Navegando por Autor "Testasicca, Miriam Conceição de Souza"

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Antibody responses induced by Leish-Tec®, an A2-basedvaccine for visceral leishmaniasis, in a heterogeneous caninepopulation.
(2014) Testasicca, Miriam Conceição de Souza; Santos, Mariana Silva dos; Machado, Leopoldo Marques; Serufo, Ângela Vieira; Doro, Daniel; Avelar, Daniel Moreira de; Tibúrcio, Ana Maria Leonardi; Abrantes, Christiane de Freitas; Coelho, George Luiz Lins Machado; Grimaldi Junior, Gabriel; Gazzinelli, Ricardo Tostes; Fernandes, Ana Paula Salles Moura
Zoonotic visceral leishmaniasis (VL) is a widespread disease, and dogs are the main reser-voirs for human parasite transmission. Hence, development of an effective vaccine thatprevents disease and reduces the transmission of VL is required. As euthanasia of seropos-itive dogs is recommended in Brazil for VL epidemiological control, to include anti-VLcanine vaccines as a mass control measure it is necessary to characterize the humoralresponses induced by vaccination and if they interfere with the reactivity of vaccinateddogs in serological diagnostic tests. Leish-Tec®is an amastigote-specific A2 recombinantprotein vaccine against canine visceral leishmaniasis (CVL) that is commercially availablein Brazil. Here, we tested the immunogenicity of Leish-Tec®in a heterogeneous dog popula-tion by measuring A2-specific antibody responses. Healthy dogs (n = 140) of various breedswere allocated to two groups: one group received Leish-Tec®(n = 70), and the other groupreceived a placebo (n = 70). Anti-A2 or anti-Leishmania promastigote antigen (LPA) antibodylevels were measured by ELISA in serum samples collected before and after vaccination.An immunochromatographic test (DPP) based on the recombinant K28 antigen was alsoused for serodiagnosis of CVL. Vaccinated animals, except one, remained seronegative foranti-LPA total IgG and anti-K28 antibodies. Conversely, seropositivity for anti-A2 total IgGantibodies was found in 98% of animals after vaccination. This value decreased to 81.13% at6 months before rising again (98%), after the vaccination boost. Anti-A2 IgG2 and IgG1 titers.
Antigenic extracts of Leishmania braziliensis and Leishmania amazonensis associated with saponin partially protects BALB/c mice against Leishmania chagasi infection by suppressing IL-10 and IL-4 production.
(2010) Grenfell, Rafaella Fortini Queiroz; Silva, Eduardo de Almeida Marques da; Testasicca, Miriam Conceição de Souza; Coelho, Eduardo Antônio Ferraz; Fernandes, Ana Paula Salles Moura; Afonso, Luís Carlos Crocco; Rezende, Simone Aparecida
This study evaluated two vaccine candidates for their effectiveness in protecting BALB/c mice against Leishma¬nia chagasi infection. These immunogenic preparations were composed of Leishmania amazonensis or Leishmania braziliensis antigenic extracts in association with saponin adjuvant. Mice were given three subcutaneous doses of one of these vaccine candidates weekly for three weeks and four weeks later challenged with promastigotes of L. chagasi by intravenous injection. We observed that both vaccine candidates induced a significant reduction in the parasite load of the liver, while the L. amazonensis antigenic extract also stimulated a reduction in spleen parasite load. This protection was associated with a suppression of both interleukin (IL)-10 and IL-4 cytokines by spleen cells in response to L. chagasi antigen. No change was detected in the production of IFN-γ. Our data show that these im-munogenic preparations reduce the type 2 immune response leading to the control of parasite replication.
Association of liposome-encapsulated trivalent antimonial with ascorbic acid: an effective and safe strategy in the treatment of experimental visceral. leishmaniasis.
