Navegando por Palavras-chave "Plasmodium vivax"

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    Adjuvant requirement for successful immunization with recombinant derivatives of Plasmodium vivax merozoite surface protein-1 delivered via the intranasal route
    (Fundaco Oswaldo Cruz, 2007-06-01) Bargieri, Daniel Y. [UNIFESP]; Rosa, Daniela S. [UNIFESP]; Simoes Lasaro, Melissa Ang; Ferreira, Luis Carlos S.; Soares, Irene S.; Rodrigues, Mauricio M. [UNIFESP]; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP)
    Recently, we generated two bacterial recombinant proteins expressing 89 amino acids of the C-terminal domain of the Plasmodium vivax merozoite surface protein-1 and the hexa-histidine tag (His6MSP1(19)). One of these recombinant proteins contained also the amino acid sequence of the universal pan allelic T-cell epitope (His(6)MSP1(19)-PADRE). in the present study, we evaluated the immunogenic properties of these antigens when administered via the intra-nasal route in the presence of distinct adjuvant formulations. We found that C57BL/6 mice immunized with either recombinant proteins in the presence of the adjuvants cholera toxin (CT) or the Escherichia coli heat labile toxin ( LT) developed high and long lasting titers of specific serum antibodies. the induced immune responses reached maximum levels after three immunizing doses with a prevailing IgG1 subclass response. in contrast, mice immunized by intranasal route with His(6)MSP1(19)-PADRE in the presence of the synthetic oligonucleotides adjuvant CpG ODN 1826 developed lower antibody titers but when combined to CT, CpG addition resulted in enhanced IgG responses characterized by lower IgG1 levels. Considering the limitations of antigens formulations that can be used in humans, mucosal adjuvants can be a reliable alternative for the development of new strategies of immunization using recombinant proteins of P. vivax.
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    Analise do agonista da imunidade inata flagelina de Salmonella enterica sorovar Typhimurium como adjuvante para proteinas recombinantes contendo epitopos da proteina do circunsporozoita de Plasmodium vivax
    (Universidade Federal de São Paulo (UNIFESP), 2013) Leal, Monica Teixeira Andrade [UNIFESP]; Tararam, Cibele Aparecida [UNIFESP]; http://lattes.cnpq.br/7864234229018488; http://lattes.cnpq.br/5370355111008263; http://lattes.cnpq.br/2773757778364751
    Em estudos recentes, demonstramos as propriedades imunogenicas melhoradas de novos candidatos vacinais baseados na expressao de proteinas de fusao contendo epitopos imunodominantes de merozoitas de Plasmodium vivax e um agonista da imunidade inata, a flagelina (FliC) de Salmonella enterica sorovar Typhimurium. No presente trabalho, comparamos a imunogenicidade de diversas proteinas recombinantes expressando epitopos imunodominantes de linfocitos B do esporozoita de P. vivax e a FliC. Tres proteinas de fusao recombinantes foram geradas expressando a His6FliC contendo no C-terminal as regioes repetidas de cada um das tres formas alelicas da proteina do circunsporozoita (CSP) de P. vivax. A imunogenicidade da mistura destas proteinas recombinantes foi comparada com a mistura de proteinas bacterianas recombinantes expressando a CSP inteira de P. vivax somente ou na presenca dos adjuvantes FliC ou Poly (I:C). Camundongos C57BL/6 imunizados subcutaneamente com as diferentes misturas induziram, com sucesso, titulos de anticorpos (AC) IgG contra as proteinas bacterianas recombinantes expressando as diferentes formas alelicas da CSP de P. vivax. A mistura de proteinas recombinantes bacterianas expressando a CSP inteira e administradas na presenca de FliC ou Poly (I:C) como adjuvantes geraram os titulos mais altos de AC. Estes resultados estendem nossas observacoes anteriores sobre a imunogenicidade destas proteinas recombinantes de fusao e do uso de FliC como um potencial adjuvante para o desenvolvimento de uma vacina contra malaria
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    Antibody response of naturally infected individuals to recombinant Plasmodium vivax apical membrane antigen-1
    (Elsevier B.V., 2005-02-01) Rodriguesa, MHC; Rodrigues, K. M.; Oliveira, T. R.; Comodo, A. N.; Rodrigues, M. M.; Kocken, CHM; Thomas, A. W.; Soares, I. S.; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP); Biomed Primate Res Ctr
    In the present study, we evaluate the naturally acquired antibody response to the Plasmodium vivax apical membrane antigen 1 (PvAMA-1), a leading vaccine candidate against malaria. the gene encoding the PvAMA-1 ectodomain region (amino acids 43-487) was cloned by PCR using genomic DNA from a Brazilian individual with patent P. vivax infection. the predicted amino acid sequence displayed a high degree of identity (97.3%) with a previously published sequence from the P. viva-v Salvador strain. A recombinant protein representing the PvAMA-1 ectodomain was expressed in Escherichia coli and refolded. By ELISA, this recombinant protein reacted with 85 and 48.5% of the IgG or IgM antibodies, respectively, from Brazilian individuals with patent P. vivax malaria. IgG I was the predominant subclass of IgG. the frequency of response increased according to the number of malaria episodes, reaching 100% in individuals in their fourth malaria episode. the high degree of recognition of PvAMA-1 by human antibodies was confirmed using a second recombinant protein expressed in Pichia pastoris (PV66/AMA-1). the observation that recognition of the bacterial recombinant PvAMA-1 was only slightly lower than that of the highly immunogenic 19 kDa C-terminal domain of the P. vivax Merozoite Surface Protein-1 was also important. DNA sequencing of the PvAMA-1 variable domain from 20 Brazilian isolates confirmed the limited polymorphism of PvAMA-1 suggested by serological analysis. in conclusion, we provide evidence that PvAMA-1 is highly immunogenic during natural infection in humans and displays limited polymorphism in Brazil. Based on these observations, we conclude that PvAMA-1 merits further immunological studies as a vaccine candidate against P. vivax malaria. (C) 2004 Australian Society for Parasitology Inc. Published by Elsevier B.V. All rights reserved.
