Made available in DSpace on 2016-05-17T16:51:22Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-08-13. Added 1 bitstream(s) on 2016-05-17T16:54:16Z : No. of bitstreams: 1 000864272_20160704.pdf: 706780 bytes, checksum: 4d6888c37d677fae1dd7bf418a013985 (MD5) Bitstreams deleted on 2016-07-25T13:17:41Z: 000864272_20160704.pdf,. Added 1 bitstream(s) on 2016-07-25T13:18:48Z : No. of bitstreams: 1 000864272.pdf: 941126 bytes, checksum: 0602961cda7c25695afee5dc324562ba (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / The progression of the canine visceral leishmaniasis (CVL) is related to the immune response profile. The effective cellular immunity is related to the predominance of Th1 cytokines such as TNF-α and the disease is related to an exacerbated humoral immune response, with the predominance of Th2 cytokines such as IL-10 and TGF-β. TLR-2 is an important receptor of the innate immunity involved in the induction of the cytokines production and the activation of iNOS in visceral leishmaniasis. To understand how the skin may become a permissive microenvironment for the multiplication of this parasite, the expression of genes encoding to TLR-2, to the iNOS enzyme and to the cytokines IL-10, TNF-α and TGF-β was evaluated in skin of dogs naturally affected by CVL and were then was related to the parasite load of this tissue. We observed that the skin of dogs naturally affected by visceral leishmaniasis has a mixed Th1/Th2 immune response profile, with an increased expression of TLR-2, IL-10 and TNF-α that correlates to the increasing of the parasitic load in this tissue, giving these mediators an important role in the pathogenesis of CVL

Orientador:Caris Maroni Nunes / Co-orientador:Valéria Marçal Félix de Lima / Banca:Gisele Fabrino Machado / Banca:Marcia Dalastra Laurenti / Resumo:A progressão da leishmaniose visceral canina (LVC) depende do perfil da resposta imune, sendo que a imunidade celular efetiva está relacionada à predominância de citocinas Th1, como o TNF-α, e o desenvolvimento da doença está mais relacionado à resposta imune humoral exacerbada, com predominância de citocinas Th2, como a IL-10 e o TGF-β. O TLR-2, por sua vez, é um receptor da imunidade inata que tem importante papel na leishmaniose visceral por participar na indução da produção de citocinas e ativação da iNOS. Para entender como a pele pode se tornar um microambiente permissivo à multiplicação do parasita, a expressão dos genes que codificam o TLR-2, a enzima iNOS e as citocinas IL-10, TNF-α e TGF-β foi avaliada na pele de cães naturalmente acometidos por LVC e relacionada à carga parasitária deste tecido, em comparação a cães não infectados. Observou-se que a pele de cães naturalmente acometidos por leishmaniose visceral apresenta perfil misto Th1/Th2 de resposta imune, com aumento da expressão do TLR-2, da IL-10 e do TNF-α, aumento este que se correlaciona com o aumento da carga parasitária neste tecido, atribuindo a estes mediadores um papel importante na patogênese da LVC / Abstract:The progression of the canine visceral leishmaniasis (CVL) is related to the immune response profile. The effective cellular immunity is related to the predominance of Th1 cytokines such as TNF-α and the disease is related to an exacerbated humoral immune response, with the predominance of Th2 cytokines such as IL-10 and TGF-β. TLR-2 is an important receptor of the innate immunity involved in the induction of the cytokines production and the activation of iNOS in visceral leishmaniasis. To understand how the skin may become a permissive microenvironment for the multiplication of this parasite, the expression of genes encoding to TLR-2, to the iNOS enzyme and to the cytokines IL-10, TNF-α and TGF-β was evaluated in skin of dogs naturally affected by CVL and were then was related to the parasite load of this tissue. We observed that the skin of dogs naturally affected by visceral leishmaniasis has a mixed Th1/Th2 immune response profile, with an increased expression of TLR-2, IL-10 and TNF-α that correlates to the increasing of the parasitic load in this tissue, giving these mediators an important role in the pathogenesis of CVL / Mestre

