Browsing by Author "Brito, Rory Cristiane Fortes de"
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Item Acarbose presents in vitro and in vivo antileishmanial activity against Leishmania infantum and is a promising therapeutic candidate against visceral leishmaniasis.(2020) Costa, Rafaella R.; Silva, João Augusto Oliveira da; Reis, Thiago Alves Rosa dos; Tavares, Grasiele de Sousa Vieira; Mendonça, Débora Vasconcelos Costa; Freitas, Camila Simões de; Lage, Daniela Pagliara; Martins, Vívian Tamietti; Antinarelli, Luciana Maria Ribeiro; Machado, Amanda Sanchez; Bandeira, Raquel Soares; Ribeiro, Fernanda Ludolf; Santos, Thaís Teodoro de Oliveira; Brito, Rory Cristiane Fortes de; Humbert, Maria Victoria; Souza, Daniel Menezes; Duarte, Mariana Costa; Chávez Fumagalli, Miguel Angel; Roatt, Bruno Mendes; Coimbra, Elaine Soares; Coelho, Eduardo Antônio FerrazTreatment against visceral leishmaniasis (VL) is mainly hampered by drug toxicity, long treatment regimens and/or high costs. Thus, the identifcation of novel and low-cost antileishmanial agents is urgent. Acarbose (ACA) is a specifc inhibitor of glucosidase-like proteins, which has been used for treating diabetes. In the present study, we show that this molecule also presents in vitro and in vivo specifc antileishmanial activity against Leishmania infantum. Results showed an in vitro direct action against L. infantum promastigotes and amastigotes, and low toxicity to mammalian cells. In addition, in vivo experiments performed using free ACA or incorporated in a Pluronic® F127-based polymeric micelle system called ACA/ Mic proved efective for the treatment of L. infantum-infected BALB/c mice. Treated animals presented signifcant reductions in the parasite load in their spleens, livers, bone marrows and draining lymph nodes when compared to the controls, as well as the development of antileishmanial Th1-type humoral and cellular responses based on high levels of IFN-γ, IL-12, TNF-α, GM-CSF, nitrite and IgG2a isotype antibodies. In addition, ACA or ACA-treated animals sufered from low organ toxicity. Treatment with ACA/Mic outperformed treatments using either Miltefosine or free ACA based on parasitological and immunological evaluations performed one and 15 days post-therapy. In conclusion, data suggest that the ACA/Mic is a potential therapeutic agent against L. infantum and merits further consideration for VL treatment.Item Avaliação da dose-resposta e da associação de adjuvantes na potência de vacinas quiméricas contra leishmaniose visceral : estudo de fase I em camundongos BALB/c.(2020) Ostolin, Thais Lopes Valentim Di Paschoale; Reis, Alexandre Barbosa; Brito, Rory Cristiane Fortes de; Reis, Alexandre Barbosa; Brito, Rory Cristiane Fortes de; Fujiwara, Ricardo Toshio; Borges, William de CastroNo Brasil, a leishmaniose visceral canina (LVC) encontra-se em expansão sendo um sério problema de saúde pública. A alta prevalência de cães infectados reforça a necessidade de uma vacina para ser empregada em campanhas de vacinação de forma profilática. Nesse trabalho foram avaliadas duas quimeras desenhadas a partir do mapeamento de epítopos de células T pertencentes a proteínas de Leishmania infantum descritas na literatura como candidatas vacinais. O objetivo do estudo foi avaliar a dose-resposta e o efeito da associação de adjuvantes na eficácia de vacinas quiméricas contra a leishmaniose visceral em camundongos BALB/c. Os animais foram divididos em 14 grupos Salina, Saponina e Monofosforil lipídio A (SM) e quimeras A e B, nas doses de 5, 10 e 20 g, associados ou não aos adjuvantes. Esses foram imunizados com 3 doses, com intervalo de 15 dias entre as doses, e desafiados com 1x107 promastigotas de L. infantum. Foi avaliada a atividade proliferativa de linfócitos T totais (CD3+ ) e suas subpopulações (CD3+CD4+ e CD3+CD8+ ) e a produção de citocinas intracitoplasmáticas (IL-2, IFN-, TNF-, IL-4 e IL-10) após estímulo com antígeno solúvel de L. infantum (ASLi) por citometria de fluxo. Além disso, foi determinada a produção de óxido nítrico (NO) em sobrenadante de cultura de esplenócitos estimulados com ASLi e produção de imunoglobulinas murinas anti-Leishmania (IgG total, IgG1 e IgG2) no soro dos camundongos por ELISA. A quantificação da carga parasitária foi feita no baço por PCR em tempo real (qPCR). Ambas quimeras nas três doses avaliadas, apresentaram aumento da proliferação de linfócitos T e suas subpopulações quando comparadas ao grupo Salina. Quando associadas aos adjuvantes, o mesmo comportamento foi observado sendo o aumento em comparação aos grupos Salina e SM. Observou-se aumento de células T CD4+ e CD8+ produtoras de IFN-, TNF- e IL-2, enquanto houve redução de IL-4 e IL-10, tanto em A quanto em B nas três doses. Cabe ressaltar, que em B na dose de 5 g associada a SM houve aumento na produção de IFN- e IL-2 e redução de IL-4 e IL-10 pelos linfócitos TCD4+ em comparação ao grupo Salina. Os resultados da reatividade anti-Leishmania, mostraram que as proteínas quiméricas A e B aumentaram a produção de IgG total e IgG2 nas três doses avaliadas. Quando associadas a SM, apenas a proteína quimérica A, mostrou-se reativa. Em relação ao subclasse IgG1, houve aumento nas doses de 5 g e 10 g. E para IgG2 houve diferença significativa das doses de 5 e 10 g com a dose de 20 g. Quando quantificamos a carga parasitária foi observado que as proteínas quiméricas sozinhas não foram capazes de reduzir a carga no baço dos animais. Em contrapartida, quando foram associadas ao sistema SM, houve redução da carga parasitária no baço em todas as doses avaliadas para ambas quimeras. Observou-se aumento na produção de NO em todos grupos que foram imunizados com as quimeras associadas ao sistema SM. Os resultados obtidos foram promissores, demonstrando que mesmo em doses reduzidas as quimeras foram capazes de desencadear uma resposta imunológica satisfatória. Os resultados mostram que as duas quimeras sozinhas e ou associadas ao sistema de adjuvantes foram imunogênicas mesmo em doses reduzidas. Além disso, esse estudo contribuirá para o desenvolvimento de novas vacinas contra a LV.Item Avaliação de quimeras como candidatos vacinais em modelo hamster (Mesocricetus auratus) desafiados por Leishmania infantum.