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    Antigenic properties of the merozoite surface protein 1 gene of Plasmodium vivax
    (Elsevier B.V., 1999-08-06) Oliveira, C. I. de; Wunderlich, G.; Levitus, G.; Soares, I. S.; Rodrigues, M. M.; Tsuji, M.; del Portillo, H. A.; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP); NYU
    Plasmodium vivax is responsible for an approximate 35 million yearly human cases of malaria. Unfortunately, due to the low mortality rate associated with it and the difficulties of continuously in vitro culturing of this parasite, vaccine development against this human malaria has been largely neglected. in here, the antigenic properties of the merozoite surface protein 1 gene of P. vivax (PvMSP-1), were studied. Thus, seven recombinant bacterial plasmids coding different regions of the PvMSP-1 protein were constructed and used to immunize BALB/c mice, the results demonstrated that a plasmid encoding the entire N-terminus comprising 682 amino acids and a plasmid encoding the C-terminus including the two juxtaposed epidermal growth factor (EGF)-like domains fused to the Hepatitis B surface antigen, were antigenic. Moreover, the elicited immune responses were similar to those reported for these same PvMSP-1 regions in natural human infections. (C) 1999 Published by Elsevier B.V. All rights reserved.
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    Cellular and humoral immune responses against the Plasmodium vivax MSP-1(19) malaria vaccine candidate in individuals living in an endemic area in north-eastern Amazon region of Brazil
    (Biomed Central Ltd, 2013-09-16) Riccio, Evelyn K. P.; Totino, Paulo R. R.; Pratt-Riccio, Lilian R.; Ennes-Vidal, Vitor; Soares, Irene S.; Rodrigues, Mauricio Martins [UNIFESP]; Souza, Jose Maria de; Daniel-Ribeiro, Claudio Tadeu; Ferreira-da-Cruz, Maria de Fatima; Fiocruz MS; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP); SVS
    Background: Plasmodium vivax merozoite surface protein-1 (MSP-1) is an antigen considered to be one of the leading malaria vaccine candidates. PvMSP-1 is highly immunogenic and evidences suggest that it is target for protective immunity against asexual blood stages of malaria parasites. Thus, this study aims to evaluate the acquired cellular and antibody immune responses against PvMSP-1 in individuals naturally exposed to malaria infections in a malaria-endemic area in the north-eastern Amazon region of Brazil.Methods: the study was carried out in Paragominas, Para State, in the Brazilian Amazon. Blood samples were collected from 35 individuals with uncomplicated malaria. Peripheral blood mononuclear cells were isolated and the cellular proliferation and activation was analysed in presence of 19 kDa fragment of MSP-1 (PvMSP-1(19)) and Plasmodium falciparum PSS1 crude antigen. Antibodies IgE, IgM, IgG and IgG subclass and the levels of TNF, IFN-gamma and IL-10 were measured by enzyme-linked immunosorbent assay.Results: the prevalence of activated CD4(+) was greater than CD8(+) T cells, in both ex-vivo and in 96 h culture in presence of PvMSP-1(19) and PSS1 antigen. A low proliferative response against PvMSP-1(19) and PSS1 crude antigen after 96 h culture was observed. High plasmatic levels of IFN-gamma and IL-10 as well as lower TNF levels were also detected in malaria patients. However, in the 96 h supernatant culture, the dynamics of cytokine responses differed from those depicted on plasma assays; in presence of PvMSP-1(19) stimulus, higher levels of TNF were noted in supernatant 96 h culture of malaria patient's cells while low levels of IFN-gamma and IL-10 were verified. High frequency of malaria patients presenting antibodies against PvMSP-1(19) was evidenced, regardless class or IgG subclass. PvMSP-1(19)-induced antibodies were predominantly on non-cytophilic subclasses.Conclusions: the results presented here shows that PvMSP-1(19) was able to induce a high cellular activation, leading to production of TNF and emphasizes the high immunogenicity of PvMSP-1(19) in naturally exposed individuals and, therefore, its potential as a malaria vaccine candidate.
