Schistosoma Tegument Proteins in Vaccine and Diagnosis Development: An Update

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

The Schistosoma mansoni cyclophilin A epitope 107-121 induces a protective immune response against schistosomiasis

Great efforts have been made to identify promising antigens and vaccine formulations against schistosomiasis. Among the previously described Schistosoma vaccine candidates, cyclophilins comprise an interesting antigen that could be used for vaccine formulations. Cyclophilin A is the target for the cyclosporine A, a drug with schistosomicide activity, and its orthologue from Schistosoma japonicum induces a protective immune response in mice. Although Schistosoma mansoni cyclophilin A also represents a promising target for anti-schistosome vaccines, its potential to induce protection has not been evaluated. In this study, we characterized the cyclophilin A (SmCyp), initially described as Smp17.7, analyzed its allergenic potential using in vitro functional assays, and evaluated its ability to induce protection in mice when administered as an antigen using different vaccine formulations and strategies. Results indicated that SmCyp could be successfully expressed by mammalian cells and bacteria. The recombinant protein did not promote IgE-reporter system activation in vitro, demonstrating its probable safety for use in vaccine formulations. T and B-cell epitopes were predicted in the SmCyp sequence, with two of them located within the active isomerase site. The most immunogenic antigen, SmCyp (107–121), was then used for immunization protocols. Immunization with the SmCyp gene or protein failed to reduce parasite burden but induced an immune response that modulated the granuloma area. In contrast, immunization with the synthetic peptide SmCyp (107–121) significantly reduced worm burden (48–50%) in comparison to control group, but did not regulate liver pathology. Moreover, the protection observed in mice immunized with the synthetic peptide was associated with the significant production of antibodies against the SmCyp (107–121) epitope. Therefore, in this study, we identified an epitope within the SmCyp sequence that induces a protective immune response against the parasite, thus representing a promising antigen that could be used for vaccine formulation against schistosomiasis

Novos antígenos de Schistosoma mansoni para o diagnóstico sorológicoda infecção ativa e controle de cura

