Bruna de Paula e Fonseca

The role of interferon-gamma on immune and allergic responses

Allergic diseases have been closely related to Th2 immune responses, which are characterized by high levels of interleukin (IL) IL-4, IL-5, IL-9 and IL-13. These cytokines orchestrate the recruitment and activation of different effector cells, such as eosinophils and mast cells. These cells along with Th2 cytokines are key players on the development of chronic allergic inflammatory disorders, usually characterized by airway hyperresponsiveness, reversible airway obstruction, and airway inflammation. Accumulating evidences have shown that altering cytokine-producing profile of Th2 cells by inducing Th1 responses may be protective against Th2-related diseases such as asthma and allergy. Interferon-gamma (IFN-gamma), the principal Th1 effector cytokine, has shown to be crucial for the resolution of allergic-related immunopathologies. In fact, reduced production of this cytokine has been correlated with severe asthma. In this review, we will discuss the role of IFN-gamma during the generation of immune responses and its influence on allergic inflammation models, emphasizing its biologic properties during the different aspects of allergic responses.

Alterations in cytokines and haematological parameters during the acute and convalescent phases of Plasmodium falciparum and Plasmodium vivax infections

Haematological and cytokine alterations in malaria are a broad and controversial subject in the literature. However, few studies have simultaneously evaluated various cytokines in a single patient group during the acute and convalescent phases of infection. The aim of this study was to sequentially characterise alterations in haematological patters and circulating plasma cytokine and chemokine levels in patients infected with Plasmodium vivax or Plasmodium falciparum from a Brazilian endemic area during the acute and convalescent phases of infection. During the acute phase, thrombocytopaenia, eosinopaenia, lymphopaenia and an increased number of band cells were observed in the majority of the patients. During the convalescent phase, the haematologic parameters returned to normal. During the acute phase, P. vivax and P. falciparum patients had significantly higher interleukin (IL)-6, IL-8, IL-17, interferon-γ, tumour necrosis factor (TNF)-α, macrophage inflammatory protein-1β and granulocyte-colony stimulating factor levels than controls and maintained high levels during the convalescent phase. IL-10 was detected at high concentrations during the acute phase, but returned to normal levels during the convalescent phase. Plasma IL-10 concentration was positively correlated with parasitaemia in P. vivax and P. falciparum-infected patients. The same was true for the TNF-α concentration in P. falciparum-infected patients. Finally, the haematological and cytokine profiles were similar between uncomplicated P. falciparum and P. vivax infections.

Viability study of a multiplex diagnostic platform for Chagas disease

A new multiplex assay platform was evaluated to detect Trypanosoma cruzi infection using the recombinant antigens CRA, FRA, CRAFRA fusion and parasite lysate. The antigens presented different sensitivity and specificity in a singleplex test when compared to a serial dilution of two pools comprising 10 positive serum samples and one pool of 10 negative samples. The recombinant protein CRA presented lower sensitivity (55%) in contrast to the 100% specificity and sensitivity of FRA, CRAFRA and T. cruzi lysate. These antigens also showed good results in a duplex test and the duplex test with CRAFRA/T. cruzi lysate showed better performance with 100% specificity and sensitivity, as well as a lower cut-off value in comparison to the other duplex test, FRA/T. cruzi lysate. Hence, when the antigens were used in duplex format, both tests showed decreased cut-off values and no interference between different bead sets, resulting in increasing sensitivity and specificity. The results of these multiplex tests show that they could be an alternative to singleplex detection for Chagas disease, and also indicate the necessity of using multiplex diagnostic tools to increase the sensitivity and specificity for diagnostic tests. Emerging data from the T. cruzi genome and from its ORFeome project will also allow the identification of new antigens for this disease detection application.

Development of a multiplex bead-based assay for detection of hepatitis C virus.

ABSTRACT Hepatitis C virus (HCV) infection is a major burden to public health worldwide, affecting approximately 3% of the human population. Although HCV detection is currently based on reliable tests, the field of medical diagnostics has a growing need for inexpensive, accurate, and quick high-throughput assays. By using the recombinant HCV antigens NS3, NS4, NS5, and Combined, we describe a new bead-based multiplex test capable of detecting HCV infection in human serum samples. The first analysis, made in a singleplex format, showed that each antigen coupled to an individual bead set presented high-level responses for anti-HCV-positive reference serum pools and lower-level responses for the HCV-negative pools. Our next approach was to determine the sensitivity and specificity of each antigen by testing 93 HCV-positive and 93 HCV-negative sera. When assayed in the singleplex format, the NS3, NS4, and NS5 antigens presented lower sensitivity values (50.5%, 51.6%, and 55.9%, respectively) than did the Combined antigen, which presented a sensitivity of 93.5%. All antigens presented 100% specificity. These antigens were then multiplexed in a 4-plex assay, which resulted in increased sensitivity and specificity values, performing with 100% sensitivity and 100% specificity. The positive and negative predictive values for the 4-plex assay were 100%. Although preliminary, this 4-plex assay showed robust results that, aligned with its small-sample-volume requirements and also its cost- and time-effectiveness, make it a reasonable alternative to tests currently used for HCV screening of potentially infected individuals.

