<p>Mammalian pregnancy is an immunological paradox. The foetus, which expresses both paternal and maternal cell-surface molecules, has to be protected from rejection by the maternal immune system. At the same time, the mother has to have an efficient immune defence and must provide her offspring with antibodies.</p><p>The first part of this thesis investigates some of the mechanisms involved in the foetal avoidance of maternal rejection reactions. Placental absence of MHC class II expression, as well as a bias for Th2-cytokines at the maternal-foetal interface are suggested to be important for foetal survival. The results showed that placental MHC class II expression cannot be induced <i>in vivo</i>. Transfections of trophoblast cells with MHC class II genes, however, resulted in detectable MHC class II cell-surface expression, indicating that a post-transcriptional block does not exist in these cells.</p><p>By using IL-4- and IL-10-double deficient mice, it was shown that neither maternal nor foetal expression of these cytokines were crucial for completion of allogeneic pregnancy.</p><p>In the second part of the thesis, the effect of transmission of immunoglobulin G (IgG) from the mother to the offspring was studied. It was observed that viable maternal Ig-secreting cells occasionally infiltrated the B cell-deficient offspring and remained functional for long periods. In this study "green fluorescent mice" were used as a tool. Furthermore, neonatal ingestion of wild type milk increased the survival of adoptively transferred B-lineage cells in B cell-deficient mice, suggesting that suckling of IgG-containing milk could be used to facilitate B cell-reconstitution in B cell-deficient mice. Finally, results from studies on normal mice showed that absence of maternal IgG-transmission during their neonatal development resulted in elevated serum-IgG production, as well as enhanced immune reactions upon immunisations in adult life. This showed that maternal IgG can have long-term immunoregulatory effects in the offspring.</p>

Mammalian pregnancy is an immunological paradox. The foetus, which expresses both paternal and maternal cell-surface molecules, has to be protected from rejection by the maternal immune system. At the same time, the mother has to have an efficient immune defence and must provide her offspring with antibodies. The first part of this thesis investigates some of the mechanisms involved in the foetal avoidance of maternal rejection reactions. Placental absence of MHC class II expression, as well as a bias for Th2-cytokines at the maternal-foetal interface are suggested to be important for foetal survival. The results showed that placental MHC class II expression cannot be induced in vivo. Transfections of trophoblast cells with MHC class II genes, however, resulted in detectable MHC class II cell-surface expression, indicating that a post-transcriptional block does not exist in these cells. By using IL-4- and IL-10-double deficient mice, it was shown that neither maternal nor foetal expression of these cytokines were crucial for completion of allogeneic pregnancy. In the second part of the thesis, the effect of transmission of immunoglobulin G (IgG) from the mother to the offspring was studied. It was observed that viable maternal Ig-secreting cells occasionally infiltrated the B cell-deficient offspring and remained functional for long periods. In this study "green fluorescent mice" were used as a tool. Furthermore, neonatal ingestion of wild type milk increased the survival of adoptively transferred B-lineage cells in B cell-deficient mice, suggesting that suckling of IgG-containing milk could be used to facilitate B cell-reconstitution in B cell-deficient mice. Finally, results from studies on normal mice showed that absence of maternal IgG-transmission during their neonatal development resulted in elevated serum-IgG production, as well as enhanced immune reactions upon immunisations in adult life. This showed that maternal IgG can have long-term immunoregulatory effects in the offspring.

