Dissertations / Theses on the topic 'Lentiviruses'
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1
Robertson, David L. "Recombination in primate lentiviruses." Thesis, University of Nottingham, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336866.
2
Vödrös, Dalma. "Receptor use of primate lentiviruses /." Stockholm, 2003. http://diss.kib.ki.se/2003/91-7349-497-6/.
3
Bailes, Elizabeth. "Origins and evolution of primate lentiviruses." Thesis, University of Nottingham, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.246384.
4
Kelly, Maureen C. "Parallels in tRNA primer acquisition by lentiviruses." Thesis, Birmingham, Ala. : University of Alabama at Birmingham, 2007. https://www.mhsl.uab.edu/dt/2009r/kelly.pdf.
5
Li, Li. "Short-term and long-term evolution of lentiviruses." Thesis, University of Nottingham, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.575475.
Abstract:
Lentiviruses have paradoxically fast short-term rate of evolution and slow long-term rate of evolution, which differ by several orders of magnitude. In this thesis, with a new method called truncated tree analysis, slower rates of evolution of transmitted viruses were estimated. However, the rate decline of the transmitted viruses is limited, and is not sufficient to explain the dramatic difference between the short-term and long-term evolutionary rates. These dramatically different rates were reconciled by an S shaped curve based on the new trend observed from this thesis. In the middle part of this new trend, the rate of evolution decreases as the time of divergence increases. Using this new trend, the time scale of HIV -1 and their closest related SIV found in apes were set. The SIV cpzPtt and SIV cpzPts isolated from the two subspecies of chimpanzees shared the most recent common ancestor around 25.2 thousand years ago. This is younger than the estimated date of these two host subspecies split, and suggests that the SIV cpz is relatively new to the chimpanzees. The second chapter of this thesis further explores lentiviral evolution by examining the feline immunodeficiency viruses (FIV's). An American origin scenario of the FIV s was proposed. In this scenario the ancestor of FIV first the invaded the ancestors of the puma lineage living in American, and then as the ancient puma lineage speciated and migrated FIV spread out to many other felids. The final chapter of this thesis further explores the evolutionary rate decline as the time span extends by introducing the idea of flip- flop sites that undergo negative frequency dependent selection pressures. Theoretical simulations confirmed that in the short time span, the presence of the flip-flop sites results in overestimation of the evolutionary rate, but in longer time spans, opposite effects of flip-flop sites were observed.
6
Broughton-Neiswanger, Liam E. "Maternal transmission is the major mode of ovine lentivirus transmission in a ewe flock a molecular epidemiology study /." Pullman, Wash. : Washington State University, 2010. http://www.dissertations.wsu.edu/Thesis/Spring2010/L_Broughton_042010.pdf.
Abstract:
Thesis (M.S. in veterinary science)--Washington State University, May 2010.Title from PDF title page (viewed on June 29, 2010). "College of Veterinary Medicine." Includes bibliographical references (p. 20-26).
7
Stewart, Meredith Ellen. "An investigation into aspects of the replication of Jembrana disease virus /." Access via Murdoch University Digital Theses Project, 2005. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20051222.104106.
8
Bichel, Katsiaryna. "Understanding post-entry pre-integration lentiviral biology." Thesis, University of Cambridge, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.648287.
9
Harris, Matthew E. "Analysis of post-transcriptional regulation of lentiviruses and mammalian hepadnaviruses /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 1999. http://wwwlib.umi.com/cr/ucsd/fullcit?p9935471.
10
Ditcham, William. "The development of recombinant vaccines against Jembrana disease." Thesis, Ditcham, William (2007) The development of recombinant vaccines against Jembrana disease. PhD thesis, Murdoch University, 2007. https://researchrepository.murdoch.edu.au/id/eprint/438/.
Abstract:
Jembrana disease virus (JDV) is a lentivirus causing an acute infection with a 17% case fatality rate in Bali cattle in Indonesia. Control of the disease is currently achieved by identification of infected areas and restriction of cattle movement. A detergent-inactivated whole virus tissue-derived vaccine is sometimes employed in affected areas.
This thesis reports initial attempts to produce genetically engineered vaccines to replace the inactivated tissue-derived vaccine, which as it is made from homogenised spleen of infected animals, is expensive to produce and could contain adventitious agents present in the donor animals.
4 potential DNA vaccine constructs were created containing the JDV genes coding for the Tat, capsid (CA), transmembrane (TM) and surface unit (SU) proteins in a commercially available vaccine plasmid. These were assessed for functionality in a range of in vitro and in vivo assays. All proteins were expressed in vitro and administration of 2 of the constructs by a commercial 'gene gun' into the epidermis of mice resulted in antibody production to the appropriate protein. Due to the difficulties of licensing such a DNA vaccine in Indonesia, these vaccines were not progressed further.
A mathematical model was developed to describe the progression of the acute phase of Jembrana disease following experimental infection with JDV. The model divided the disease into 6 phases based on the rates of viral replication and clearance calculated from data on sequential plasma viral RNA load detected by quantitative reverse-transcription polymerase chain reaction. This allowed statistical comparison of each phase of the disease and comparison of the severity of the disease process in groups of animals. The use of the model overcame the difficulty of comparing the disease in different animals as a consequence of the animal-to-animal variation in the disease process.
The mathematical model was used to identify differences in the pathogenicity of 2 strains of JDV. One strain, JDVTAB caused a more rapid onset of disease in non-vaccinated controls, a significantly higher virus load at the onset of the febrile period and a higher peak viraemia than in animals infected with JDVPUL. This provided the first evidence of variation in pathogenicity of JDV strains.
The measurement of virus load also demonstrated that some JDV infected animals developed a clinical disease that was not typical of that which had been reported previously. When infected with less than 1,000 infectious virus particles, up to 20% of infected animals failed to develop a febrile response. Infection of these animals was confirmed, however, by the detection of a high titre of circulating virus particles in plasma. These atypical infections had not been reported previously.
