Evaluation of an RBD-nucleocapsid fusion protein as a booster candidate for COVID-19 vaccine.

Despite successful vaccines and updates, constant mutations of SARS-CoV-2 makes necessary the search for new vaccines. We generated a chimeric protein that comprises the receptor-binding domain from spike and the nucleocapsid antigens (SpiN) from SARS-CoV-2. Once SpiN elicits a protective immune response in rodents, here we show that convalescent and previously vaccinated individuals respond to SpiN. CD4+ and CD8+ T cells from these individuals produced greater amounts of IFN-γ when stimulated with SpiN, compared to SARS-CoV-2 antigens. Also, B cells from these individuals were able to secrete antibodies that recognize SpiN. When administered as a boost dose in mice previously immunized with CoronaVac, ChAdOx1-S or BNT162b2, SpiN was able to induce a greater or equivalent immune response to homologous prime/boost. Our data reveal the ability of SpiN to induce cellular and humoral responses in vaccinated human donors, rendering it a promising candidate.

Signatures of CD4+ T and B cells are associated with distinct stages of chronic chagasic cardiomyopathy.

Introduction: Chagas disease is a neglected parasitic disease caused by Trypanosoma cruzi. While most patients are asymptomatic, around 30% develop Chronic Chagasic Cardiomyopathy (CCC). Methods: Here, we employed high-dimensional flow cytometry to analyze CD4+ T and B cell compartments in patients during the chronic phase of Chagas disease, presenting the asymptomatic and mild or moderate/severe cardiac clinical forms. Results: Effector CD27-CD4+ T cells were expanded in both CCC groups, and only mild CCC patients showed higher frequencies of effector memory and T follicular helper (Tfh) cells than healthy donors (CTL) and asymptomatic patients. Unsupervised analysis confirmed these findings and further revealed the expansion of a specific subpopulation composed of Tfh, transitional, and central memory CD4+ T cells bearing a phenotype associated with strong activation, differentiation, and exhaustion in patients with mild but not moderate/severe CCC. In contrast, patients with mild and moderate/severe CCC had lower frequencies of CD4+ T cells expressing lower levels of activation markers, suggesting resting status, than CTL. Regarding the B cell compartment, no alterations were found in naïve CD21-, memory cells expressing IgM or IgD, marginal zone, and plasma cells in patients with Chagas disease. However, expansion of class-switched activated and atypical memory B cells was observed in all clinical forms, and more substantially in mild CCC patients. Discussion: Taken together, our results showed that T. cruzi infection triggers changes in CD4+ T and B cell compartments that are more pronounced in the mild CCC clinical form, suggesting an orchestrated cellular communication during Chagas disease. Conclusion: Overall, these findings reinforce the heterogeneity and complexity of the immune response in patients with chronic Chagas disease and may provide new insights into disease pathology and potential markers to guide clinical decisions.

Comprehensive landscape of neutralizing antibody and cell-mediated response elicited by the 1/5 fractional dose of 17DD-YF primary vaccination in adults.

The present study aimed at evaluating the YF-specific neutralizing antibody profile besides a multiparametric analysis of phenotypic/functional features of cell-mediated response elicited by the 1/5 fractional dose of 17DD-YF vaccine, administered as a single subcutaneous injection. The immunological parameters of each volunteer was monitored at two time points, referred as: before (Day 0) [Non-Vaccinated, NV(D0)] and after vaccination (Day 30-45) [Primary Vaccinees, PV(D30-45)]. Data demonstrated high levels of neutralizing antibodies for PV(D30-45) leading to a seropositivity rate of 93%. A broad increase of systemic soluble mediators with a mixed profile was also observed for PV(D30-45), with IFN-γ and TNF-α presenting the highest baseline fold changes. Integrative network mapping of soluble mediators showed increased correlation numbers in PV(D30-45) as compared to NV(D0) (532vs398). Moreover, PV(D30-45) exhibited increased levels of Terminal Effector (CD45RA+CCR7-) CD4+ and CD8+ T-cells and Non-Classical memory B-cells (IgD+CD27+). Dimensionality reduction of Mass Cytometry data further support these findings. A polyfunctional cytokine profile (TNF-α/IFN-γ/IL-10/IL-17/IL-2) of T and B-cells was observed upon in vitro antigen recall. Mapping and kinetics timeline of soluble mediator signatures for PV(D30-45) further confirmed the polyfunctional profile upon long-term in vitro culture, mediated by increased levels of IFN-γ and TNF-α along with decreased production of IL-10. These findings suggest novel insights of correlates of protection elicited by the 1/5 fractional dose of 17DD-YF vaccine.

The absence of eosinophils is associated with early metastatic lesions in Leishmania amazonensis-infected mice.

