Antigen Targeting to Dendritic Cells Allows the Identification of a CD4 T-Cell Epitope within an Immunodominant Trypanosoma cruzi Antigen

Targeting antigens to dendritic cells (DCs) by using hybrid monoclonal antibodies (mAbs) directed against DC receptors is known to improve activation and support long-lasting T cell responses. in the present work, we used the mAb alpha DEC205 fused to the Trypanosoma cruzi amastigote surface protein 2 (ASP-2) to identify a region of this protein recognized by specific T cells. the hybrid alpha DEC-ASP2 mAb was successfully generated and preserved its ability to bind the DEC205 receptor. Immunization of BALB/c mice with the recombinant mAb in the presence of polyriboinosinic: polyribocytidylic acid (poly (I:C)) specifically enhanced the number of IFN-gamma producing cells and CD4+ T cell proliferation when compared to mice immunized with a mAb without receptor affinity or with the non-targeted ASP-2 protein. the strong immune response induced in mice immunized with the hybrid alpha DEC-ASP2 mAb allowed us to identify an ASP-2-specific CD4+ T cell epitope recognized by the BALB/c MHCII haplotype. We conclude that targeting parasite antigens to DCs is a useful strategy to enhance T cell mediated immune responses facilitating the identification of new T-cell epitopes.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)BNP-Paribas Bankcommercial source BNP-Paribas BankUniv São Paulo, Inst Biomed Sci, Dept Parasitol, Lab Antigen Targeting Dendrit Cells, São Paulo, BrazilUniversidade Federal de São Paulo, CTCMol, São Paulo, BrazilNatl Inst Sci & Technol Vaccines, Belo Horizonte, MG, BrazilUniversidade Federal de São Paulo, CTCMol, São Paulo, BrazilCNPq: 15203*12FAPESP: 2007/08648-9Web of Scienc

Development of a genetic tool for functional screening of anti-malarial bioactive extracts in metagenomic libraries

BACKGROUND: The chemical treatment of Plasmodium falciparum for human infections is losing efficacy each year due to the rise of resistance. One possible strategy to find novel anti-malarial drugs is to access the largest reservoir of genomic biodiversity source on earth present in metagenomes of environmental microbial communities. METHODS: A bioluminescent P. falciparum parasite was used to quickly detect shifts in viability of microcultures grown in 96-well plates. A synthetic gene encoding the Dermaseptin 4 peptide was designed and cloned under tight transcriptional control in a large metagenomic insert context (30 kb) to serve as proof-of-principle for the screening platform. RESULTS: Decrease in parasite viability consistently correlated with bioluminescence emitted from parasite microcultures, after their exposure to bacterial extracts containing a plasmid or fosmid engineered to encode the Dermaseptin 4 anti-malarial peptide. CONCLUSIONS: Here, a new technical platform to access the anti-malarial potential in microbial environmental metagenomes has been developed

Development of a genetic tool for functional screening of anti-malarial bioactive extracts in metagenomic libraries

Ajuts: Departamento Administrativo de Ciencias, Tecnología e Innovación (Colciencias), República de Colombia; Convocatoria 489 - 2009, Código 657048925406, Contrato de financiación RC. 427 - 2009 Colciencias - CorpoGen; Programa de Asistencias Graduadas de Universidad de los Andes, Bogotá, Colombia; i Programa Jóvenes Investigadores de ColcienciasBACKGROUND: The chemical treatment of Plasmodium falciparum for human infections is losing efficacy each year due to the rise of resistance. One possible strategy to find novel anti-malarial drugs is to access the largest reservoir of genomic biodiversity source on earth present in metagenomes of environmental microbial communities. METHODS: A bioluminescent P. falciparum parasite was used to quickly detect shifts in viability of microcultures grown in 96-well plates. A synthetic gene encoding the Dermaseptin 4 peptide was designed and cloned under tight transcriptional control in a large metagenomic insert context (30 kb) to serve as proof-of-principle for the screening platform. RESULTS: Decrease in parasite viability consistently correlated with bioluminescence emitted from parasite microcultures, after their exposure to bacterial extracts containing a plasmid or fosmid engineered to encode the Dermaseptin 4 anti-malarial peptide. Here, a new technical platform to access the anti-malarial potential in microbial environmental metagenomes has been develope