Application of the mathematical model describing the progression of the disease in individual animals was used to examine the effect of vaccination with the inactivated tissue-derived vaccine on the progression of the disease. Several effects were noted in vaccinated animals that were subsequently infected with JDV: a reduction in the duration of the febrile response, a reduction in the severity of the febrile response in the early phases of the acute disease, and a reduction in virus load in the early and later phases of the disease process.
The effect of vaccination with recombinant Tat, matrix (MA) and CA protein vaccines expressed in a bacterial expression system on subsequent JDV infection was also examined. A vaccine incorporating recombinant Tat and CA vaccine emulsified with Freund's incomplete adjuvant decreased the febrile response particularly in the later stages of the acute disease process, decreased the severity of the leucopenia in the later phases of the acute disease, and decreased the virus load in some but not all phases of the acute disease process. Vaccines administered with Freund's incomplete adjuvant were more efficacious than vaccines administered with QuilA, the latter actually exacerbating the disease process in vaccinated animals.
11
Ditcham, William. "The development of recombinant vaccines against Jembrana disease." Ditcham, William (2007) The development of recombinant vaccines against Jembrana disease. PhD thesis, Murdoch University, 2007. http://researchrepository.murdoch.edu.au/438/.
Abstract:
Jembrana disease virus (JDV) is a lentivirus causing an acute infection with a 17% case fatality rate in Bali cattle in Indonesia. Control of the disease is currently achieved by identification of infected areas and restriction of cattle movement. A detergent-inactivated whole virus tissue-derived vaccine is sometimes employed in affected areas.
This thesis reports initial attempts to produce genetically engineered vaccines to replace the inactivated tissue-derived vaccine, which as it is made from homogenised spleen of infected animals, is expensive to produce and could contain adventitious agents present in the donor animals.
4 potential DNA vaccine constructs were created containing the JDV genes coding for the Tat, capsid (CA), transmembrane (TM) and surface unit (SU) proteins in a commercially available vaccine plasmid. These were assessed for functionality in a range of in vitro and in vivo assays. All proteins were expressed in vitro and administration of 2 of the constructs by a commercial 'gene gun' into the epidermis of mice resulted in antibody production to the appropriate protein. Due to the difficulties of licensing such a DNA vaccine in Indonesia, these vaccines were not progressed further.
A mathematical model was developed to describe the progression of the acute phase of Jembrana disease following experimental infection with JDV. The model divided the disease into 6 phases based on the rates of viral replication and clearance calculated from data on sequential plasma viral RNA load detected by quantitative reverse-transcription polymerase chain reaction. This allowed statistical comparison of each phase of the disease and comparison of the severity of the disease process in groups of animals. The use of the model overcame the difficulty of comparing the disease in different animals as a consequence of the animal-to-animal variation in the disease process.
The mathematical model was used to identify differences in the pathogenicity of 2 strains of JDV. One strain, JDVTAB caused a more rapid onset of disease in non-vaccinated controls, a significantly higher virus load at the onset of the febrile period and a higher peak viraemia than in animals infected with JDVPUL. This provided the first evidence of variation in pathogenicity of JDV strains.
The measurement of virus load also demonstrated that some JDV infected animals developed a clinical disease that was not typical of that which had been reported previously. When infected with less than 1,000 infectious virus particles, up to 20% of infected animals failed to develop a febrile response. Infection of these animals was confirmed, however, by the detection of a high titre of circulating virus particles in plasma. These atypical infections had not been reported previously.
Application of the mathematical model describing the progression of the disease in individual animals was used to examine the effect of vaccination with the inactivated tissue-derived vaccine on the progression of the disease. Several effects were noted in vaccinated animals that were subsequently infected with JDV: a reduction in the duration of the febrile response, a reduction in the severity of the febrile response in the early phases of the acute disease, and a reduction in virus load in the early and later phases of the disease process.
The effect of vaccination with recombinant Tat, matrix (MA) and CA protein vaccines expressed in a bacterial expression system on subsequent JDV infection was also examined. A vaccine incorporating recombinant Tat and CA vaccine emulsified with Freund's incomplete adjuvant decreased the febrile response particularly in the later stages of the acute disease process, decreased the severity of the leucopenia in the later phases of the acute disease, and decreased the virus load in some but not all phases of the acute disease process. Vaccines administered with Freund's incomplete adjuvant were more efficacious than vaccines administered with QuilA, the latter actually exacerbating the disease process in vaccinated animals.
12
Feyertag, Felix. "Evolutionary dynamics of lentiviruses associated with drug resistance and host adaptation." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/evolutionary-dynamics-of-lentiviruses-associated-with-drug-resistance-and-host-adaptation(cf1aaffa-c1c2-450d-8d25-538c0bcc0d02).html.
Abstract:
Studying evolutionary dynamics is crucial for epidemiological containment and/or eradication of viral diseases. With recent advancements in genetic sequencing, the spread of viruses can be monitored and sequenced almost in real-time as epidemics unfold, and sophisticated statistical analytical methods allow for the inference of population genetic and evolutionary characteristics directly from epidemiologic and genetic data. In this thesis, I have investigated various evolutionary aspects of the human immunodeficiency virus, the causative agent of AIDS, in the context of (a) within-host evolution of the virus in the emergence of resistance to CCR5 antagonist anti-retroviral agents and (b) between-host global evolutionary dynamics of the virus including an investigation of closely related simian immunodeficiency virus endemic in simian hosts. The main outcomes of my work have been, firstly, the development of a novel computational predictor for determining viral tropism from genetic sequences and a study investigating the efficacy of utilising this approach, and other genotypic methods, for screening patients prior to therapy; secondly, the characterisation of complex within-host mutational pathways and population genetic dynamics that give rise to the emergence of a rare form of resistance to CCR5 antagonists, namely the ability for the virus to utilise antagonist-bound CCR5 coreceptor; thirdly, an investigation of the global spread of HIV-1 group O and a proposed reconciliation of previous attempts to characterise genetic diversity observed which were discordant; and fourthly, en exploratory study comparing differences in rates of intrinsic disorder in both HIV and species-specific SIV, as well as human host genes and homologous simian host genes, and investigating the hypothesis that HIV pathogenicity might be attributable to promiscuous protein-protein interactions facilitated through protein intrinsic disorder. These studies have all highlighted aspects that are collectively important for epidemiological and genomic surveillance of infectious disease, especially in characterising transmission dynamics, monitoring changes and adaptation of viruses. Ultimately, I hope that these contributions will asset the wealth of knowledge that exists in this field, which collectively guides research into the development of new drugs and treatment regimens, as well as guidance on public health measures for control of infectious disease.
