http://hdl.handle.net/10362/4557 Sun, 26 May 2013 09:07:14 GMT 2013-05-26T09:07:14Z http://hdl.handle.net/10362/5247 Title: Downstream processing development of enveloped viruses for clinical applications: innovative tools for rational process optimization Authors: Vicente, Tiago Abstract: Viral vectors and virus-like particles hold a tremendous potential in various clinical applications in the areas of gene therapy and/or vaccination, drawing the attention of biotechnology and pharmaceutical companies. The majority of these products are manufactured in animal cell cultures, inherently making the process costly. A great deal of effort is taking place to generate optimized biological and engineering strategies to find scalable and cost-effective processes, easily transferable to cGMP facilities. However, the implementation of robust downstream processes generating this type of biopharmaceuticals in the amounts required for pre-clinical and clinical trials is still lacking and lagging. By including a labile lipid membrane layer harboring glycoproteins (often critical for infection) over the viral capsid, enveloped viruses bring extra challenges in terms of their bioprocessing particularly downstream. The work developed during this thesis aimed at improving the state-of-the-art purification processes for these types of viral particles. The rationale was to integrate process understanding with product characterization, still scarce in such biological systems.(...) Description: Dissertation presented to obtain a Ph.D. degree in Engineering and Technology Sciences, Biotechnology at the Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa Wed, 01 Sep 2010 00:00:00 GMT http://hdl.handle.net/10362/5247 2010-09-01T00:00:00Z http://hdl.handle.net/10362/5246 Title: Production optimization of rotavirus-like particles: a system biology approach Authors: Roldão, António Manuel Missionário Abstract: Rotavirus-like particles (RLPs), a vaccine candidate against rotavirus disease, were produced by infecting Spodoptera frugiperda Sf-9 cells with genetically engineered recombinant baculoviruses. RLPs are spherically shaped particles composed by three viral proteins (vp) of rotavirus, vp2, vp6 and vp7, arranged in a triple layered structure. A diversity of protein structures, other than the correctly assembled RLP, are observed at the end of a typical production run suggesting that the protein assembly process is rather inefficient. Contaminants such as trimers of vp6 and vp7, vp6 tube-like structures, single-layered vp2 particles, double layered particles of vp2 and vp6 or RLPs lacking one or more subunits represent almost 88% of the total mass of proteins expressed. Thus, optimal control of protein expression concomitant with efficient particle assembly are critical factors for economical RLP production in the baculovirus/insect cells system. Description: Dissertation presented to obtain a Ph.D. degree in Engineering and Technology Sciences, Systems Biology at the Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa Tue, 01 Jun 2010 00:00:00 GMT http://hdl.handle.net/10362/5246 2010-06-01T00:00:00Z http://hdl.handle.net/10362/5241 Title: Gammaretroviral and lentiviral vectors for gene therapy: stability and inactivation mechanisms Authors: Carmo, Marlene Description: Dissertation presented to obtain a Ph.D degree in Engineering and Technology Sciences, Gene Therapy at the Instituto de Tecnologia Quimica e Biológica, Universidade Nova de Lisboa Thu, 01 Jan 2009 00:00:00 GMT http://hdl.handle.net/10362/5241 2009-01-01T00:00:00Z