Thesis (MSc (Veterinary Science))--University of Pretoria, 2001. / Includes bibliographical references.

Thesis (MMedVet (Bov.)-University of Pretoria, 1997.

Tierärztl. Hochsch., Diss., 2003--Hannover.

Tierärztl. Hochsch., Diss., 2004--Hannover.

Orientador: Julio Defaveri / Resumo: A paracoccidioidomicose (Pbmicose) é micose sistêmica na qual complexos eventos inflamatórios e imunológicos são desencadeados pela interação fungo-hospedeiro, resultando em duas características importantes da doença: freqüente instalação de distúrbios imunorregulatórios e reação inflamatória granulomatosa. Este trabalho teve por objetivo estudar em pacientes portadores da forma crônica multifocal da Pbmicose, na fase pré-tratamento, as características da resposta granulomatosa em lesões de pele e mucosa, considerando suas populações celulares e a presença in situ de citocinas de padrão Th1 e Th2. Estes achados foram correlacionados com a gravidade clínica, níveis de competência imunológica humoral e celular e níveis séricos dessas mesmas citocinas. Foram estudados 27 pacientes com gravidade clínica moderada (13 pacientes), moderada/grave (8 pacientes), grave (5 pacientes) e não avaliada (1 paciente). As biópsias foram realizadas por punch de lesões de pele ou mucosa. Os soros foram separados de sangue obtido por punção venosa, e o teste cutâneo realizado pela paracoccidioidina. Nas biópsias foram analisados o número e padrão de distribuição de neutrófilos, eosinófilos, células gigantes, plasmócitos, linfócitos T CD3+ e CD8+, linfócitos B e células NK (estes três últimos caracterizados pela imuno-histoquímica), contagem de fungos e a detecção imuno-histoquímica de IL-4, IFN- , IL-10, TNF- e TGF- . No soro dos pacientes foram realizadas dosagens de IL-2, IL-4, IL-10 e TGF- e de anticorpos específicos anti-Pb por ensaio imunoenzimático (ELISA)... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Paracoccidioidomycosis (Pbmycosis) is a systemic mycosis in which a complex inflammatory and immunological events are unchained by the interaction of the fungus (Pb) with the host tissues, resulting in two important characteristics of the disease: frequent immunoregulatory disturbances and a granulomatous inflammation. The aim of this work was to study in patients with the chronic multifocal form of Pbmycosis, before treatment, the characteristics of the granulomatous response in skin and mucosal lesions, considering the cellular populations and the presence in situ of Th1 and Th2 cytokines patterns. These results were correlated with the clinical severity, the levels of humoral and cellular immune competence and serum levels of those cytokines. Twenty seven patients were studied, distributed accordingly to clinical severity: moderate (13 patients), moderate/severe (8 patients), severe (5 patients), and not evaluated (1 patient). Punch biopsies were collected from skin or mucosal lesions, the serum obtained from venous blood samples to measured antibodies levels, and the skin test accomplished by the paracoccidioidin. In biopsies the following parameters were evaluated: the number and distribution pattern of neutrophils, eosinophils, giant cells, plasma cells, T CD3+ and CD8+ cells, B cells and NK cells (the last three characterized by immunohistochemistry), number of fungi, and detection of IL-4, IFN- , IL-10, TNF- and TGF- by immunohistochemistry. It was also measured the serum levels of IL-2, IL-4, IL-10 and TGF- and the level of specific antibodies anti-Pb by ELISA test. Specific granulomatous lesions, composed with epithelioid, well organized granuloma together with epithelioid loose, ill organized granuloma were observed in the same lesion of the dermis and submucosa. Neutrophils... (Complete abstract, click electronic address below) / Doutor

As lower respiratory infections are a leading cause of morbidity and mortality worldwide, and have been linked to periodic pandemics, there is a heightened interest in understanding how protective immune cells are mobilized in response to pathogens and contribute to local tissue resistance. The existence of non-recirculating lung resident memory B (BRM) cells was recently defined in an influenza virus infection model and inferred to be protective. Our body of knowledge has since grown significantly, but many unknowns including BRM cell establishment dynamics and requirements for maintenance remain. We previously used a murine model of serotype-independent immunity against Streptococcus pneumoniae (Sp) to show that resident memory B (BRM) cells are seeded extravascularly in the lung after local bacterial exposures independently of mature tertiary lymphoid structure formation. Using a transgenic mouse model which allowed for the depletion of PD-L2+ memory B cells, we demonstrated that lung PD-L2+ BRM cells directly contribute to clearance of a heterotypic Sp challenge infection, and that their absence correlated with diminished local antibody secreting cell (ASC) activities. Our findings provide evidence of serotype-independent protection mediated by the PD-L2+ BRM cell population and suggest that this is due to their capacity to rapidly differentiate into local ASCs upon memory recall. We carried out additional studies to elucidate lung B cell population dynamics, locations, and T-dependent requirements for establishment and maintenance after Sp infections. Singular exposure to self-limiting pneumococcal infection was insufficient to generate lasting BRM cells, as well as other heterogeneous extravascular B cell populations which were tracked over time. This included a transient population of proliferatively active lung GC B cells whose accumulation in the lung corresponded with the temporary appearance of organized lymphoid tissue. After an initial respiratory infection was administered to allow for immune priming in the lung and in draining lymph nodes, disruption of T cell interactions during a 2nd infection prevented pan extravascular B cell accumulation and abrogated lung BRM cells. We posit that our findings are relevant for the development of improved serotype-independent preventative strategies against pneumococcal pneumonia, and all respiratory pathogens in general. Advancing our understanding of tissue-resident B cell populations will aid in the development of next generation vaccines that leverage mucosal memory against respiratory pathogens. / 2025-02-12T00:00:00Z