13
Carnell, George William. "Development of hybrid haemagglutinin pseudotyped lentiviruses to assess heterosubtypic immunity to influenza." Thesis, University of Kent, 2017. https://kar.kent.ac.uk/66363/.
Abstract:
The influenza virus still causes hundreds of thousands of deaths globally, on top of morbidity and associated economic burden. We are currently at the height of efforts surrounding the development and employment of 'universal' vaccines against this virus, with clinical trials commencing on the most promising candidates. Despite this, the influenza virus poses more of a threat to human life than it ever has previously, with multiple subtypes of pandemic potential circulating around the globe. The key to current efforts lies in the priming of the immune system towards generating long lasting defences against conserved epitopes and conferring heterosubtypic immunity against the surface glycoprotein haemagglutinin. While vaccine strategies have expanded rapidly over recent years with the advent of 'headless' constructs as well as those derived from consensus, mosaic or chimeric sequences, the serological techniques to test how effective these vaccines are, have advanced less rapidly. Classical serological assays have been shown to be ineffective at detecting the antibodies which modern 'universal' vaccines strife to elicit, replaced by ELISA based approaches combined with mouse models measuring in vivo protection. In this thesis, an alternative method for the detection of heterosubtypic antibodies is used in depth across multiple platforms. Influenza pseudotypes have been employed using chimeric haemagglutinin constructs in a comprehensive project aimed at dissecting head and stalk directed antibodies present in human serum. Characterised broadly neutralising monoclonal antibodies have been tested on panels of influenza pseudotypes including divergent bat influenza viruses which hitherto have not been encountered in humans. A further aspect of influenza immunity has been covered in the detection of anti neuraminidase antibodies which have an important role to play in influenza heterosubtypic immunity. Finally, influenza pseudotypes bearing the glycoproteins from the less studied influenza B virus have been assayed in a large scale project aimed at correlating pseudotype assays with classical approaches.
14
Stivahtis, Gina Lynn. "The role of Vpr in cell-cycle regulation by diverse primate lentiviruses /." Thesis, Connect to this title online; UW restricted, 1999. http://hdl.handle.net/1773/5017.
15
au, w. ditcham@murdoch edu, and William Ditcham. "The development of recombinant vaccines against Jembrana disease." Murdoch University, 2007. http://wwwlib.murdoch.edu.au/adt/browse/view/adt-MU20071119.94111.
Abstract:
Jembrana disease virus (JDV) is a lentivirus causing an acute infection with a 17% case fatality rate in Bali cattle in Indonesia. Control of the disease is currently achieved by identification of infected areas and restriction of cattle movement. A detergent-inactivated whole virus tissue-derived vaccine is sometimes employed in affected areas.
This thesis reports initial attempts to produce genetically engineered vaccines to replace the inactivated tissue-derived vaccine, which as it is made from homogenised spleen of infected animals, is expensive to produce and could contain adventitious agents present in the donor animals.
4 potential DNA vaccine constructs were created containing the JDV genes coding for the Tat, capsid (CA), transmembrane (TM) and surface unit (SU) proteins in a commercially available vaccine plasmid. These were assessed for functionality in a range of in vitro and in vivo assays. All proteins were expressed in vitro and administration of 2 of the constructs by a commercial gene gun into the epidermis of mice resulted in antibody production to the appropriate protein. Due to the difficulties of licensing such a DNA vaccine in Indonesia, these vaccines were not progressed further.
A mathematical model was developed to describe the progression of the acute phase of Jembrana disease following experimental infection with JDV. The model divided the disease into 6 phases based on the rates of viral replication and clearance calculated from data on sequential plasma viral RNA load detected by quantitative reverse-transcription polymerase chain reaction. This allowed statistical comparison of each phase of the disease and comparison of the severity of the disease process in groups of animals. The use of the model overcame the difficulty of comparing the disease in different animals as a consequence of the animal-to-animal variation in the disease process.
The mathematical model was used to identify differences in the pathogenicity of 2 strains of JDV. One strain, JDVTAB caused a more rapid onset of disease in non-vaccinated controls, a significantly higher virus load at the onset of the febrile period and a higher peak viraemia than in animals infected with JDVPUL. This provided the first evidence of variation in pathogenicity of JDV strains.
The measurement of virus load also demonstrated that some JDV infected animals developed a clinical disease that was not typical of that which had been reported previously. When infected with less than 1,000 infectious virus particles, up to 20% of infected animals failed to develop a febrile response. Infection of these animals was confirmed, however, by the detection of a high titre of circulating virus particles in plasma. These atypical infections had not been reported previously.
Application of the mathematical model describing the progression of the disease in individual animals was used to examine the effect of vaccination with the inactivated tissue-derived vaccine on the progression of the disease. Several effects were noted in vaccinated animals that were subsequently infected with JDV: a reduction in the duration of the febrile response, a reduction in the severity of the febrile response in the early phases of the acute disease, and a reduction in virus load in the early and later phases of the disease process.
