published_or_final_version / Paediatrics and Adolescent Medicine / Master / Master of Philosophy

published_or_final_version / Pathology / Master / Master of Philosophy

published_or_final_version / Paediatrics / Master / Master of Philosophy

published_or_final_version / Paediatrics / Master / Master of Philosophy

Entamoeba histolytica, etiological agent of amebiasis, continues to be a significant threat to human health worldwide. The disease affects 10% of the world's population and leads to an estimated 100, 000 deaths a year. The parasite's surface Gal-lectin is an immunodominant protein that also mediates colonization and pathogenicity. The Gal-lectin is the most promising vaccine candidate against amebiasis. However, the immune mechanisms involved in protection against disease remain unclear. The objective of this study was to characterize the immunological basis of the host defense mechanisms using a Gal-lectin based vaccine. Exposure of the Gal-lectin with immature dendritic cells increased cell maturation and activation and upregulated co-stimulatory molecules and pro-inflammatory cytokines production. Dendritic cell activation was dependent on NF-kappaB and MAPK activation. In vaccination studies, the adjuvant effect of CpG-ODN, a synthetic oligodeoxynucleotide capable of stimulating Th1 immune responses enhanced the immune response to the Gal-lectin when administered systemically or mucosally. Protected animals had elevated anti-Gal-lectin serum and stool IgA antibodies capable of blocking parasite adherence in vitro. Analysis of cytokine responses in vaccinated and protected animals revealed increased IFN-gamma production compared to controls. Finally, E. histolytica DNA was shown to activate macrophages in a TLR9 and MYD88-dependent manner. Immunized gerbils with Gal-lectin and E. histolytica DNA induced protective immunity against a challenge infection. Taken together, these findings underscore the importance of multivalent subunit vaccines in Th1 mediated immune responses in host defense against amebiasis.

Thesis (M.Sc.). / Written for the Dept. of Plant Science. Title from title page of PDF (viewed 2008/05/29). Includes bibliographical references.

Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 155-165). Also available on the World Wide Web.

Thesis (Ph. D.)--University of Virginia, 1998. / Spine title: Control of E. histolytica lectin. Includes bibliographical references (p. 93-105). Also available online through Digital Dissertations.