BACKGROUND: Eosinophils are granulocytes that rapidly increase frequency in the bloodstream during helminthic infections and allergic responses. They are found in tissue infected by Leishmania during early disease, but their role during infection is not entirely understood. OBJECTIVES: We aim to compare the disease due to Leishmania amazonensis in BALB/c and Δdbl-GATA1 mice, which lack eosinophils. METHODS: BALB/c and Δdbl-GATA1 mice infected with L. amazonensis were observed for several weeks. The parasite load and dissemination pattern were assessed. FINDINGS: The Δdbl-GATA1 mice developed an anticipated dissemination of L. amazonensis and a worsening disease. No differences were found in the lesion development or the parasite load in the footpad among Δdbl-GATA1 mice and BALB/c eight weeks after infection. However, nine weeks after infection, massive growth of metastatic lesions appeared in several parts of the skin in Δdbl-GATA1 mice, weeks earlier than BALB/c. We observed increased parasites in the bloodstream, probably an essential dissemination route. Thirteen weeks after infection, metastatic lesions were found in all Δdbl-GATA1 mice. MAIN CONCLUSION: These results suggest a protective role of eosinophils in delaying the disease caused by L. amazonensis, although several limitations of this mice strain must be considered.

The absence of eosinophils is associated with early metastatic lesions in Leishmania amazonensis-infected mice

BACKGROUND Eosinophils are granulocytes that rapidly increase frequency in the bloodstream during helminthic infections and allergic responses. They are found in tissue infected by Leishmania during early disease, but their role during infection is not entirely understood. OBJECTIVES We aim to compare the disease due to Leishmania amazonensis in BALB/c and Δdbl-GATA1 mice, which lack eosinophils. METHODS BALB/c and Δdbl-GATA1 mice infected with L. amazonensis were observed for several weeks. The parasite load and dissemination pattern were assessed. FINDINGS The Δdbl-GATA1 mice developed an anticipated dissemination of L. amazonensis and a worsening disease. No differences were found in the lesion development or the parasite load in the footpad among Δdbl-GATA1 mice and BALB/c eight weeks after infection. However, nine weeks after infection, massive growth of metastatic lesions appeared in several parts of the skin in Δdbl-GATA1 mice, weeks earlier than BALB/c. We observed increased parasites in the bloodstream, probably an essential dissemination route. Thirteen weeks after infection, metastatic lesions were found in all Δdbl-GATA1 mice. MAIN CONCLUSION These results suggest a protective role of eosinophils in delaying the disease caused by L. amazonensis, although several limitations of this mice strain must be considered.

Setting priorities for mental health research in Brazil / Agenda de prioridades de pesquisa para saúde mental no Brasil

BACKGROUND: The main aim of this study is to review the agenda for research priorities of mental health in Brazil. METHODOLOGY: The first step was to gather 28 experts (22 researchers, five policy makers, and the coordinator) representing all mental health fields from different geographical areas of the country. Participants were asked to list what they considered to be the most relevant mental health research questions for the country to address in the next 10 years. Seventeen participants answered this question; after redundancies were excluded, a total of 110 responses were collected. As the second step, participants were asked to rank which questions were the 35 most significant. The final step was to score 15 items for each of the 35 selected questions to determine whether it would be a) answerable, b) effective, c) deliverable, d) equitable, and e) effective at reducing the burden of mental health. The ten highest ranked questions were then selected. RESULTS: There were four questions addressing primary care with respect to a) the effectiveness of interventions, b) "matrix support", c) comparisons of different models of stepped care, and d) interventions to enhance identification and treatment of common mental disorders at the Family Health Program. The other questions were related to the evaluation of mental health services for adults and children/adolescents to clarify barriers to treatment in primary care, drug addiction, and severe mental disorders; to investigate the cost-benefit relationship of anti-psychotics; to design interventions to decrease alcohol consumption; and to apply new technologies (telemedicine) for education and supervision of non-specialists. CONCLUSION: This priority-setting research exercise highlighted a need for implementing investments at the primary-care level, particularly in the family health program; the urgent need to evaluate services; and policies to improve equity by increasing accessibility to services and testing interventions to reduce barriers for seeking mental health treatment.

INTRODUÇÃO: O principal objetivo desse estudo foi revisar a agenda de prioridades em pesquisa em saúde mental no Brasil. MÉTODO: Foram selecionados 28 especialistas (22 pesquisadores, cinco legisladores e o coordenador) de diferentes regiões. Responderam ao que consideravam mais relevante em pesquisa para a saúde mental para os próximos 10 anos. Dezessete responderam e configuraram 110 questões, que foram reavaliadas por eles, com atribuição de escore, a partir de 15 itens distribuídos segundo grau de responsividade, eficácia, aplicabilidade, equidade e impacto na redução da carga da doença mental. 35 questões, e dentre elas as 10 mais bem pontuadas, foram destacadas. RESULTADOS: Prevaleceram indicações para estudos de efetividade das intervenções, matriciamento, comparação entre modelos de intervenção e detecção e tratamento de transtornos mais prevalentes na Estratégia da Saúde da Família. Avaliação de serviços quanto às barreiras ao tratamento; custo-efetividade dos antipsicóticos, intervenções contra efeitos do álcool e outras drogas, e aplicação de tecnologias (telemedicina) para educação e supervisão dos generalistas foram outros. CONCLUSÃO: Apontou-se para necessidade de investimentos na saúde mental na atenção primária à saúde; avaliação do sistema de serviços de cuidados de saúde mental, e pesquisas para romper barreiras ao acesso e à equidade no tratamento dos transtornos mentais.