Mucosal associated invariant T-cells (MAIT) are a phylogenetically conserved subset of alpha/beta T-cells with natural killer-like (NK) activity. MAIT are defined by the expression of an invariant T-cell receptor alpha (TCRα) chain; in mice and humans this chain uses the orthologous mVα19/hVα7.2-Jα33 genes respectively. Available evidence indicates that MAIT are restricted by MR1, a highly conserved MHC class I-related molecule, and that their development is dependent on B lymphocytes. They appear to constitute part of the innate immune response, but their precise functional role is poorly understood. This study aimed to characterise MAIT and MR1 in ruminants, and to further the knowledge and understanding of these unique cells. Using PCR primers based on partial database sequences, orthologous full-length TCRα chains were identified in circulating bovine and ovine T cells. The germline elements of the respective α chains were identified and their overall frequency of expression within the bovine TCRα repertoire determined. Experiments using the orthologous TCRα chain as a marker for MAIT cells to examine expression in bovine and ovine blood and various tissues showed that spleen and mesenteric lymph nodes contained the highest frequency of MAIT cells. Use of the same technique to study levels of this marker in cattle of different ages revealed very low numbers of MAIT cells in neonatal animals, followed by a marked increase in the first 3 weeks of life. Analyses of MAIT TCRα expression in different T cell subsets showed that, unlike mice and humans in which MAIT cells are predominantly within the CD4-/CD8- T-cell population, MAIT cells in bovine blood are predominantly CD8+. Full-length cDNAs were isolated for bovine and sheep MR1 and their sequences were found to display marked cross-species conservation. Using a specific PCR, MR1 was shown to be expressed in peripheral blood and by different lineages of Theileria-transformed cells. Alternatively-spliced transcripts of MR1 were detected in both cattle and sheep and several of these retained an intact open-reading frame. Constructs of bovine MR1 and an MR1/MHC chimera were prepared in a eukaryotic expression vector but these failed to give detectable cell surface expression following transfection into Cos-7, despite positive intracellular expression.

Os antiinflamatórios não esteroidais (AINEs) constituem um grupo de medicamentos de uso rotineiro na terapêutica clínica, principalmente no tratamento do processo inflamatório e doloroso. O efeito colateral mais comum constatado pelo seu uso é a irritação da mucosa gástrica. A atividade ulcerogênica dos AINEs tem variabilidade diária, uma vez que quando administrados à noite, são melhor tolerados que durante o dia. Tal observação chama a atenção para a possível ação do hormônio pineal, melatonina, sintetizado no período de escuro, tanto por animais de hábitos noturnos como diurnos. No presente estudo foram investigados os efeitos da administração de melatonina sobre a atividade antiinflamatória e lesão gástrica induzida pelo piroxicam e o efeito da melatonina e do piroxicam sobre a síntese de PGE2 pela mucosa gástrica, testando esse hormônio nos seguintes modelos: edema de pata de rato induzido por carragenina, lesão da mucosa gástrica induzida pelo piroxicam e determinação da síntese de PGE2 por enzima-imunoensaio (EIA). A administração intragástrica de melatonina não alterou o efeito aniinflamatório do piroxicam, mas inibiu o efeito colateral ulcerogênico. O efeito antiulcerogênico da melatonina foi observado após administração intragástrica, mas não após a administração subcutânea. As diferenças observadas entre as duas vias de de administração sugere um efeito local desse hormônio sobre a mucosa gástrica. O efeito antiulcerogênico da mealtonina intragástrica esta relacionada à prevenção da inibição da produção der PGE2 da mucosa gástrica pelo piroxicam. A pinealectomia aumentou o efeito ulcerogênico da adminstração noturna de piroxicam. Mesmo utilizando fenilbutazona, que é um AINEs ulcerogenicamente mais potente, no período da manhã, quando o efeito ulcerogênico dos AINEs parece ser acentuado, a melatonina administrada intragastricamente promoveu proteção da mucosa gástrica. Por outro lado, a melatonina administrada intragastricamente não interferiu com ulceração induzida pelo estresse, sugerindo que o efeito antiulcerogênico da melatonina está relacionado mais especificamente com fatores importantes na patogênese da lesão gástrica induzida pelos AINEs (piroxicam e fenilbutazona) em ratos, prevenindo a inibição da síntese de PGE2 da mucosa gástrica induzida pelo piroxicam, sem afetar a ação antiinflamatória. / Non-steroidal antiinflammatory drugs are, the most frequently consumed drugs worlwide. They also cause gastrointestinal adverse effects, like gastric ulceration and bleedig. Several reports indicate that, both antiinflammatory effect and the susceptibility to mucosal damage produced by NSAIDs in rats and humans show a circadian variation. Nighttime administration of NSAIDs is better tolerated than morning administration in human and rats. Melatonin, the principal hormone of the pineal gland is secreted at night both in nocturnal and diurnal animals. The purpose of this experiment was to study the effect of melatonin on the antiinflammatory action and gastric mucosal damage induced by piroxicam and the effect of melatonin and piroxicam on the gastric mucosal prostaglandin E2 (PGE2) synthesis. Intragastric administration of melatonin significantly attenuated the gastric lesions induced by piroxicam, but, did not entiinflammatory action accessed by measuring paw edema after carrageenin adminstration. Melatonin anti-ulcerogenic effect was observed after intragastric, but not subcutaneus administration. The differences observed between the two administration routes point to a local effect of the hormone on the stomach mucosa. Pinealectomy increases the ulcerogenic effect of nocturnal administred piroxicam. The anti-ulcerogenic effect of intragastric melatonin was related to prevention of the inhibition of gastric mucosal PGE2 production induced by piroxicam. Indeed, intragastric administration of melatonin protect the gastric mucosa damage induced by effect on stress-induced gastric ulceration. These data suggest that melatonin may attenuate the severity of NSAID-induced gastric mucosal lesions in rats by preventing NSAID-induced inhibition of mucosal PGE2 production whithout affecting th anti-inflamamtory action.