Made available in DSpace on 2016-08-19T17:47:06Z (GMT). No. of bitstreams: 1 Cristiane Costa de Carvalho.pdf: 1454881 bytes, checksum: 831238c6d9864b9fca7efc9ba6164541 (MD5) Previous issue date: 2007-09-25 / FUNDAÇÃO DE AMPARO À PESQUISA E AO DESENVOLVIMENTO CIENTIFICO E TECNOLÓGICO DO MARANHÃO / The municipal district of Raposa located in the State of Maranhão, Brazil, is an endemic area of human and canine visceral leishmaniasis. Dogs are considered to be the principal Leishmania chagasi reservoir in this location. The objective of this study was to examine the relative levels of parasitic DNA in different tissues of infected dogs and their association with clinical signs of Leishmaniasis. We initiated this study by collecting blood samples from 233 distinct dogs that were analyzed by means of serological diagnosis. Of all examined dogs, 69 were positive in the anti-Leishmania ELISA. According to technical reasons only 27 of the Leishmania infected dogs could be recaptured and studied. The animals were classified according to their clinical signs in asymptomatics (10 animals), oligosymptomatics (8 animals) and polysymptomatics (9 animals) groups. A quantitative PCR method was developed and established in order to examine the parasitic load in blood, bone marrow, lymph node, spleen and skin. The parasite could be detected in lymph nodes of all animals analyzed (100%). The tissue with the highest parasitic load was lymph nodes followed by spleen, blood, bone marrow and skin. Comparing all analyzed tissues, the lymph nodes presented the highest levels of parasitic DNA, without exception, regardless their symptoms classification. Contrary to various other studies, we have detected the lowest parasitic DNA concentration in skin tissues. The quantitative PCR assay established in this study was sensitive, fast and inexpensive for qualitative and quantitative analyses of the Leishmania chagasi DNA. The canine lymph node is the most frequently infected tissue, with greater levels of parasitic DNA, and may be considered a target tissue for leishmaniasis monitoring in dogs. / O município de Raposa (Maranhão, Brasil) é uma área endêmica de leishmaniose visceral humana e canina. Neste município, cães são considerados o principal reservatório de Leishmania chagasi. O objetivo deste estudo foi investigar a concentração do DNA parasitário em diferentes tecidos de cães infectados e sua associação com sinais clínicos de leishmaniose. Iniciamos este estudo com a coleta de sangue de 233 cães para diagnóstico sorológico da infecção. Dentre todos os cães examinados, 69 apresentaram anticorpos anti-Leishmania no teste ELISA. Destes, apenas 27 puderam ser recapturados e estudados. Os animais foram classificados de acordo com avaliação clínica em assintomáticos (n=10); oligossintomáticos (n=8) e polissintomáticos (n=9). A técnica de PCR quantitativa foi desenvolvida e padronizada para avaliar a concentração de DNA parasitário em sangue, medula, linfonodo, baço e pele. O parasito foi detectado em todas as amostras de linfonodo analisadas (100%). O tecido com os maiores níveis de DNA parasitário foi o linfonodo, seguido pelo baço, sangue, medula e pele. Comparando-se os tecidos analisados, o linfonodo foi o tecido com as maiores cargas parasitárias, sem exceção, entre animais assintomáticos, oligossintomáticos e polissintomáticos. Contrariamente a outros estudos, detectamos baixos níveis de DNA parasitário em amostras de pele. A PCR quantitativa padronizada neste estudo foi um método sensível, rápido e econômico para detectar e determinar os níveis de DNA parasitário de Leishmania chagasi. Em cães, o linfonodo é o tecido mais acometido pelo parasito e com maiores níveis de DNA, podendo ser considerado o sítio ideal para o monitoramento da leishmaniose canina.