(2020) Gusmão, Miriã Rodrigues; Roatt, Bruno Mendes; Brito, Rory Cristiane Fortes de; Roatt, Bruno Mendes; Souza, Daniel Menezes; Béla, Samantha RibeiroA leishmaniose visceral é considerada a mais grave dentre as formas clínicas das leishmanioses e até o presente momento não há uma vacina que possa ser empregada em campanhas de controle e profilaxia dessa doença. No intuito de aprimorar estratégias para o desenvolvimento de vacinas, a vacinologia reversa, por meio da imunoinformática é uma moderna tecnologia que aborda metodologias computacionais para a busca de novos alvos e candidatos vacinais. Em um estudo prévio do nosso grupo de pesquisa, duas quimeras foram desenhadas empregando a estratégia da imunoinformática, Quimera A e Quimera B, e quando associadas ao adjuvante saponina, apresentaram resultados promissores em modelo murino. Entretanto, este modelo não reflete a evolução clínica observada em cães e humanos infectados pelo parasito. Neste sentido, é fundamental avaliar estes potenciais imunobiológicos em um modelo experimental que desenvolva de forma semelhante aspectos, clínicos-patológicos, imunológicos e parasitológicos observados em cães e humanos durante a progressão da LV. Desse modo, o objetivo deste trabalho foi avaliar a imunogenicidade e eficácia das quimeras isoladas e/ou associadas ao sistema de adjuvantes saponina e monofosforil lipídeo A (MPL) em modelo hamster (M. auratus) desafiados com L. infantum. Os animais foram divididos em seis grupos experimentais compreendendo: grupo salina (SAL), sitema de adjuvantes saponina e MPL (SM), quimera A (QA), quimera A associada a saponina+MPL (QASM), quimera B (QB) e quimera B associada a saponina+MPL (QBSM). Esses animais foram imunizados com três doses de cada uma das composições vacinais em intervalos de 15 dias entre as doses. Após 21 dias da última dose, os hamsters foram desafiados com promastigotas de L. infantum em fase estacionária de crescimento, pela via intraperitoneal e após 60 dias os animais foram necropsiados. Amostras de sangue, soro, fragmentos do baço foram obtidos para a realização de diferentes análises laboratoriais através de análises hematológicas, bioquímicas, imunológicas e parasitológicas. Em relação às análises hemato-bioquímicas, observamos que os grupos imunizados apresentaram parâmetros de leucograma, eritrograma e das funções renais, hepáticas e proteinograma normais. Entretanto, foram observadas nos grupos controle (SAL) e sistema de adjuvantes (SM) queda nos valores de plaquetas e alterações nas dosagens hepáticas, principalmente de ALT. A análise da resposta humoral pelo perfil de IgG-total anti-Leishmania, evidenciou uma redução na reatividade desse anticorpo nos grupos imunizados em relação aos grupos controles. Além disso, foi evidenciado nos grupos imunizados uma elevada resposta próinflamatória de esplenócitos com aumento da produção de citocinas como IFN- e TNF-, tanto por linfócitos totais e pela subpopulação CD4+ , bem como uma redução na produção da citocina IL-10 por estas células. As vacinas demonstraram eficácia constatada pela redução do parasitismo esplênico nos grupos imunizados chegando a mais de 90% de redução da carga parasitária o que pode estar relacionado também com a alta produção de óxido nítrico (NO) encontrada nesses grupos. Dessa forma, os resultados obtidos no presente trabalho sugerem o potencial de imunogenicidade e proteção das quimeras avaliadas, a relevância da utilização do hamster como modelo experimental para LV, bem como a importância de novas estratégias como a imunoinformática para o desenvolvimento de vacinas para a LV.Item Cell immune response in mice skin stimulated with different adjuvants by intradermal route.(2022) Mathias, Fernando Augusto Siqueira; Cardoso, Jamille Mirelle de Oliveira; Reis, Levi Eduardo Soares; Souza, Juliana Vitoriano de; Moreira, Nádia das Dores; Ostolin, Thais Lopes Valentim Di Paschoale; Brito, Rory Cristiane Fortes de; Soares, Rodrigo Dian de Oliveira Aguiar; Vieira, Paula Melo de Abreu; Carneiro, Cláudia Martins; Roatt, Bruno Mendes; Reis, Alexandre BarbosaAdjuvants act in the innate immunity and, when combined to vaccine antigens, can produce a more intense response, improving the antigen presentation, directing the immune system, excellent for new vaccine formulations. This study evaluated the use of the intradermal route and the immune response triggered by a single dose of the adjuvants Aluminum Hydroxide (Al(OH)3 ), Montanide Pet Gel A (MPGA), Glucopyranosyl Lipid A Stable Emulsion (GLA-SE), and Resiquimod (R-848) in the mice skin. As control mice received sterile saline. MPGA and GLA-SE led to cell recruitment when compared with control group, with intense presence of neutrophils in first 12 hours, replaced by macrophages after 168 hours. R-848 and Al(OH)3 showed similar cell recruitment profiles. Regarding cytokine production, groups that received MPGA and GLA-SE produced high levels of IL-6, TNF-α, and IFN-γ. R-848 and Al(OH)3 groups displayed similar profile of cytokine production only at the first hour. Our results suggest that the intradermal route is efficient inducing immune system activation and GLA-SE was promising adjuvants for a type 1 immune response vaccine.Item A chimeric vaccine combined with adjuvant system induces immunogenicity and protection against visceral leishmaniasis in BALB/c mice.