Submitted by Marlene Santos (marlene.bc.ufg@gmail.com) on 2016-04-19T18:10:39Z No. of bitstreams: 2 Tese - Greyciele Rodrigues de Almeida - 2015.pdf: 2860659 bytes, checksum: c6b139400f7d4d535cf2e4ccecbabaed (MD5) license_rdf: 19874 bytes, checksum: 38cb62ef53e6f513db2fb7e337df6485 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-04-20T15:16:36Z (GMT) No. of bitstreams: 2 Tese - Greyciele Rodrigues de Almeida - 2015.pdf: 2860659 bytes, checksum: c6b139400f7d4d535cf2e4ccecbabaed (MD5) license_rdf: 19874 bytes, checksum: 38cb62ef53e6f513db2fb7e337df6485 (MD5) / Made available in DSpace on 2016-04-20T15:16:36Z (GMT). No. of bitstreams: 2 Tese - Greyciele Rodrigues de Almeida - 2015.pdf: 2860659 bytes, checksum: c6b139400f7d4d535cf2e4ccecbabaed (MD5) license_rdf: 19874 bytes, checksum: 38cb62ef53e6f513db2fb7e337df6485 (MD5) Previous issue date: 2015-08-24 / Member of the Herpesviridae family, subfamily Alphaherpesvirinae, gender Varicellovirus, the bovine herpesvirus 1 (BoHV-1) has been associated with different clinical conditions (respiratory and genital/reproductive diseases) in cattle. There is no standard procedure to control or prevent infections caused by herpesviruses. In this sense, phage display was used to select new glycoprotein mimotopes antigen of BoHV-1 that has potential for use in vaccines and diagnostics. The phage display technique was performed using a linear random peptide library consisting of 12 amino acid residues fused to the protein III of M13 phage (no peptide) against BoHV-1 specific IgGs, purified by affinity chromatography. After three cycles of selection (biopanning) and amplification, 44 clones were isolated and their amino acid sequences were determined by sequencing generating 16 different sequences. ELISA, demonstrating the efficiency of selection from the specific antibodies, confirmed the reactivity of pooled clones. Another ELISA evaluated the individual specificity of the most frequent clones, the M13 phage was used as a negative control. We selected three peptides (B, C and E) with affinity for anti-BoHV-1 antibodies, and the E peptide (pepE), showed to have potential as antigen for antibody detection in a serological test for BoHV-1. Immunization of rabbits with the peptides induced specific production of serum antibodies, but they were not able do neutralize BoHV-1 cell lysis. The in silico analysis of the dodecapeptide E (1DRALYGPTVIDH12) enabled the identification of a new discontinuous epitope on the envelope glycoprotein B (gB Env) of bovine herpesvirus type 1 (BoHV-1). There is a short motif (338YKRD341) within a region of the env gB BoHV-1 with high similarity to motifs shared by dodecapeptide the N-terminal region (5YxARD1) of gB and HSV-1 (326YARD329), wherein the 328Arg residue is described as a target for neutralizing monoclonal antibodies (mAb) for HSV-1 gB. Besides the characterization of an antibody-binding site of the BoHV-1 Env gB, we have demonstrated that the phage-fused peptide has potential use as a reagent for virus diagnosis by phage-ELISA assay, discriminating BoHV-1 positive serum samples from negative ones. / Membro da família Herpesviridae, subfamília Alphaherpesvirinae, gênero Varicellovirus, o herpesvírus bovino 1 (BoHV-1) tem sido associado a diferentes condições clínicas em bovinos (doenças respiratórias, genitais e falhas reprodutivas). Não existe um procedimento padrão para medidas de controle e profilaxia das infecções causadas por herpesvírus. Nesse sentido, o phage display foi utilizado com o objetivo de selecionar novos antígenos mimetopos de glicoproteínas do herpesvírus bovino 1 (BoHV-1) e que apresentam potencial para uso em vacinas e diagnóstico. A técnica de phage display foi realizada com a utilização de uma biblioteca de peptídeos randômicos e lineares composta de 12 resíduos de aminoácidos fusionada à pIII de fagos M13 (sem peptídeo), contra anticorpos anti-BoHV-1, purificados em coluna de cromatografia por afinidade. Após três ciclos de seleção (biopanning) e amplificação, 44 clones foram isolados e as sequências de aminoácidos dos peptídeos foram determinadas pelo sequenciamento gerando 16 sequencias diferentes. A reatividade do pool de clones foi confirmada por ELISA, demonstrando a eficiência da seleção a partir dos anticorpos específicos. Para avaliação da especificidade individual, realizou-se o ELISA dos clones mais frequentes, tendo como controle negativo o fago M13. Foram selecionados três peptídeos (B, C e E) com afinidade por anticorpos anti-BoHV-1, e um destes, o peptídeo E (pepE), apresentou potencial antigênico na detecção de anticorpos para o diagnóstico sorológico do BoHV-1. Nos testes de imunização em coelhos, os três peptídeos induziram a produção de anticorpos específicos, porém, estes não foram capazes de neutralizar a lise celular ocasionada pelo BoHV-1 em placa. A análise in silico do dodecapeptídeo E (1DRALYGPTVIDH12) possibilitou a identificação de um novo epitopo descontínuo na glicoproteína B de envelope (Env gB) do BoHV-1. Há um curto motivo (338YKRD341) dentro de uma região do gene Env gB do BoHV-1, com alta similaridade com os motivos compartilhados pelo dodecapeptídio da região N-terminal (5YxARD1) da gB e do Herpesvirus Humano 1 (HSV-1) (326YARD329), em que o resíduo 328Arg é descrito como um alvo para anticorpos monoclonais neutralizantes (mAb) para a gB do HSV-1. Concluindo, além da caracterização de um sítio de ligação ao anticorpo na Env gB do BoHV-1, o pepE expresso pelo fago tem potencial de utilização como reagente para o diagnóstico virológico por ensaio ELISA-fago, que discrimina amostras de soro positivas e negativas para o BoHV-1.