(2014) Castro, Renata Alves de Oliveira e; Barcellos, Neila Marcia Silva; Licio, Carolina Souza Andrade; Souza, Janine Braga de; Testasicca, Miriam Conceição de Souza; Ferreira, Flávia Monteiro; Batista, Maurício Azevedo; Lemos, Denise da Silveira; Moura, Sandra Aparecida Lima de; Frezard, Frederic Jean Georges; Rezende, Simone Aparecida
Visceral leishmaniasis (VL) is a chronic debilitating disease endemic in tropical and subtropical areas, caused by protozoan parasites of the genus Leishmania. Annually, it is estimated the occurrence of 0.2 to 0.4 million new cases of the disease worldwide. Considering the lack of an effective vaccine the afflicted population must rely on both, an accurate diagnosis and successful treatment to combat the disease. Here we propose to evaluate the efficacy of trivalent antimonial encapsulated in conventional liposomes, in association with ascorbic acid, by monitoring its toxicity and efficacy in BALB/c mice infected with Leishmania infantum. Methodology/Principal Findings:: Infected mice were subjected to single-dose treatments consisting in the administration of either free or liposome-encapsulated trivalent antimony (SbIII), in association or not with ascorbic acid. Parasite burden was assessed in the liver, spleen and bone marrow using the serial limiting dilution technique. After treatment, tissue alterations were examined by histopathology of liver, heart and kidney and confirmed by serum levels of classic biomarkers. The phenotypic profile of splenocytes was also investigated by flow cytometry. Treatment with liposome-encapsulated SbIII significantly reduced the parasite burden in the liver, spleen and bone marrow. Co-administration of ascorbic acid, with either free SbIII or its liposomal form, did not interfere with its leishmanicidal activity and promoted reduced toxicity particularly to the kidney and liver tissues. Conclusions/Significance:: Among the evaluated posological regimens treatment of L. infantum-infected mice with liposomal SbIII, in association with ascorbic acid, represented the best alternative as judged by its high leishmanicidal activity and absence of detectable toxic effects. Of particular importance, reduction of parasite burden in the bone marrow attested to the ability of SbIII-carrying liposomes to efficiently reach this body compartment.
Avaliação da atividade leishmanicida do extrato hidroalcoólico da própolis verde.
(2017) Cunha, Beatriz Carvalho; Moura, Sandra Aparecida Lima de; Testasicca, Miriam Conceição de Souza; Moura, Sandra Aparecida Lima de; Barcelos, Luciola da Silva; Rezende, Simone Aparecida
As leishmanioses, que tem protozoários parasitos do gênero Leishmania como agentes etiológicos, são doenças de grande importância em saúde pública no Brasil. Há uma gama muito restrita de fármacos para o tratamento da leishmaniose e, além disso, estes apresentam alta toxicidade, comprometendo a eficácia da terapia. Assim, a busca por outras alternativas terapêuticas se faz necessária. Neste contexto, a própolis representa uma potencial alternativa para auxiliar no tratamento da leishmaniose, uma vez que a sua atividade leishmanicida vem sendo avaliada e relatada na literatura. Este estudo tem como finalidade avaliar a atividade leishmanicida do extrato hidroalcoólico da própolis verde sobre Leishmania amazonensis, tanto in vitro, quanto in vivo. Para tanto, a atividade leishmanicida do extrato hidroalcoólico da própolis verde foi avaliada em cultura de formas promastigotas, de formas amastigotas axênicas e de macrófagos peritoneais murinos infectados, e em camundongos C57BL/6 infectados por L. amazonensis. Nos testes in vitro, observou-se que o extrato hidroalcoólico da própolis verde não foi tóxico para macrófagos peritoneais murinos nas concentrações testadas e foi capaz de inibir a proliferação de L. amazonensis a partir da concentração 62,5 μg/mL para formas promastigotas, 31,25 μg/mL para formas amastigotas axênicas e 250 μg/mL para formas amastigotas intracelulares. Para os ensaios in vivo, foram utilizados camundongos C57BL/6 divididos em quatro grupos: grupos tratados com o extrato hidroalcoólico da própolis verde na dose de 250 mg/kg/dia, por 2 e 8 semanas e os respectivos grupos controle. No tempo de 2 semanas, houve uma redução da carga parasitária no linfonodo poplíteo drenante, mas não houve redução da carga na pata infectada. No tempo de 8 semanas, houve aumento da carga parasitária no linfonodo poplíteo drenante, mas não houve alteração na pata infectada. Para ambos os tempos de tratamento, não houve influência significativa no tamanho da lesão na pata infectada. Conclui-se que o extrato hidroalcoólico da própolis verde possui efeitos inibitórios sobre L. amazonensis in vitro, de maneira concentração-dependente e, na infecção in vivo, este extrato possui efeito leishmanicida apenas nos estágios iniciais da infecção.