(2021) Ostolin, Thais Lopes Valentim Di Paschoale; Gusmão, Miriã Rodrigues; Mathias, Fernando Augusto Siqueira; Cardoso, Jamille Mirelle de Oliveira; Roatt, Bruno Mendes; Soares, Rodrigo Dian de Oliveira Aguiar; Ruiz, Jeronimo Conceição; Resende, Daniela de Melo; Brito, Rory Cristiane Fortes de; Reis, Alexandre BarbosaIn Brazil, canine visceral leishmaniasis is an important public health problem due to its alarming growth. The high prevalence of infected dogs reinforces the need for a vaccine for use in prophylactic vaccination campaigns. In the present study, we evaluate the immunogenicity and protection of the best dose of Chimera A selected through the screening of cytokines production important in disease. BALB/c mice were vaccinated subcutaneously with three doses and challenged intravenously with 1 107 L. infantum promastigotes. Spleen samples were collected to assess the intracellular cytokine profile production, T cell proliferation and parasite load. At first, three different doses of Chimera A (5 lg, 10 lg and 20 lg) were evaluated through the production of IFN-c and IL-10 cytokines. Since the dose of 20 lg showed the best results, it was chosen to continue the study. Secondarily, Chimera A at dose of 20 lg was formulated with Saponin plus Monophosphoryl lipid A. Vaccination with Chimera A alone and formulated with SM adjuvant system was able to increase the percentage of the proliferation of specific T lymphocytes and stimulated a Th1 response with increased levels of IFN-c, TNF-a and IL-2, and decreased of IL-4 and IL-10. The vaccine efficacy through real-time PCR demonstrated a reduction in the splenic parasite load in animals that received Chimera A formulated with the SM adjuvant system (92%). Additionally, we observed increased levels of nitric oxide in stimulated-culture supernatants. The Chimera A formulated with the SM adjuvant system was potentially immunogenic, being able to induce immunoprotective mechanisms and reduce parasite load. Therefore, the use of T-cell multi-epitope vaccine is promising against visceral leishmaniasis.Item Chimeric vaccines designed by immunoinformatics-activated polyfunctional and memory T cells that trigger protection against experimental visceral leishmaniasis.(2020) Brito, Rory Cristiane Fortes de; Ruiz, Jeronimo Conceição; Cardoso, Jamille Mirelle de Oliveira; Ostolin, Thais Lopes Valentim Di Paschoale; Reis, Levi Eduardo Soares; Mathias, Fernando Augusto Siqueira; Soares, Rodrigo Dian de Oliveira Aguiar; Roatt, Bruno Mendes; Oliveira, Rodrigo Corrêa de; Resende, Daniela de Melo; Reis, Alexandre BarbosaMany vaccine candidates against visceral leishmaniasis (VL) have been proposed; however, to date, none of them have been efficacious for the human or canine disease. On this basis, the design of leishmaniasis vaccines has been constantly changing, and the use of approaches to select specific epitopes seems to be crucial in this scenario. The ability to predict T cell-specific epitopes makes immunoinformatics an even more necessary approach, as in VL an efficient immune response against the parasite is triggered by T lymphocytes in response to Leishmania spp. immunogenic antigens. Moreover, the success of vaccines depends on the capacity to generate long-lasting memory and polyfunctional cells that are able to eliminate the parasite. In this sense, our study used a combination of different approaches to develop potential chimera candidate vaccines against VL. The first point was to identify the most immunogenic epitopes of Leishmania infantum proteins and construct chimeras composed of Major histocompatibility complex (MHC) class I and II epitopes. For this, we used immunoinformatics features. Following this, we validated these chimeras in a murine model in a thorough memory study and multifunctionality of T cells that contribute to a better elucidation of the immunological protective mechanisms of polyepitope vaccines (chimera A and B) using multicolor flow cytometry. Our results showed that in silico-designed chimeras can elicit polyfunctional T cells producing T helper (Th)1 cytokines, a strong immune response against Leishmania antigen, and the generation of central and effector memory T cells in the spleen cells of vaccinated animals that was able to reduce the parasite burden in this organ. These findings contribute two potential candidate vaccines against VL that can be used in further studies, and help in this complex field of vaccine development against this challenging parasite.Item Comparative evaluation of meglumine antimoniate encapsulated in a mixture of conventional and PEGylated liposomes and immunotherapy using an anti-canine IL-10 receptor-blocking monoclonal antibody on canine visceral leishmaniasis.(2022) Cardoso, Jamille Mirelle de Oliveira; Brito, Rory Cristiane Fortes de; Mathias, Fernando Augusto Siqueira; Reis, Levi Eduardo Soares; Vieira, João Filipe Pereira; Ostolin, Thais Lopes Valentim Di Paschoale; Andrade, Hélida Monteiro de; Ramos, Guilherme Santos; Frezard, Frederic; Soares, Rodrigo Dian de Oliveira Aguiar; Roatt, Bruno Mendes; Reis, Alexandre BarbosaThis study compared the therapeutic potential of the chemotherapy using meglumine antimoniate encapsulated in a mixture of conventional and PEGylated liposomes (Nano Sbv ) and immunotherapy with anti-canine IL-10 receptor-blocking monoclonal antibody (Anti IL-10R) on canine visceral leishmaniasis (CVL). Twenty mongrel dogs naturally infected by L. infantum, displaying clinical signs of visceral leishmaniasis were randomly divided in two groups. In the first one, nine dogs received six intravenous doses of a mixture of conventional and PEGylated liposomes containing meglumine antimoniate at 6.5 mg Sb/kg/dose. In the second one, eleven dogs received two intramuscular doses of 4 mg of anti-canine IL-10 receptor-blocking monoclonal antibody. The animals were evaluated before (T0) and 30, 90, and 180 days after treatments. Our major results demonstrated that both treatments were able to maintain hematological and biochemical parameters, increase circulating T lymphocytes subpopulations, increase the IFN-γ producing T-CD4 lymphocytes, restore the lymphoproliferative capacity and improve the clinical status. However, although these improvements were observed in the initial post-treatment times, they did not maintain until the end of the experimental follow-up. We believe that the use of booster doses or the association of chemotherapy and immunotherapy (immunochemotherapy) is promising to improve the effectiveness of treating CVL for improving the clinical signs and possibly reducing the parasite burden in dogs infected with Leishmania infantum.Item Digitoxigenin presents an effective and selective antileishmanial action against Leishmania infantum and is a potential therapeutic agent for visceral leishmaniasis.