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    Comparative recognition by human IgG antibodies of recombinant proteins representing three asexual erythrocytic stage vaccine candidates of Plasmodium vivax
    (Instituto Oswaldo Cruz, Ministério da Saúde, 2007-06-01) Barbedo, Mayara B; Ricci, Ricardo; Jimenez, Maria Carolina S; Cunha, Maristela G; Yazdani, Syed S; Chitnis, Chetan E; Rodrigues, Mauricio Martins [UNIFESP]; Soares, Irene S; Universidade de São Paulo (USP); Universidade Federal do Pará Centro de Ciências Biológicas Departamento de Patologia; International Centre for Genetic Engineering and Biotechnology Centro de Ciências Biológicas Malaria Research Group; Universidade Federal de São Paulo (UNIFESP)
    In previous immuno-epidemiological studies of the naturally acquired antibody responses to merozoite surface protein-1 (MSP-1) of Plasmodium vivax, we had evidence that the responses to distinct erythrocytic stage antigens could be differentially regulated. The present study was designed to compare the antibody response to three asexual erythrocytic stage antigens vaccine candidates of P. vivax. Recombinant proteins representing the 19 kDa C-terminal region of MSP-1(PvMSP19), apical membrane antigen n-1 ectodomain (PvAMA-1), and the region II of duffy binding protein (PvDBP-RII) were compared in their ability to bind to IgG antibodies of serum samples collected from 220 individuals from the state of Pará, in the North of Brazil. During patent infection with P. vivax, the frequency of individuals with IgG antibodies to PvMSP1(19), PvAMA-1, and PvDBP-RII were 95, 72.7, and 44.5% respectively. Although the frequency of responders to PvDBP-RII was lower, this frequency increased in individuals following multiple malarial infections. Individually, the specific antibody levels did not decline significantly nine months after treatment, except to PvMSP1(19). Our results further confirm a complex regulation of the immune response to distinct blood stage antigens. The reason for that is presently unknown but it may contribute to the high risk of re-infection in individuals living in the endemic areas.
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    Deficiência de piruvato quinase e risco de malária: estudo de base populacional na Amazônia Brasileira
    (Universidade Federal de São Paulo, 2024-09-06) Macedo, Evelyn Gonçalves [UNIFESP]; Ferreira, Marcelo Urbano; Ladeia, Winni Alves; http://lattes.cnpq.br/2164972047087980; http://lattes.cnpq.br/5136161277318799; http://lattes.cnpq.br/2252240863702221
    A suscetibilidade à infecção por estágios sanguíneos dos plasmódios e à malária clínica é modulada por características hereditárias dos hospedeiros que facilitam ou bloqueiam a invasão de glóbulos vermelhos (RBCs) e a multiplicação intracelular de parasitas. Um exemplo é a deficiência de piruvato quinase (PKD), um defeito hereditário de uma enzima eritrocitária decorrente de heterozigosidade composta ou homozigosidade para mutações no gene pklr. A PKD causa anemia hemolítica não esferocítica e limita o crescimento de Plasmodium falciparum nos eritrócitos humanos, mas pode aumentar o risco de malária vivax. Investigamos aqui a associação entre PKD e o risco de malária em nível populacional em uma coorte populacional exposta a P. falciparum e P. vivax. Em primeiro lugar, determinamos a frequência de três polimorfismos de nucleotídeo único (SNPs) representativos (tag SNPs) no gene pklr ou adjacentes – ou seja, rs1052176 (G>T), rs4971072 (A>G) e rs11264359 (A>G) – e o genótipos resultantes e testamos se esses polimorfismos estavam associados ao risco de infecção e doença por P. vivax e P. falciparum em mais de 2.000 participantes de uma coorte de base populacional em Mâncio Lima, Acre, o principal foco de malária urbana do Brasil. Ao todo, foram genotipados 2.043 participantes para rs1052176, 2.045 para rs4971072 e 2.044 para rs11264359. As frequências dos alelos mutantes variaram entre 0,46 e 0,55. Com o uso de modelos de regressão logística de efeitos mistos, testamos se havia associação entre alelos e genótipos de pklr e o risco de monoinfecção por P. vivax ou P. falciparum durante 7 inquéritos transversais realizados entre 2018 e 2021 (cerca de 9.000 observações), com resultados negativos. A heterozigosidade nos loci rs4971072 e rs11264359 pareceu conferir proteção contra a malária clínica (qualquer espécie) em modelos logísticos parcialmente ajustados, mas a significância estatística de tal associação desapareceu após o ajuste para outro polimorfismo de “resistência à malária”, a substituição T>C no motivo de ligação ao fator de transcrição GATA1 específico para eritrócitos, que elimina a expressão de DARC em hemácias, levando ao fenótipo Duffy-negativo. A seguir, investigamos a associação entre os três SNPs representativos e a atividade PK em hemácias. Para