Microsoft Word - 02 14 15 Tesis parte I para imprimir Cover-Agrad-Indices-resumenes
Bovine viral diarrhea virus (BVDV) is a pathogen that affects cattle causing immune-suppression by killing\nlymphocytes and monocytes-macrophages. BVDV does not seem to interfere with dendritic cells (DC).\nHowever, the effects of the virus on DC during the first day of infection have not been studi...
Guardado en:
| Autor principal: | |
|---|---|
| Otros Autores: | |
| Formato: | Tesis doctoral acceptedVersion |
| Lenguaje: | Español |
| Publicado: |
Universidad de Buenos Aires. Facultad de Ciencias Veterinarias
2014
|
| Materias: | |
| Acceso en línea: | http://repositoriouba.sisbi.uba.ar/gsdl/cgi-bin/library.cgi?a=d&c=avaposgra&cl=CL1&d=HWA_1255 https://repositoriouba.sisbi.uba.ar/gsdl/collect/avaposgra/index/assoc/HWA_1255.dir/1255.PDF |
| Aporte de: |
| Sumario: | Bovine viral diarrhea virus (BVDV) is a pathogen that affects cattle causing immune-suppression by killing\nlymphocytes and monocytes-macrophages. BVDV does not seem to interfere with dendritic cells (DC).\nHowever, the effects of the virus on DC during the first day of infection have not been studied. There is a\nneed of new vaccines to control this disease. Currently used inactivated vaccines are not protective, and\nthere are not recombinant vaccines available. One of the main issues in the evaluation of vaccine efficacy\nor even sero-conversion, is the difficulty of getting BVDV-free animals, especially in endemic areas.\nThese facts support the development of new-creative strategies to select vaccine antigens, reducing the\nnumber of animal trials needed. In this study we investigated the possibility of selecting vaccine antigens\nbased on their activity on DC. We also studied the interaction between BVDV and DC shortly after\ninfection, to bring information on the influence of these cells in the viral immunopathogenesis.\nWe developed a protocol to select antigens based on their capacity to activate DC in vitro, using both\nmurine and bovine DC. We evaluated several antigens: inactivated virus, the truncated form of the E2\nglycoprotein of the viral envelope (main target of the neutralizing response) expressed by a recombinant\nBaculovirus in insect cells ?Bt-E2?, and plasmids expressing t-E2. Activation of DC was measured by\ndetermining the up-regulation of co-stimulatory molecules and expression of pro-inflammatory cytokines.\nOnly the plasmids were able to induce a complete activation of the DC, indicating they might not require\nadjuvants; while Bt-E2 and the inactivated virus were unable to induce a complete activation of the DC.\nSimilar results were obtained when using murine or bovine DC.\nCandidate antigens were then tested for immunogenicity in mice, guinea-pigs and bovines. DNA vaccines\nwere no efficient inducing antibodies (Abs), while Bt-E2 formulated with adjuvants induced high levels of\nneutralizing Abs and, depending on the adjuvant, also cell-mediated immunity. The use of a nanoparticulated\nadjuvant, designed to activate DC, induced high levels of Abs with low antigen payload.\nLevels of neutralizing Abs were related to the amount of E2 in the vaccine, either recombinant or viral. In\nfact, Bt-E2 could be used an additive for the inactivated vaccine to achieve a protective E2-payload.\nBVDV was able to infect and replicate rapidly in the DC, and even though a cytopathic biotype was used,\nno effect on DC viability was observed. Infected DC could not get an activated phenotype during the first\nhours post-infection. We propose that by infecting DC and rescuing them from apoptosis, BVDV gets\naccess to the lymph-nodes were it can rapidly kill large numbers of T-cells present in the follicles.\nThe methodology developed in this study is particularly useful to compare different antigens of similar\nchemical composition. Selecting antigen candidates based on their capacity to activate DC is a useful tool\nto be applied in vaccine development, reducing the number of formulations that are finally taken to in vivo\ntesting. This technology supports the efforts focused in reducing, refining and finally replacing the use of\nanimals for the evaluation of the biological products. |
|---|