Identification of novel antigens within the Schistosoma japonicum tetraspanin family based on molecular characterization (original) (raw)
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Identification and characterization of six novel tetraspanins from Schistosoma japonicum
2011
Background Tetraspanins (TSPs), also known as members of the trans-membrane 4 super-family (TM4SF), comprise an assemblage of surface antigens reported in eukaryotic organisms. In the work presented here, six novel TSP proteins from the human blood fluke Schistosoma japonicum (S. japonicum) were produced and analyzed through a combination of bioinformatics and experimental approaches. Results Six novel TSP proteins of Schistosoma japonicum (designated as Sj-TSP-#1~6) contained four trans-membrane regions and one large extracellular loop (LEL) with a conserved CCG motif. Size of the proteins varied from 227 to 291 amino acid residues. All the six proteins were produced in E.coli and immune sera to each protein were prepared. Analysis of transcription profiles of the proteins by RT-PCR showed that Sj-TSP-#4 was transcribed only in the egg stage while transcription of the Sj-TSP-#2 was detected in female worms but not in males. The similar results were obtained by Western blot. Immunolocalization of the TSP proteins by immunofluorescence assay showed that the Sj-TSP-#2, Sj-TSP-#5 and Sj-TSP-#6 were located in the tegument of worms. Conclusions This study provided six novel TSP members of S. japonicum including their sequences and recombinant proteins. Availability of the novel proteins and information on their expression profile and location provided a basis for further investigation of the TSP proteins for their biological functions and as vaccine candidates.
Tetraspanins on the surface of Schistosoma mansoni are protective antigens against schistosomiasis
Nature Medicine, 2006
Schistosomes are blood-dwelling flukes that infect 200 million people worldwide and are responsible for hundreds of thousands of deaths annually 1 . Using a signal sequence trap, we cloned from Schistosoma mansoni two cDNAs, Sm-tsp-1 and Sm-tsp-2, encoding the tetraspanin (TSP) integral membrane proteins TSP-1 and TSP-2. We raised antibodies to recombinant TSP fusion proteins and showed that both proteins are exposed on the surface of S. mansoni. Recombinant TSP-2, but not TSP-1, is strongly recognized by IgG1 and IgG3 (but not IgE) from naturally resistant individuals but is not recognized by IgG from chronically infected or unexposed individuals. Vaccination of mice with the recombinant proteins followed by challenge infection with S. mansoni resulted in reductions of 57% and 64% (TSP-2) and 34% and 52% (TSP-1) for mean adult worm burdens and liver egg burdens, respectively, over two independent trials. Fecal egg counts were reduced by 65-69% in both test groups. TSP-2 in particular provided protection in excess of the 40% benchmark set by the World Health Organization for progression of schistosome vaccine antigens into clinical trials. When coupled with its selective recognition by naturally resistant people, TSP-2 seems to be an effective vaccine antigen against S. mansoni.
Molecular and Biochemical Parasitology, 2013
Sj7TR is a 13 kDa repetitive region of a 31 kDa protein in Schistosoma japonicum known as Sjp 0110390 that showed high sensitivity and specificity in antibody detection against schistosomiasis patients. However, the current database for S. japonicum genes characterized it only as an expressed protein. A more thorough understanding of this antigenic protein is therefore necessary to possibly give more information about the nature of this protein and its role in the parasite. In this study, immunolocalization and expression profiling were done for Sjp 0110390 on the different stages of the parasite. Immunofluorescent assay showed that Sjp 0110390 was expressed in the young stages of the parasites including the schistosomula, eggs, aquatic and intra-molluscan stages. This was supported by the reverse-transcriptase PCR which confirmed the stage-specific expression of Sjp 0110390 and Western blot test which detected the protein in the extracted eggs proteins, but not in the adults. Furthermore, it was also highly expressed in infected Oncomelania hupensis nosophora snails suggesting that Sjp 0110390 might have a role in the development of the parasite inside the intermediate host. This result also suggests that Sj7TR might be used not only for human diagnosis but to detect snail infection as well.