Intestinal Parasites Coinfection Does Not Alter Plasma Cytokines Profile Elicited in Acute Malaria in Subjects from Endemic Area of Brazil

In Brazil, malaria is prevalent in the Amazon region and these regions coincide with high prevalence of intestinal parasites but few studies explore the interaction between malaria and other parasites. Therefore, the present study evaluates changes in cytokine, chemokine, C-reactive protein, and nitric oxide (NO) concentrations in 264 individuals, comparing plasma from infected individuals with concurrent malaria and intestinal parasites to individuals with either malaria infection alone and uninfected. In the studied population 24% of the individuals were infected with Plasmodium and 18% coinfected with intestinal parasites. Protozoan parasites comprised the bulk of the intestinal parasites infections and subjects infected with intestinal parasites were more likely to have malaria. The use of principal component analysis and cluster analysis associated increased levels of IL-6, TNF-α, IL-10, and CRP and low levels of IL-17A predominantly with individuals with malaria alone and coinfected individuals. In contrast, low levels of almost all inflammatory mediators were associated predominantly with individuals uninfected while increased levels of IL-17A were associated predominantly with individuals with intestinal parasites only. In conclusion, our data suggest that, in our population, the infection with intestinal parasites (mainly protozoan) does not modify the pattern of cytokine production in individuals infected with P. falciparum and P. vivax.

Dengue research networks: building evidence for policy and planning in Brazil

BackgroundThe analysis of scientific networks has been applied in health research to map and measure relationships between researchers and institutions, describing collaboration structures, individual roles, and research outputs, and helping the identification of knowledge gaps and cooperation opportunities. Driven by dengue continued expansion in Brazil, we explore the contribution, dynamics and consolidation of dengue scientific networks that could ultimately inform the prioritisation of research, financial investments and health policy.MethodSocial network analysis (SNA) was used to produce a 20-year (1995–2014) retrospective longitudinal evaluation of dengue research networks within Brazil and with its partners abroad, with special interest in describing institutional collaboration and their research outputs.ResultsThe analysis of institutional co-authorship showed a significant expansion of collaboration over the years, increased international involvement, and ensured a shift from public health research toward vector control and basic biomedical research, probably as a reflection of the expansion of transmission, high burden and increasing research funds from the Brazilian government. The analysis identified leading national organisations that maintained the research network connectivity, facilitated knowledge exchange and reduced network vulnerability.ConclusionsSNA proved to be a valuable tool that, along with other indicators, can strengthen a knowledge platform to inform future policy, planning and funding decisions. The paper provides relevant information to policy and planning for dengue research as it reveals: (1) the effectiveness of the research network in knowledge generation, sharing and diffusion; (2) the near-absence of collaboration with the private sector; and (3) the key central organisations that can support strategic decisions on investments, development and implementation of innovations. In addition, the increase in research activities and collaboration has not yet significantly affected dengue transmission, suggesting a limited translation of research efforts into public health solutions.

Mapping the dengue scientific landscape worldwide: a bibliometric and network analysis

BACKGROUND Despite the current global trend of reduction in the morbidity and mortality of neglected diseases, dengue’s incidence has increased and occurrence areas have expanded. Dengue also persists as a scientific and technological challenge since there is no effective treatment, vaccine, vector control or public health intervention. Combining bibliometrics and social network analysis methods can support the mapping of dengue research and development (R&D) activities worldwide. OBJECTIVES The aim of this paper is to map the scientific scenario related to dengue research worldwide. METHODS We use scientific publication data from Web of Science Core Collection - articles indexed in Science Citation Index Expanded (SCI-EXPANDED) - and combine bibliometrics and social network analysis techniques to identify the most relevant journals, scientific references, research areas, countries and research organisations in the dengue scientific landscape. FINDINGS Our results show a significant increase of dengue publications over time; tropical medicine and virology as the most frequent research areas and biochemistry and molecular biology as the most central area in the network; USA and Brazil as the most productive countries; and Mahidol University and Fundação Oswaldo Cruz as the main research organisations and the Centres for Disease Control and Prevention as the most central organisation in the collaboration network. MAIN CONCLUSIONS Our findings can be used to strengthen a global knowledge platform guiding policy, planning and funding decisions as well as to providing directions to researchers and institutions. So that, by offering to the scientific community, policy makers and public health practitioners a mapping of the dengue scientific landscape, this paper has aimed to contribute to upcoming debates, decision-making and planning on dengue R&D and public health strategies worldwide.

