Typescript (photocopy) / 157 leaves : / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (M.D.)--Dept. of Medicine, University of Adelaide, 1983

Thesis (M.D.) - Dept. of Medicine, University of Adelaide, 1983. / Typescript (photocopy).

No description available.

<p>Immune complexes (ICs) are produced during normal immune responses and facilitate clearance of foreign antigens. ICs not efficiently cleared from the circulation can cause tissue damage. This might happen if ICs are formed with autoantibodies and autoantigens. Well described effects of ICs are neutralization of antigen, classical complement activation or FcR-mediated phagocytosis, whereas cytokine inducing effects of ICs in human clinical settings are less well described. I have investigated cytokine-inducing properties <i>in vitro</i> of ICs from patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and cryoglobulinemia in association with lymphoproliferative diseases. </p><p>Cryoglobulin (CG)-induced cytokine production varied with changes in temperature and ionic strength in parallel to CG precipitation. IgG CG-induced cytokine production was also mediated via FcγIIa on monocytes. Blockade of the complement system, resembling the <i>in vivo</i> situation of complement consumption in CG-associated diseases, increased IgG CG induced IL-10 and decreased TNF-α production. This represents hitherto not described mechanisms for CG-associated inflammation.</p><p>ICs from SLE patients induced IL-10 and IL-6 production from PBMC cultures via FcγRIIa. Occurrence of anti-SSA autoantibodies and signs of <i>in vivo</i> complement activation contributed to increased levels of circulating ICs in SLE patients, corresponding to increased amounts of IC-induced IL-10 <i>in vitro</i>. This represents a possible vicious cycle that might perpetuate antibody dependent pathology in SLE, and put anti-SSA in a new pathological context.</p><p>RF-associated ICs from RA joints and ICs formed with antibodies against collagen type II from RA serum induced pro-inflammatory cytokine production from monocytes via FcγRIIa, showing how specific autoantibodies might induce or perpetuate joint inflammation in RA. </p><p>I have described how ICs can induce significant amounts of pathophysiologically important monocyte-derived cytokines in three major IC-dependent diseases. Blockade of FcγRIIa and suppression of monocytes/macrophages might be a means of reducing pathogenic IC-induced cytokine production in these diseases. </p>

Immune complexes (ICs) are produced during normal immune responses and facilitate clearance of foreign antigens. ICs not efficiently cleared from the circulation can cause tissue damage. This might happen if ICs are formed with autoantibodies and autoantigens. Well described effects of ICs are neutralization of antigen, classical complement activation or FcR-mediated phagocytosis, whereas cytokine inducing effects of ICs in human clinical settings are less well described. I have investigated cytokine-inducing properties in vitro of ICs from patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE) and cryoglobulinemia in association with lymphoproliferative diseases. Cryoglobulin (CG)-induced cytokine production varied with changes in temperature and ionic strength in parallel to CG precipitation. IgG CG-induced cytokine production was also mediated via FcγIIa on monocytes. Blockade of the complement system, resembling the in vivo situation of complement consumption in CG-associated diseases, increased IgG CG induced IL-10 and decreased TNF-α production. This represents hitherto not described mechanisms for CG-associated inflammation. ICs from SLE patients induced IL-10 and IL-6 production from PBMC cultures via FcγRIIa. Occurrence of anti-SSA autoantibodies and signs of in vivo complement activation contributed to increased levels of circulating ICs in SLE patients, corresponding to increased amounts of IC-induced IL-10 in vitro. This represents a possible vicious cycle that might perpetuate antibody dependent pathology in SLE, and put anti-SSA in a new pathological context. RF-associated ICs from RA joints and ICs formed with antibodies against collagen type II from RA serum induced pro-inflammatory cytokine production from monocytes via FcγRIIa, showing how specific autoantibodies might induce or perpetuate joint inflammation in RA. I have described how ICs can induce significant amounts of pathophysiologically important monocyte-derived cytokines in three major IC-dependent diseases. Blockade of FcγRIIa and suppression of monocytes/macrophages might be a means of reducing pathogenic IC-induced cytokine production in these diseases.

Thesis (Ph. D.)--University of Adelaide, 1986. / Includes bibliographical references (leaves 119-136).