The effect of vaccination with recombinant Tat, matrix (MA) and CA protein vaccines expressed in a bacterial expression system on subsequent JDV infection was also examined. A vaccine incorporating recombinant Tat and CA vaccine emulsified with Freunds incomplete adjuvant decreased the febrile response particularly in the later stages of the acute disease process, decreased the severity of the leucopenia in the later phases of the acute disease, and decreased the virus load in some but not all phases of the acute disease process. Vaccines administered with Freunds incomplete adjuvant were more efficacious than vaccines administered with QuilA, the latter actually exacerbating the disease process in vaccinated animals.
16
Setiyaningsih, Surachmi. "Molecular and immunogenic analysis of Jembrana disease virus Tat." Thesis, Setiyaningsih, Surachmi (2006) Molecular and immunogenic analysis of Jembrana disease virus Tat. PhD thesis, Murdoch University, 2006. https://researchrepository.murdoch.edu.au/id/eprint/299/.
Abstract:
Jembrana disease is an acute and severe disease of Bali cattle (Bos javanicus) endemic in Indonesia that is caused by a bovine lentivirus designated Jembrana disease virus (JDV). Previous studies have demonstrated that it is possible to induce a protective immunity against the disease by immunisation with a crude whole virus vaccine prepared from the tissues of infected cattle. This vaccine has been demonstrated to ameliorate the clinical signs of disease resulting from exposure to virus infection but a safer vaccine amenable to commercial production techniques is required.
JDV, like all lentiviruses, encodes a transcriptional trans-activator Tat protein that is encoded from one or both of two exons of the tat gene. Tat is particularly essential for virus replication and it was hypothesised that the induction of an immune response in cattle against JDV Tat may effect protection against virus infection. Investigations were therefore conducted on JDV Tat to provide basic information on the protein that would enable it to be further investigated as a potential immunogen for incorporation into vaccines for the control of Jembrana disease.
Analysis of tat transcripts obtained from tissues of cattle infected with three strains of JDV suggested that, during the acute clinical disease, Tat produced at this stage of the disease process was translated from the first coding exon only. Nucleotide variation in this exon, which would have translated into amino acid variations in the Tat protein, was evident especially between strains from geographically different regions of Indonesia. There was; however, conservation of the essential functional domains of cysteine-rich, core and basic regions, which suggested immunity to a single Tat protein might protect against infection by heterologous strains. Subsequent studies on Tat reported in the thesis therefore concentrated on the protein encoded by tat exon 1 of a single strain of JDV. The exon 1 of tat was cloned into the pGEX vector and recombinant Tat expressed in Escherichia coli. Methods for the purification of the expressed protein were developed. Immunogenicity of the recombinant protein was initially demonstrated by inoculation of the protein into a sheep which developed a high titred specific antibody response. Antibodies induced by this recombinant protein recognised native Tat proteins produced by three JDV strains in Bali cattle and provided a valuable reagent for the subsequent detection of Tat in vitro and in vivo.
Aspects of the antibody response to Tat were determined in cattle that had been infected naturally or experimentally with JDV, and compared with the levels of antibody to the immunodominant capsid protein. Tat antibodies were detected in 23 % of 128 Bali cattle from Jembrana disease-endemic areas of Indonesia; in all these cattle, evidence of previous virus infection had been demonstrated by detection of antibody to the JDV capsid protein by Western blot analysis. In cattle experimentally infected with JDV, low levels of serum antibody to Tat were detected by Western blot in the first month post-infection but the levels of antibody then decreased; levels of antibody to the JDV capsid protein increased over the 6-month observation period following infection. The detection of Tatantibody soon after the acute clinical disease suggested that this protein is secreted extracellularly during JDV infection in cattle. In contrast to the antibody response to Tat in JDV-infected cattle, an apparently greater antibody response to Tat was induced by injection of recombinant Tat in Bali cattle. The strong antibody response resulting from inoculation of the recombinant Tat and low levels of Tat antibody in animals that had been naturally or experimentally infected with virus suggested there might be a conformational difference in the recombinant and native Tat protein and that the native protein was a poor immunogen, or that the levels of Tat in infected cattle were too low to induce a strong antibody response. As an alternative means of inducing an immune response to JDV Tat, perhaps one associated with a greater cell-mediated rather than an antibody response, a candidate tat DNA vaccine was produced by insertion of tat exon 1 into a DNA vaccine vector. Transfection of this naked DNA plasmid into mammalian cells induced the expression of a functional Tat protein which maintained antigenicity. The results suggested this construct merits further animal studies attempting to induce a protective immune response against Jembrana disease in cattle. A method of assaying the trans-acting function of Tat was also developed which will have application for quality control procedures for large-scale production of tat DNA vaccine.
17
Setiyaningsih, Surachmi. "Molecular and immunogenic analysis of Jembrana disease virus Tat." Setiyaningsih, Surachmi (2006) Molecular and immunogenic analysis of Jembrana disease virus Tat. PhD thesis, Murdoch University, 2006. http://researchrepository.murdoch.edu.au/299/.
Abstract:
Jembrana disease is an acute and severe disease of Bali cattle (Bos javanicus) endemic in Indonesia that is caused by a bovine lentivirus designated Jembrana disease virus (JDV). Previous studies have demonstrated that it is possible to induce a protective immunity against the disease by immunisation with a crude whole virus vaccine prepared from the tissues of infected cattle. This vaccine has been demonstrated to ameliorate the clinical signs of disease resulting from exposure to virus infection but a safer vaccine amenable to commercial production techniques is required.
JDV, like all lentiviruses, encodes a transcriptional trans-activator Tat protein that is encoded from one or both of two exons of the tat gene. Tat is particularly essential for virus replication and it was hypothesised that the induction of an immune response in cattle against JDV Tat may effect protection against virus infection. Investigations were therefore conducted on JDV Tat to provide basic information on the protein that would enable it to be further investigated as a potential immunogen for incorporation into vaccines for the control of Jembrana disease.