NFAT1 transcription factor in dendritic cells is required to modulate T helper cell differentiation

The NFAT family of transcription factors plays a central role in the regulation of cytokine gene expression during the immune response. NFAT functions have been extensively explored in lymphocyte activation and differentiation, but the involvement of NFAT proteins in dendritic cells (DCs) is still not well known. Here, we investigated the role of the NFAT1 transcription factor in murine DCs. Initially, we demonstrated by western blot that the NFAT1 protein is present in splenic DCs and is rapidly activated upon calcium influx. We then used NFAT1-deficient mice (NFAT1-/-) to investigate whether NFAT1 influences the ability of DCs to induce Th differentiation. Our data demonstrated that NFAT1-/- DCs showed an increased capacity to differentiate CD4 T cells to the Th1 phenotype. CD4 cells that were primed in vitro with NFAT1-/- DCs had increased IFN-γ production. The same results were observed when the CD4 cells were primed in vivo through the sensitization of NFAT1-/- mice with ovalbumin. Furthermore, our results demonstrated that the cytokine IL-12 is one of the factors involved in this process because its production is increased in NFAT1-/- mice, and neutralizing anti-IL-12 antibodies almost completely eliminated the IFN-γ production. These results demonstrated that the NFAT1 transcription factor regulates specific functions in DCs that are involved in CD4 differentiation, suggesting that the inhibition of NFAT1 in DCs may be used as a therapy to modulate specific immune responses.

Mapping the Brazilian microscopy landscape: A bibliometric and network analysis

Understanding how a technology is introduced and shared in a society has a strategic value for the planning of technological development and assessing new market opportunities. Among other technologies, microscopy has had a significant role in advancing different fields of science. In Brazil, its use spans from biomedical to engineering areas. Here, we used social network analysis (SNA) to map and quantify the flow of interaction between Brazilian researchers involved in microscopy techniques. The analysis examines co-occurrence of thematic networks and scientific co-authorship in articles published in a ten years window, as retrieved from Scopus database. The results showed an increasing volume of publications using microscopy in Brazil. The two major areas of interest are material and life sciences, which present significant intra-regional interaction. USA, Spain, Germany, Portugal and the United Kingdom are the main partner countries for international scientific collaborations. The share of Brazilian publications applying microscopy follows the global trends, with a slight predominance in health and life sciences. Our results provide a context of the strengths and gaps of the field in Brazil and may help to inform researchers and policy makers for further advancing the field.

Network analysis for science and technology management: Evidence from tuberculosis research in Fiocruz, Brazil

Collaborative networks are of great value for science and technology (S&T) institutions as a way of sharing, generating and disseminating new knowledge that could ultimately lead to innovations. Driven by the need to assess the contribution and effectiveness of these networks in informing S&T management, we explored the evolution and dynamics of tuberculosis scientific networks involving the Oswaldo Cruz Foundation (Fiocruz), the major public health S&T Institution in Brazil. Social network analysis (SNA) was used to produce a 10-year (2005–2009, 2010–2014) retrospective longitudinal mapping of Brazilian tuberculosis research networks within the country and internationally, highlighting Fiocruz collaborations. Co-authorship analysis showed a significant expansion of collaboration in Brazil and the role of Fiocruz and other leading national institutions in maintaining connectivity, facilitating knowledge exchange and reducing network vulnerability. It also identified influential researchers that can act as information leaders and support strategic decisions. When we focused on networks inside the institution, the analysis showed a clear discontinuation between the clinical and the public health research areas, which needs specific internal policies to improve collaborations since outcomes in TB are expected to provide better diagnostic tools and more effective treatments. The approach provides evidence to support S&T management by pinpointing: key central institutions maintaining network connectivity; most influential researchers that can act as advisors/experts for investment and induction policies; key Fiocruz researchers that could improve information exchange, systems integration and innovation within the institution; opportunities for synergy between internal research groups working in complementary areas. In summary, we observed that SNA parameters proved to be a valuable tool that, along with other indicators, can strengthen knowledge platforms to support S&T management efforts.