Dendritic cells (DCs) function mainly as antigen presenting cells (APCs) and as such they play a significant role in activating the adaptive immune system. Dendritic cells express toll-like receptors (TLR), and when these receptors are engaged by their cognate agonists, they promote DC maturation, which is critical in the induction of potent T helper (Th) cell -1 responses. Due to the multifunctional abilities of DCs, they have been explored as vaccine carriers, largely in cancer immunotherapy and some infectious diseases including hepatitis C. Previous studies showed that DCs loaded with mRNA of hepatitis C virus (HCV) antigen(s) induced strong immune responses but immune protection was not complete. Therefore, I expected that adoptive transfer of DCs transfected with HCV NS3/4A and/or NS5A mRNA and further treated with TLR agonist(s) ex vivo would induce HCV-specific immunity in vivo. Bone marrow-derived DCs generated with Flt3L (FL-DCs) or GM-CSF (GM-DCs), and loaded with HCV NS3/4A and/or NS5A mRNA showed maturation characteristics and produced substantial amounts of IL-12 after ex vivo activation with CpG ODN or CpG ODN plus Poly I:C, when compared to their untreated counterparts. Treatment with a combination of CpG ODN and Poly I:C synergized to augment IL-12 production in comparison with stimulation with CpG ODN alone. IL-12 secretion by DCs is pivotal in directing immune responses towards a Th1-bias response, which is needed to eliminate HCV. However, the ex vivo responses of stimulated DCs bearing HCV antigen(s) were not efficiently translated in mice to potentiate vigorous antigen-specific T cell responses. This resulted in a lack of protection after challenge with recombinant vaccinia virus expressing HCV NS3/NS4/NS5 in immunized mice. In contrast, both antigen-specific humoral and cell-mediated immune responses were induced in mice vaccinated with HCV recombinant NS3 or NS5A protein co-formulated with CpG ODN, host defense peptide and polyphosphazene. These responses, however, did not mediate viral clearance, as vaccinated mice remained unprotected from infection with recombinant vaccinia virus expressing HCV antigens. Taken together, these results suggest HCV recombinant protein co-formulated with triple adjuvant to be a better vaccine candidate than the DC-based vaccine.

Hepatitis C virus (HCV) infects millions of people worldwide and is one of the leading causes of liver damage. Infection with HCV is strongly correlated with an increased risk of steatosis, or fatty liver disease, which is caused by a build-up of fat deposits in hepatocytes. All genotypes of HCV appear to cause some degree of steatosis in approximately 50% of infected individuals, especially in the presence of contributing host factors such as diabetes, obesity and alcoholism. However, approximately 70% of genotype 3a infections exhibit steatosis. Furthermore, successful clearance of the genotype 3a virus results in eradication of the steatosis, suggesting the genotype 3a virus may be able to directly cause steatosis.<p> Research suggests a role for the core protein of HCV, which forms the capsid of the virus, in the alteration of lipid metabolism pathways during infection. As such, I hypothesized that: 1) HCV alters lipid metabolism pathways and causes the build up of lipid in hepatocytes and the development of steatosis; 2) HCV-3a core protein has a differential or increased effect on these pathways in comparison to 1b core protein; and 3) other HCV proteins could also play a role in the altering of lipid metabolism. My research characterized the subcellular localization on lipid droplets of the HCV-3a core protein in comparison to HCV-1b core protein. It was found that HCV-3a core causes increased transcriptional activity from the Fatty Acid Synthase (FAS) promoter, an important enzyme involved in the synthesis of triglycerides in hepatocytes. In addition, one specific amino acid of HCV-3a core was determined to be partially responsible for this effect. Further research determined that the effect of HCV-3a core on FAS was dependent on the transcription factor Sterol Response Element Binding Protein-1 (SREBP-1) and the presence of HCV-3a core increased the processing and activity of SREBP-1. HCV core was also able to increase activity of Akt 1 and Akt2; inhibition of Akt activity resulted in decreased SREBP-1 activity thereby indicating that HCV core partially mediates SREBP-1 via Akt. Further experiments examined the role of another HCV protein, NS2, in these same lipid metabolism pathways. NS2 was also able to increase transcription from the FAS promoter via SREBP-1, suggesting that this HCV protein may also be important in the development of steatosis during HCV infection.<p> The evidence provided in these studies shows a very important role for HCV in altering lipid metabolism during infection that may lead to the development of steatosis. Current research suggests that the SREBP-1 pathway may be critical in the life cycle of the virus and these studies have provided important information on how lipid metabolism pathways are being changed by the virus. Hopefully this work can help identify potential treatment options for HCV that can slow down disease progression by preventing the development of steatosis or by decreasing viral replication.