Analysis of tat transcripts obtained from tissues of cattle infected with three strains of JDV suggested that, during the acute clinical disease, Tat produced at this stage of the disease process was translated from the first coding exon only. Nucleotide variation in this exon, which would have translated into amino acid variations in the Tat protein, was evident especially between strains from geographically different regions of Indonesia. There was; however, conservation of the essential functional domains of cysteine-rich, core and basic regions, which suggested immunity to a single Tat protein might protect against infection by heterologous strains. Subsequent studies on Tat reported in the thesis therefore concentrated on the protein encoded by tat exon 1 of a single strain of JDV. The exon 1 of tat was cloned into the pGEX vector and recombinant Tat expressed in Escherichia coli. Methods for the purification of the expressed protein were developed. Immunogenicity of the recombinant protein was initially demonstrated by inoculation of the protein into a sheep which developed a high titred specific antibody response. Antibodies induced by this recombinant protein recognised native Tat proteins produced by three JDV strains in Bali cattle and provided a valuable reagent for the subsequent detection of Tat in vitro and in vivo.
Aspects of the antibody response to Tat were determined in cattle that had been infected naturally or experimentally with JDV, and compared with the levels of antibody to the immunodominant capsid protein. Tat antibodies were detected in 23 % of 128 Bali cattle from Jembrana disease-endemic areas of Indonesia; in all these cattle, evidence of previous virus infection had been demonstrated by detection of antibody to the JDV capsid protein by Western blot analysis. In cattle experimentally infected with JDV, low levels of serum antibody to Tat were detected by Western blot in the first month post-infection but the levels of antibody then decreased; levels of antibody to the JDV capsid protein increased over the 6-month observation period following infection. The detection of Tatantibody soon after the acute clinical disease suggested that this protein is secreted extracellularly during JDV infection in cattle. In contrast to the antibody response to Tat in JDV-infected cattle, an apparently greater antibody response to Tat was induced by injection of recombinant Tat in Bali cattle. The strong antibody response resulting from inoculation of the recombinant Tat and low levels of Tat antibody in animals that had been naturally or experimentally infected with virus suggested there might be a conformational difference in the recombinant and native Tat protein and that the native protein was a poor immunogen, or that the levels of Tat in infected cattle were too low to induce a strong antibody response. As an alternative means of inducing an immune response to JDV Tat, perhaps one associated with a greater cell-mediated rather than an antibody response, a candidate tat DNA vaccine was produced by insertion of tat exon 1 into a DNA vaccine vector. Transfection of this naked DNA plasmid into mammalian cells induced the expression of a functional Tat protein which maintained antigenicity. The results suggested this construct merits further animal studies attempting to induce a protective immune response against Jembrana disease in cattle. A method of assaying the trans-acting function of Tat was also developed which will have application for quality control procedures for large-scale production of tat DNA vaccine.
18
Zhu, Xiaonan. "Identification of the Function of the Vpx Protein of Primate Lentiviruses: A Dissertation." eScholarship@UMMS, 2009. https://escholarship.umassmed.edu/gsbs_diss/447.
Abstract:
Primate lentiviruses encode four “accessory proteins” including Vif, Vpu, Nef, and Vpr/ Vpx. Vif and Vpu counteract the antiviral effects of cellular restrictions to early and late steps in the viral replication cycle. The functions of Vpx/ Vpr are not well understood. This study presents evidence that the Vpx proteins of HIV-2/ SIVSMpromote HIV-1 infection by antagonizing an antiviral restriction in myeloid cells.
Fusion of macrophages in which Vpx was essential for virus infection, with COS cells in which Vpx was dispensable for virus infection, generated heterokaryons that supported infection by wild-type SIV but not Vpx-deleted SIV. The restriction potently antagonized infection of macrophages by HIV-1, and expression of Vpx in macrophages in transovercame the restriction to HIV-1 and SIV infection. Similarly, the cellular restriction is the obstacle to transduction of macrophages by MLV. Neutralization of the restriction by Vpx rendered macrophages permissive to MLV infection. Vpx was ubiquitylated and both ubiquitylation and the proteasome regulated the activity of Vpx. The ability of Vpx to counteract the restriction to HIV-1 and SIV infection was dependent upon the HIV-1 Vpr interacting protein, damaged DNA binding protein 1 (DDB1), and DDB1 partially substituted for Vpx when fused to Vpr.
This study further demonstrates that this restriction prevents transduction of quiescent monocytes by HIV-1. Although terminally differentiated macrophages are partially permissive to HIV-1, quiescent monocytes, which are macrophage precursors, are highly refractory to lentiviral infection. Monocyte-HeLa heterokaryons were resistant to HIV-1 infection, while heterokaryons formed between monocytes and HeLa cells expressing Vpx were permissive to HIV-1 infection, suggesting the resistance of quiescent monocytes to HIV-1 transduction is governed by a restriction factor. Encapsidation of Vpx within HIV-1 virions conferred the ability to infect quiescent monocytes. Introduction of Vpx into monocytes by pre-infection also rendered quiescent monocytes permissive to HIV-1 infection. Infection of monocytes by HIV-1 either with or without Vpx did not have an effect on temporal expression of CD71. In addition, Vpx increased permissivity of CD71– and CD71+cells to HIV-1 infection with no apparent bias. These results confirm that Vpx directly renders undifferentiated monocytes permissive to HIV-1 transduction without inducing their differentiation. The introduction of Vpx did not significantly alter APOBEC3G complex distribution, suggesting a restriction other than APOBEC3G was responsible for the resistance of monocytes to HIV-1.
Collectively our results indicate that macrophages and monocytes harbor a potent antiviral restriction that is counteracted by the Vpx protein. The relative ability of primate lentiviruses and gammaretroviruses to transduce non-dividing myeloid-cells is dependent upon their ability to neutralize this restriction.