Les proprotéines convertases (PCs) sont des enzymes impliquées de nombreux processus pathologiques. Nous avons étudié deux substrats des PCs: l'apeline et la glycoprotéine B (gB) du virus d'Epstein Barr (EBV), et le rôle de cette maturation protéolytique dans la médiation de leurs fonctions. L'apeline est surexprimée dans plusieurs cancers dont le cancer colorectal (CCR), et nous avons montré que la furine, un membre des PCs, clive l’apeline. Pour déterminer le rôle de ce clivage dans le CCR métastatique, nous avons généré un mutant non clivable (apeline-DM). In vitro, ce mutant inhibe la croissance de cellules cancéreuses du côlonet ne les protège pas de l'apoptose, contrairement à l'apeline sauvage. In vivo, l'apeline-DM diminue drastiquement la croissance tumorale et la formation de métastases hépatiques chez la souris. Les mêmes résultats sont obtenus dans des modèles de souris déficientes pour l’apeline, démontrant l'intérêt d'utiliser l'apeline-DM ou des dérivés comme potentiels agents anticancéreux dans le traitement des CCR métastatiques. La gB du virus EBV, virus impliqué dans certains cancers lymphoïdes et épithéliaux chez l'homme, permet l'entrée du virus dans la cellule lors de l'infection. Nous avons montré que les PCs, et notamment la furine, clivent la gB. In vitro, l'induction de la protéine virale LMP1 augmente l'expression de la furine, qui se traduit par une augmentation de l'infection par EBV. Ces résultats suggèrent l'existence d'une boucle de régulation entre la furine et LMP1 permettant d'améliorer la propagation cellulaire du virus. L'utilisation d'inhibiteurs de l'activité des PCs permettrait donc de bloquer l'infection par EBV. / Proprotein convertases (PCs) are enzymes involved in many pathological processes. We have identified two novel substrates of the PCs: apelin and glycoprotein B (gB) of Epstein Barr Virus (EBV), and studied the role of PC-mediated proteolytic maturation in their functions. Apelin is overexpressed in some cancers including colorectal cancer (CRC), and we demonstrated that furin, one of the PCs member, cleaves apelin in two peptides. To determine the role of apelin cleavage by furin in the metastatic CRC, we generated a non-cleavable mutant (apelin-DM). This mutant inhibited the growth of colon cancer cells in vitro and could not protect against apoptosis, unlike the wild-type apelin. In vivo, apelin-DM drastically reduces tumor growth and the formation of hepatic metastases in mice. These results were confirmed in apelin deficient mouse models thus demonstrating the potential interest of using apelin-DM, or its derivatives, as anticancer agents in the treatment of metastatic CRC. The gB of EBV, a virus involved in some lymphoid and epithelial cancers in humans, is involved in the entry of the virus into the cell during infection. We have shown that PCs, especially furin, cleave gB. In vitro,induction of the LMP1 viral protein increases furin expression, which results in an increase in EBV infection. These results suggest the existence of a regulatory loop between furin and LMP1 to improve the cellular propagation of the virus. The use of inhibitors of PCs activity would thus block EBV infection, a virus against which there is no treatment nowadays.

Human cytomegalovirus (HCMV, Herpesviridae) can cause severe complications in the infected individuals undergoing hematopoietic stem cell transplantation. Nowadays, these patients are treated using antivirotics or HCMV-specific T cells derived from the seropositive graft donor. This study explored the possibility of redirecting HCMV-non-specific T cells from a seronegative donor towards HCMV-infected cells via chimeric antigen receptor (CAR), i.e. artificially designed T cell receptor. Viral glycoprotein B (gB) has been selected as a target for this receptor. Published sequence of a single chain variable fragment of a human antibody was used for the design of the CAR against gB (gBCAR). After the verification of production and surface localization in cell lines, gBCAR was being introduced into human T cells via lentiviral vectors. Human fetal lung fibroblasts (LEP) infected with HCMV were used as target cells after the expression of gB at their surface was demonstrated. gBCAR functionality was evaluated by the incubation of modified T cells with infected cells and subsequent analysis of media for IFNγ concentration, which was significantly higher in the setting of gBCAR T cells incubated with HCMV-LEP than in the control incubations. The results obtained show the specificity of gBCAR against...