<p>Antibodies are proteins capable of specific interactions to a wide range of molecules. These interactions are facilitated by the complementary determining regions (CDR).</p><p>Carcinomas are the most common of human cancers and they release significant amount of cytokeratins (CK) in the necrotic areas of the tumors. The CKs stay in the tumor, since they have low solubility. The antibody studied in this thesis, the anti-CK 8 antibody TS1, has shown to be effective in tumor targeting and is proposed to be useful in therapy.</p><p>Single-chain antibodies (scFv) are recombinant antibodies which are much smaller than the intact IgG. This is an advantage when used in tumor therapy, since they can penetrate the tumors more easily than the larger IgG. Moreover, they are expressed by one single gene which make them easy to modify, for example by site-directed mutagenesis.</p><p>The anti-idiotypic antibody αTS1 can be used to clear the TS1 form the circulation and thereby clear the body from non-tumor bound TS1 in therapy. To be able to modify the binding of an antibody to its antigen and or anti-idiotype, these interactions must be studied. In this study this is accomplished by chemical modifications of the IgGs TS1 and αTS1 and the antigen CK 8. Guided by these results, amino acid residues were mutated by using site-directed mutagenesis in the TS1-218 scFv and the effects were studied. From mutational study results, the functional epitope could be mapped and it was found that there are mainly tyrosines, but also charged residues, serine and a tryptophan that are important for both interactions. The binding of TS1-218 to both αTS1 and CK 8 could be improved by changing the negatively charged side-chains by mutations to their corresponding amide or alanine.</p><p>Both the IgG and scFv versions of TS1 were administered in vivo. The IgG αTS1 was used to clear the TS1 from the circulation by forming immune complexes. The immune complexes, consisting of four or more antibodies, were mainly metabolized by the liver. The scFv TS1-218 could localize to the tumor in a tumor xenograft mouse model, although a higher uptake would be desired in a therapeutic strategy. The scFv was cleared rapidly by the kidneys, but the clearance could be slowed by pre-formed immune complexes with anti-TS1 scFv in vitro, prior to administration in vivo.</p>

O sistema imune inato é organizado por processos complexos que envolvem os diversos tipos celulares que culminam na eliminação de uma variedade de microorganismos a fim de proteger o organismo de infecções. Os neutrófilos são células importantes neste sistema, sendo capazes de migrar rapidamente ao foco da infecção. Estas células reconhecem e fagocitam partículas estranhas e atuam no sentido de elimina-los através da produção de espécies reativas de oxigênio (EROs), proteínas antimicrobianas e enzimas proteolíticas dos grânulos, que são liberadas no fagossomo e no espaço extracelular. Entretanto, em algumas doenças inflamatórias e autoimunes têm sido encontradas lesões nos tecidos envolvendo a produção excessiva de EROs pelos neutrófilos, desencadeada por imunocomplexos (ICs) via receptores Fc gama (Fc) e de complemento (CR). Assim, a modulação da ativação destes receptores e da produção de EROs é importante na manutenção da homeostasia. Nas últimas décadas, flavonóides são considerados como metabólitos secundários promissores mostrando atividade antioxidante e imunomodulatória. Neste trabalho foi avaliado o efeito modulatório dos flavonóides galangina, kaempferol, quercetina e miricetina em algumas funções efetoras de neutrófilos humanos, como o metabolismo oxidativo estimulado via receptores de membrana Fc e/ou CR, fagocitose e atividade microbicida, além do efeito citotóxico, antioxidante e inibitório dessas substâncias sobre a atividade das enzimas mieloperoxidase (MPO) e NADPH oxidase. Os flavonóides analisados mostraram um efeito modulatório negativo no metabolismo oxidativo dos neutrófilos humanos na seguinte ordem: galangina> kaempferol> quercetina > miricetina. Embora a galangina tenha exercido maior atividade, sua ação antioxidante e inibitória na atividade das enzimas MPO e NADPH oxidase foi a menos efetiva dentre os flavonóides avaliados. Além disso, esta substância inibiu de maneira mais acentuada a resposta celular mediada por ambos os receptores Fc e CR quando comparado a estimulação destes receptores individualmente. As substâncias contendo o grupo catecol, quercetina e miricetina mostraram elevada eficiência na inibição da atividade das enzimas NADPH oxidase e MPO, e na redução do radical livre 2,2-difenil-1-picrilhidrazil (DPPH). De maneira geral, os flavonóides não interferiram no processo fagocítico e no mecanismo microbicida, e não induziram toxicidade e morte celular por apoptose ou necrose. Os resultados apresentados neste trabalho mostram uma possível aplicação destes flavonóides como fármacos de origem natural em doenças inflamatórias que apresentem acúmulo de neutrófilos, sendo uma ferramenta promissora para o tratamento efetivo destas doenças. / The innate immune system is composed of complex biological processes involving a variety of cell types that eliminate invading microorganisms to protect the host against infection. Neutrophils are key effector cells of this system, being able to migrate rapidly to infection sites. These cells recognize and engulf foreign particles by phagocytosis, and act to destroy them through production and release of reactive oxygen species (ROS), antimicrobial proteins and proteolytic granule enzymes, which are delivered to the phagossomes and to the extracellular environment. However, tissue damage related to excessive neutrophil ROS production triggered by immune complexes (ICs) via Fc-gamma (FcR) and complement receptors (CR) has been found in some inflammatory and autoimmune diseases. So, modulation of both the activation of these receptors and ROS generation are important to the maintenance of body homeostasis. In the last decades, flavonoids have been considered promising plant secondary metabolites with antioxidant and immunomodulatory activity. This study evaluated the modulator effect of four flavonoids (galangin, kaempferol, quercetin and myricetin) in some human neutrophil effector functions, such as the oxidative metabolism stimulated via FcR and CR classes of membrane receptors, phagocytosis and microbicidal activity, as well as the cytotoxic, antioxidant and inhibitory effect of these compounds in the MPO and NADPH oxidase activity. The flavonoids studied showed a negative modulator effect in the human neutrophils oxidative metabolism in the following ranking order: galangin > kaempferol > quercetin > myricetin. Although galangin had shown the highest activity, it was the least effective antioxidant and inhibitor of MPO and NADPH oxidase activity among the flavonoids tested herein. Furthermore, this compound inhibited more the cellular response mediated by both Fc and CR receptors than by each one of them individually. The flavonoids bearing the catechol group, quercetin and myricetin, had a high efficiency to inhibit NADPH oxidase and MPO activity, as well as to reduce the 2,2-diphenyl-1-picrylhidrazil (DPPH) free radical. In general, the flavonoids did not interfere in the phagocytic process and microbicidal mechanism, and also did not induce toxicity and cell death by apoptosis or necrosis. The group of results presented here provides a possible application of these flavonoids as drugs of natural source in inflammatory diseases with excessive neutrophil infiltration, being a promising tool for an effective treatment of these illnesses.