19
Price, Amanda Jane. "Host-pathogen interactions in lentiviral post-entry restriction and nuclear import." Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609671.
20
Tristem, Michael. "Sequence of a novel isolate of HIV-2 and its relationship to other lentiviruses." Thesis, University of Cambridge, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239787.
21
Pryszlak, Anna Marta [Verfasser], and Felix [Akademischer Betreuer] Hoppe‐Seyler. "Functional Crosstalk between Human Papillomaviruses and Lentiviruses / Anna Marta Pryszlak ; Betreuer: Felix Hoppe‐Seyler." Heidelberg : Universitätsbibliothek Heidelberg, 2016. http://d-nb.info/1180607856/34.
22
Cordeil, Stéphanie. "Etude de la différence de susceptibilité des lentivirus de primates aux interférons de type I." Thesis, Lyon, École normale supérieure, 2012. http://www.theses.fr/2012ENSL0781.
Abstract:
Les IFN-I (interférons de type I), principalement IFN et , constituent un mécanisme de défense primordial de l’hôte contre les pathogènes. Pourtant, dans le cas du VIH-1 (virus de l’immunodéficience humaine), la relation entre les IFN-I et la réplication virale apparaît plus complexe. En effet, si les IFN-I inhibent la réplication du VIH-1 ex vivo, un état d’hyperactivation permanent de la réponse IFN-I a été récemment associé à la progression vers le SIDA ainsi qu’à une forte virémie chez les patients infectés par le VIH-1. De même, la dérégulation de la réponse IFN-I est un critère déterminant dans l’issue pathogénique de certains modèles d’infection virale chez le singe. Si l’hypothèse du rôle pathogénique des IFN-I s’avère correcte, le VIH-1 pourrait avoir évolué afin de se répliquer même en présence d’une telle réponse, qui semble être au final, plus délétère pour l’hôte que pour le virus. L’objectif de ce travail a été d’évaluer la résistance du VIH-1 aux IFN. Dans ce contexte, le VIH-1 a été comparé au VIH-2 et au SIVmac (virus de l’immunodéficience simienne), virus phylogénétiquement proches mais peu ou pas pathogènes pour l’homme, lors de l’infection de plusieurs types cellulaires tels que des lymphocytes, des macrophages et des cellules dendritiques. En accord avec l’hypothèse initiale de travail, les expériences réalisées ont montré que le VIH-1 est capable de se répliquer dans les cellules primaires prétraitées avec des doses d’IFN comparables à celles mesurées in vivo, alors que la réplication des virus VIH-2/SIVmac est complètement bloquée, même à des concentrations très faibles d’IFN. Ce travail a permis de démontrer que le blocage induit par l’IFN s’exerce au niveau des phases précoces de l’infection et plus précisément à l’étape de la transcription inverse. En effet, les données obtenues suggèrent que l’IFN induit l’expression d’un effecteur cellulaire qui affecte différentiellement la stabilité des complexes viraux, ce qui se traduit par un défaut d’accumulation de l’ADN viral plus important pour le VIH-2 et le SIVmac, que pour le VIH-1. La différence de susceptibilité des lentivirus de primates aux IFN-I pourrait ainsi expliquer en partie, les différents niveaux de réplication de ces virus, associés à leurs degrés de pathogénicité in vivoType I Interferons (IFN-α/β, herein IFNs) provide an important mechanism of defense against pathogens and regulate in a paracrine and autocrine manner both intrinsic and adaptive immune responses. In the case of HIV-1 however, the relationship between IFNs and viral replication appears more complex. Indeed, if IFNs have been described to interfere with HIV-1 at basically all phases of its life cycle ex vivo, an IFN-induced state is linked to AIDS progression and to high viral loads in HIV-1 infected individuals. Similarly, a deregulated and prolonged IFN production/state seems one of the main distinguishing features between pathogenic and non-pathogenic SIV infection in primate animal models, suggesting that a deregulated IFN-state may be more detrimental to the host than to the virus itself in vivo.If this hypothesis is correct and if HIV-1 plays an active role in the perpetration of this antiviral state, it is possible that HIV-1 may have overall evolved to cope with this environment, remaining able to replicate despite it.To determine whether HIV-1 was better armed to replicate in the presence of an IFN-state environment than other primate lentiviruses, we compared HIV-1 to SIVmac and more importantly to HIV-2 that albeit capable of inducing AIDS in humans does so in a much less aggressive manner. In agreement with the initial hypothesis, our results indicate that HIV-1 is better fit to replicate in primary cells in the presence of amounts of IFN comparable to the ones measured in vivo, while the replication of HIV-2/SIVmac viruses is completely blocked even in the presence of low levels of IFN. By decorticating the effects of IFNs on the early and late phases of the viral life cycle in primary macrophages, we show here that the main target of the differential action of IFNs are the early phases of infection. More specifically, with time kinetics that we determine herein, IFNs induce cellular factor/s that differentially affect the stability of pre-reverse transcription complexes of HIV-2, but not of HIV-1. Our results could underlie a different evolutionary adaptation of primate lentiviruses to interferons that might be responsible for their different pathogenicity in vivo
23
Limberis, Maria. "A lentiviral gene transfer vector for the treatment of cystic fibrosis airway disease." Title page, synopsis and list of contents only, 2002. http://web4.library.adelaide.edu.au/theses/09PH/09phl735.pdf.
