Orientador: Noeme Sousa Rocha / Resumo: O tumor venéreo transmissível canino (TVTC) ocorre naturalmente em cães, sem predileção por raça ou sexo sendo transmitido durante o coito ou hábitos sociais. É também um tumor transplantável experimentalmente e tem sido utilizado como modelo para o estudo da relação entre tumor e hospedeiro. Apesar da maior infiltração inflamatória intratumoral e da expressão de moléculas do complexo principal de histocompatibilidade (MHC) estar associada à regressão do tumor, o papel central das células imunes do hospedeiro na evolução clínica do TVTC ainda não está claro. Neste estudo nós buscamos analisar a interação entre TVTC natural e hospedeiro, especialmente sob o ponto de vista da imunidade celular tumoral. Aqui nós identificamos e quantificamos por citometria de fluxo células T (CD3+, CD4+ e CD8+), células NK, células B, macrófagos, em amostras de sangue e de tumor, além da expressão imunoistoquímica de moléculas do MHC de classe I e II, sobretudo nas diferentes fases clínicas do tumor, assim como classificamos os subtipos citológicos do tumor e avaliamos o comportamento tumoral frente ao tratamento quimioterápico com sulfato de vincristina em uma amostra de 22 cães com TVTC natural. A quimioterapia foi efetiva no tratamento da maioria dos casos. Encontramos predomínio de TVTC linfocitóide e que metástases e resistência quimioterápica ocorreram apenas nos tumores de fenótipo linfocitóide e misto. Identificamos aumento significativo na expressão de moléculas de MHC classe I e II na ... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The transmissible venereal canine tumor (CTVT) occurs naturally in dogs, without predilection for race or gender being transmitted during intercourse or social habits. It is also an experimentally transplantable tumor and it has been used as a pattern for the study about the relationship between the tumor and the host. Despite the greater intratumoral inflammatory infiltration and the expression of major histocompatibility complex molecules (MHC) is associated with tumor regression, the central role of host immune cells in the CTVT clinical evolution is not clear yet. In this study we sought to analyze the interaction between natural and host CTVT, especially from the point of view of tumor cell immunity. Here we identify and quantify by flow cytometry cells T (CD3+, CD4+ e CD8+), cells NK, cells B, macrophages, in blood and tumor samples, besides the immune histochemical expression of MHC class I and II molecules, specially in the different clinical phases of the tumor as well as classifying the cytological subtypes of the tumor and evaluating the tumor behavior against the chemotherapy treatment with vincristine sulfate in a sample of 22 dogs with natural CTVT. Chemotherapy was effective in the treatment of most cases. We found a predominance of lymphocytoid CTVT and that metastases and chemotherapeutic resistance occurred only in tumors of lymphocytoid and mixed phenotype. We identified a significant increase in the expression of MHC class I and II molecules in the regress... (Complete abstract click electronic access below) / Mestre

The aim of the presented experimental work was to study an acute cell and antibody- mediated immune response in recipients of abdominal aortic grafts treated by a new standardized clinical cryopreservation/slow thawing protocol used in the "Vascular graft transplant program in the Czech Republic" in a rat model. Another aim of our study was to compare the influence of two basic types of conservation protocols used in this program (cryopreservation/slow thawing protocol and cold-stored protocol) on the acute immune response after transplantation of such treated abdominal aortic grafts in rats. Cryopreserved abdominal aortic grafts were transplanted syngeneously between Lewis rats (CRYO-ISO group, cryopreservation period 172.6 days) and allogeneically between Brown-Norway and Lewis rats (CRYO-ALO group, cryopreservation period 179.3 days). The grafts were explanted on day 30 after transplantation and subsequently examined by histological and immunohistochemical methods, focusing on typical signs of acute rejection in the three basic layers of the aortic wall. We monitored the presence of endothelial cells, signs of intimal hyperplasia, tunica media thickness, the presence of necrosis and deposition of imunoglobulin class G in this layer, the number of CD4+, CD8+ and LEW MHC II+ immunocompetent cells...