Thesis (Ph. D.)--Ohio State University, 2008. / Non-Latin script record

SILVA, Luana Maria Castelo Melo. Efeito da lectina da alga marinha vermelha Pterocladiella capillace em feridas limpas induzidas em ratos. 2012. 135 f. Tese (Doutorado em bioquímica)- Universidade Federal do Ceará, Fortaleza-CE, 2012. / Submitted by Elineudson Ribeiro (elineudsonr@gmail.com) on 2016-07-20T16:16:36Z No. of bitstreams: 1 2012_tese_lmcmsilva.pdf: 10225620 bytes, checksum: 67dadb7130fbee0f6137beb9f3cec43e (MD5) / Approved for entry into archive by José Jairo Viana de Sousa (jairo@ufc.br) on 2016-08-02T18:10:12Z (GMT) No. of bitstreams: 1 2012_tese_lmcmsilva.pdf: 10225620 bytes, checksum: 67dadb7130fbee0f6137beb9f3cec43e (MD5) / Made available in DSpace on 2016-08-02T18:10:12Z (GMT). No. of bitstreams: 1 2012_tese_lmcmsilva.pdf: 10225620 bytes, checksum: 67dadb7130fbee0f6137beb9f3cec43e (MD5) Previous issue date: 2012 / Based on the need for new formulations that are more efficient and on the properties provided by molecules derived from seaweed, it is believed that these can be effective in healing process. The lectin from the red seaweed Pterocladiella capillacea (PcL) and the polysaccharides of red algae Solieria filiformis (SfP) were initially analyzed in toxicity testing. PcL was applied to the paw edema test followed by measurement of myeloperoxidase (MPO). We evaluated the effect of the seaweed Pterocladiella capillacea lectin (PcL) and algal polysaccharides Solieria filiformis (SfP) in healing wounds in rats induced. Both molecules were submitted to microbiological tests and assayed for the effect on wound healing in wounds clean induced on the back of rats. SfP was used as a possible vehicle for the administration of PcL and compared to Carbopol 940 (C). The gels (0.9%) were analyzed rheological and then applied to the lesions during a treatment period of 10 days, using kollagenase ® as control. The healing process was evaluated on the size of the wounds, levels of MPO and histological analysis. The molecule SfP and PcL is not toxic for the parameters of body weight, organ and biochemical measurements. However, the histological analysis showed minor changes in liver and kidney. PcL (1, 3 and 9 mg / kg, i.v) reduced the edema induced by carrageenan and its inhibitor when administered with mucin was not possible to check the reduction of edema which was confirmed by measurement of MPO. The two molecules were used in microbiological assays and not inhibit growth of any microorganism tested and unable to use SfP as carbon source. The rheological analysis showed that the SfP used in the formulation of the gels (PcL+SfP and SfP) had the characteristic of a pseudoplastic. Macroscopic analysis of wounds showed a reduction in lesion area in the animals treated with PCL, PCL+SfP, PCL+C (53.5 and 60% respectively) on the sixth day of administration. In histological analysis, there was no severe inflammatory infiltrate in the tissues obtained until 4th day of administration of the gels (PcL and PcL+SfP, PcL+C) and Kollagenase® (positive control). On day 6, the untreated animals and those treated only with SfP showed inflammatory infiltrate. The measurement of MPO showed a reduction in the inflammatory process in the samples containing PcL, whose results corroborate the histological analysis. In conclusion, PcL aid in wound repair, suggesting its use as a possible future tool for the treatment of lesions. The biological and pharmacological role of lectins and polysaccharides of seaweed is part of a study area little explored, where a lot of knowledge should be invested since these biomolecules can be promising for the pharmaceutical industry. / Com base na necessidade de obter novas formulações mais eficientes e diante das propriedades apresentadas pelas moléculas oriundas de algas marinhas, acredita-se que estas possam ser eficazes no processo de cicatrização. A lectina da alga marinha vermelha Pterocladiella capillacea (PcL) e os polissacarídeos da alga vermelha Solieria filiformis (SfP) inicialmente foram analisados em ensaio de toxicidade. PcL foi aplicada no ensaio do edema de pata seguido da dosagem de mieloperoxidase (MPO). Avaliou-se o efeito da lectina da alga Pterocladiella capillacea (PcL) e os polissacarídeos das algas Solieria filiformis (SfP) na cicatrização de feridas induzidas em ratos. Ambas as moléculas foram submetidas a ensaios microbiológicos e analisadas quanto ao efeito no processo de cicatrização em feridas limpas induzidas no dorso de ratos. SfP foi utilizado como um possível veículo para a administração de PcL e comparado ao Carbopol 940 (C). Os géis (0,9%) foram submetidos a análise reológica e então aplicados nas lesões durante um período de tratamento de 10 (dez) dias, utilizando kollagenase® como controle. O processo de cicatrização foi avaliado quanto ao tamanho das feridas, dosagem de MPO e análise histológica. PcL e SfP não demonstraram toxicidade quanto aos parâmetros de peso corpóreo, órgãos e dosagens bioquímicas. Entretanto a análise histológica mostrou pequenas alterações no fígado e rim. PcL (1, 3 e 9 mg/kg, i.v.) reduziu o edema induzido por carragenana e quando administrada com seu inibidor mucina não foi possível verificar a redução do edema o qual foi confirmado pela dosagem de MPO. As duas moléculas foram aplicadas em ensaios microbiológicos e não inibiram o crescimento de nenhum micro-organismo testado, os quais também não foram capazes de utilizar SfP como fonte de carbono. A análise reológica mostrou que os SfP utilizados na formulação dos géis (PcL+SfP e SfP) apresentaram a característica de um pseudoplástico. A análise macroscópica das feridas mostrou uma redução da área da lesão nos animais tratados com PcL+SfP e PcL+C (53,5 e 60%, respectivamente) no sexto dia de administração. Na análise histológica, não foi observado infiltrado inflamatório acentuado nos tecidos obtidos até o 4º dia da administração dos géis (PcL+SfP e PcL+C) e Kollagenase® (controle positivo). No 6º dia, os animais não tratados e os tratados apenas com SfP mostraram infiltrado inflamatório. A dosagem de MPO demonstrou redução no processo inflamatório nas amostras contendo PcL, cujo resultado corrobora com a análise histológica. Em conclusão, PcL auxiliou no reparo de feridas, sugerindo seu uso futuro como uma possível ferramenta para o tratamento de lesões. O papel biológico e farmacológico das lectinas e polissacarídeos de algas marinhas faz parte de uma área de estudos ainda pouco explorada, onde muito conhecimento deverá ser investido visto que estas biomoléculas podem ser promissoras para a indústria farmacêutica.