Abstract:
"16th September 2002." Accompanying CD contains 2 MPEG clips with accompanying text, and a copy in PDF format of: Recovery of airway cystic fibrosis transmembrane conductance regulator function in mice with cystic fibrosis after single-dose lentivirus-mediated gene transfer / M. Limberis ... [et al.], published in Human gene therapy vol. 13 (2002). Bibliography: leaves xxix-li. This thesis focuses on modulating the physical barriers of the airway epithelium with mild detergents, so as to enhance gene transfer by a HIV-1 based lentivirus vector in vivo. The efficiency of the gene transfer was evaluated in the nasal airway of C57B1/6 mice using the Lac Z marker gene. This demonstration of lentivirus-mediated in vivo recovery of CFTR function in CF airway epithelium illustrated the potential of combining a pre-conditioning of the airway surface with a simple and brief HIV-1 based gene transfer vector exposure to produce therapeutic gene expression in the intact airway.
24
Gelinas, Jean-Francois. "Enhancement of lentiviral vector production through alteration of virus-cell interactions." Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:9921b8b4-e2b5-4eec-9efc-6036765c8d55.
Abstract:
Gene therapy is the introduction or alteration of genetic material with the intention to treat disease. To support this aim, viruses have been modified, with elements linked to viral pathogenicity removed from their genome and replaced by the genetic material to be delivered. Gene therapy vectors based on lentiviruses have many advantages, such as the ability to transduce non-dividing cells and to target specific cell types via pseudotyping. They have been successfully used in ex vivo clinical trials for several haematopoietic stem cell disorders. Lentiviral vectors, however, suffer from substantially lower titres than the more popular adeno-associated virus (AAV)-based vectors and therefore have limited applicability for in vivo gene therapy which requires much greater quantities of virus. The main aim of this thesis was to investigate strategies to improve lentiviral vector productivity during manufacture, in order to increase the likelihood of lentiviruses being adopted for disease treatment. Initial experiments were based on the lentiviral vector manufacturing process currently being developed by the United Kingdom Cystic Fibrosis Gene Therapy Consortium for the generation of highly concentrated, purified lentivirus for clinical use. Supplementation of FreeStyle 293 Expression Medium used during upstream processing was attempted, but none of the assessed supplements led to significant increases in lentiviral vector production. Investigation into intrinsic immunity to viral infection indicated that over-expression of the protein kinase RNA-activated (PKR) led to lower production titres, but over-expression of its inhibitors was not successful at increasing titres. The focus then shifted to reducing, or 'knocking-down', inhibitory factors present in the host cells, which could adversely affect viral titres. Investigation of the published HIV-1 literature revealed a possible 152 candidate inhibitory factors described as having a negative impact on HIV-1 replication in the late stages of the life cycle of the virus. A novel siRNA screen was developed to assess the effect of âknock-down' of inhibitory factors on lentiviral vector titre. Application of the screen to 89 candidate inhibitory factors identified nine genes which, when knocked-down, resulted in increased lentiviral vector production by more than 40%. Further work will be necessary to understand the role of the inhibitory factors in lentiviral vector production, but novel cell lines in which genes encoding these factors have been permanently deleted from producer cells could lead to higher titres, reducing costs in the manufacture of lentiviral vectors and making in vivo gene therapy more feasible from a health economics perspective.
25
Jung, Cindy. "Quantitative analysis of lentivirus incorporation of heterologous viral and non-viral proteins for lung gene therapy." Diss., Atlanta, Ga. : Georgia Institute of Technology, 2007. http://hdl.handle.net/1853/26648.
Abstract:
Thesis (Ph.D)--Biomedical Engineering, Georgia Institute of Technology, 2008.Committee Chair: Joseph M. Le Doux; Committee Member: Andrés J. Garcia; Committee Member: Cheng Zhu; Committee Member: Nael McCarty; Committee Member: Richard Compans. Part of the SMARTech Electronic Thesis and Dissertation Collection.
26
Osejindu, Emma. "Investigation of the effects of virus integration on host gene expression in mouse tumour samples." Thesis, Brunel University, 2011. http://bura.brunel.ac.uk/handle/2438/6565.
Abstract:
Clonally derived liver tumours and an ovarian cyst developed in mice following EIAV and FIV delivery in utero. LAM PCR and 454 sequencing was used to retrieve proviral insertion sites. TaqMan analysis revealed gene expression changes in lentiviral infected tumours. STRING and IPA networks identified links between genes flanking the lentivirus provirus and oncogenic pathways supporting the role of insertional mutagenesis in Hepatocellular Carcinoma (HCC). Global methylation analysis demonstrated increased relative methylation levels in lentivirus (EIAV, FIV, and HIV) infected normal and tumour samples. This provided strong evidence for host defence against lentivirus infection by epigenetic means. Microarray data showed altered expression of Dnmt1 and Dnmt3b and TaqMan analysis revealed specific changes in Dnmts levels when compared to uninfected liver. The evidence found for involvement of DNA methylation associated with lentivirus infection and possibly tumour development required that this study be repeated in vitro. DNA methylation was investigated at early time points after lentivirus and retrovirus infection in HepG2 cells. Results revealed sharp increases in global methylation and Dnmt levels at 24 and 30hrs post infection. E2F targets play a key role in the regulation of gene expression and aberrations result in the development of cancer. Of the 94 E2F target genes analysed 77.7% were involved in DNA damage and repair mechanisms, 21.3% were known oncogenes or shown to exert oncogenic activity and 80.9% were categorised as HCC target genes. The fact that all lentiviral/retroviral vectors used in this study were found to cause changes in methylation and gene expression in vivo and in vitro suggests that these vectors, at least in the mouse, are genotoxic. Findings here support the use of the fetal animal model to identify vector genotoxicity and the mechanisms of lentiviral vector-induced tumorigenesis. This model may be a valuable tool to evaluate the safety of lentiviruses for gene therapy.
27
Bell, Ian. "T-cell signalling dysfunction associated with expression of NEF derived from the primate lentiviruses, HIV-1 and SIV." Thesis, Imperial College London, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299904.
28
Landázuri, Natalia. "Effects of flocculation on retrovirus processing, delivery and transduction." Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-04042005-120801/unrestricted/landazuri%5Fnatalia%5F200505%5Fphd.pdf.