Zugl.: Giessen, Universiẗat, Diss., 2009.

<p>Several labs have previously demonstrated that humoral immune responses at one mucosal tissue can disseminate to other mucosal sites, giving rise to the theory of the common mucosal immune system (CMIS). Evidence that demonstrates a similar link between systemic immune responses and mucosal protection is lacking despite indications that both mucosal and systemic memory B cells share common circulatory pathways. The focus of this study is to determine the contribution of blood-borne B cells to mucosal immunity in humans, and how B cells trafficking through blood can be induced to traffic to mucosal tissues.</p> <p>To address these aims, I have performed several analyses of active and inactive peripheral blood memory B cell (MBC) populations in normal, healthy humans. Analysis of recently activated blood B cells confirmed the revealed that the majority of pre-plasma cells (PPC) in blood of healthy, normal humans secrete IgA, and that the majority of IgA- positive PPC secrete primarily polymeric IgA. A large fraction of blood PPC also express CCR10, and this population contains the highest fraction of IgA-expressing and pIgA-secreting PPC in blood. In contrast, most CCR10- PPC secrete IgG, although a small fraction secretes and stains positive for IgA, and analysis of α4β7expression by blood MBC revealed that CCR10 is more inclusive of IgA-switched and pIgA-secreting PPC in blood. The data presented in this study demonstrate that IgA+/CCR10+ PPC represent the mucosal subset of PPC in the blood of healthy humans, and can be investigated as representative of recent or ongoing mucosal immune responses.</p> <p><em>In vitro </em>polyclonal stimulation of blood MBC through CD40 was able to induce CCR10 expression by blood MBC treated with IL-21, IL-2, IL-10 with additions of other germinal center (GC) cytokines such as IL-5 and TGF-β enhancing CCR10 induction. Surprisingly, CCR10 expression by IgG MBC stimulated under these conditions was similar to that of IgA MBC, demonstrating that CCR10 expression is not limited to IgA- switched B cell clones. The results of this study demonstrate that CCR10 expression is inducible by many GC factors, and importantly, is not limited to IgA-switched B cells.</p> <p>Systemic immunization of healthy volunteers with tetanus toxoid/diphtheria vaccine induced a robust systemic IgG response, but also resulted in a post-immunization mobilization of IgA PPC in blood. These PPC were not specific for tetanus or diphtheria, and in several volunteers showed specificity for mucosal pathogens such as poliovirus (PV) and herpes simplex virus (HSV) glycoproteins. In addition, stimulation of anti-HSV IgG memory was also observed. Thus we have demonstrated that a systemic immune response is capable of inducing antibody relevant to mucosal immunity, possibly exposing a mechanism through which systemic and mucosal humoral immune responses are linked.</p> <p>The studies presented here demonstrate the presence of mucosal B cell memory in blood and thus provide new insight into ways to assess and manipulate mucosal immunity.</p> / Doctor of Philosophy (Medical Science)