tanto, utilizamos hemácias recém-colhidas tratadas com EDTA em um ensaio colorimétrico padrão. A atividade enzimática de PK foi maior em hemácias de 77 participantes com a sequência de tipo selvagem em todos os SNPs (genótipo GG/AA/AA), com uma média de 7,45 U/g de hemoglobina, em comparação com 74 participantes com mutações em todos os SNPs (genótipo TT/GG/GG), com uma média de 6,58 U/g de hemoglobina. No entanto, encontramos taxas de prevalência semelhantes de PKD entre participantes com o genótipo de tipo selvagem GG/AA/AA (7 de 77, 9,1%) e aqueles com o genótipo mutado TT/GG/GG (7 de 74, 9,5%), sugerindo que os polimorfismos nos três loci analisados não eram capazes de predizer PKD nesta população. Concluímos que os SNPs representativos do gene pklr ou adjacentes são frequentemente encontrados nesta população exposta à malária, mas não estão associados à redução do risco de malária e nem são preditivos de PKD.
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    Descoberta de novos compostos derivados de cloroquina como candidatos a antimaláricos
    (Universidade Federal de São Paulo, 2024-03-21) Peres, Erica Paloma Maso Lopes [UNIFESP]; Aguiar, Anna Caroline Campos [UNIFESP]; http://lattes.cnpq.br/6217232206685846; https://lattes.cnpq.br/2241425834402728; Universidade Federal de São Paulo (UNIFESP)
    Introdução: A malária é uma doença tropical grave, caracterizada por sua alta taxa de mortalidade e morbidade, representando um significativo problema de saúde pública com impacto socioeconômico. O controle da malária enfrenta desafios devido dificuldade no combate ao vetor e à rápida disseminação de linhagens de parasitos resistentes aos antimaláricos convencionais. O surgimento de resistência compromete a eficácia dos tratamentos atuais, tornando a luta contra a malária um desafio cada vez mais complexo sendo de extrema importância a busca por novos candidatos a antimaláricos potentes, de baixo custo e não tóxico ao hospedeiro vertebrado. Objetivo: Avaliar a atividade antiplasmodial e o alvo de ação contra estágios assexuados sanguíneos de 8 novos análogos de cloroquina, utilizando cepa de Plasmodium falciparum sensível e resistentes. Métodos: Realizamos ensaios in vitro para determinar o IC50 dos novos compostos contra as cepas de P. falciparum 3D7 (sensível), Dd2, K1 e SB1 (resistentes), utilizando o ensaio de SBYR Green I. Em seguida, prosseguimos com a avaliação citotóxica, a partir do método de rezarsurina, utilizando linhagens celulares de hepatoma humano (HepG2) e rim embrionário (HEK-293). Após essa fase, examinamos o mecanismo de resistência dos novos análogos de CQ na presença do verapamil, um inibidor de bombas de efluxo de P. falciparum e que está relacionada a resistência aos antimaláricos. Posteriormente, identificamos o vacúolo digestivo de P. falciparum como alvo intracelular dos novos compostos, utilizamos o marcador fluorescente Acridina Orange (AO). Em sequência, selecionamos os compostos 1, 2, 6 e 7 e realizamos ensaios ex vivo contra isolados de campo com P. falciparum e P. vivax circulantes na região amazônica brasileira. Resultados: Os compostos 6 e CEQ foram os mais potentes in vitro, apresentando IC50 de 7 nM e 15 nM, respectivamente, contra a cepa 3D7. Frente às cepas resistentes, os compostos mais potentes foram CEQ e 1 (cepa Dd2) com o IC50 de 30 nM e 75 nM, respectivamente, para a cepa K1, os compostos mais potentes foram 5, 7 e 8 com IC50 de 33 nM à 81 nM e para a cepa SB1 os compostos testados foram 1, 2 e 3 e todos se mostraram potentes com IC50 variando de 10 nM a 89 nM. A resistência cruzada dos compostos foi avaliada comparando seus valores de IC50 tanto para cepa sensível quanto resistentes à cloroquina. Os compostos 1, 2, 5, 7 e 8, não apresentaram índice de resistência cruzada (IRC) nos ensaios in vitro com valores de IRC <5. Os compostos CEQ, 3, 4 e 6 apresentaram IRC moderada a alta com valores de IRC >5. No ensaio com verapamil os compostos testados foram 1, 2, 3, 4 e 6 e foi observado uma redução do IC50, após incubação com verapamil, sugerindo resistência frente a cepa Dd2. Os compostos não se mostraram tóxicos para as células HepG2 e HEK-293. Para os ensaios de identificação do vacúolo digestivo (VD) com o marcador AO, pudemos identificar que ouve interação dos compostos com esta organela á partir da alteração da homeostase iônica, assim como observado para a CQ. Quando avaliamos a potência dos compostos frente aos isolados de campo circulantes em Porto Velho, foi possível observar que estes compostos foram mais potentes contra o P. vivax quando comparado com o P. falciparum, indicando uma baixa sensibilidade a essa espécie. Conclusão: Podemos concluir que esta nova classe de análogos de cloroquina apresentou resultados promissores in vitro, no entanto, não foram ativos contra os isolados circulantes na Amazônia brasileira de P. falciparum.