Submitted by Nuzia Santos ([email protected]) on 2017-06-28T18:58:53Z No. of bitstreams: 1 Tese_BCM_GardêniaBrazFigueiredodeCarvalho.pdf: 4683488 bytes, checksum: 02e54be7e480a297bc2d3f1f0801cd42 (MD5)Approved for entry into archive by Nuzia Santos ([email protected]) on 2017-06-28T19:08:01Z (GMT) No. of bitstreams: 1 Tese_BCM_GardêniaBrazFigueiredodeCarvalho.pdf: 4683488 bytes, checksum: 02e54be7e480a297bc2d3f1f0801cd42 (MD5)Made available in DSpace on 2017-06-28T19:08:01Z (GMT). No. of bitstreams: 1 Tese_BCM_GardêniaBrazFigueiredodeCarvalho.pdf: 4683488 bytes, checksum: 02e54be7e480a297bc2d3f1f0801cd42 (MD5) Previous issue date: 2016Centro de Pesquisas René RachouFundação Oswaldo Cruz. Instituto René Rachou. Belo Horizonte, MG, Brasil.A esquistossomose continua sendo uma das infecções parasitárias mais prevalentes no mundo , e para o controle e monitoramento efetivo dessa doença é essencial que se disponha de métodos diagnósticos cada vez mais acurados. Utilizando ferramentas de bioinformática e o proteom a do parasito S. mansoni, nosso grupo selecionou in silico , antígenos candidatos do S. mansoni para serem utilizados no diagnóstico sorológico da esquistossomose e no control e de cura da doença pós - tratamento . A estratégia baseou - se em critérios para seleç ão de potenciais antígenos que levaram em consideração a predição de presença de peptídeo sinal, baixa similaridade com proteínas humanas e de camundongos, presença de epítopos lineares de células B e T preditos, localização predita favorável (secretada ou de membrana) e prediçã o de expressão em estágio s de vida do parasito presentes no hospedeiro definitivo. Estas condicionais foram aplicadas em um banco de dados relacional construído para integrar os resultados das diferentes predições. Sete proteínas f or am selecionadas e diante da inviabilidade de expressar todas elas, nosso grupo identificou epítopos lineares de célula B nas proteínas selecionadas , que foram produzidos como peptídeos sintéticos e utilizados na validação da estratégia de seleção in silico utilizada. Esses epítopos foram identificados por predição in silico dos programas AAP12, BCPred12 , BepiPred e predição de regiões intrinsecamente desordenadas (IDRs) . Adicionalmente, duas proteínas também foram expressas como proteínas recombinantes em s istema procarioto e avaliadas em ensaios de ELISA. Para os ensaios de ELISA com os peptídeos sintéticos e com as proteínas recombinantes, foram utilizados soro de camundongos infectados com S. mansoni e soros de indivíduos provenientes de uma área endêmica de baixa intensidade de infecção para S. mansoni e de doadores saudáveis não residentes em áreas endêmicas para esquistossomose . Dentre os sete peptídeos sintéticos utilizados nos ensaios de ELISA, cinco foram capazes de diferenciar indivíduos infectados de áreas endêmicas (INF), de indivíduos negativos de área endêmica (NEG) e doadores saudáveis não residentes de área endêmica (HD) . Além disso, um dos peptídeos também foi capaz de diferenciar soro de indivíduos infectados de área endêmica , de soro de indi víduos infectados 30 e 180 dias após tratamento, o que poderia ser utilizado para controle de cura. O uso de soros de indivíduos que vivem em área s endêmicas para esquistossomose demonstraram que as proteínas rSm200(1069 - 1520) - ELISA e a rSmVal7 - ELISA fo ram capaz es de discriminar os doadores saudáveis (HD) e ndivíduos infectados (INF) que vivem em áreas endêmicas para esquistossomose , porém não fo ram eficiente s para o controle de cura a pós tratamento . Nossos resultados demosntram que a estratégia de s eleção in silico de antígenos potencias para o diagnóstico da esquistossomose apre sentou um racional promissor e com resultados promissoresSchistosomiasis remains one of the most prevalent parasitic infections in the world . In order to control and effectively monitor this disease , it is essential t he availability of more accurate diagnosis methods. Taking advantage of bioinformatics tools and S. mansoni proteome informations , our group selected , in silico , candidate antigens for the immunodiagnosis of schistososmiasis based on ELISA assays . The strategy of selection was based on criteria such as: presence of signal peptide ; low similarity with human and mouse proteins ; the presence of predicted linear B and T cells epitopes; favorable location (secreted or membrane) and expression during different parasite life stage within the definitive host. These conditionals were applied to a relational database developed to integrate the resul ts for all predictions performed. Seven proteins were selected, and d ue to unfeasibility of expressing all of them, our group identified B cell linear epitopes in the selected proteins that were produced as synthe tic peptides and used to validate the in s ilico selection strategy used. These epitopes were identified using in silico prediction of AAP12 programs BCPred12, BepiPred and prediction of intrinsically disordered regions (IDRs). Additionally, two proteins were expressed as recombinant proteins using procaryote system and also evaluated in ELISA assays. For the ELISA assays using synthetic peptides and recombinant proteins, se ra of mice infected with S. mansoni , ser a of individuals from an endemic area of low intensity of infection for S. mansoni and sera of healthy donors , non - residents of endemic areas , were used. Among the seven synthetic peptides used in the ELISA assays, five were able to e differentiate between infected individuals living in endemic areas (INF) and negative individuals living in e ndemic area (NEG) or healthy donors (HD). Furthermore, one of the peptides was also capable of distinguishing se ra of infected individuals from endemic area from ser a of infected individuals 30 and 180 days after treatment, which could be used to control c ure after treatment . The use of the sera of individuals living in endemic area for schistosomiasis demonstrated that rSm200(1069 - 1520) - ELISA and rSmVal7 - ELISA were able to discriminate the uninfected healthy donors (HD) and infected individuals (INF) livin g in endemic areas for schistosomiasis and it was not effective for the diagnosis of cure after treatment. Our results demo n strate that the in silico selection strategy of potential antigens to be used in the diagnosis of chistosomiasis showed a promising rational with promising results

Schistosoma tegument proteins in vaccine and diagnosis development: an update

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

A Schistosoma mansoni Immunomodulatory Protein, Fails to Elicit a Protective Immune Response and Does Not Have an Essential Role in Parasite Survival in the Definitive Host