Bakgrund: Hepatit C är en leverinflammation som orsakas av ett virus. HCV räknas som blodburen smitta. Den största riskgruppen för att få smittan är sprutnarkomaner, vårdpersonal och patienter som fick smittan i vårdsammanhang, innan blod som användes inom sjukvården testades på viruset. Syftet: Att beskriva hur människor med kronisk hepatit C upplever att leva med sin sjukdom och hur bemötandet från sjukvården och omgivningen upplevs. Metod: Litteraturöversikt med kvalitativ ansats. Sju vetenskapliga, kvalitativa artiklar användes och en manifest innehållsanalys genomfördes. Resultat: Informanterna upplevde en förlorad tro på den egna kroppsförmågan och en sämre livssituation på grund av de fysiska sjukdomssymtomen. Att leva med hepatit C gjorde att framtiden kändes osäker och oförutsägbar. Familjen var ett viktigt stöd. De upplevde ofta negativa attityder och bemötande från omgivningen och sjukvården. Informanterna valde oftast att inte avslöja sin sjukdom på grund av rädsla för social utstötning. Sjukvårdens bemötande upplevdes ofta som fördomsfull och dömande av informanterna. Slutsats: Sjukdomens fysiska symtom var tidvis så dominanta att hela personens liv påverkades. Omgivningens attityder kunde leda till utsatthet och utanförskap. Det fördomsfulla bemötandet medförde att många drabbade distanserade sig från sjukvården och fattade egna beslut kring sin vård. Bristen på kunskap om sjukdomen hos allmänheten och i sjukvården är viktig att uppmärksamma för att minska lidande.

<p>HDV antigenomic RNA is processed in two distinct pathways; it can be cleaved at the polyA site and polyadenylated to become mRNA for the delta antigens, or the RNA can be cleaved by the antigenomic ribozyme to become full-length antigenomic RNA that is used for synthesis of genomic HDV RNA. The polyA site is located just 33 nucleotides upstream of the ribozyme cleavage site. If processing occurs primarily at the upstream polyA site, there may not be enough full-length antigenomic RNA to support replication. On the other hand, ribozyme cleavage downstream of the polyA site could inhibit polyadenylation by interfering with polyadenylation complex assembly. Thus, it appears that HDV may need a mechanism to control RNA processing so that both products can be generated in the proper amounts during the infection cycle. </p><p>A model has been proposed in which the choice between ribozyme cleavage and polyadenylation is determined by alternative RNA secondary structures formed by the polyA sequence (Wadkins and Been 2002). One of the hypothetical structures, AltP2, is a pairing between part of the upstream polyA sequence and the 3' end of the ribozyme sequence. For this model, the same upstream sequence that forms AltP2 could also form a stem loop, P(-1), within the leader, by pairing with sequences located farther upstream. A processing choice is possible because AltP2 is predicted to inhibit ribozyme cleavage and favor polyadenylation resulting in mRNA production, whereas P(-1) would inhibit polyadenylation and favor ribozyme cleavage resulting in full-length replication product. </p><p>The P(-1) vs. AltP2 model was tested using an antigenomic HDV ribozyme construct with the 60-nucleotide sequence upstream of the ribozyme cleavage site. This leader sequence contains the proposed polyA sequence elements. In vitro analysis of this construct revealed that the kinetic profile of ribozyme self-cleavage was altered in two ways. Relative to the ribozyme without upstream sequences, the fraction of precursor RNA that cleaved decreased to about 50%, but the active ribozyme fraction cleaved faster. Native gel electrophoresis revealed that the active and inactive precursor RNAs adopted persistent alternative structures, and structure mapping with Ribonuclease T1 and RNase H provided evidence for structures resembling P(-1) and AltP2.</p><p>Sequence changes in the 5' leader designed to alter the relative stability of P(-1) and AltP2 increased or decreased the extent of ribozyme cleavage in a predictable way, but disrupting AltP2 did not completely restore ribozyme activity. The analysis of deletion and base change variants supported a second alternative pairing, AltP4, formed by the pyrimidine-rich sequence immediately 5' of the ribozyme cleavage site and a purine-rich sequence from the 5' side of P4. A similar approach was used to test if the effect of disrupting both AltP2 and AltP4 might be additive, and the results suggested that ribozyme precursors with 5' leader sequences could fold into multiple inactive conformations, which can include, but may not be limited to, AltP2, AltP4, or a combination of both.</p><p>Luciferase expression constructs with HDV polyA and ribozyme sequences were used to investigate the effects of RNA structure and ribozyme cleavage on polyadenylation in cells. One hypothesis was that P(-1) could inhibit polyadenylation by making the polyA sequence elements less accessible to polyA factors, but sequence changes designed to alter the stability of the stem loop had no effect on polyadenylation. The model also predicts that the ribozyme sequence downstream of the polyA site could affect polyadenylation, possibly in two different ways. Ribozyme cleavage could interfere with polyadenylation by uncoupling transcription from processing, however, the ribozyme sequence might also influence polyadenylation in a manner independent of the ribozyme cleavage activity. As such, the AltP2 structure could potentially have a positive effect on polyadenylation either by inhibiting ribozyme cleavage or by making the polyA signal sequences more accessible to the polyA factors. To distinguish between the effects of ribozyme cleavage and alternative RNA structures, luciferase expression levels from constructs with an HDV polyA sequence followed by the active wild-type ribozyme or the inactive C76u version of the ribozyme were compared. For the wild-type HDV polyA sequence, the active ribozyme reduced expression, whereas the inactive ribozyme control had no effect on expression. However, for the modified leader sequences, which were efficiently polyadenylated in the absence of ribozyme, there were changes in expression that appeared to be independent of ribozyme cleavage. Based on these findings, two alternative models are proposed. One model predicts that protein factors might affect antigenomic RNA processing, and the other model suggests that additional alternative structures, such as AltP4, might influence the choice between ribozyme cleavage and polyadenylation.</p> / Dissertation

This dissertation, studies two specific topics related to the research of computer-aided drug design(CADD) by employing the molecular simulations approach, that of protein drugs and that of small agents. These results can help drug designers to improve their products for treating special diseases. This work is divided into two parts: Protein drugs: Potential of mean force of the hepatitis C virus core protein¡Vmonoclonal 19D9D6 antibody interaction: Antigen-antibody interactions are critical for understanding antigen-antibody associations in immunology. To shed further light on this question, we studied a dissociation of the 19D9D6-HCV core protein antibody complex structure. However, forced separations in single molecule experiments are difficult, and therefore molecular simulation techniques were applied in our study. The stretching, that is, the distance between the centre of mass of the HCV core protein and the 19D9D6 antibody, has been studied using the potential of mean force calculations based on molecular dynamics and the explicit water model. Our simulations indicate that the 7 residues Gly70, Gly72, Gly134, Gly158, Glu219, Gln221 and Tyr314, the interaction region (antibody), and the 14 interprotein molecular hydrogen bonds might play important roles in the antigen-antibody interaction, and this finding may be useful for protein engineering of this antigen-antibody structure. In addition, the 3 residues Gly134, Gly158 and Tyr314 might be more important in the development of bioactive antibody analogues. Potential of mean force for syrian hamster prion epitope protein - monoclonal fab 3f4 antibody interaction studies: Simulating antigen-antibody interactions is crucial for understanding antigen-antibody associations in immunology. To shed further light into this question, we study a dissociation of syrian hamster prion epitope protein-fab3f4 antibody complex structure. The stretching (the distance between the center of mass of the prion epitope protein and the fab3f4 antibody) have been studied using potential of mean force (PMF) calculations based on molecular dynamics (MD) and implicit water model. For the complex structure, there are four important intermediates and two inter protein molecular hydrogen bonds in the stretching process. Inclusion of our simulations may help to understand the binding mechanics of the complex structure and will be an important consideration in design of antibodies against the prion disease. Potential of mean force for human lysozyme - camelid vhh hl6 antibody interaction studies: Calculating antigen-antibody interaction energies is crucial for understanding antigen-antibody associations in immunology. To shed further light into this equation, we study a separation of human lysozyme-camelid vhh hl6 antibody (cAb-HuL6) complex. The c-terminal end-to-end stretching of the lysozyme-antibody complex structures have been studied using potential of mean force (PMF) calculations based on molecular dynamics (MD) and explicit water model. For the lysozyme-antibody complex, there are six important intermediates in the c-terminal extensions process. Inclusion of our simulations may help to understand the binding mechanics of lysozym- cAb-HuL6 antibody complex. Small agents: Predictions of binding for dopamine D2 receptor antagonists by the SIE method: The control of tetralindiol derivative antagonists released through the inhibition of dopamine D2 receptors has been identified as a potential target for the treatment of schizophrenia. We employed molecular dynamics simulation techniques to identify the predicted D2 receptor structure. Homology models of the protein were developed on the basis of crystal structures of four receptor crystals. Compound docking revealed the possible binding mode. In addition, the docking analyses results indicate that five residues (Asp72, Val73, Cys76, Leu183, and Phe187) were responsible for the selectivity of the tetralindiol derivatives. Our molecular dynamics simulations were applied in combination with the solvated interaction energies (SIE) technique to predict the compounds' docking modes in the binding pocket of the D2 receptor. The simulations revealed satisfactory correlations between the calculated and experimental binding affinities of all seven tetralindiol derivative antagonists, as indicated by the obtained R2 value of 0.815. Combining homology modeling, docking, and molecular dynamics to predict the binding modes of oseltamivir, zanamivir, and Chinese natural herb products with the neuramindase of the H1N1 influenza A virus: The neuraminidase of the influenza virus is the target of the anti-flu drugs oseltamivir and zanamivir. Clinical practices show that zanamivir and oseltamivir are effective to treat the 2009 H1N1 influenza virus. Herein, we report the findings of molecular simulations for zanamivir, oseltamivir, and Chinese natural herb products with the neuramindase of the 2009 H1N1 influenza. Our approach theoretically suggests that the Glu278 residue is responsible for the neuramindase of the 2009 influenza drug selectivity.

Hepatitis B virus (HBV), which belongs to the family Hepadnaviridae, is responsible for acute and chronic hepatitis. The vaccines presently used to immunize patients against HBV are recombinant subunit vaccines consisting of viral surface antigens (S protein). However, they are expensive and their use is limited in poor countries. For that reason, HBV remains an important worldwide health problem. Of the 2 billion people who have been infected with the HBV, more than 350 million have chronic (lifelong) infections, who face increased risk of developing cirrhosis and hepatocellular carcinoma. In this study, high-level expression of recombinant Hepatitis B surface Antigen (rHBsAg), PreS2-S was achieved in the methylotrophic yeast, Pichia pastoris. For this aim, a single copy of HBV M gene (PreS2-S) was inserted at the downstream of the alcohol oxidase (AOX1) promoter of the pPICZA vector. rHBsAg protein could then be expressed intracellularly by induction with methanol. High cell density fermentation was followed by chromatographic separation to obtain pure rHBsAg. Humoral response after immunization with the purified protein was observed in mice using commercial Hepatitis B surface antigen kits. It was verified by the atomic force microscopy that rHBsAg has been produced in the desired conformation.

No description available.

No description available.

<p>Bakgrund: Hepatit C är en leverinflammation som orsakas av ett virus. HCV räknas som blodburen smitta. Den största riskgruppen för att få smittan är sprutnarkomaner, vårdpersonal och patienter som fick smittan i vårdsammanhang, innan blod som användes inom sjukvården testades på viruset.</p><p>Syftet: Att beskriva hur människor med kronisk hepatit C upplever att leva med sin sjukdom och hur bemötandet från sjukvården och omgivningen upplevs.</p><p>Metod: Litteraturöversikt med kvalitativ ansats. Sju vetenskapliga, kvalitativa artiklar användes och en manifest innehållsanalys genomfördes.</p><p>Resultat: Informanterna upplevde en förlorad tro på den egna kroppsförmågan och en sämre livssituation på grund av de fysiska sjukdomssymtomen. Att leva med hepatit C gjorde att framtiden kändes osäker och oförutsägbar. Familjen var ett viktigt stöd. De upplevde ofta negativa attityder och bemötande från omgivningen och sjukvården. Informanterna valde oftast att inte avslöja sin sjukdom på grund av rädsla för social utstötning. Sjukvårdens bemötande upplevdes ofta som fördomsfull och dömande av informanterna.</p><p>Slutsats: Sjukdomens fysiska symtom var tidvis så dominanta att hela personens liv påverkades. Omgivningens attityder kunde leda till utsatthet och utanförskap. Det fördomsfulla bemötandet medförde att många drabbade distanserade sig från sjukvården och fattade egna beslut kring sin vård. Bristen på kunskap om sjukdomen hos allmänheten och i sjukvården är viktig att uppmärksamma för att minska lidande.</p><p> </p><p> </p>

Tez (Uzmanlık) - Süleyman Demirel Üniversitesi, Tıp Fakültesi, Enfeksiyon Hastalıkları ve Klinik Mikrobiyoloji Anabilim Dalı, 2008. / Kaynakça var.