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    Estudo da resposta imune humana contra a proteina de superficie do merozoito 1 de Plasmodium vivax (PvMSP1)
    (Universidade Federal de São Paulo (UNIFESP), 1998) Soares, Irene da Silva [UNIFESP]
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    Generation, characterization and immunogenicity of a novel chimeric recombinant protein based on Plasmodium vivax AMA-1 and MSP1(19)
    (Elsevier Sci Ltd, 2017) Rocha, Mariana Vilela; Francoso, Katia Sanches; Lima, Luciana Chagas; Camargo, Tarsila Mendes; Machado, Ricardo L. D.; Costa, Fabio T. M.; Renia, Laurent; Nosten, Francois; Russell, Bruce; Rodrigues, Mauricio M. [UNIFESP]; Soares, Irene S.
    Plasmodium vivax is the most widely distributed malaria species and the most prevalent species of malaria in America and Asia. Vaccine development against P. vivax is considered a priority in the global program for the eradication of malaria. Earlier studies have characterized the Apical Membrane Antigen 1 (AMA-1) ectodomain and the C-terminal region (19 kDa) of the Merozoite Surface Protein 1 (MSP-1) of P. vivax as immunodominant antigens. Based on this characterization, we designed a chimeric recombinant protein containing both merozoite immunodominant domains (PvAMA1(66)-MSP1(19)). The recombinant PvAMA166-MSP119 was successfully expressed in Pichia pastoris and used to immunize two different mouse strains (BALB/c and C57BL/6) in the presence of the Poly (I:C) as an adjuvant. Immunization with the chimeric protein induced high antibody titers against both proteins in both strains of mice as detected by ELISA. Antisera also recognized the native proteins expressed on the merozoites of mature P. vivax schizonts. Moreover, this antigen was able to induce IFN-gamma-secreting cells in C57BL/6 mice. These findings indicate that this novel yeast recombinant protein containing PvAMA1(66) and PvMSP1(19) is advantageous, because of improved antibody titers and cellular immune response. Therefore, this formulation should be further developed for pre-clinical trials in non-human primates as a potential candidate for a P. vivax vaccine. (C) 2017 Elsevier Ltd. All rights reserved.
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    Immunogenicity of a recombinant protein containing the Plasmodium vivax vaccine candidate MSP1(19) and two human CD4(+) T-cell epitopes administered to non-human primates (Callithrix jacchus jacchus)
    (Elsevier B.V., 2006-07-01) Rosa, Daniela S.; Iwai, Leo K.; Tzelepis, Fanny; Bargieri, Daniel Y.; Medeiros, Magda A.; Soares, Irene S.; Sidney, John; Sette, Alessandro; Kalil, Jorge; Mello, Luiz Eugenio; Cunha-Neto, Edecio; Rodrigues, Mauricio M.; Universidade Federal de São Paulo (UNIFESP); Universidade de São Paulo (USP); Universidade Federal do Rio de Janeiro (UFRJ); La Jolla Inst Allergy & Immunol
    One of the most promising vaccine candidates against the erythrocytic forms of malaria is the 19 kDa C-terminal region of the merozoite surface protein 1 (MSP1(19)). As part of our studies aimed at the development of a Plasmodium vivax malaria vaccine, we characterized the immunogenic properties of a new bacterial recombinant protein containing the P. vivax MSPI 19 and two helper T-cell epitopes, the synthetic universal pan allelic DR epitope (PADRE) and a new internal MSP1 P. vivax epitope (DYDVVYLKPLAGMYK). We found that the recognition of HiS(6)MSP1(19)-DYDVVYLKPLAGMYK-PADRE was as good as the recognition of HiS(6)MSP1(19) indicating that the presence of the T-cell epitopes PADRE and DYDVVYLKPLAGMYK did not modify the MSP1(19) epitopes recognized by human IgG. the recombinant protein HiS(6)MSP1(19)-DYDVVYLKPLAGMYK-PADRE proved to be highly immunogenic in marmosets (Callithrix jacchus jacchus) when administered in incomplete Freund's adjuvant. However, when administered in other adjuvant formulations such as Quil A, CpG ODN 2006 or MPL/TDM, antibody titers to MSP1(19) were significantly lower. Among these three adjuvants, Quil A proved to be the most efficient one generating antibody titers significantly higher than the others. These results indicated that under the circumstances evaluated, adjuvants were key for the immumogenicity of the recombinant protein HiS(6)MSP1(19)-DYDVVYLKPLAGMYK-PADRE. (c) 2006 Elsevier SAS. All rights reserved.
