine, cysteine, aspartic, threonine, and metalloproteases. Proteases of all five catalytic classes have been identified from S. mansoni through proteomic or genetic analysis. The study aimed to produce polyclonal antibodies (pAbs) against schistosomal cysteine proteases (CP) to be used in the diagnosis of schistosomiasis. This study was conducted on S. mansoni-infected patients from highly endemic areas and from outpatients' clinic and hospitals and other patients infected with other parasites (Fasciola, hookworm, hydatid, and trichostrongyloids). In this study, the produced polyclonal antibodies against S. mansoni cysteine protease antigens were labeled with horseradish peroxidase (HRP) conjugate and used to detect CP antigens in stool and serum samples of S. mansoni-infected patients by sandwich ELISA. The study involved 200 S. mansoni-infected patients (diagnosed by finding characteristic eggs in the collected stool samples), 100 patients infected with other parasites (Fasciola, hookworm, hydatid, and trichostrongyloids), and 100 individuals who served as parasite-free healthy negative control. The prepared pAb succeeded in detecting CP antigens in stool and serum samples of S. mansoni-infected patients by sandwich ELISA with a sensitivity of 98.5% and 98.0% respectively. A positive correlation was observed between S. mansoni egg counts and both stool and serum antigen concentrations. Purified 27.5 kDa CP could be introduced as a suitable candidate antigen for early immunodiagnosis using sandwich ELISA for antigen detection. KEY POINTS: • Detection of cysteine protease antigens can replace parasitological examination. • Sandwich ELISA has a higher sensitivity than microscopic examination of eggs. • Identification of antigens is important for the goal of obtaining diagnostic tools.

iTRAQ-Based Identification of Proteins Related to Muscle Growth in the Pacific Abalone, Haliotis discus hannai

The abalone Haliotis discus hannai is an important aquaculture species that is grown for human consumption. However, little is known of the genetic mechanisms governing muscle growth in this species, particularly with respect to proteomics. The isobaric tag for relative and absolute quantitation (iTRAQ) method allows for sensitive and accurate protein quantification. Our study was the first to use iTRAQ-based quantitative proteomics to investigate muscle growth regulation in H. discus hannai. Among the 1904 proteins identified from six samples, 125 proteins were differentially expressed in large specimens of H. discus hannai as compared to small specimens. In the large specimens, 47 proteins were upregulated and 78 were downregulated. Many of the significant Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, including these differentially expressed proteins, were closely related to muscle growth, including apoptosis, thyroid hormone signaling, regulation of the actin cytoskeleton, and viral myocarditis (p < 0.05). Our quantitative real-time polymerase chain reaction (qRT-PCR) analyses suggested that the alterations in expression levels observed in the differentially expressed proteins were consistent with the alterations observed in the encoding mRNAs, indicating the repeatability of our proteomic approach. Our findings contribute to the knowledge of the molecular mechanisms of muscle growth in H. discus hannai.

Serological approaches for the diagnosis of schistosomiasis - A review

Schistosomiasis is a common disease in endemic areas of Sub-Saharan Africa, South America and Asia. It is rare in Europe, mainly imported from endemic countries due to travelling or human migration. Available methods for the diagnosis of schistosomiasis comprise microscopic, molecular and serological approaches, with the latter detecting antigens or antibodies associated with Schistosoma spp. infection. The serological approach is a valuable screening tool in low-endemicity settings and for travel medicine, though the interpretation of any diagnostic results requires knowledge of test characteristics and a patient's history. Specific antibody detection by most currently used assays is only possible in a relatively late stage of infection and does not allow for the differentiation of acute from previous infections for therapeutic control or the discrimination between persisting infection and re-infection. Throughout the last decades, new target antigens have been identified, and assays with improved performance and suitability for use in the field have been developed. For numerous assays, large-scale studies are still required to reliably characterise assay characteristics alone and in association with other available methods for the diagnosis of schistosomiasis. Apart from S. mansoni, S. haematobium and S. japonicum, for which most available tests were developed, other species of Schistosoma that occur less frequently need to be taken into account. This narrative review describes and critically discusses the results of published studies on the evaluation of serological assays that detect antibodies against different Schistosoma species of humans. It provides insights into the diagnostic performance and an overview of available assays and their suitability for large-scale use or individual diagnosis, and thus sets the scene for serological diagnosis of schistosomiasis and the interpretation of results.