Submitted by Nuzia Santos ([email protected]) on 2020-02-17T12:12:12Z No. of bitstreams: 1 Sm16, A Schistosoma mansoni Immunomodulatory Protein, Fails to Elicit a Protective Immune Response and Does Not Have an Essential Role in Parasite Survival in the Definitive Host.pdf: 18513912 bytes, checksum: b16a4c95b374bfe5e9e81e84d5297ff4 (MD5)Approved for entry into archive by Nuzia Santos ([email protected]) on 2020-02-17T13:17:58Z (GMT) No. of bitstreams: 1 Sm16, A Schistosoma mansoni Immunomodulatory Protein, Fails to Elicit a Protective Immune Response and Does Not Have an Essential Role in Parasite Survival in the Definitive Host.pdf: 18513912 bytes, checksum: b16a4c95b374bfe5e9e81e84d5297ff4 (MD5)Made available in DSpace on 2020-02-17T13:17:58Z (GMT). No. of bitstreams: 1 Sm16, A Schistosoma mansoni Immunomodulatory Protein, Fails to Elicit a Protective Immune Response and Does Not Have an Essential Role in Parasite Survival in the Definitive Host.pdf: 18513912 bytes, checksum: b16a4c95b374bfe5e9e81e84d5297ff4 (MD5) Previous issue date: 2019Fundação Oswaldo Cruz. Instituto René Rachou. Laboratório de Biologia e Imunologia de Doenças Infeciosas e Parasitárias. Belo Horizonte, MG, Brasil.Fundação Oswaldo Cruz. Instituto René Rachou. Laboratório de Helmintologia e Malacologia Médica. Belo Horizonte, MG, Brasil.Fundação Oswaldo Cruz. Instituto René Rachou. Laboratório de Biologia e Imunologia de Doenças Infeciosas e Parasitárias. Belo Horizonte, MG, Brasil.Fundação Oswaldo Cruz. Instituto René Rachou. Laboratório de Biologia e Imunologia de Doenças Infeciosas e Parasitárias. Belo Horizonte, MG, Brasil.Universidade Federal de São João Del Rei. Laboratório de Patologia Experimental. Divinópolis, MG, Brasil.Fundação Oswaldo Cruz. Instituto René Rachou. Laboratório de Helmintologia e Malacologia Médica. Belo Horizonte, MG, Brasil.Fundação Oswaldo Cruz. Instituto René Rachou. Laboratório de Diagnóstico e Terapia de Doenças Infecciosas e Oncológicas. Belo Horizonte, MG, Brasil.Universidade Federal de São João Del Rei. Laboratório de Patologia Experimental. Divinópolis, MG, Brasil.Fundação Oswaldo Cruz. Instituto René Rachou. Laboratório de Helmintologia e Malacologia Médica. Belo Horizonte, MG, Brasil.Fundação Oswaldo Cruz. Instituto René Rachou. Laboratório de Biologia e Imunologia de Doenças Infeciosas e Parasitárias. Belo Horizonte, MG, Brasil.Fundação Oswaldo Cruz. Instituto René Rachou. Laboratório de Biologia e Imunologia de Doenças Infeciosas e Parasitárias. Belo Horizonte, MG, Brasil.Sm16 is an immunomodulatory protein that seems to play a key role in the suppression of the cutaneous inflammatory response duringSchistosoma mansonipenetration of the skin of definitive hosts. Therefore, Sm16 represents a potential target for protective immuneresponses induced by vaccination. In this work, we generated the recombinant protein rSm16 and produced polyclonal antibodies against this protein to evaluate its expression during different parasite life-cycle stages and its location on the surface of the parasite.In addition, we analyzed the immune responses elicited by immunization with rSm16 using two different vaccine formulations, aswell as its ability to induce protection in Balb/c mice. In order to explore the biological function of Sm16 during the course ofexperimental infection, RNA interference was also employed. Our results demonstrated that Sm16 is expressed in cercaria and schistosomula and is located in the schistosomula surface. Despite humoral and cellular immune responses triggered by vaccination using rSm16 associated with either Freund’s or alum adjuvants, immunized mice presented no reduction in either parasite burdenor parasite egg laying. Knockdown of Sm16gene expression in schistosomula resulted in decreased parasite sizein vitrobut had noeffect on parasite survival or egg productionin vivo. Thus, ourfindings demonstrate that although the vaccine formulations used inthis study succeeded in activating immune responses, these failed to promote parasite elimination. Finally, we have shown that Sm16 is not vital for parasite survival in the definitive host and hence may not represent a suitable target for vaccine development

Table_1_Assessment of the accuracy of 11 different diagnostic tests for the detection of Schistosomiasis mansoni in individuals from a Brazilian area of low endemicity using latent class analysis.XLSX

