Navegando por Autor "Teixeira, Santuza Maria Ribeiro"
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Item Adjusting the cut-off and maximum pool size in RT-qPCR pool testing for SARS-CoV-2.(2021) Costa, Murilo Soares; Sato, Hugo I.; Rocha, Raissa Prado; Carvalho, Alex Fiorini Coelho; Guimarães, Nathalia Sernizon; Machado, Elaine Leandro; Alves, Claudia Regina Lindgren; Teixeira, Santuza Maria Ribeiro; Takahashi, Ricardo Hiroshi Caldeira; Tupinambás, Unaí; Fonseca, Flávio Guimarães daReverse transcription quantitative real-time polymerase chain reaction (RT-qPCR) to detect SARS-CoV-2 RNA is an essential test to monitor the occurrence of COVID-19. A methodology is proposed for the determination of maximum pool size and adjustments of cut-off values of cycle threshold (Ct in RT-qPCR pool testing, to compensate for the dilution caused by pooling. The trade off between pool size and test sensitivity is stated explicitly. The procedure was designed to ensure that samples that would be detectable in individual testing remain detectable in pool testing. The proposed relaxation in cut-off is dependent on the pool size, allowing a relatively tight correction to avoid loss of detection of positive samples. The methodology was evaluated in a study of pool testing of adults attending a public emergency care unit, reference for COVID-19 in Belo Horizonte, Brazil, and presenting flu-like symptoms. Even samples on the edge of detectability in individual testing were detected correctly. The proposed procedure enhances the consistency of RT-qPCR pool testing by enforcing that the scales of detectability in pool processing and in individual sample processing are compatible. This may enhance the contribution of pool testing to large-scale testing for COVID-19.Item ASP-2/Trans-sialidase chimeric protein induces robust protective immunity in experimental models of chagas’ disease.(2023) Castro, Júlia Teixeira de; Brito, Rory Cristiane Fortes de; Souza, Natália Satchiko Hojo de; Azevedo, Bárbara Ribeiro Batista Vaz de; Castro, Natália Salazar de; Ferreira, Camila Pontes; Giusta, Caroline Junqueira; Fernandes, Ana Paula Salles Moura; Vasconcellos, José Ronnie Carvalho de; Cardoso, Jamille Mirelle de Oliveira; Soares, Rodrigo Dian de Oliveira Aguiar; Vieira, Paula Melo de Abreu; Carneiro, Cláudia Martins; Valiate, Bruno Vinícius Santos; Toledo, Cristiane; Salazar, Andres M.; Caballero, Otávia; Vieira, Joseli Lannes; Teixeira, Santuza Maria Ribeiro; Reis, Alexandre Barbosa; Gazzinelli, Ricardo TostesImmunization with the Amastigote Surface Protein-2 (ASP-2) and Trans-sialidase (TS) antigens either in the form of recombinant protein, encoded in plasmids or human adenovirus 5 (hAd5) confers robust protection against various lineages of Trypanosoma cruzi. Herein we generated a chimeric protein containing the most immunogenic regions for T and B cells from TS and ASP-2 (TRASP) and evaluated its immunogenicity in comparison with our standard protocol of heterologous prime-boost using plasmids and hAd5. Mice immunized with TRASP protein associated to Poly-ICLC (Hiltonol) were highly resistant to challenge with T. cruzi, showing a large decrease in tissue parasitism, parasitemia and no lethality. This protection lasted for at least 3 months after the last boost of immunization, being equivalent to the protection induced by DNA/hAd5 protocol. TRASP induced high levels of T. cruzispecific antibodies and IFNγ-producing T cells and protection was primarily mediated by CD8+ T cells and IFN-γ. We also evaluated the toxicity, immunogenicity, and efficacy of TRASP and DNA/hAd5 formulations in dogs. Mild collateral effects were detected at the site of vaccine inoculation. While the chimeric protein associated with Poly-ICLC induced high levels of antibodies and CD4+ T cell responses, the DNA/hAd5 induced no antibodies, but a strong CD8+ T cell response. Immunization with either vaccine protected dogs against challenge with T. cruzi. Despite the similar efficacy, we conclude that moving ahead with TRASP together with Hiltonol is advantageous over the DNA/hAd5 vaccine due to pre-existing immunity to the adenovirus vector, as well as the cost-benefit for development and large-scale production.Item Evaluation of three recombinant proteins for the development of ELISA and immunochromatographic tests for visceral leishmaniasis serodiagnosis.(2019) Santos, Anna Raquel Ribeiro dos; Serufo, Ângela Vieira; Figueiredo, Maria Marta; Godoi, Lara Carvalho; Vitório, Jéssica Gardone; Marcelino, Andreza Pain; Avelar, Daniel Moreira de; Rodrigues, Fernandes Tenório Gomes; Coelho, George Luiz Lins Machado; Medeiros, Fernanda Alvarenga Cardoso; Jeronimo, Selma Maria Bezerra; Oliveira, Edward José de; Nascimento, Frederico Crepaldi; Teixeira, Santuza Maria Ribeiro; Gazzinelli, Ricardo Tostes; Nagem, Ronaldo Alves Pinto; Fernandes, Ana Paula Salles MouraBACKGROUND Visceral Leishmaniasis (VL) is an infectious disease that is a significant cause of death among infants aged under 1 year and the elderly in Brazil. Serodiagnosis is a mainstay of VL elimination programs; however, it has significant limitations due to low accuracy. OBJECTIVE This study aimed to evaluate three recombinant Leishmania infantum proteins (rFc, rC9, and rA2) selected from previous proteomics and genomics analyses to develop enzyme-linked immunosorbent assay (ELISA) and immunochromatographic tests (ICT) for the serodiagnosis of human VL (HVL) and canine VL (CVL). METHODS A total of 186 human (70 L. infantum-infected symptomatic, 20 other disease-infected, and 96 healthy) and 185 canine (82 L. infantum-infected symptomatic, 27 L. infantum-infected asymptomatic, and 76 healthy) sera samples were used for antibody detection. FINDINGS Of the three proteins, rA2 (91.5% sensitivity and 87% specificity) and rC9 (95.7% sensitivity and 87.5% specificity) displayed the best performance in ELISA-HVL and ELISA-CVL, respectively. ICT-rA2 also displayed the best performance for HVL diagnosis (92.3% sensitivity and 88.0% specificity) and had high concordance with immunofluorescence antibody tests (IFAT), ELISA-rK39, IT-LEISH®, and ELISAEXT. ICT-rFc, ICT-rC9, and ICT-rA2 had sensitivities of 88.6%, 86.5%, and 87.0%, respectively, with specificity values of 84.0%, 92.0%, and 100%, respectively for CVL diagnosis. MAIN CONCLUSIONS The three antigens selected by us are promising candidates for VL diagnosis regardless of the test format, although the antigen combinations and test parameters may warrant further optimisation.