Submitted by Erika Demachki (erikademachki@gmail.com) on 2014-10-14T17:05:51Z No. of bitstreams: 2 Dissertação - Thaís Domingos Meneses - 2013.pdf: 1894235 bytes, checksum: 41d8ee83924f2c998abe4f713c7f8f16 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Jaqueline Silva (jtas29@gmail.com) on 2014-10-16T18:46:31Z (GMT) No. of bitstreams: 2 Dissertação - Thaís Domingos Meneses - 2013.pdf: 1894235 bytes, checksum: 41d8ee83924f2c998abe4f713c7f8f16 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2014-10-16T18:46:31Z (GMT). No. of bitstreams: 2 Dissertação - Thaís Domingos Meneses - 2013.pdf: 1894235 bytes, checksum: 41d8ee83924f2c998abe4f713c7f8f16 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2013-10-15 / Studies have shown that periodontal disease affects approximately 85 % of dogs older than three years of age, being responsible for inflammation and destruction of the tooth supporting tissues. This study aimed at evaluating the relationship between periodontal disease and glomerulonephritis in dogs. We evaluated and classified 61 dogs with periodontal disease into groups according to the severity of the case. Clinical evaluation consisted of complete blood count, serum biochemistry (urea, creatinine, total protein, albumin, cholesterol and phosphorus), blood pressure measurement, urinalysis and urinary biochemistry (GGT, ALP, protein and creatinine), and determination of urine protein:creatinine ratio. Of the 14 dogs with glomerulonephritis compatible alterations at the first exam, nine were submitted to a second laboratory evaluation, after periodontal treatment, in order to verify if they continued with persistent proteinuria associated with inactive urinary sediment. Of these, eight dogs continued to show abnormalities suggestive of glomerulonephritis, even after periodontal treatment. The diagnostic tools used in this study allowed to identify and characterize both glomerulonephritis secondary to periodontal disease, establishing a relationship between them and tubular damage and urinary tract infections that occur concurrently with periodontal disease. These findings help to establish the use of early markers of kidney injury in clinical laboratory tests, in order to prevent the process evolution, promoting animal welfare and contributing to increase longevity of dogs. / Estudos mostram que a doença periodontal acomete cerca de 85% de cães acima dos três anos de idade, sendo responsável pela inflamação e destruição dos tecidos de sustentação do dente. Este estudo teve como objetivo avaliar a relação existente entre a doença periodontal e a glomerulonefrite em cães. Sessenta e um cães com doença periodontal foram avaliados e classificados em grupos, conforme a gravidade, além da avaliação clínica foram realizados hemograma, bioquímica sérica (ureia, creatinina, proteínas totais, albumina, colesterol e fósforo), mensuração da pressão arterial, urinálise e bioquímica urinária (GGT, ALP, proteína e creatinina), com determinação da razão proteína:creatinina urinária. Dos 14 cães com alterações compatíveis para glomerulonefrite neste primeiro exame, após o tratamento periodontal, nove deles foram submetidos a uma segunda avaliação laboratorial, com o intuito de verificar se continuavam com a proteinúria persistente associado ao sedimento urinário inativo. Destes, oito cães continuaram apresentando alteração sugestiva de glomerulonefrite, mesmo após a realização do tratamento periodontal. As ferramentas de diagnóstico utilizadas em conjunto neste estudo permitiram identificar e caracterizar a glomerulonefrite secundária à doença periodontal, estabelecendo uma relação entre elas, além dos danos tubulares e infecções do trato urinário que ocorrem concomitantemente à doença periodontal. Esse conhecimento auxilia na instituição do uso de marcadores precoces de lesão renal na prática clínica de exames laboratoriais, com a finalidade de impedir a evolução do processo, promovendo bem-estar animal e contribuindo para o aumentando da longevidade dos cães.

Bibliography: leaves 119-136.