Prospective, randomized trial comparing fluids and dobutamine optimization of oxygen delivery in high-risk surgical patients [ISRCTN42445141]

INTRODUCTION: Preventing perioperative tissue oxygen debt contributes to a better postoperative recovery. Whether the beneficial effects of fluids and inotropes during optimization of the oxygen delivery index (DO(2)I) in high-risk patients submitted to major surgeries are due to fluids, to inotropes, or to the combination of the two is not known. We aimed to investigate the effect of DO(2)I optimization with fluids or with fluids and dobutamine on the 60-day hospital mortality and incidence of complications. METHODS: A randomized and controlled trial was performed in 50 high-risk patients (elderly with coexistent pathologies) undergoing major elective surgery. Therapy consisted of pulmonary artery catheter-guided hemodynamic optimization during the operation and 24 hours postoperatively using either fluids alone (n = 25) or fluids and dobutamine (n = 25), aiming to achieve supranormal values (DO(2)I > 600 ml/minute/m(2)). RESULTS: The cardiovascular depression was an important component in the perioperative period in this group of patients. Cardiovascular complications in the postoperative period occurred significantly more frequently in the volume group (13/25, 52%) than in the dobutamine group (4/25, 16%) (relative risk, 3.25; 95% confidence interval, 1.22–8.60; P < 0.05). The 60-day mortality rates were 28% in the volume group and 8% in the dobutamine group (relative risk, 3.00; 95% confidence interval, 0.67–13.46; not significant). CONCLUSION: In patients with high risk of perioperative death, pulmonary artery catheter-guided hemodynamic optimization using dobutamine determines better outcomes, whereas fluids alone increase the incidence of postoperative complications

Targeting the non-structural protein 1 from dengue virus to a dendritic cell population confers protective immunity to lethal virus challenge

Dengue is the most prevalent arboviral infection, affecting millions of people every year. Attempts to control such infection are being made, and the development of a vaccine is a World Health Organization priority. Among the proteins being tested as vaccine candidates in preclinical settings is the non-structural protein 1 (NS1). In the present study, we tested the immune responses generated by targeting the NS1 protein to two different dendritic cell populations. Dendritic cells (DCs) are important antigen presenting cells, and targeting proteins to maturing DCs has proved to be an efficient means of immunization. Antigen targeting is accomplished by the use of a monoclonal antibody (mAb) directed against a DC cell surface receptor fused to the protein of interest. We used two mAbs (αDEC205 and αDCIR2) to target two distinct DC populations, expressing either DEC205 or DCIR2 endocytic receptors, respectively, in mice. The fusion mAbs were successfully produced, bound to their respective receptors, and were used to immunize BALB/c mice in the presence of polyriboinosinic: polyribocytidylic acid (poly (I:C)), as a DC maturation stimulus. We observed induction of strong anti-NS1 antibody responses and similar antigen binding affinity irrespectively of the DC population targeted. Nevertheless, the IgG1/IgG2a ratios were different between mouse groups immunized with αDEC-NS1 and αDCIR2-NS1 mAbs. When we tested the induction of cellular immune responses, the number of IFN-γ producing cells was higher in αDEC-NS1 immunized animals. In addition, mice immunized with the αDEC-NS1 mAb were significantly protected from a lethal intracranial challenge with the DENV2 NGC strain when compared to mice immunized with αDCIR2-NS1 mAb. Protection was partially mediated by CD4(+) and CD8(+) T cells as depletion of these populations reduced both survival and morbidity signs. We conclude that targeting the NS1 protein to the DEC205(+) DC population with poly (I:C) opens perspectives for dengue vaccine development.Brazilian National Research Council (CNPq)National Institute of Science and Technology Research Funding Agency (INCTV) - 15203*12São Paulo State Research Funding Agency (FAPESP) - 2007/08648-9, 2011/51761-6BNP-Paribas BankRio de Janeiro State Research Funding Agency (FAPERJ

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost