National Repository of Grey Literature 58 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Effect of polyhistidine modification of viral particles on their intracellular localization and gene delivery to the nucleus
Číhařová, Barbora ; Španielová, Hana (advisor) ; Grantz Šašková, Klára (referee)
Viral vectors derived from mouse polyomavirus are a convenient tool for studying the targeted delivery of therapeutical agents into the cells and cellular organelles. Vectors derived from mouse polyomavirus face difficulties similar to other nanoparticles, as they often end up trapped inside an endosome where they are subsequently degraded. This diploma explored the potential of vector modifications, which have the potential to make the transport to the nucleus or cytosol more effective. This work had particularly focused on increasing the transduction efficiency by modifying particle's internally localized VP3 capsid protein with covalently bound membrane-penetrating peptides. Primary covalent genetic modification to the VP3 protein was the polyhistidine peptide KH27K. Its potential of improving the transduction effectivity was compared with two other peptide modifications - LAH4 and R8. The results of the transduction test showed that covalently bound R8 peptide had many-fold improved the transport to the nucleus when compared to the unmodified particles. The modification with LAH4 peptide had been regarded more effective only when was associated with the particles non-covalently. In such scenario the transduction efficiency rose 40-times when compared with unmodified particles. Polyhistidine...
Analysis of antibody response during BK virus infection
Tomanová, Tereza ; Španielová, Hana (advisor) ; Saláková, Martina (referee)
BK virus is a human polyomavirus which is highly prevalent in the population. The virus is usually not very dangerous to its host, but it may cause complicati- ons in immunosuppressed patients. These complications commonly appear after kidney transplantation because BK virus persists in kidney epithelial cells. There are four subtypes of BK virus and it might be clinically important to screen for the identity of subtypes in matched pairs of donors and recipients of the kidney. This determination of the subtype specific antibodies by simple test could help to manage complications after the surgery. During previous project the ELISA test that could serologically differentiate between two main BK virus subtypes (I and IV) was designed, but its development is complicated by the fact that there is a strong cross-reactivity between the BK virus subtypes and antibodies. The modification of antigen towards better specificity might be required to succeed. Consequently, the main aim of this diploma thesis was to map important spots of major capsid protein VP1 of BK virus, particulary in EF and DE loops, which could participate in binding of antibodies. This aim was addressed by targeted mutagenesis of the gene coding VP1 protein in the region of the respective loop. Nucleotides coding two surface aminoacids...
Experimental system for production of IL-15 on viral carriers
Musil, Dominik ; Španielová, Hana (advisor) ; Šmahel, Michal (referee)
Interleukin 15 has great application potential such as in the biological treatment of cancer. It is involved in a variety of immunological processes, the most important of these involve influencing and induction of NK cells and T-lymphocytes proliferation. However, its therapeutic usages are limited by a low stability and short half-life. For this reason, there are various approaches of stabilization and expansion of its biological activity being explored. In this work, we analysed and developed a new approach, which uses viral nanostructures derived from major capsid VP1 protein of mouse polyomavirus as a carrier of IL-15. Moreover, VP1 proteins can be relatively easily modified and they are also capable to penetrate into the tumour cells. There were prepared two variants of IL-15 together with control nanostructures in the baculovirus expression system, one was composed of IL-15 and the other of the IL-15 fusion protein and truncated variant of VP1. Protein constructs were characterized by electron microscopy and biochemical methods. The total protein yield of VP1ΔC-IL15-HIS fusion variant was higher (up to 53 mg/L of complete medium) than IL-15 alone (8,5 mg/L). However, testing of the biological activity of the prepared proteins in vitro did not show any induction of proliferation on Jurkat...
Development of a technique for gene transfer into T-lymphocytes using polyomavirus structures and the LAH4 peptide
Schreiberová, Lucie ; Španielová, Hana (advisor) ; Vopálenský, Václav (referee)
Efficient delivery of genetic material to T-lymphocytes is key in gene therapy using T-lymphocytes with chimeric antigen receptors. Current procedures require the use of potentially dangerous viral vectors or large amount of input material. The diploma thesis therefore focuses on exploring new approaches for gene transfer into T-lymphocytes: use of safe virus-like particles (VLPs) derived from mouse polyomavirus in combination with the amphipathic cationic peptide LAH4. LAH4 has the potential to increase the efficiency of DNA and viral vector transport into cells. The system which combines VLPs and the LAH4 peptide was optimized for the delivery of reporter gene (encoding GFP and luciferase) to the model T-cell line Jurkat. It has been found that Jurkat cells cannot be efficiently transduced by DNA packed into VLPs. When cells were transfected only with DNA and LAH4, consistent results were not obtained, and the transfection efficiency ranged from 0.5 to 19%. The diploma thesis also analysed the effect of phosphorylation of viral structures on gene transfer. The impact of treatment of virus particles by alkaline phosphatase on the infectivity of the virus was studied and it was necessary to analyse the effect of the reaction components. Sublytic concentration of Triton-X100 in the reaction buffer...
Preparation and characterization of modified viral particles derived from mouse polyomavirus for the transport of genes to increase the efficiency of transduction
Škvára, Petr ; Španielová, Hana (advisor) ; Sýkora, Michal (referee)
Viral particles derived from mouse polyomavirus can be potentially used as a delivery system for therapeutic genes and drugs into target cells. This thesis focuses on preparation and characterization of polyomaviral particles that are modified with cell-penetrating peptides in order to increase efficiency of transduction of reporter genes into human cells. Viral particles that are composed of major capsid protein VP1 in combination with minor capsid protein VP2 and minor capsid protein VP3 that is modified with octaarginine, LAH4 peptide or with transduction domain of adenoviral protein VI are analysed in transduction assays. The thesis also provides information about the effect of the modification on encapsidation of heterologous DNA. The results of transduction assays performed with modified particles containing encapsidated luciferase gene revealed that efficiency of transduction did not increase but decreased in comparison with unmodified particles. These findings help to elucidate the role of polyomaviral minor capsid proteins in gene transfer mediated by viral particles and contribute to the design of new strategies for modifications of viral particles derived from mouse polyomavirus for their successful application in nanomedicine. Key words: mouse polyomavirus, pseudovirions, virus-like...
Targeting of Viral Nanoparticles to CD44 via Hyaluronic Acid
Hustedová, Anna ; Španielová, Hana (advisor) ; Hubálek Kalbáčová, Marie (referee)
Hyaluronic acid (HA) is widely studied as a targeting moiety to CD44 overexpressing cancer cells. Various types of nanoparticles (NPs) were modified by HA. Virus-like particles (VLPs) derived from mouse polyomavirus are an interesting class of NPs that can be modified by various targeting agents to increase their potential as gene or drug delivery vehicles for e.g. theragnostic purposes. HA has not been tested as a targeting moiety on VLPs, hence this was the focus of the current study. HA (~14 kDa) was attached to the VLPs via a bispecific Bodipy-derived fluorescent probe. To test the targeting potential of HA on comparable non-viral NPs, nanodiamonds were prepared in a similar manner. NPs functionalized with HA, together with Bodipy-labeled control variants, were tested on interactions with MDA-MB-231 cells overexpressing CD44. The NP-cell interaction via CD44 was assessed by a competitive cell-binding assay, where non-labeled HA competed for HA-binding sites at CD44 with the NPs. CD44 specific cell interactions were detected in studies with HA functionalized nanodiamonds, whereas VLP-HA* associated with cells in a less specific manner. Control VLPs with polyethylene glycol (PEG) did not interact with the cells. Results indicate that the HA targeting strategy for the VLPs requires optimization to...
Characterization of viral nanoparticles derived from mouse papillomavirus
Vomáčka, Petr ; Španielová, Hana (advisor) ; Šmahelová, Jana (referee)
The L1 and L2 capsid proteins of papillomaviruses are characterized by the ability to self- assemble into viral capsids, which can be divided into pseudovirions (PsVs) and virus-like particles (VLPs) by inner content. In addition to the fact that such particles can serve as "nano-containers" for diagnostic and therapeutic agents, it has also been shown that papillomaviruses, whether wild, PsVs or VLPs have a higher affinity for tumor tissue than non-tumor tissue. This thesis deals with relatively newly discovered (2011) mouse papillomavirus (MusPV) and nanoparticles derived from this virus. This papillomavirus has been chosen for its positives, including easy preparation of VLPs and PsVs, as well as an available model organism for possible testing. Furthermore, MusPV has the potential for use in gene therapy and cancer diagnosis, because there is no immune response in the human population. The aim of this diploma thesis is to prepare an expression system for the production of PsVs and VLPs. In additional it will also look at the quality and quantity of PsVs and VLPs, characterization of these particles and verification of existing postulates regarding higher affinity of papillomaviruses for tumor cells. Finally, it will also to verify whether the same effect is observed in MusPV. In the results of...
Analysis of antibody response during BK virus infection
Tomanová, Tereza ; Španielová, Hana (advisor) ; Saláková, Martina (referee)
BK virus is a human polyomavirus which is highly prevalent in the population. The virus is usually not very dangerous to its host, but it may cause complicati- ons in immunosuppressed patients. These complications commonly appear after kidney transplantation because BK virus persists in kidney epithelial cells. There are four subtypes of BK virus and it might be clinically important to screen for the identity of subtypes in matched pairs of donors and recipients of the kidney. This determination of the subtype specific antibodies by simple test could help to manage complications after the surgery. During previous project the ELISA test that could serologically differentiate between two main BK virus subtypes (I and IV) was designed, but its development is complicated by the fact that there is a strong cross-reactivity between the BK virus subtypes and antibodies. The modification of antigen towards better specificity might be required to succeed. Consequently, the main aim of this diploma thesis was to map important spots of major capsid protein VP1 of BK virus, particulary in EF and DE loops, which could participate in binding of antibodies. This aim was addressed by targeted mutagenesis of the gene coding VP1 protein in the region of the respective loop. Nucleotides coding two surface aminoacids...
Pseudotyping in baculoviruses
Zobalová, Eliška ; Španielová, Hana (advisor) ; Fraiberk, Martin (referee)
The baculoviruses are a group of enveloped DNA viruses that infect the larval stage of arthropods, mainly insects. They are widely used in biotechnology and well known for their utility as biological pesticides and gene expression vectors for the production of proteins in insect cells and larvae. However, they are also able to enter in mammalian cells and deliver-genes for expression under the control of mammalian cell-active promoters. Recombination or pseudotyping can result in formation of baculoviruses that provide a higher transduction frequency or are able to recognize specific mammalian cells. This bachelor thesis describes the phenomenon of viral pseudotyping and summarizes published information about the use of pseudotyped baculoviruses for gene therapy and vaccination.

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