Developmental gene expression profiles of the human pathogen Schistosoma japonicum
BMC Genomics, 2009
Background: The schistosome blood flukes are complex trematodes and cause a chronic parasitic disease of significant public health importance worldwide, schistosomiasis. Their life cycle is characterised by distinct parasitic and free-living phases involving mammalian and snail hosts and freshwater. Microarray analysis was used to profile developmental gene expression in the Asian species, Schistosoma japonicum. Total RNAs were isolated from the three distinct environmental phases of the lifecycle-aquatic/snail (eggs, miracidia, sporocysts, cercariae), juvenile (lung schistosomula and paired but pre-egg laying adults) and adult (paired, mature males and eggproducing females, both examined separately). Advanced analyses including ANOVA, principal component analysis, and hierarchal clustering provided a global synopsis of gene expression relationships among the different developmental stages of the schistosome parasite. Results: Gene expression profiles were linked to the major environmental settings through which the developmental stages of the fluke have to adapt during the course of its life cycle. Gene ontologies of the differentially expressed genes revealed a wide range of functions and processes. In addition, stage-specific, differentially expressed genes were identified that were involved in numerous biological pathways and functions including calcium signalling, sphingolipid metabolism and parasite defence. Conclusion: The findings provide a comprehensive database of gene expression in an important human pathogen, including transcriptional changes in genes involved in evasion of the host immune response, nutrient acquisition, energy production, calcium signalling, sphingolipid metabolism, egg production and tegumental function during development. This resource should help facilitate the identification and prioritization of new anti-schistosome drug and vaccine targets for the control of schistosomiasis.
The gene family encoding eggshell proteins of Schistosoma japonicum
Molecular and Biochemical Parasitology, 1990
The four closely related genes encoding eggshell proteins in the human parasite Schistosoma japonicum are described. A cDNA and a genomic DNA library were constructed and members of the eggshell protein gene family isolated. The four genes in this family do not contain introns, and differ in organization and nucleotide sequence from the related set of genes in Schistosoma mansoni and Schistosoma haematobium. The coding sequences of two of the S. japonicum genes and their flanking regions were determined. Transcription start sites for these genes were shown by primer extension analysis to occur 47 and 50 nucleotides in front of the start codon. A female-specific component in nuclear extracts binds to a DNA fragment containing conserved sequences upstream of the transcription start sites. The deduced protein sequences of 207 and 212 amino acids are composed of 50% glycine with continuous glycine regions as long as 11 residues. In vitro translations of male and female RNAs revealed female-specific translation products, the sizes of which were consistent with the eggshell proteins,
Schistosoma Tegument Proteins in Vaccine and Diagnosis Development: An Update
Journal of Parasitology Research, 2012
The development of a vaccine against schistosomiasis and also the availability of a more sensitive diagnosis test are important tools to help chemotherapy in controlling disease transmission. Bioinformatics tools, together with the access to parasite genome, published recently, should help generate new knowledge on parasite biology and search for new vaccines or therapeutic targets and antigens to be used in the disease diagnosis. Parasite surface proteins, especially those expressed in schistosomula tegument, represent interesting targets to be used in vaccine formulations and in the diagnosis of early infections, since the tegument represents the interface between host and parasite and its molecules are responsible for essential functions to parasite survival. In this paper we will present the advances in the development of vaccines and diagnosis tests achieved with the use of the information from schistosome genome focused on parasite tegument as a source for antigens.
PLoS Pathogens, 2006
Schistosomiasis remains a serious public health problem with an estimated 200 million people infected in 76 countries. Here we isolated ; 8,400 potential protein-encoding cDNA contigs from Schistosoma japonicum after sequencing circa 84,000 expressed sequence tags. In tandem, we undertook a high-throughput proteomics approach to characterize the protein expression profiles of a number of developmental stages (cercariae, hepatic schistosomula, female and male adults, eggs, and miracidia) and tissues at the host-parasite interface (eggshell and tegument) by interrogating the protein database deduced from the contigs. Comparative analysis of these transcriptomic and proteomic data, the latter including 3,260 proteins with putative identities, revealed differential expression of genes among the various developmental stages and sexes of S. japonicum and localization of putative secretory and membrane antigens, enzymes, and other gene products on the adult tegument and eggshell, many of which displayed genetic polymorphisms. Numerous S. japonicum genes exhibited high levels of identity with those of their mammalian hosts, whereas many others appeared to be conserved only across the genus Schistosoma or Phylum Platyhelminthes. These findings are expected to provide new insights into the pathophysiology of schistosomiasis and for the development of improved interventions for disease control and will facilitate a more fundamental understanding of schistosome biology, evolution, and the host-parasite interplay. SJ, et al. (2006) New perspectives on host-parasite interplay by comparative transcriptomic and proteomic analyses of Schistosoma japonicum. PLoS Pathog 2(4): e29.