(2020) Freitas, Camila Simões de; Silva, João Augusto Oliveira da; Lage, Daniela Pagliara; Costa, Rafaella R.; Mendonça, Débora Vasconcelos Costa; Martins, Vívian Tamietti; Reis, Thiago Alves Rosa dos; Antinarelli, Luciana Maria Ribeiro; Machado, Amanda Sanchez; Tavares, Grasiele de Sousa Vieira; Ramos, Fernanda Fonseca; Coelho, Vinicio Tadeu da Silva; Brito, Rory Cristiane Fortes de; Ribeiro, Fernanda Ludolf; Chávez Fumagalli, Miguel Angel; Roatt, Bruno Mendes; Ramos, Gabriela S.; Munkert, Jennifer; Ottoni, Flaviano Melo; Campana, Priscilla Rodrigues Valadares; Humbert, Maria Victoria; Coimbra, Elaine Soares; Braga, Fernão Castro; Pádua, Rodrigo Maia de; Coelho, Eduardo Antônio FerrazTreatment for visceral leishmaniasis (VL) is hampered mainly by drug toxicity, their high cost, and parasite resistance. Drug development is a long and pricey process, and therefore, drug repositioning may be an alternative worth pursuing. Cardenolides are used to treat cardiac diseases, especially those obtained from Digitalis species. In the present study, cardenolide digitoxigenin (DIGI) obtained from a methanolic extract of Digitalis lanata leaves was tested for its antileishmanial activity against Leishmania infantum species. Results showed that 50% Leishmania and murine macrophage inhibitory concentrations (IC50 and CC50, respectively) were of 6.9 ± 1.5 and 295.3 ± 14.5 μg/mL, respectively. With amphotericin B (AmpB) deoxycholate, used as a control drug, values of 0.13 ± 0.02 and 0.79 ± 0.12 μg/mL, respectively, were observed. Selectivity index (SI) values were of 42.8 and 6.1 for DIGI and AmpB, respectively. Preliminary studies suggested that the mechanism of action for DIGI is to cause alterations in the mitochondrial membrane potential, to increase the levels of reactive oxygen species and induce accumulation of lipid bodies in the parasites. DIGI was incorporated into Pluronic® F127-based polymeric micelles, and the formula (DIGI/Mic) was used to treat L. infantum–infected mice. Miltefosine was used as a control drug. Results showed that animals treated with either miltefosine, DIGI, or DIGI/Mic presented significant reductions in the parasite load in their spleens, livers, bone marrows, and draining lymph nodes, as well as the development of a specific Th1-type response, when compared with the controls. Results obtained 1 day after treatment were corroborated with data corresponding to 15 days after therapy. Importantly, treatment with DIGI/Mic induced better parasitological and immunological responses when compared with miltefosine- and DIGI-treated mice. In conclusion, DIGI/Mic has the potential to be used as a therapeutic agent to protect against L. infantum infection, and it is therefore worth of consideration in future studies addressing VL treatment.Item Down regulation of IL-10 and TGF-β1 mRNA expression associated with reduced inflammatory process correlates with control of parasitism in the liver after treating L. infantum infected dogs with the LBMPL vaccine therapy.(2022) Roatt, Bruno Mendes; Cardoso, Jamille Mirelle de Oliveira; Brito, Rory Cristiane Fortes de; Reis, Levi Eduardo Soares; Moreira, Gabriel José Lucas; Vieira, Paula Melo de Abreu; Souza, Flávia Marques de; Lima, Wanderson Geraldo de; Soares, Rodrigo Dian de Oliveira Aguiar; Giunchetti, Rodolfo Cordeiro; Reis, Alexandre BarbosaThe liver plays an important role in human and canine visceral leishmaniasis, then it is considered as target to understand the mechanisms involved in the parasite control and a parameter to assess therapeutic responses. In this sense, our study focuses on evaluating the major alterations in the liver by histological (morphometric parenchyma inflammation/semi-quantitative portal inflammation), immunohistochemical assays (parasitism), and qPCR (parasitism and cytokine gene expression) in Leishmania infantum naturally infected dogs and treated with LBMPL vaccine. Animals were divided in four groups: NI group (n = 5): uninfected and untreated dogs; INT group (n = 7): L. infantum-infected dogs and not treated; MPL group (n = 6): L. infantum-infected dogs that received only monophosphoryl lipid A adjuvant, and LBMPL group (n = 10): L. infantum-infected dogs that received treatment with the vaccine composed by L. braziliensis disrupted promastigotes associated with MPL adjuvant. Ninety days after the end of treatments, the dogs were euthanized, and the liver was collected for the proposed evaluations. Significantly lower portal inflammatory reactions, and lower parenchyma inflammation were observed in the LBMPL group compared to INT and MPL groups. iNOS mRNA expression was higher in LBMPL group and in contrast, IL-10 and TGF-β1 mRNA expression was lower in this group when compared to INT group. Immunohistochemical and qPCR analysis showed significant parasite load reduction in LBMPL group compared to INT and MPL animals. Our data suggest that in naturally Leishmania-infected dogs, LBMPL vaccine reduces the damage in the hepatic tissue, being able to attenuate the type 2 immune response. It could be associated with a marked reduction in the parasitism decreasing liver inflammation in treated dogs. Along with previously obtained data, our results suggest that LBMPL vaccine can significantly contribute to the therapy strategy for L. infantum infected dogs.Item Effect on cellular recruitment and the innate immune response by combining saponin, monophosphoryl lipid-A and incomplete freund’s adjuvant with Leishmania (Viannia) braziliensis antigens for a vaccine formulation.(2019) Souza, Juliana Vitoriano de; Mathias, Fernando Augusto Siqueira; Moreira, Nádia das Dores; Soares, Rodrigo Dian de Oliveira Aguiar; Vieira, Paula Melo de Abreu; Carvalho, Andréa Teixeira de; Carneiro, Cláudia Martins; Giunchetti, Rodolfo Cordeiro; Brito, Rory Cristiane Fortes de; Fujiwara, Ricardo Toshio; Roatt, Bruno Mendes; Melo, Maria Norma; Reis, Alexandre BarbosaThe poor immunogenicity displayed by some antigens has encouraged the development of strategies to improve the immune response and safety of vaccine candidates, resulting in an intense search for substances that potentiate vaccine response. Adjuvants have these properties helping vaccine candidates to induce a strong, durable, and fast immune response. In this study, we evaluated the specific immune response of adjuvants alone, Saponin (SAP), Incomplete Freund’s Adjuvant (IFA) and Monophosphoryl lipid-A SE (MPL-SE ) and in combination with total antigen of L. braziliensis (LB): LBSAP, LBIFA and LBMPL. The specific immune response induced by these compositions demonstrated that they were powerfully immunogenic, increasing cellular infiltration in the skin. Draining lymph nodes cultures showed that LBIFA and LBMPL have higher ability to increase the capacity of APCs to present antigens, with increased frequency of CD11c+ CD86+ cells. SAP, MPL, LBSAP, LBIFA and LBMPL could activate lymphocytes increasing expression of CD69 and CD25. LBSAP group was an excellent inducer of pro-inflammatory cytokines at 24 h. At 48 h, higher cytokines production was observed in IFA, LBIFA, MPL and LBMPL groups. Our data demonstrate that LBSAP and LBMPL are potential formulations to be tested in other experimental models. Also, the data obtained could expand the knowledge about immune response after sensitization and also contribute to the development of safe, immunogenic and effective vaccines.Item Emprego da vacinologia reversa para a identificação, triagem e avaliação de peptídeos de L. infantum para o desenho e desenvolvimento de vacinas poliepítopos e de coquetel de peptídeos contra a leishmaniose visceral.(2018) Brito, Rory Cristiane Fortes de; Reis, Alexandre Barbosa; Resende, Daniela de Melo; Luca, Paula Mello de; Guimarães, Ana Carolina Ramos; Afonso, Luís Carlos Crocco; Reis, Alexandre BarbosaNo contexto de desenvolvimento de vacinas, a vacinologia reversa, ou imunoinformática, é uma abordagem que integra diferentes metodologias computacionais para a busca de alvos e o desenho de vacinas. Assim, a imunoinformática vem se destacando ao permitir o uso de programas para a predição de epítopos imunogênicos in silico. Essa estratégia tem o potencial de buscar alvos para o desenvolvimento de vacinas em todo o proteoma predito de organismos patogênicos. Até a presente data, não existe uma vacina eficaz contra a leishmaniose visceral empregada em campanhas de vacinação. Diante desse cenário, este projeto propõe a utilização da imunoinformática para selecionar epítopos e construir vacinas quiméricas poliepítopos e/ou coquetel de peptídeos a serem testadas contra leishmaniose visceral. No capítulo II desta tese foi apresentado um sistema de predição de epítopos de células T e B, além de vias de sinalização de proteínas. Este sistema foi validado utilizando dados experimentais de proteínas imunogênicas já descritas na literatura, comprovando a existência de uma correlação e associação entre o número de epítopos preditos para células T/B e os resultados experimentais relatados. Em seguida, no capítulo III encontram-se os dados relacionados a duas quimeras poliepítopos que foram desenhadas a partir da abordagem proposta em proteínas imunogênicas já escritas na literatura. Tais quimeras formuladas deram origem a duas vacinas, VAC-1 (quimera A) e VAC-2 (quimera B) ambas associadas ao adjuvante saponina. Assim, foi avaliada a imunogenicidade, a geração de memória imunológica e eficácia das vacinas em camundongos BALB/c submetidos ao protocolo de imunização e desafio com promastigotas de Leishmania infantum. Essas vacinas apresentaram imunogenicidade e capacidade para induzir linfócitos T de memória além de promoverem redução da carga parasitária no baço. Finalmente, no capítulo IV, são mostrados os resultados obtidos de peptídeos imunogênicos identificados através da abordagem de imunoinformática no proteoma predito de L. infantum. Para a seleção destes peptídeos foi realizada uma triagem em cães naturalmente infectados por L. infantum. Estes testes permitiram selecionar os peptídeos que obtiveram melhor performance após o inóculo intradérmico. Assim, foram constituídas as vacinas VAC-3 (coquetel 1) e VAC-4 (coquetel 2) ambas associadas à saponina que foram avaliadas em relação a imunogenicidade, a ativação de células T de memória e a eficácia frente ao desafio com L. infantum. Os resultados obtidos demostraram que a VAC-3 apresentou-se promissora no que se refere a imunogenicidade, indução de memória imunológica de células T e diminuição da carga parasitária no tecido esplênico. Este estudo permitiu certificar e ratificar o potencial da imunoinformática como ferramenta a ser empregada no desenvolvimento de vacinas contra a leishmaniose visceral. Assim sendo, torna-se relevante a realização de maiores estudos para comprovar a real eficácia das vacinas propostas em cães.Item Establishment of monoclonal antibodies to evaluate the cellular immunity in a hamster model of L. infantum infection.(2021) Carvalho, Lívia Mendes; Brito, Rory Cristiane Fortes de; Gusmão, Miriã Rodrigues; Soares, Rodrigo Dian de Oliveira Aguiar; Reis, Alexandre Barbosa; Roatt, Bruno MendesSyrian hamsters (Mesocricetus auratus) are largely used as a model for infectious diseases because it is very susceptible to several pathogens, including Leishmania spp. parasites. However, the research community faces limitations in its use due to the lack of immunological reagents and tools to study the immune system in this model. In this context, we proposed the validation of some important commercially antimouse mAbs (CD4, TNF-α, IFN-γ and IL-10) and how this could be useful to evaluate a specific cellular immune response in Leishmania-infected hamster using flow cytometry experiments. Our data demonstrated a cross-reactivity between these anti-mouse mAbs and hamster molecules that were herein studied. Beyond that, it was able to characterize the development of a specific cellular immune response through cytokine production in L infantum-infected hamsters when compared to uninfected ones. These data not only aid the usage of hamsters as experimental model to investigate various infectious diseases, but they contribute to the design of novel approaches to further investigate the immunological mechanisms associated to pathogen infections.Item Heterologous vaccine therapy associated with half course of Miltefosine promote activation of the proinflammatory response with control of splenic parasitism in a hamster model of visceral leishmaniasis.(2021) Carvalho, Lívia Mendes; Ferreira, Francielle Carvalho; Gusmão, Miriã Rodrigues; Costa, Ana Flávia Pereira; Brito, Rory Cristiane Fortes de; Soares, Rodrigo Dian de Oliveira Aguiar; Reis, Alexandre Barbosa; Cardoso, Jamille Mirelle de Oliveira; Carneiro, Cláudia Martins; Roatt, Bruno MendesVisceral leishmaniasis (VL) is a serious and neglected disease present worldwide. Chemotherapy using pentavalent antimony (SbV) is the most practical and inexpensive strategy available for the VL treatment today, however, it has high toxicity. Alternatively, other drugs are used as viable leishmanicidal therapeutic options. Miltefosine is the only anti-leishmanial agent administered orally, however, it has been reducing its effectiveness. In this sense, there is no ideal therapy for VL since the drugs currently used trigger severe side effects causing discontinuation of treatment, which carries an imminent risk for the emergence of parasite resistance. With that, other therapeutic strategies are gaining prominence. Among them, immunotherapy and/or immunochemotherapy, which the activation/modulation of the immune system can redirect the host’s immune response to an effective therapeutic result. Therefore, this work was designed to assess an immunochemotherapy protocol composed of half course of Miltefosine associated with LBSap vaccine (Milt+LBSap) using the hamster Mesocricetus auratus as an experimental model for VL treatment. When evaluating the main hematobiochemical, immunological and therapeutic efficacy parameters, it was demonstrated that the treatment with Milt+LBSap showed restoration of hematobiochemical condition and reduced serum levels of IgG-anti-Leishmania compared to animals infected non treated (INT). Beyond that, an increase in the number of CD4+ lymphocytes producers of IFN-γ in relation to INT or to animals treated with miltefosine during 28 days, and TNF-α increased compared to INT were observed. Also, it was found a reduction of IL-10-production in relation to INT, or animals that received LBSap vaccine only, or miltefosine, following by a reduction in the splenic parasitic burden. These results demonstrate that the immunochemotherapy protocol used can stimulate the immune response, inducing an expressive cellular response sufficient to control spleen parasitism, standing out as a promising proposal for the VL treatment.Item Identificação de novos antígenos candidatos vacinais contra leishmaniose visceral canina no genoma de L. infantum utilizando a bioinformática como ferramenta.(2014) Brito, Rory Cristiane Fortes de; Reis, Alexandre Barbosa; Resende, Daniela de Melo; Reis, Cristina Helena dos Santos; Marinho, Flávia Dias Marques; Souza, Jacqueline deA leishmaniose visceral canina (LVC) é uma zoonose na América Latina, e o cão possui um papel central como reservatório do parasito e na transmissão da infecção para o vetor no ciclo urbano da Leishmania infantum. A vacinologia reversa permite realizar a predição de epítopos in silico de células B e T, que são importantes na resposta imune, permitindo o desenho de vacinas com tempo reduzido. O objetivo deste trabalho foi selecionar genes do protozoário L. infantum candidatos à vacina contra LVC. Esse objetivo foi divido em duas etapas, sendo a primeira a seleção de antígenos utilizando ferramentas de bioinformática e a segunda a clonagem e expressão dos antígenos selecionados em um sistema eucarioto. Na ETAPA I foi realizado o download do proteoma predito da espécie L. infantum, com 8.241 proteínas, que foi usado em todas as análises subsequentes. As predições foram feitas utilizando-se os seguintes algoritmos: a) para MHC-I, NetCTL e NetMHC; b) para MHC-II, NetMHCII; c) para células B, BepiPred, AAP12 e BCPred12 enquanto que para a predição da localização subcelular das proteínas foram utilizados Sigcleave, TargetP e WoLF PSORT. Foram analisados 12 alelos MHC-I humanos e sete alelos MHC-I de camundongos, e no contexto de MHC-II, foram analisados 14 alelos humanos e três de camundongos. Após a realização das predições, foi necessário o desenvolvimento de um Banco de Dados relacional em um Sistema Gerenciador de Banco de Dados (SGBD), o MySQL, para a integração dos resultados e pré-seleção das proteínas baseado nos seguintes critérios: proteínas secretadas/excretadas ou de membrana plasmática, com epítopos preditos com afinidade pelos 19 alelos de MHC-I utilizados e epítopos preditos com afinidade por no mínimo 14 alelos de MHC-II, além de epítopos preditos para células B. Em seguida, foi feita uma busca por similaridade de sequências com os proteomas preditos de humano, de cão e de camundongo a fim de evitar reações autoimunes no ato da vacinação, para isso foi utilizado o algoritmo BLASTp, do pacote Blastall. Após o alinhamento de sequências, as proteínas com pouca similaridade foram confrontadas com a rede predita de interação proteínaproteína do parasito, desenvolvida pelo grupo de pesquisa. Na ETAPA II, as proteínas selecionadas foram clonadas no vetor de clonagem pGEM T easy, seguido da clonagem no vetor de expressão pPICZα-A, onde os clones foram confirmados pela PCR e digestão enzimática. Após essa etapa, os plasmídeos pPICZα-A recombinantes foram linearizados e transformados na levedura Pichia pastoris, integrando-se no gemona da levedura. Os clones recombinantes foram selecionados por PCR. Através das ferramentas de bioinformática, foram selecionadas quatro proteínas candidatas a uma vacina contra LVC. Neste trabalho foi mostrado o resultado de clonagem e expressão de dois genes que codificam duas proteínas.Item IL-10 receptor blockade controls the in vitro infectivity of Leishmania infantum and promotes a Th1 activation in PBMC of dogs with visceral leishmaniasis.(2021) Cardoso, Jamille Mirelle de Oliveira; Brito, Rory Cristiane Fortes de; Costa, Ana Flávia Pereira; Mathias, Fernando Augusto Siqueira; Reis, Levi Eduardo Soares; Vieira, João Filipe Pereira; Soares, Rodrigo Dian de Oliveira Aguiar; Reis, Alexandre Barbosa; Roatt, Bruno MendesAn important strategy to reduce the risk of visceral leishmaniasis (VL) in humans is to control the infection and disease progression in dogs, the domestic reservoir of Leishmania infantum parasites. Certain therapeutic strategies that modulate the host immune response show great potential for the treatment of experimental VL, restoring the impaired effector functions or decreasing host excessive responses. It is known that the overproduction of interleukin-10 (IL-10) promotes parasite replication and disease progression in human VL as well as in canine visceral leishmaniasis (CVL). Thus, in the present study we investigated the potential of the anticanine IL-10 receptor-blocking monoclonal antibody (Bloq IL-10R) to control and reduce in vitro infectivity of L. infantum and improve the ability of PBMC isolated from VL dogs to alter the lymphoproliferative response and intracytoplasmic cytokines. Overall, GFP+ Leishmania showed lower capacity of in vitro infectivity in the presence of Bloq IL-10R. Moreover, addition of Bloq IL-10R in cultured PBMC enhanced T-CD4 and CD8 proliferative response and altered the intracytoplasmic cytokine synthesis, reducing CD4+IL-4+ cells and increasing CD8+IFNγ+ cells after specific antigen stimulation in PBMC of dogs. Furthermore, we observed an increase of TNF-α levels in supernatant of cultured PBMC under IL-10R neutralizing conditions. Together, our findings are encouraging and reaffirm an important factor that could influence the effectiveness of immune modulation in dogs with VL and suggest that blocking IL-10R activity has the potential to be a useful approach to CVL treatment.Item Immunoinformatics features linked to leishmania vaccine development : data integration of experimental and in silico studies.(2017) Brito, Rory Cristiane Fortes de; Guimarães, Frederico Gonçalves; Velloso, João Paulo Linhares; Oliveira, Rodrigo Corrêa de; Ruiz, Jeronimo Conceição; Reis, Alexandre Barbosa; Resende, Daniela de MeloLeishmaniasis is a wide-spectrum disease caused by parasites from Leishmania genus. There is no human vaccine available and it is considered by many studies as apotential effective tool for disease control. To discover novel antigens, computational programs have been used in reverse vaccinology strategies. In this work, we developed a validation antigen approach that integrates prediction of B and T cell epitopes, analysis of Protein-Protein Interaction (PPI) networks and metabolic pathways. We selected twenty candidate proteins from Leishmania tested in murine model, with experimental outcome published in the literature. The predictions for CD4+ and CD8+ T cell epitopes were correlated with protection in experimental outcomes. We also mapped immunogenic proteins on PPI networks in order to find Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways associated with them. Our results suggest that non-protective antigens have lowest frequency of predicted T CD4+ and T CD8+ epitopes, compared with protective ones. T CD4+ and T CD8+ cells are more related to leishmaniasis protection in experimental outcomes than B cell predicted epitopes. Considering KEGG analysis, the proteins considered protective are connected to nodes with few pathways, including those associated with ribosome biosynthesis and purine metabolism.Item In vitro and in vivo antileishmanial activity of b-acetyl-digitoxin, a cardenolide of Digitalis lanata potentially useful to treat visceral leishmaniasis.(2021) Freitas, Camila Simões de; Lage, Daniela Pagliara; Silva, João Augusto Oliveira da; Costa, Rafaella R.; Mendonça, Débora Vasconcelos Costa; Martins, Vívian Tamietti; Reis, Thiago Alves Rosa dos; Antinarelli, Luciana Maria Ribeiro; Machado, Amanda Sanchez; Tavares, Grasiele de Sousa Vieira; Ramos, Fernanda Fonseca; Brito, Rory Cristiane Fortes de; Ribeiro, Fernanda Ludolf; Chávez Fumagalli, Miguel Angel; Roatt, Bruno Mendes; Ramos, Gabriela S.; Munkert, Jennifer; Ottoni, Flaviano Melo; Campana, Priscilla Rodrigues Valadares; Duarte, Mariana Costa; Gonçalves, Denise Utsch; Coimbra, Elaine Soares; Braga, Fernão Castro; Pádua, Rodrigo Maia de; Coelho, Eduardo Antônio FerrazCurrent treatments of visceral leishmaniasis face limitations due to drug side effects and/or high cost, along with the emergence of parasite resistance. Novel and low-cost antileishmanial agents are therefore required. We report herein the antileishmanial activity of b-acetyl-digitoxin (b-AD), a cardenolide isolated from Digitalis lanata leaves, assayed in vitro and in vivo against Leishmania infantum. Results showed direct action of b-AD against parasites, as well as efficacy for the treatment of Leishmania-infected macrophages. In vivo experiments using b-AD-containing Pluronic F127 polymeric micelles (b-AD/Mic) to treat L. infantum-infected mice showed that this composition reduced the parasite load in distinct organs in more significant levels. It also induced the development of anti-parasite Th1-type immunity, attested by high levels of IFN-c, IL-12, TNF-a, GM-CSF, nitrite and specific IgG2a antibodies, in addition to low IL-4 and IL-10 contents, along with higher IFN-c-producing CD4+ and CD8+ T-cell frequency. Furthermore, low toxicity was found in the organs of the treated animals. Comparing the therapeutic effect between the treatments, b-AD/Mic was the most effective in protecting animals against infection, when compared to the other groups including miltefosine used as a drug control. Data found 15 days after treatment were similar to those obtained one day post-therapy. In conclusion, the results obtained suggest that b-AD/Mic is a promising antileishmanial agent and deserves further studies to investigate its potential to treat visceral leishmaniasis.Item Ivermectin presents effective and selective antileishmanial activity in vitro and in vivo against Leishmania infantum and is therapeutic against visceral leishmaniasis.