BackgroundSchistosomiasis is a parasitic disease associated with poverty. It is estimated that 7.1 million people are infected with Schistosoma mansoni in Latin America, with 95% of them living in Brazil. Accurate diagnosis and timely treatment are important measures to control and eliminate schistosomiasis, but diagnostic improvements are needed to detect infections, especially in areas of low endemicity.MethodologyThis research aimed to evaluate the performance of 11 diagnostic tests using latent class analysis (LCA). A cross-sectional survey was undertaken in a low endemicity area of the municipality of Malacacheta, Minas Gerais, Brazil. Feces, urine, and blood samples were collected from 400 residents older than 6 years of age, who had not been treated with praziquantel in the 12 months previous to the collection of their samples. The collected samples were examined using parasitological (Helm Test® kit Kato-Katz), nucleic acid amplification tests -NAATs (PCR, qPCR and LAMP on urine; PCR-ELISA, qPCR and LAMP on stool), and immunological (POC-CCA, the commercial anti-Schistosoma mansoni IgG ELISA kit from Euroimmun, and two in-house ELISA assays using either the recombinant antigen PPE or the synthetic peptide Smp150390.1) tests.ResultsThe positivity rate of the 11 tests evaluated ranged from 5% (qPCR on urine) to 40.8% (commercial ELISA kit). The estimated prevalence of schistosomiasis was 12% (95% CI: 9–15%) according to the LCA. Among all tests assessed, the commercial ELISA kit had the highest estimated sensitivity (100%), while the Kato-Katz had the highest estimated specificity (99%). Based on the accuracy measures observed, we proposed three 2-step diagnostic approaches for the active search of infected people in endemic settings. The approaches proposed consist of combinations of commercial ELISA kit and NAATs tests performed on stool. All the approaches had higher sensitivity and specificity than the mean values observed for the 11 tests (70.4 and 89.5%, respectively).ConclusionWe showed that it is possible to achieve high specificity and sensitivity rates with lower costs by combining serological and NAATs tests, which would assist in the decision-making process for appropriate allocation of public funding aiming to achieve the WHO target of eliminating schistosomiasis as a public health problem by 2030.</p

Table_3_Assessment of the accuracy of 11 different diagnostic tests for the detection of Schistosomiasis mansoni in individuals from a Brazilian area of low endemicity using latent class analysis.DOCX

BackgroundSchistosomiasis is a parasitic disease associated with poverty. It is estimated that 7.1 million people are infected with Schistosoma mansoni in Latin America, with 95% of them living in Brazil. Accurate diagnosis and timely treatment are important measures to control and eliminate schistosomiasis, but diagnostic improvements are needed to detect infections, especially in areas of low endemicity.MethodologyThis research aimed to evaluate the performance of 11 diagnostic tests using latent class analysis (LCA). A cross-sectional survey was undertaken in a low endemicity area of the municipality of Malacacheta, Minas Gerais, Brazil. Feces, urine, and blood samples were collected from 400 residents older than 6 years of age, who had not been treated with praziquantel in the 12 months previous to the collection of their samples. The collected samples were examined using parasitological (Helm Test® kit Kato-Katz), nucleic acid amplification tests -NAATs (PCR, qPCR and LAMP on urine; PCR-ELISA, qPCR and LAMP on stool), and immunological (POC-CCA, the commercial anti-Schistosoma mansoni IgG ELISA kit from Euroimmun, and two in-house ELISA assays using either the recombinant antigen PPE or the synthetic peptide Smp150390.1) tests.ResultsThe positivity rate of the 11 tests evaluated ranged from 5% (qPCR on urine) to 40.8% (commercial ELISA kit). The estimated prevalence of schistosomiasis was 12% (95% CI: 9–15%) according to the LCA. Among all tests assessed, the commercial ELISA kit had the highest estimated sensitivity (100%), while the Kato-Katz had the highest estimated specificity (99%). Based on the accuracy measures observed, we proposed three 2-step diagnostic approaches for the active search of infected people in endemic settings. The approaches proposed consist of combinations of commercial ELISA kit and NAATs tests performed on stool. All the approaches had higher sensitivity and specificity than the mean values observed for the 11 tests (70.4 and 89.5%, respectively).ConclusionWe showed that it is possible to achieve high specificity and sensitivity rates with lower costs by combining serological and NAATs tests, which would assist in the decision-making process for appropriate allocation of public funding aiming to achieve the WHO target of eliminating schistosomiasis as a public health problem by 2030.</p

Table_2_Assessment of the accuracy of 11 different diagnostic tests for the detection of Schistosomiasis mansoni in individuals from a Brazilian area of low endemicity using latent class analysis.XLSX

