MARCELO ALVES FERREIRA
Projetos de Pesquisa
Unidades Organizacionais
Departamento de Patologia, Faculdade de Medicina
LIM/59 - Laboratório de Biologia Celular, Hospital das Clínicas, Faculdade de Medicina
LIM/59 - Laboratório de Biologia Celular, Hospital das Clínicas, Faculdade de Medicina
3 resultados
Resultados de Busca
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- Immunodominant antibody responses directed to SARS-CoV-2 hotspot mutation sites and risk of immune escape(2023) OLIVEIRA, Jamille Ramos; RUIZ, Cesar Manuel Remuzgo; MACHADO, Rafael Rahal Guaragna; MAGAWA, Jhosiene Yukari; DAHER, Isabela Pazotti; URBANSKI, Alysson Henrique; SCHMITZ, Gabriela Justamante Haendel; ARCURI, Helen Andrade; FERREIRA, Marcelo Alves; SASAHARA, Greyce Luri; MEDEIROS, Giuliana Xavier de; JR, Roberto Carlos Vieira Silva; DURIGON, Edison Luiz; BOSCARDIN, Silvia Beatriz; ROSA, Daniela Santoro; SCHECHTMAN, Deborah; NAKAYA, Helder. I. I.; CUNHA-NETO, Edecio; GADERMAIER, Gabriele; KALIL, Jorge; COELHO, Veronica; SANTOS, Keity SouzaIntroductionConsidering the likely need for the development of novel effective vaccines adapted to emerging relevant CoV-2 variants, the increasing knowledge of epitope recognition profile among convalescents and afterwards vaccinated with identification of immunodominant regions may provide important information. MethodsWe used an RBD peptide microarray to identify IgG and IgA binding regions in serum of 71 COVID-19 convalescents and 18 vaccinated individuals. ResultsWe found a set of immunodominant RBD antibody epitopes, each recognized by more than 30% of the tested cohort, that differ among the two different groups and are within conserved regions among betacoronavirus. Of those, only one peptide, P44 (S415-429), recognized by 68% of convalescents, presented IgG and IgA antibody reactivity that positively correlated with nAb titers, suggesting that this is a relevant RBD region and a potential target of IgG/IgA neutralizing activity. DiscussionThis peptide is localized within the area of contact with ACE-2 and harbors the mutation hotspot site K417 present in gamma (K417T), beta (K417N), and omicron (K417N) variants of concern. The epitope profile of vaccinated individuals differed from convalescents, with a more diverse repertoire of immunodominant peptides, recognized by more than 30% of the cohort. Noteworthy, immunodominant regions of recognition by vaccinated coincide with mutation sites at Omicron BA.1, an important variant emerging after massive vaccination. Together, our data show that immune pressure induced by dominant antibody responses may favor hotspot mutation sites and the selection of variants capable of evading humoral response.
- Analysis of genetic polymorphisms associated with the presence of freckles for phenotypic prediction(2022) FRIDMAN, Cintia; FERREIRA, Marcelo Alves; MARANO, Leonardo Arduino; FORLENZA, Bettina StingelinThe prediction of externally visible characteristics (EVCs) is a commonly used practice by the forensic sciences as an important resource in the investigation of criminal cases in which the identity of perpetrators or victims is unknown or even to recognize decomposed cadavers. With this purpose, genetic markers associated with pigmentation traits have been widely studied by forensic scientists and, nowadays, it is possible to predict phenotypic characteristics such as hair, eyes and skin colour, as well as the presence of skin freckles by analysing single nucleotide polymorphisms (SNPs). In this study, we analysed the association of six SNPs located in pigmentation genes to the presence of freckles in individuals from the Brazilian population for forensic DNA phenotyping. The study was based within the context of a larger project on a population sample of 534 adult Brazilians of both sexes and different skin colours. DNA was extracted from peripheral blood and genotyped using the TaqMan & REG; OpenArray & REG; Real-Time PCR System (ThermoFischer Scientific) technique. Statistical analyses were carried out with the R software (version 4.0.2). As for the results obtained, three SNPs were shown to be statistically associated to the freckling, rs12203592, rs1800404 and rs222847, with CT, AG and AA genotypes being the main contributors, respectively. Variables such as sex of the individuals and skin colour were found to also contribute to the manifestation of this pigmentation trait. Further statistical analyses will be carried out to evaluate the possibility of using the SNPs in this study for phenotyping prediction of the Brazilian population, improving existing DNA phenotyping models in forensic sciences.
- Development, validation and application of a questionnaire to qualify the indoor environmental exposure of patients with respiratory allergy(2023) SOUZA, Barbara de; FERREIRA, Marcelo Alves; KALIL, Jorge; GIAVINA-BIANCHI, Pedro; AGONDI, Rosana CamaraObjective Environmental control includes measures to prevent exposure to common aeroallergens in an individual's home. Questionnaires are part of the clinical practice of health assessment, and are also widely used in research. Our aim was to develop and validate a questionnaire to identify possible sources of aeroallergens present in the indoor environment. Methods This study describes the development, validation and application of a questionnaire. For content validation the Content Validation Index and Ordinal Cronbach's Alpha Index have been used; Polychoric Correlations for the agreement between judges; and an Exploratory Factor Analysis for the structure of the questionnaire, while for reliability assessment, Intraclass Correlation Coefficient has been applied. Results Twenty-one doctors participated as judges to validate the questionnaire, which 204 patients answered. The Content Validity Index for all the questions on the ""Clarity"" aspect was 0.846 +/- 0.152 and on the ""Relevance"" aspect, 0.954 +/- 0.080. Cronbach's alpha coefficient for the ""Clarity"" aspect was 0.88 with a 95% confidence intervals (CI) and the ""Relevance"" aspect, 0.94 with a 95% CI. The average Intraclass Correlation Coefficient was 0.94 and all the F tests were highly significant. Conclusions The questionnaire developed by our group was considered valid and reliable, and is capable of portraying the home environment without the need for a personal visit to the patient's home. This questionnaire would be a good tool to use in research or during patient consultations to assess the patient's home environment, as this latter assessment is essential for the management of patients with respiratory allergies.