ALVINA CLARA FELIX
Projetos de Pesquisa
Unidades Organizacionais
Departamento de Moléstias Infecciosas e Parasitárias, Faculdade de Medicina
LIM/52 - Laboratório de Virologia, Hospital das Clínicas, Faculdade de Medicina
LIM/52 - Laboratório de Virologia, Hospital das Clínicas, Faculdade de Medicina
4 resultados
Resultados de Busca
Agora exibindo 1 - 4 de 4
- NS1-based ELISA test efficiently detects dengue infections without cross-reactivity with Zika virus(2021) PEREIRA, Samuel Santos; ANDREATA-SANTOS, Robert; PEREIRA, Lennon Ramos; SOARES, Camila Pereira; FELIX, Alvina Clara; ANDRADE, Patricia de Mello Jungmann Cardoso de; DURIGON, Edison Luis; ROMANO, Camila Malta; FERREIRA, Luis Carlos de SouzaObjectives: The aim of this study was to achieve greater specificity of dengue virus (DENV) serological tests based on a recombinant antigen derived from non-structural protein 1 (Delta NS1) with regard to cross-reactive Zika virus (ZIKV) anti-NS1 antibody responses. This is of relevance in endemic regions for the serological discrimination of both DENV and ZIKV, such as Brazil and other tropical countries. Methods: The Delta NS1 proteins were obtained as recombinant antigens and were evaluated as solid-phase-bound antigens in the ELISA test to detect anti-NS1 IgG antibodies. The performance of the Delta NS1-based DENV IgG ELISA was assessed with both mouse and human serum samples previously exposed to DENV or ZIKV. Results: The Delta NS1-based DENV IgG ELISA detected anti-DENV NS1 IgG without cross-reactivity with ZIKV-positive serum samples. The sensitivity and specificity of the assay determined using samples previously characterized by real-time PCR (qRT-PCR) or plaque reduction neutralization assay (PRNT) were 82% and 93%, respectively. Conclusion: The Delta NS1-based DENV IgG ELISA conferred enhanced diagnostic specificity for anti-DENV serological tests and may be particularly useful for serological analyses in endemic regions for both DENV and ZIKV transmission. (C) 2021 The Authors.
- Evaluation of serological cross-reactivity between yellow fever and other flaviviruses(2019) SOUZA, Nathalia Caroline Santiago e; FELIX, Alvina Clara; PAULA, Anderson Vicente de; LEVI, Jose Eduardo; PANNUTI, Claudio Sergio; ROMANO, Camila MaltaObjectives: This study was performed to determine whether neutralizing antibodies against yellow fever virus (YFV) generated by YFV vaccine could interfere in the specificity of dengue virus (DENV) and Zika virus (ZIKV) IgG ELISA tests. Methods: Seventy-nine pairs of serum samples (pre- and post-vaccination), collected during the years 1997-1998 from children with no history of yellow fever disease who had been vaccinated against YFV, were tested. The seroconversion post-vaccination was evaluated through plaque reduction neutralization test (PRNT), and four different commercial ELISA kits were used for the detection of DENV and ZIKV IgG antibodies. Results: A cross-reactivity rate of 3.9% with DENV IgG antibodies was found only with the Dengue Virus IgG Dx Select kit (Focus Diagnostics). Conclusions: As several countries have local transmission of multiple arboviruses, the absence of cross-reactivity or minimum cross-reactivity of YFV neutralizing antibodies with DENV and ZIKV antigens is a relevant finding, since the interpretation of sero-epidemiological investigations would be seriously impacted in many regions where YFV vaccination is mandatory. (C) 2019 The Authors.
- Low prevalence after the first Zika virus epidemic wave in Southeastern Brazil(2018) LUNA, E.; ROMANO, C.; ARAUJO, E.; FELIX, A. C.; NAKASONE, O.; CAMPOS, S.; FERNANDES, L.; LEVI, J. E.; SANTIAGO, N.; FERNANDES, J.; FRAGOSO, D.; KALLAS, E.; PANNUTI, C.
- Specificity of NS1-based immunochromatographic tests for dengue virus with regard to the Zika virus protein(2020) ANDREATA-SANTOS, Robert; PEREIRA, Samuel Santos; PEREIRA, Lennon Ramos; FELIX, Alvina Clara; ROMANO, Camila Malta; FERREIRA, Luis Carlos de SouzaObjectives: This study was performed to determine whether Dengue virus (DENV) immunochromatographic tests can detect and differentiate nonstructural protein 1 (NS1) from each of the four DENV serotypes and do not cross-react with the Zika virus (ZIKV) NS1 protein. Methods: We compared the specificity of six NS1-based DENV immunochromatographic tests (point of care) in the detection of NS1 proteins from each of the four DENV serotypes and ZIKV. The tests were performed with NS1 proteins produced in mammalian cells. Cross-reactivity was confirmed with a purified recombinant ZIKV NS1 protein and DENV+ or ZIKV(+) human serum samples. Results: Cross-reaction was observed in 2 out of the 6 evaluated tests using cell culture supernatants containing NS1 protein of each tested virus. Cross-reactivity with ZIKV was confirmed with purified recombinant ZIKV NS1 produced in Escherichia coli. Further analyses with serum samples collected from DENV+ or ZIKV(+) patients confirmed the cross-reactivity with ZIKV protein in 2 tests. Conclusions: The detection of the NS1 protein is the basis for several commercially available serological DENV diagnostic tests. The present results emphasize the relevance of testing specificity of presently available NS1-based DENV serological tests and the need of adjustments of tests that cross-react with the ZIKV protein. Our results are particularly relevant for regions where both viruses are endemically found, as in the case of Brazil. (c) 2020 The Authors.