Brazilian green propolis hydroalcoholic extract as a therapeutic adjuvant to treat cutaneous leishmaniasis.
(2020) Cunha, Beatriz Carvalho; Miranda, Marina Barcelos de; Afonso, Luís Carlos Crocco; Abreu, Sheila Rago Lemos; Testasicca, Miriam Conceição de Souza; Silva, Gisele Rodrigues da; Moura, Sandra Aparecida Lima de
Cutaneous leishmaniasis is caused by Leishmania parasites. There are a limited number of drugs to treat the cutaneous leishmaniasis, and most of them cause severe adverse effects. Therefore, new therapeutic strategies to treat cutaneous leishmaniasis should be developed. In this study, a standardized Brazilian green propolis (BGP) hydroalcoholic extract (Cytopropolis®, Nectar Pharma Brazil) was evaluated as a therapeutic adjuvant, aiming at the treatment of cutaneous leishmaniasis. The antileishmanial effects of different concentrations of BGP hydroalcoholic extract (500, 250, 125, 62.5, 31.25, 15.6, 7.8, and 3.9 µg ml−1) were determined in vitro against amastigotes and promastigotes and in a murine model of leishmaniasis. High concentrations of BGP hydroalcoholic extract (500, 250, 125, and 62.5 µg ml−1) reduced the viability of promastigotes. All concentrations acted against amastigotes. BGP hydroalcoholic extract (500 and 250 µg ml−1) decreased the number of promastigotes in macrophages. In addition, after 2 weeks of oral treatment, BGP hydroalcoholic extract (250 mg/kg/day) decreased the parasites and induced the macrophage infiltration in the lesion caused by the Leishmania amazonensis on the paw of mice. BGP hydroalcoholic extract may represent a therapeutic adjuvant to treat cutaneous leishmaniasis.
Características da resposta imune desenvolvida frente à infecção por Leishmania (Leishmania) amazonensis mantida em cultura axênica por passagens sucessivas.
(Programa de Pós-Graduação em Ciências Biológicas. Núcleo de Pesquisas em Ciências Biológicas, Pró-Reitoria de Pesquisa e Pós Graduação, Universidade Federal de Ouro Preto., 2009) Testasicca, Miriam Conceição de Souza; Afonso, Luís Carlos Crocco
Diferentes espécies de parasitos do gênero Leishmania causam infecções expressivamente distintas em uma mesma espécie de hospedeiro. Enquanto alguns hospedeiros são resistentes à infecção por diversas espécies do parasito, quase todas as linhagens de camundongos são susceptíveis à infecção por L. amazonensis, desenvolvendo lesões crônicas e progressivas em resposta à infecção. Esta pronunciada virulência dos parasitos pode estar relacionada à expressão de moléculas superficiais que favoreçam sua interação com os hospedeiros. As ecto-enzimas envolvidas no metabolismo de nucleotídeos são um possível fator de virulência para parasitos do gênero Leishmania. Para caracterizar a resposta imune desenvolvida por animais infectados com parasitos que apresentam distintos perfis de atividade ectonucleotidásica, foram avaliadas infecções por L. amazonensis mantida em cultura por poucas ou muitas passagens. Esses parasitos, quando mantidos em cultura axênica por muitas passagens, apresentam menor virulência, bem como menor atividade ectonucleotidásica. A atividade das suas enzimas envolvidas no metabolismo de nucleotídeos extracelulares pode ser modulada pela cultura em presença de determinadas moléculas. Assim, os parasitos cultivados em meio suplementado com adenosina, produto final da via catabólica, apresentam redução na sua capacidade hidrolítica e levam a lesões menores em camundongos C57BL/6. Já os parasitos submetidos a muitas passagens em cultura, quando cultivados em meio suplementado com suramina, um inibidor de ecto-ATPases, apresentam aumento na capacidade de hidrólise de ATP e causam lesões maiores em camundongos C57BL/6. De modo interessante, os animais infectados com os parasitos que apresentam maior atividade ATPásica produziram menores quantidades de IFN- , após oito semanas de infecção. A infecção de macrófagos pelos parasitos mantidos em cultura axênica por poucas ou muitas passagens também apresenta diferenças marcantes, tanto para macrófagos