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    Impacto da malária sobre o estado nutricional e micronutrientes (vitamina a, betacaroteno, zinco e ferro) de uma coorte de crianças no estado do Amazonas
    (Universidade Federal de São Paulo (UNIFESP), 2016-04-15) Benzecry, Silvana Gomes [UNIFESP]; Leite, Heitor Pons [UNIFESP]; http://lattes.cnpq.br/5958169766712503; http://lattes.cnpq.br/6862747416741090; Universidade Federal de São Paulo (UNIFESP)
    Background. There is a growing body of evidence linking micronutrient deficiencies and malaria incidence arising mostly from P. falciparum endemic areas. We assessed the impact of micronutrient deficiencies on malaria vivax incidence and vice versa in the Brazilian state of Amazonas. Methodology/Principal Findings. We evaluated children <10 years old living in rural communities in the state of Amazonas, Brazil, from May 2010 to May 2011. All children were assessed for sociodemographic, anthropometric and laboratory parameters, including vitamin A, beta-carotene, zinc and iron serum levels at the beginning of the study (May 2010) and one year later (May 2011). Children were followed in between using passive surveillance for detection of symptomatic malaria. Those living in the study area at the completion of the observation period were reassessed for micronutrient levels. Univariate Cox-proportional Hazards models were used to assess whether micronutrient deficiencies had an impact on time to first P. vivax malaria episode. We included 95 children median age 4.8 years (interquartile range [IQR]: 2.3?6.6), mostly males (60.0%) and with high maternal illiteracy (72.6%). Vitamin A deficiencies were found in 36% of children, beta-carotene deficiency in 63%, zinc deficiency in 61% and iron deficiency in 51%. Most children (80%) had at least one intestinal parasite. During follow-up, 16 cases of vivax malaria were diagnosed amongst 13 individuals. Micronutrient deficiencies were not associated with increased malaria incidence: vitamin A deficiency [Hazard ratio (HR): 1.51; P-value: 0.45]; beta-carotene [HR: 0.47; P-value: 0.19]; zinc [HR: 1.41; P-value: 0.57] and iron [HR: 2.31; P-value: 0.16]). Upon reevaluation, children with al least one episode of malaria did not present significant changes in micronutrient levels. Conclusion. Micronutrient serum levels were not associated with a higher malaria incidence nor the malaria episode influenced micronutrient levels. Future studies targeting larger populations to assess micronutrients levels in P. vivax endemic areas are warranted in order to validate these results.
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    Imunogenicidade de proteínas recombinantes da superfície do merozoíta de Plasmodium vivax candidatas à vacina contra malária.
    (Universidade Federal de São Paulo (UNIFESP), 2006-01-01) Rosa, Daniela Santoro [UNIFESP]; Rodrigues, Mauricio Martins [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)
    The aim of this study was to evaluate in a murine model, the capacity of the helper epitope PADRE (Pan Allelic DR epitope) to improve the immunizations with the P. vivax MSP119 in the presence of distinct adjuvant formulations. We observed that immunization of mice with the recombinant protein His6MSP119PADRE in the presence of different adjuvants was able to induce antibody titers similar to those generated by complete/incomplete Freund’s adjuvant (CFA/IFA) in terms of magnitude, affinity, IgG subclasses and longevity. However, immunizations with the recombinant protein His6MSP119, strong antibody responses could be generated in the presence of CFA/IFA but not other classes of adjuvants such as CpG ODN 1826 or MPL/TDM. Our results indicated that when adjuvants that are not as strong as CFA/IFA are employed, the presence of PADRE greatly improved adjuvant-assisted antibody immune response induced by a malarial recombinant antigen. Subsequently, we characterized the immunogenic properties of a new recombinant protein containing the P. vivax MSP119. This new recombinant protein contain in addition to the MSP119, two helper T-cell epitopes, the synthetic universal Pan Allelic DR epitope (PADRE) and a new internal MSP1 P.vivax epitope (DYDVVYLKPLAGMYK). The recombinant protein His6MSP119-DYDVVYLKPLAGMYK-PADRE proved to be highly immunogenic in marmosets (Callithrix jaccus jaccus) when administered in the presence of incomplete Freund’s adjuvant (IFA). However, when administered in other adjuvant formulations such as Quil A, CpG ODN 2006 or MPL/TDM, antibody titers to MSP119 were significantly lower. These results indicated that under the circumstances evaluated, adjuvants were key for the immunogenicity of the recombinant protein His6MSP119-DYDVVYLKPLAGMYK-PADRE. Finally, we have investigated the participation of selected cytokines during the generation of antigen-specific antibody responses upon immunization with recombinant antigens in the presence of the adjuvant CpG ODN 1826. We found that endogenous interferon (IFN) was critical for the induction of humoral immune response after immunization in the presence of CpG ODN 1826. Other cytokines like IL-12/IL-23 or IL-4 caused a dramatic change in the pattern of IgG isotypes. To determine the cell type responsible for the IFN-g production we did adoptive transfer experiments. We observed that CD4+ or CD8+ spleen cells were relevant sources of IFN-g in vivo. Our study suggests a critical role for endogenous IFN-g during CpG ODN-assisted immune response and a possible new link between the innate and adaptive immune responses in which this cytokine plays a previously unrecognized role.