(2021) Reis, Thiago Alves Rosa dos; Silva, João Augusto Oliveira da; Tavares, Grasiele de Sousa Vieira; Mendonça, Débora Vasconcelos Costa; Freitas, Camila Simões de; Costa, Rafaella R.; Lage, Daniela Pagliara; Martins, Vívian Tamietti; Machado, Amanda Sanchez; Ramos, Fernanda Fonseca; Silva, Alessandra M.; Ribeiro, Fernanda Ludolf; Antinarelli, Luciana Maria Ribeiro; Brito, Rory Cristiane Fortes de; Chávez Fumagalli, Miguel Angel; Humbert, Maria Victoria; Roatt, Bruno Mendes; Coimbra, Elaine Soares; Coelho, Eduardo Antônio FerrazTreatment for visceral leishmaniasis (VL) is hindered mainly by the toxicity and/or high cost of therapeutic drugs. In addition, parasite resistance has been registered. Thus, there is an urgent need for the identification of novel, effective and low-cost antileishmanial agents. Since drug discovery is a long and expensive process, drug repositioning for treatment of leishmaniasis should be considered. In the present study, Ivermectin (IVE), a broad-spectrum drug used for treatment of parasitic diseases, was evaluated in vitro and in vivo against Leishmania infantum species. Results in vitro showed that IVE presented 50% Leishmania and macrophage inhibitory concentrations (IC50 and CC50, respectively) of 3.64 ± 0.48 μM and 427.50 ± 17.60 μM, respectively, with a selectivity index (SI) of 117.45; whereas Amphotericin B (AmpB), which was used as control, showed IC50 and CC50 values of 0.12 ± 0.05 μM and 1.06 ± 0.23 μM, respectively, with a corresponding SI of 8.90. Treatment with IVE effectively reduced the infection percentage and parasite burden in infected and treated macrophages and displayed a prophylactic activity by inhibiting macrophage infection with pre-treated parasites. Furthermore, preliminary studies suggested that IVE targets the parasite’s mitochondria. Activity of IVE in its free format or incorporated into Pluronic® F127-based polymeric micelles (IVE/Mic) was also evaluated in vivo as a treating drug for L. infantum-infected BALB/c mice. Miltefosine was used as a control. Results showed that Miltefosine, IVE and IVE/Mic-treated animals presented significant reductions in the parasite load in their spleens, livers, bone marrows and draining lymph nodes, as well as development of an antileishmanial Th1-type immune response one and 15 days after treatment. Notably, IVE/Mic showed a better parasitological and immunological response in comparison to other alternative treatments. In conclusion, results suggest that IVE/Mic could be considered in future studies as a therapeutic alternative to treat VL.Item Liver infusion tryptose (LIT) : the best choice for growth, viability, and infectivity of Leishmania infantum parasites.(2020) Costa, Ana Flávia Pereira; Brito, Rory Cristiane Fortes de; Carvalho, Lívia Mendes; Cardoso, Jamille Mirelle de Oliveira; Vieira, Paula Melo de Abreu; Reis, Alexandre Barbosa; Soares, Rodrigo Dian de Oliveira Aguiar; Roatt, Bruno MendesLeishmania spp. parasites have a complex biological cycle presenting basically two different morphological stages, the amastigote and promastigote forms. In vitro cultivation allows a more complete study of the biological aspects of these parasites, indicating better conditions for infection, immunoassay tests, drug evaluations, and vaccines. Thus, we evaluated the three most used culture media for Leishmania spp., Grace’s insect cell culture medium (Grace’s), liver infusion tryptose (LIT), and Schneider’s insect medium (Schneider’s), without supplementation or supplemented with fetal calf serum (FCS) and bovine serum albumin (Albumin) to evaluate the growth, viability, and infectivity of the L. infantum promastigotes. It was observed that promastigote forms have a better growth in LIT and Schneider’s with or without FCS when compared to that in Grace’s. The supplementation with albumin promoted greater viability of the parasites independent of the medium. For in vitro infection of J774.A1 macrophages using light microscopy and flow cytometry analyses, FCS-supplemented LIT and Grace’s promoted higher percentage of infected macrophages and parasite load compared with Schneider’s media. Taken together, our results demonstrated that the supplementation of LIT culture medium with FCS is the most suitable strategy to cultivate Leishmania infantum parasites enabling the maintenance of growth and infective parasites for research uses.Item Mixed formulation of conventional and pegylated meglumine antimoniate-containing liposomes reduces inflammatory process and parasite burden in Leishmania infantum-infected BALB/c mice.(2017) Reis, Levi Eduardo Soares; Brito, Rory Cristiane Fortes de; Cardoso, Jamille Mirelle de Oliveira; Mathias, Fernando Augusto Siqueira; Soares, Rodrigo Dian de Oliveira Aguiar; Carneiro, Cláudia Martins; Vieira, Paula Melo de Abreu; Ramos, Guilherme Santos; Frezard, Frederic Jean Georges; Roatt, Bruno Mendes; Reis, Alexandre BarbosaPentavalent antimonial has been the first choice treatment for visceral leishmaniasis; however, it has several side effects that leads to low adherence to treatment. Liposome-encapsulated meglumine antimoniate (MA) arises as an important strategy for chemotherapy enhancement. We evaluated the immunopathological changes using the mixture of conventional and pegylated liposomes with MA. The mice were infected with Leishmania infantum and a single-dose treatment regimen. Comparison was made with groups treated with saline, empty liposomes, free MA, and a liposomal formulation of MA (Lipo MA). Histopathological analyses demonstrated that animals treated with Lipo MA showed a significant decrease in the inflammatory process and the absence of granulomas. The in vitro stimulation of splenocytes showed a significant increase of gamma interferon (IFN-γ) produced by CD8+ T cells and a decrease in interleukin-10 (IL-10) produced by CD4+ and CD8+ T cells in the Lipo MA. Furthermore, the Lipo MA group showed an increase in the IFN-γ/IL-10 ratio in both CD4+ and CD8+ T cell subsets. According to the parasite load evaluation using quantitative PCR, the Lipo MA group showed no L. infantum DNA in the spleen (0.0%) and 41.4% in the liver. In addition, we detected a low positive correlation between parasitism and histopathology findings (inflammatory process and granuloma formation). Thus, our results confirmed that Lipo MA is a promising antileishmanial formulation able to reduce the inflammatory response and induce a type 1 immune response, accompanied by a significant reduction of the parasite burden into hepatic and splenic compartments in treated animals.