Os adjuvantes são moléculas, compostos ou complexos macromoleculares que aumentam a potência e a longevidade da resposta imune específica aos antígenos. A sua adição na preparação vacinal aumenta, sustenta e dirige a imunogenicidade de antígenos, modulando de forma eficaz respostas imunes apropriadas, reduzindo a quantidade de antígeno ou número de imunizações necessárias e melhorando a eficácia de vacinas em recém-nascidos, idosos ou indivíduos imunocomprometidos. O objetivo desse estudo foi avaliar a imunogenicidade das preparações antigênicas baseadas em OMVs de Neisseria meningitidis B complexados com dois diferentes adjuvantes, o lípide catiônico brometo de dioctadecildimetilamônio (DODAB-BF) e hidróxido de alumínio (HA) utilizando a via intranasal e a via subcutânea em camundongos neonatos Swiss aplicando o sistema heterólogo prime-booster. Como métodos de estudo foram utilizadas as técnicas universais imunológicas como: Immunoblot, DOT-ELISA, ELISA e ELISpot visando à avaliação da resposta imunológica humoral e celular de camundongos machos e fêmeas. Na análise por Immunoblot avaliou-se a especificidade dos anticorpos com a cepa homóloga e com as bactérias íntegras de N. meningitidis da cepa B:4:P1.19,15. Por DOT-ELISA verificou-se a reatividade cruzada com DODAB-BF para diferentes sorogrupos (B, C, W e Y) e o mesmo não foi observado com HA. Por ELISA foram quantificados e comparados os títulos de anticorpos nos soros pool dos camundongos imunizados com DODAB-BF+OMVs e HA+OMVs para IgG, IgG1 e IgG2a as vias de imunização utilizadas exibiram títulos de IgG. E ambos adjuvantes promoveram a produção de IgG1 e IgG2a variando de acordo com a via de imunização utilizada. Por ELISpot foram analisadas as citocinas IFN-&#947; e IL-4 e os resultados demonstraram uma resposta direcionada para o perfil Th1 e Th2. / Adjuvants are molecules, compounds or macromolecular complexes that increase the power and longevity of the specific immune response to antigens.Their addition in the vaccine preparation increases, sustains and directs immunogenicity of antigens, effectively modulating appropriate immune responses, reducing the amount of antigen or number of immunizations required, and improving the efficacy of vaccines in infants, the elderly, or immunocompromised patients.The aim of this study was to evaluate the immunogenicity of antigenic from OMVs of N. meningitidis B complexed with two different adjuvants: DODAB-BF and aluminium hydroxide (HA) comparing the evaluation of subcutaneous and intranasal route of immunization for the first time using the prime-boost system in outbred neonatal mice. As universal methods of antibody detection were used: Immunoblot, DOT-ELISA, ELISA and ELISpot aiming for the humoral and cellular immune response and of male and female mice. By Immunoblot analysis the specificity of antibodies with the homologous strain N. meningitidis B:4:P1.19.15. By DOT-ELISA was verified the cross-reactivity with DODAB-BF to different sorogroups (B, C, W and Y) that was not observed with HA. By ELISA the antibodies titers were quantified and compared in the sera of mice immunized with DODAB-BF+OMVs and HA+OMVs for IgG, IgG1 and IgG2a. The immunization routes used exhibited IgG titers, and both adjuvants promoted the production of IgG1 and IgG2a varying according to the route of immunization used. By ELISpot was analyze IFN-&#947;- and IL-4 and the results showed the response directly to Th1 and Th2 profile.

Cardiovascular disease remains the number one cause or mortally in the western world. Heart failure is the most rapidly growing cardiovascular disease (Hobbs, 2004; Levy, et al., 2002). Heart failure, by definition, is progressive deteriorating function of the heart due to progressive cardiac myocytes loss. Though after decades of endeavor of searching the pathophysiology and treatments for heart failure, it remains highly lethal. Therefore, it is vital to find novel therapies to help treat such chronic disease. Replace the lost cardiomyocyte with new ones could restore cardiac function and reduce mortality. The purpose of this study is to investigate on how TTCCs (T-type calcium channels) affect cardiomyocyte proliferation. In mice after birth, the major TTCC expressed in the heart is Cav3.1/α1G, and therefore we used Cav3.1/α1G transgenic (TG), knockout (-/-) and wild type mice respectively to define the role of TTCC in cardiomyocyte proliferation. In neonatal mouse ventricular myocyte (NMVMs) right after birth, there is almost no TTCC after birth in α1G-/- NMVMs, whereas there are around 35% NMVMs in wild type (WT) show TTCC. On day 7 after birth, there are no T-type calcium currents in both α1G-/- NMVMs and WT NMVMs. Using BrdU, a DNA synthesis marker, we identified plenty of BrdU positive cardiomyocyte during the first seven days after birth. Cardiomyocyte is special due to its double nucleation property. Our cell cycle studies showed that there is significant difference in cell cycle distribution between α1G-/- and WT NMVMs on day seven after birth. Significantly more NMVMs are arrested in G1 phase in α1G-/-, compared to WT NMVMs. Even until 2 month old, there are still significantly more mono-nucleated cardiomyocyte in α1G-/- than in WT. In conclusion, all these evidence showed that blocking T-type calcium channel could partially prevent binucleation from happening and stop cardiomyocytes withdrawal from cell cycle. Mononucleated cardiomyocyte is still able to proliferate. Hence, mononucleated cardiomyocytes in adult still have potential to proliferation because these cardiomyoctes are arrested in their cell-cycle before their terminal differentiation, which could offer a novel approach for cardiac repair. / Physiology