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Effect of porcine reproductive and respiratory syndrome virus (PRRSV) on the adaptive immune system.
Šinkora, Šimon ; Štěpánová, Kateřina (advisor) ; Toman, Miroslav (referee)
The porcine reproductive and respiratory syndrome virus (PRRSV) causes large economic losses in pork production because of its ability to persist and spread in herds despite vaccination. An essential feature of the infection is a strong but ineffective antibody response with limited immunological memory. The ability of the virus to dysregulate the host immune system is explained by various mechanisms, including antibody-dependent enhancement of infection, polyclonal activation of B cells by the superantigen effect, the presence of immunodominant epitopes, inhibition of nonspecific immunity, or a different role of cytotoxic T cells. Recent evidence suggests that PRRSV affects the nascent T cell repertoire in the thymus and induces tolerance to viral epitopes that are crucial for virus neutralization. Specific T helper cells are absent and cannot initiate an adequate B cell response to produce high-affinity virus-neutralizing antibodies. However, the remaining T helper cells are not affected and help to produce anti-PRRSV antibodies, which are ineffective and cannot eliminate the virus. The cytotoxic T cells needed for the elimination of infected cells are also affected. This bachelor thesis describes the various features of PRRSV infection and compares the known information on the immune response...
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Působení bisfenolu S na lymfatické orgány potkanů
HOMOLKOVÁ, Alexandra
The presented bachelor thesis investigated the impact of a ten-week oral exposure to BPS (4 g/kg body weight/day, 50 g/kg body weight/day) in outbred Wistar Han rats. The study assessed the effect of chronic oral BPS exposure on body weight, absolute and relative weight, and dimensional parameters of the spleen, as well as histopathological changes in the thymus and spleen. Additionally, hematological parameters were monitored, including total leukocyte count and the percentage of monocytes, granulocytes, and lymphocytes.
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Heterogeneity of antigen-presenting cells in the thymus and its relevance for the establishment of central tolerance
Sýkora, Vojtěch ; Filipp, Dominik (advisor) ; Černý, Jan (referee)
The crucial function of the thymus is the establishment of central tolerance. In this process, developing T-cells are tested for their self-reactivity, since self-reactive T-cells might cause the autoimmunity if they would escape from the thymus to the periphery. Many thymic antigen-presenting cells are essential for establishment of central tolerance. Their role is to present self-antigens to the developing T-cells. Such presentation is capable to reveal the self-reactive potential of T-cells which can be then directly removed or deviated into suppressive T-regulatory cells. In the last several years, a high level of heterogeneity has been described among the thymic antigen-presenting cells and the molecular mechanisms that govern their functions towards enforcement of tolerance began to be uncovered. This thesis summarises recent knowledge in the field of heterogeneity of the thymic antigen-presenting cells and its relevance for establishment of the central tolerance, with the major focus on conventional dendritic cells and post-AIRE medullary thymic epithelial cells. This thesis also outlines recent advances in understanding of functional mechanisms and regulations of maturation of the antigen-presenting cells.
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