peritoneais, quanto para macrófagos derivados de medula óssea. Os parasitos mantidos em cultura por poucas passagens são capazes de infectar maior proporção de macrófagos; entretanto, não são observadas grandes diferenças no parasitismo celular. Não há alterações na produção de citocinas, quimiocinas e NO pelas células infectadas pelos diferentes parasitos. Dados obtidos in vivo permitem inferir que células T reguladoras naturais parecem ser importantes para o retardo do desenvolvimento da lesão. Porém, sua participação parece ser idêntica em animais infectados com parasitos mantidos em cultura axênica por poucas ou muitas passagens. Após uma semana de infecção, há maior produção da quimiocina CCL2 em animais infectados com parasitos mantidos em cultura por poucas passagens. Como esta quimiocina participa do recrutamento de monócitos, pode-se cogitar que os parasitos mantidos em cultura por poucas passagens promovem um maior recrutamento dessas células para o sítio da infecção. Uma vez diferenciadas em macrófagos, são eficazmente infectadas por estes parasitos. Em conjunto, esses resultados demonstram que as enzimas envolvidas no metabolismo de nucleotídeos extracelulares desempenham um papel importante na infecção por L. amazonensis, podendo ter função direta na aderência do parasito às células-alvo e na modulação da resposta imune subseqüente.
Efeito da administração diária de cafeína sobre a infecção por Leishmania amazonensis.
(2017) Carvalho Júnior, Jaime Márcio de; Afonso, Luís Carlos Crocco; Testasicca, Miriam Conceição de Souza; Afonso, Luís Carlos Crocco; Bahia, Maria Terezinha; Maioli, Tatiani Uceli
A leishmaniose pode ser descrita como um conjunto de manifestações clínicas causadas pela infecção de protozoários do gênero Leishmania. Essas manifestações clínicas podem ser agrupadas em quatro quadros bem definidos: leishmaniose cutânea localizada, leishmaniose muco-cutânea, leishmaniose visceral e leishmaniose cutânea difusa. As diferentes condições dependerão de fatores inerentes ao hospedeiro humano e por características do parasito. Por exemplo, L. amazonensis é o único causador da leishmaniose cutânea difusa. Para essa condição clínica o balanço das citocinas produzidas pelas células T CD4 positivas é de grande importância. A infecção por L. amazonensis resulta no desenvolvimento de uma fraca resposta celular T CD4 Th1 em pacientes que são negativos para a reação de hipersensibilidade a antígenos de Leishmania. A deficiência na resposta celular pode ser consequência de mecanismos de evasão específicos de L. amazonensis que podem induzir imunossupressão no hospedeiro. A presença de ectonucleotidases e produção de adenosina extracelular pode representar um desses mecanismos. Atuando nesses receptores, a adenosina pode induzir respostas antiinflamatórias, o que favorece a multiplicação do parasito. Sendo a cafeína por sua vez, uma metilxantina capaz de antagonizar os efeitos da adenosina nos receptores P1, nosso objetivo foi investigar os efeitos da administração diária de cafeína sobre a infecção por L. amazonensis no modelo murino. Camundongos C57BL/6J foram tratados com diferentes concentrações de cafeína em água de beber e posteriormente infectados com metacíclicas de L. amazonensis. Os animais tratados com cafeína apresentaram menor tamanho de lesão quando comparados com os animais não tratados e não observamos diferença no número de parasitos na lesão. A produção de IFN-ɣ por células do linfonodo foi significativamente maior nos animais tratados com cafeína. Concluímos, portanto, que o tratamento com cafeína possuiu a capacidade de interferir no curso da infecção por L. amazonensis. Essa interferência pode ser explicada pela alteração na produção de citocinas como o IFN-ɣ. Dessa maneira o tratamento com cafeína pode oferecer mais um meio de expandir os conhecimentos a respeito dos mecanismos de evasão da resposta imune utilizados pelo parasito, através da sinalização purinérgica, e melhorando o entendimento do papel desta via no curso da infecção por L. amazonensis.