Development of "-omics" research in Schistosoma spp. and -omics-based new diagnostic tools for schistosomiasis

Schistosomiasis, caused by dioecious flatworms in the genus Schistosoma, is torturing people from many developing countries nowadays and frequently leads to severe morbidity and mortality of the patients. Praziquantel based chemotherapy and morbidity control for this disease adopted currently necessitate viable and efficient diagnostic technologies. Fortunately, those “-omics” researches, which rely on high-throughput experimental technologies to produce massive amounts of informative data, have substantially contributed to the exploitation and innovation of diagnostic tools of schistosomiasis. In its first section, this review provides a concise conclusion on the progresses pertaining to schistosomal “-omics” researches to date, followed by a comprehensive section on the diagnostic methods of schistosomiasis, especially those innovative ones based on the detection of antibodies, antigens, nucleic acids, and metabolites with a focus on those achievements inspired by “-omics” researches. Finally, suggestions about the design of future diagnostic tools of schistosomiasis are proposed, in order to better harness those data produced by “-omics” studies.

Identification and characterization of myophilin-like protein: a life stage and tissue-specific antigen of Clonorchis sinensis

Clonorchiasis, caused by Clonorchis sinensis infection, has been an important public health problem in China. More messages about biology and pathogenicity of C. sinensis will be better for development of new strategies for clonorchiasis control. In the current study, using data from the published genomic and cDNA sequences for C. sinensis, we identify a gene encoding a myophilin-like protein (Cs myophilin-like). The cDNA sequence is 573 bp in length which encoded a protein of 190 amino acids. DNA sequence of Cs myophilin-like consists of four extrons and three introns. By mapping the draft genome of C. sinensis, single copy of myophilin-like gene is annotated. Bioinformatic analysis shows Cs myophilin-like comprises a calponin homology domain and three actin binding surfaces. It expresses at the life stage of adult worm and metacercaria but not in eggs. It intensively distributes in muscular locations such as oral sucker and pharynx of adult worm and sucker of metacercaria. The transcript level of Cs myophilin-like in oral sucker and pharynx is significantly higher than that in the rest of adult worm. Moreover, recombinant Cs myophilin-like is obtained and of antigenicity and immunoreactivity. It can be probed by sera from patients infected with trematode or cestode. Our data suggests that Cs myophilin-like may be involved in the host tissue invasion besides regulating the contraction of smooth muscle and movement of worm body. Taken together, the stable and soluble expression in Escherichia coli and immunogenicity of recombinant Cs myophilin-like proteins suggest that Cs myophilin-like may be a potential candidate for vaccine and drug target for clonorchiasis.

A highly sensitive TaqMan real-time PCR assay for early detection of Schistosoma species

Schistosomiasis is a major infectious disease and a public health concern in many areas in China and other countries. Sensitive method for detection of the parasite is critical for early diagnosis and for monitoring of effective treatment of the disease. In this study, we developed a highly sensitive TaqMan real-time PCR assay for the detection of Schistosoma japonicum DNA in mouse feces and serum samples. This assay was based on the DNA sequence of the S. japonicum 18S rRNA gene and was able to detect 10 fg of S. japonicum genomic DNA, which is 100 times more sensitive than conventional PCR. We were able to detect the S. japonicum DNA one week post-infection in mouse sera and 4 weeks post-infection in feces, which was one week earlier than egg detection by microscopy in feces. This assay was also highly specific for Asian Schistosomes which are causative species of human Schistosomiasis. In single sex male cercariae infected mice, parasite DNA was only detected in the first 4 weeks post-infection, suggesting that the DNA was derived from decaying worms' corpse in the first 4 weeks whereas the DNA was mainly from decaying parasite eggs afterwards. Therefore we conclude that the established TaqMan real-time PCR assay is a sensitive, specific and convenient method that could be used for the early diagnostic evaluation of S. japonicum infection in humans and for monitoring outbreaks in endemic areas with low prevalence.