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    Long-lasting humoral and cellular immune responses elicited by immunization with recombinant chimeras of the Plasmodium vivax circumsporozoite protein
    (Elsevier B.V., 2014-04-17) Morais Martins Almeida, Ana Paula; Dias, Mariana Oliveira; Fagundes Vieira, Carolina de Almeida; Chavez-Olortegui, Carlos; Gazzineli, Ricardo Tostes; Rodrigues, Mauricio Martins [UNIFESP]; Fujiwara, Ricardo Toshio; Bruna-Romero, Oscar; Universidade Federal de Minas Gerais (UFMG); Universidade Federal de São Paulo (UNIFESP); Universidade Federal de Santa Catarina (UFSC)
    The circumsporozoite protein (CSP), the most abundant surface antigen of sporozoites, has been extensively studied in different expression platforms as a vaccine candidate. Clinical trials have shown the necessity of broad and highly avid humoral immune responses together with high numbers of CSP-specific TCD4+ and TCD8+ cells, especially those producing IFN gamma, to induce protection. To this aim, we designed two distinct recombinant immunogens based on previously-described antigenic fragments of Plasmodium vivax CSP (PvCSP) to be used as vaccine candidates. the first one is a virus-like particle (VLP) comprising the repeat region of PvCSP (B and TCD4+ epitopes) within the loop of the hepatitis B virus core antigen (HBcAgPvCSP). the second one is a PvCSP multi-epitope polypeptide, rPvCSP-ME, designed based on antigenic regions of PvCSP recognized by lymphocytes of individuals from endemic areas. Mice immunized with 2 doses of these proteins, administered individually or combined and formulated in Montanide ISA 720 adjuvant, were able to induce strong effector and memory humoral responses with IgG titers ranging from 10(4) to 10(5) and avidity indexes toward full-length PvCSP reaching up to 66%, even 3 months after the last immunization. Furthermore, balanced Th1/Th2 responses were generated, as determined by titers of IgG subclasses and further confirmed by ELISPOT analyses, which detected that these vaccination protocols were able to elicit long-term IFN gamma and IL-2-secreting memory T-cells. Overall, these results show that our vaccine candidates generate, in mice, immune responses against regions within PvCSP that have been associated with protection against malaria in humans. (c) 2014 Elsevier B.V. All rights reserved.
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    Plasmodium vivax apical membrane antigen-1: comparative recognition of different domains by antibodies induced during natural human infection
    (Elsevier B.V., 2008-10-01) Mufalo, Bruno C.; Gentil, Fernanda; Bargieri, Daniel Y. [UNIFESP]; Costa, Fabio Trindade Maranhão [UNIFESP]; Rodrigues, Mauricio M. [UNIFESP]; Soares, Irene S.; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP); Universidade Estadual de Campinas (UNICAMP)
    The Apical Membrane Antigen-1 (AMA-1) of Plasmodium sp. has been suggested as a vaccine candidate against malaria. This protein seems to be involved in merozoite invasion and its extra-cellular portion contains three distinct domains: DI, DII, and DIII. Previously, we described that Plasmodium vivax AMA-1 (PvAMA-1) ectodomain is highly immunogenic in natural human infections. Here, we expressed each domain, separately or in combination (DI-II or DII-III), as bacterial recombinant proteins to map immunodominant epitopes within the PvAMA-1 ectodomain. IgG recognition was assessed by ELISA using sera of P. vivax-infected individuals collected from endemic regions of Brazil or antibodies raised in immunized mice. the frequencies of responders to recombinant proteins containing the DII were higher than the others and similar to the ones observed against the PvAMA-1 ectodomain. Moreover, ELISA inhibition assays using the PvAMA-1 ectodomain as substrate revealed the presence of many common epitopes within DI-II that are recognized by human immune antibodies. Finally, immunization of mice with the PvAMA-1 ectodomain induced high levels of antibodies predominantly to DI-II. Together, our results indicate that DII is particularly immunogenic during natural human infections, thus indicating that this region could be used as part of an experimental sub-unit vaccine to prevent vivax malaria. (C) 2008 Elsevier Masson SAS. All rights reserved.