Leishmania amazonensis-induced caMP triggered by adenosine a2B receptor is important to inhibit dendritic cell activation and evade immune response in infected mice.
(2017) Figueiredo, Amanda Braga de; Testasicca, Miriam Conceição de Souza; Mineo, Tiago Wilson Patriarca; Afonso, Luís Carlos Crocco
Differently from others Leishmania species, infection by the protozoan parasite L. amazonensis is associated with a lack of antigen-specific T-cell responses. Dendritic cells (DC) are essential for the innate immune response and for directing the differentiation of T-helper lymphocytes. Previously, we showed that L. amazonensis infection impairs DC activation through the activation of adenosine A2B receptor, and here, we evaluated the intracellular events triggered by this receptor in infected cells. To this aim, bone marrow-derived DC from C57BL/6J mice were infected with metacyclic promastigotes of L. amazonensis. Our results show, for the first time, that L. amazonensis increases the production of cAMP and the phosphorylation of extracellular signal-regulated protein kinases 1/2 (ERK1/2) in infected DC by a mechanism dependent on the A2B receptor. Furthermore, L. amazonensis impairs CD40 expression and IL-12 production by DC, and the inhibition of adenylate cyclase, phosphoinositide 3-kinase (PI3K), and ERK1/2 prevent these effects. The increase of ERK1/2 phosphorylation and the inhibition of DC activation by L. amazonensis are independent of protein kinase A (PKA). In addition, C57BL/6J mice were inoculated in the ears with metacyclic promastigotes, in the presence of PSB1115, an A2B receptor antagonist. PSB1115 treatment increases the percentage of CD40+ DC on ears and draining lymph nodes. Furthermore, this treatment reduces lesion size and tissue parasitism. Lymph node cells from treated mice produce higher levels of IFN-γ than control mice, without altering the production of IL-10. In conclusion, we suggest a new pathway used by the parasite (A2B receptor → cAMP → PI3K → ERK1/2) to suppress DC activation, which may contribute to the decrease of IFN-γ production following by the deficiency in immune response characteristic of L. amazonensis infection.
New lager brewery strains obtained by crossing techniques using cachaça (Brazilian Spirit) yeasts.
(2017) Figueiredo, Bruna Inez Carvalho de; Saraiva, Margarete Alice Fontes; Pimenta, Paloma Patrick de Souza; Testasicca, Miriam Conceição de Souza; Sampaio, Geraldo Magela Santos; Cunha, Aureliano Claret da; Afonso, Luís Carlos Crocco; Queiroz, Marisa Vieira de; Castro, Ieso de Miranda; Brandão, Rogélio Lopes
The development of hybrids has been an effective approach to generate novel yeast strains with optimal technological profile for use in beer production. This study describes the generation of a new yeast strain for lager beer production by direct mating between two Saccharomyces cerevisiae strains isolated from cachaça distilleries: one that was strongly flocculent, and the other with higher production of acetate esters. The first step in this procedure was to analyze the sporulation ability and reproductive cycle of strains belonging to a specific collection of yeasts isolated from cachaça fermentation vats. Most strains showed high rates of sporulation, spore viability, and homothallic behavior. In order to obtain new yeast strains with desirable properties useful for lager beer production, we compare haploid-to-haploid and diploid-to-diploid mating procedures. Moreover, an assessment of parental phenotype traits showed that the segregant diploid C2-1d generated from a diploid-to-diploid mating experiment showed good fermentation performance at low temperature, high flocculation capacity, and desirable production of acetate esters that was significantly better than that of one type lager strain. Therefore, strain C2-1d might be an important candidate for the production of lager beer, with distinct fruit traces and originating using a non-genetically modified organism (GMO) approach.
Purinergic signaling and infection by Leishmania : a new approach to evasion of the immune response.
(2016) Figueiredo, Amanda Braga de; Testasicca, Miriam Conceição de Souza; Afonso, Luís Carlos Crocco
Infection by protozoan parasites is part of the most common Tropical Neglected Diseases. In the case of leishmaniasis, several millions of people are at risk of contracting the disease. In spite of innumerous studies that elucidated the immune response capable of killing the parasite, the understanding of the evasion mechanisms utilized by the parasite to survive within the very cell responsible for its destruction is still incomplete. In this review, we offer a new approach to the control of the immune response against the parasite. The ability of the parasite to modulate the levels of extracellular ATP and adenosine either by directly acting on the levels of these molecules or by inducing the expression of CD39 and CD73 on the infected cell may influence the magnitude of the immune response against the parasite contributing to its growth and survival.