BackgroundSchistosomiasis is a parasitic disease associated with poverty. It is estimated that 7.1 million people are infected with Schistosoma mansoni in Latin America, with 95% of them living in Brazil. Accurate diagnosis and timely treatment are important measures to control and eliminate schistosomiasis, but diagnostic improvements are needed to detect infections, especially in areas of low endemicity.MethodologyThis research aimed to evaluate the performance of 11 diagnostic tests using latent class analysis (LCA). A cross-sectional survey was undertaken in a low endemicity area of the municipality of Malacacheta, Minas Gerais, Brazil. Feces, urine, and blood samples were collected from 400 residents older than 6 years of age, who had not been treated with praziquantel in the 12 months previous to the collection of their samples. The collected samples were examined using parasitological (Helm Test® kit Kato-Katz), nucleic acid amplification tests -NAATs (PCR, qPCR and LAMP on urine; PCR-ELISA, qPCR and LAMP on stool), and immunological (POC-CCA, the commercial anti-Schistosoma mansoni IgG ELISA kit from Euroimmun, and two in-house ELISA assays using either the recombinant antigen PPE or the synthetic peptide Smp150390.1) tests.ResultsThe positivity rate of the 11 tests evaluated ranged from 5% (qPCR on urine) to 40.8% (commercial ELISA kit). The estimated prevalence of schistosomiasis was 12% (95% CI: 9–15%) according to the LCA. Among all tests assessed, the commercial ELISA kit had the highest estimated sensitivity (100%), while the Kato-Katz had the highest estimated specificity (99%). Based on the accuracy measures observed, we proposed three 2-step diagnostic approaches for the active search of infected people in endemic settings. The approaches proposed consist of combinations of commercial ELISA kit and NAATs tests performed on stool. All the approaches had higher sensitivity and specificity than the mean values observed for the 11 tests (70.4 and 89.5%, respectively).ConclusionWe showed that it is possible to achieve high specificity and sensitivity rates with lower costs by combining serological and NAATs tests, which would assist in the decision-making process for appropriate allocation of public funding aiming to achieve the WHO target of eliminating schistosomiasis as a public health problem by 2030.</p

Image_1_Assessment of the accuracy of 11 different diagnostic tests for the detection of Schistosomiasis mansoni in individuals from a Brazilian area of low endemicity using latent class analysis.TIFF

BackgroundSchistosomiasis is a parasitic disease associated with poverty. It is estimated that 7.1 million people are infected with Schistosoma mansoni in Latin America, with 95% of them living in Brazil. Accurate diagnosis and timely treatment are important measures to control and eliminate schistosomiasis, but diagnostic improvements are needed to detect infections, especially in areas of low endemicity.MethodologyThis research aimed to evaluate the performance of 11 diagnostic tests using latent class analysis (LCA). A cross-sectional survey was undertaken in a low endemicity area of the municipality of Malacacheta, Minas Gerais, Brazil. Feces, urine, and blood samples were collected from 400 residents older than 6 years of age, who had not been treated with praziquantel in the 12 months previous to the collection of their samples. The collected samples were examined using parasitological (Helm Test® kit Kato-Katz), nucleic acid amplification tests -NAATs (PCR, qPCR and LAMP on urine; PCR-ELISA, qPCR and LAMP on stool), and immunological (POC-CCA, the commercial anti-Schistosoma mansoni IgG ELISA kit from Euroimmun, and two in-house ELISA assays using either the recombinant antigen PPE or the synthetic peptide Smp150390.1) tests.ResultsThe positivity rate of the 11 tests evaluated ranged from 5% (qPCR on urine) to 40.8% (commercial ELISA kit). The estimated prevalence of schistosomiasis was 12% (95% CI: 9–15%) according to the LCA. Among all tests assessed, the commercial ELISA kit had the highest estimated sensitivity (100%), while the Kato-Katz had the highest estimated specificity (99%). Based on the accuracy measures observed, we proposed three 2-step diagnostic approaches for the active search of infected people in endemic settings. The approaches proposed consist of combinations of commercial ELISA kit and NAATs tests performed on stool. All the approaches had higher sensitivity and specificity than the mean values observed for the 11 tests (70.4 and 89.5%, respectively).ConclusionWe showed that it is possible to achieve high specificity and sensitivity rates with lower costs by combining serological and NAATs tests, which would assist in the decision-making process for appropriate allocation of public funding aiming to achieve the WHO target of eliminating schistosomiasis as a public health problem by 2030.</p