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    A recombinant vaccine based on domain II of Plasmodium vivax Apical Membrane Antigen 1 induces high antibody titres in mice
    (Elsevier B.V., 2010-08-31) Gentil, Fernanda; Bargieri, Daniel Y. [UNIFESP]; Leite, Juliana A.; Francoso, Katia S.; Patricio, Mariana B. M.; Espindola, Noeli M.; Vaz, Adelaide J.; Palatnik-de-Sousa, Clarisa B.; Rodrigues, Mauricio M. [UNIFESP]; Costa, Fabio Trindade Maranhão [UNIFESP]; Soares, Irene S.; Universidade de São Paulo (USP); Universidade Federal de São Paulo (UNIFESP); Universidade Estadual de Campinas (UNICAMP); Universidade Federal do Rio de Janeiro (UFRJ)
    The Apical Membrane Antigen 1 (AMA-1) is considered a promising candidate for development of a malaria vaccine against asexual stages of Plasmodium. We recently identified domain II (DII) of Plasmodium vivax AMA-1 (PvAMA-1) as a highly immunogenic region recognised by IgG antibodies present in many individuals during patent infection with P. vivax. the present study was designed to evaluate the immunogenic properties of a bacterial recombinant protein containing PvAMA-1 DII. To accomplish this, the recombinant protein was administered to mice in the presence of each of the following six adjuvants: Complete/Incomplete Freund's Adjuvant (CFA/IFA), aluminium hydroxide (Alum), Quil A, QS21 saponin, CpG-ODN 1826 and TiterMax. We found that recombinant DII was highly immunogenic in BALB/c mice when administered in the presence of any of the tested adjuvants. Importantly, we show that DII-specific antibodies recognised the native AMA-1 protein expressed on the surface of P. vivax merozoites isolated from the blood of infected patients. These results demonstrate that a recombinant protein containing PvAMA-1 DII is immunogenic when administered in different adjuvant formulations, and indicate that this region of the AMA-1 protein should continue to be evaluated as part of a subunit vaccine against vivax malaria. (C) 2010 Elsevier B.V. All rights reserved.
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    Vaccine Containing the Three Allelic Variants of the Plasmodium vivax Circumsporozoite Antigen Induces Protection in Mice after Challenge with a Transgenic Rodent Malaria Parasite
    (Frontiers Media Sa, 2017) Gimenez, Alba Marina [UNIFESP]; Lima, Luciana Chagas [UNIFESP; Francoso, Katia Sanches; Denapoli, Priscila M. A. [UNIFESP; Panatieri, Raquel; Bargieri, Daniel Y.; Thiberge, Jean-Michel; Andolina, Chiara; Nosten, Francois; Renia, Laurent; Nussenzweig, Ruth S.; Nussenzweig, Victor; Amino, Rogerio; Rodrigues, Mauricio M. [UNIFESP; Soares, Irene S.
    Plasmodium vivax is the most common species that cause malaria outside of the African continent. The development of an efficacious vaccine would contribute greatly to control malaria. Recently, using bacterial and adenoviral recombinant proteins based on the P. vivax circumsporozoite protein (CSP), we demonstrated the possibility of eliciting strong antibody-mediated immune responses to each of the three allelic forms of P. vivax CSP (PvCSP). In the present study, recombinant proteins representing the PvCSP alleles (VK210, VK247, and P. vivax-like), as well as a hybrid polypeptide, named PvCSP-All epi-topes, were generated. This hybrid containing the conserved C-terminal of the PvCSP and the three variant repeat domains in tandem were successfully produced in the yeast Pichia pastoris. After purification and biochemical characterization, they were used for the experimental immunization of C57BL/6 mice in a vaccine formulation containing the adjuvant Poly(I: C). Immunization with a recombinant protein expressing all three different allelic forms in fusion elicited high IgG antibody titers reacting with all three different allelic variants of PvCSP. The antibodies targeted both the C-terminal and repeat domains of PvCSP and recognized the native protein on the surface of P. vivax sporozoites. More importantly, mice that received the vaccine formulation were protected after challenge with chimeric Plasmodium berghei sporozoites expressing CSP repeats of P. vivax sporozoites (Pb/PvVK210). Our results suggest that it is possible to elicit protective immunity against one of the most common PvCSP alleles using soluble recombinant proteins expressed by P. pastoris. These recombinant proteins are promising candidates for clinical trials aiming to develop a multiallele vaccine against P. vivax malaria.