Sensitive and specific serodiagnosis of Leishmania infantum infection in dogs using peptides selected from hypothetical proteins identified by an immunoproteomic approach.
(2013) Chávez Fumagalli, Miguel Angel; Martins, Vívian Tamietti; Testasicca, Miriam Conceição de Souza; Lage, Daniela Pagliara; Costa, Lourena Emanuele; Lage, Paula Souza; Duarte, Mariana Costa; Ker, Henrique Gama; Ribeiro, Tatiana Gomes; Carvalho, Fernando Aécio de Amorim; Régis, Wiliam César Bento; Reis, Alexandre Barbosa; Tavares, Carlos Alberto Pereira; Soto, Manuel; Fernandes, Ana Paula Salles Moura; Coelho, Eduardo Antônio Ferraz
In Brazil, the percentage of infected dogs living in areas where canine visceral leishmaniasis (CVL) is endemic ranges from 10 to 62%; however, the prevalence of infection in dogs is probably higher than figures reported from serological studies. In addition, problems with the occurrence of false-positive or false-negative results in the serodiagnosis of CVL have been reported. The present work analyzed the potential of synthetic peptides mapped from hypothetical proteins for improvement of the serodiagnosis of Leishmania infantum infection in dogs. From 26 identified leishmanial proteins, eight were selected, considering that no homologies between these proteins and others from trypanosomatide sequence databases were encountered. The sequences of these proteins were mapped to identify linear B-cell epitopes, and 17 peptides were synthesized and tested in enzyme-linked immunosorbent assays (ELISAs) for the serodiagnosis of L. infantum infection in dogs. Of these, three exhibited sensitivity and specificity values higher than 75% and 90%, respectively, to differentiate L. infantum-infected animals from Trypanosoma cruziinfected animals and healthy animals. Soluble Leishmania antigen (SLA) showed poor sensitivity (4%) and specificity (36%) to differentiate L. infantum-infected dogs from healthy and T. cruzi-infected dogs. Lastly, the three selected peptides were combined in different mixtures and higher sensitivity and specificity values were obtained, even when sera from T. cruzi-infected dogs were used. The study’s findings suggest that these three peptides can constitute a potential tool for more sensitive and specific serodiagnosis of L. infantum infection in dogs.
The influence of ecto-nucleotidases on Leishmania amazonensis infection and immune response in C57B/6 mice.
(2010) Testasicca, Miriam Conceição de Souza; Assis, Elisângela Aparecida de; Gomes, Rodrigo Saar; Silva, Eduardo de Almeida Marques da; Melo, Maria Norma; Fietto, Juliana Lopes Rangel; Afonso, Luís Carlos Crocco
Previous results from our laboratory and from the literature have implicated the expression of ectonucleotidases in the establishment of Leishmania infection. In the present study we evaluated the correlation between ecto-nucleotidasic activity and the infectivity of L. amazonensis promastigotes that were kept in culture for short or extended numbers of passages, a condition that is known to decrease parasite infectivity. We also analyzed the immune response associated with the infection by these parasites. As expected, we found that long-term cultured parasites induce the development of smaller lesions than the short-term cultured counterparts. Interestingly, long-term cultured parasites presented reduced ecto-nucleotidasic activity. In addition, cells recovered from animals infected with long-term cultured parasites produced higher amounts of IFN-_ and have smaller parasite load, after 8 weeks of infection. Furthermore, after 1 week of infection, there is increased expression of the chemokine CCL2 mRNA in animals infected with short-term cultured parasites. Finally, infection of peritoneal macrophages by these parasites also shows marked differences. Thus, while short-term cultured parasites are able to infect a greater proportion of macrophages, cells infected by long-term cultured parasites express higher amounts of CXCL10 mRNA, which may activate these cells to kill the parasites. We suggest that the enzymes involved in metabolism of extracellular nucleotides may have an important role in infection by L. amazonensis, by acting directly in its adhesion to target cells and by modulating host cell chemokine production.