Abstract:
Thesis (Ph. D.)--Biomedical Engineering, Georgia Institute of Technology, 2005.Niren Murthy, Committee Member ; Andrš J. Garca̕, Committee Member ; Joseph M. Le Doux, Committee Chair ; Mark R. Prausnitz, Committee Member ; H. Trent Spencer, Committee Member. Includes bibliographical references.
29
Martin, Michaël. "Mécanisme moléculaire de l'antagonisme du complexe HUSH par les protéines lentivirales Vpx et Vpr." Electronic Thesis or Diss., Université Paris Cité, 2021. http://www.theses.fr/2021UNIP5160.
Abstract:
Les VIH-1 et VIH-2, lentivirus responsables du SIDA, sont issus de transmissions inter-espèces de virus simiens (SIV) à l'homme. Outre leurs protéines de structure et de régulation, les lentivirus codent pour des protéines auxiliaires qui favorisent la réplication virale dans la cellule hôte en contrecarrant des facteurs cellulaires antiviraux, appelés facteurs de restriction. Le mécanisme d'action de ces protéines virales auxiliaires repose souvent sur le détournement de complexes Ubiquitine-Ligases, un mécanisme très répandu chez une grande variété de pathogènes, en vue de dégrader des protéines de la cellule hôte. Ce mécanisme est utilisé par la protéine Vpx, exprimée uniquement par VIH-2 (et non par VIH-1), qui induit la dégradation de SAMDH1, un facteur de restriction bloquant l'étape de transcription inverse. Ainsi, Vpx fait un pont moléculaire entre l'adaptateur DCAF1 du complexe Ubiquitine-Ligase Cul4A-DDB1(DCAF1) et SAMHD1, ce qui entraîne l'ubiquitination et la dégradation de SAMHD1. En 2018, notre équipe a montré que Vpx induisait la dégradation d'un facteur cellulaire supplémentaire : le complexe HUSH, composé de TASOR, MPP8 et Périphiline. Ce complexe intervient dans la répression épigénétique non seulement de nombreux gènes cellulaires, d'éléments rétro-transposables et de rétrovirus endogènes, mais aussi du génome du VIH intégré dans celui de la cellule infectée. En dégradant HUSH, Vpx favorise l'expression virale. Dans ce contexte, les objectifs de ma thèse ont été de : (i) Déterminer si le mécanisme de dégradation de HUSH induit par Vpx de VIH2 était identique au mécanisme de dégradation de SAMHD1. J'ai pu mettre en évidence des différences importantes entre les deux mécanismes bien que Vpx utilise, dans les deux cas, le même adaptateur d'Ubiquitine-Ligase, DCAF1 (coeur principal du travail de thèse, article soumis). (ii) Caractériser les déterminants moléculaires en jeu dans l'antagonisme de HUSH par d'autres protéines lentivirales. Premièrement, il s'agissait de savoir si les différentes protéines virales apparentées à Vpx chez différentes espèces de virus simiens avaient toutes la même capacité à dégrader le complexe HUSH. Nous avons ainsi pu mettre en évidence une spécificité lentivirale de l'antagonisme du complexe HUSH, une caractéristique majeure des facteurs de restriction (contribution à l'article Chougui et al., Nature microbiology, 2018). Dans un second temps, ceci m'a conduit à débuter l'étude des déterminants viraux de ces protéines apparentées à Vpx, telles les protéines Vpr de différentes souches de SIVagm (infectant le singe vert africain) qui présentent des phénotypes différents quant à la dégradation de SAMHD1 ou de HUSH (travail en cours). L'ensemble des résultats a permis, d'une part de mieux caractériser le mécanisme d'antagonisme de HUSH par les protéines lentivirales Vpx/Vpr, et d'autre part de fournir de premiers outils moléculaires pour différencier l'antagonisme de HUSH de celui de SAMHD1 dans les cellules primaires. Dans le futur, les données pourront aider à mieux comprendre comment diverses protéines lentivirales se sont adaptées à leurs différents substrats cellulaires (et vice-versa) au cours de l'évolution. Enfin, cibler HUSH grâce à l'identification de déterminant d'interaction ou de dégradation pourrait être intéressant pour le développement de nouvelles cibles thérapeutiquesHIV-1 and HIV-2, lentiviruses responsible for AIDS, appeared in humans after cross-species transmissions from simian viruses (SIV). In addition to their structural and regulatory proteins, lentiviruses encode auxiliary proteins that promote viral replication in the host cell by counteracting antiviral cellular factors, called restriction factors. The mechanism of action of these viral auxiliary proteins often relies on the hijacking of Ubiquitin-Ligase complexes, a mechanism widely used by various pathogens, to degrade host cell proteins. This mechanism is used by the Vpx protein, expressed only by HIV-2 (and not by HIV-1), which induces the degradation of SAMDH1, a restriction factor blocking the reverse transcription step. Thus, Vpx molecularly bridges the DCAF1 adaptor of the Cul4A-DDB1(DCAF1) Ubiquitin-Ligase complex with SAMHD1, resulting in ubiquitination and degradation of SAMHD1. In 2018, our team showed that Vpx induces the degradation of an additional cellular factor: the HUSH complex, composed of TASOR, MPP8 and Periphilin. This complex is involved in the epigenetic repression not only of many cellular genes, retro-transposable elements and endogenous retroviruses, but also of the HIV genome integrated into the infected cell. By degrading HUSH, Vpx promotes viral expression. In this context, the objectives of my thesis were to: (i) Determine whether HUSH degradation mechanism induced by HIV-2 Vpx was identical to SAMHD1 degradation mechanism. I was able to highlight important differences between the two mechanisms although Vpx uses, in both cases, the same Ubiquitin-Ligase adaptor, DCAF1 (main focus of the thesis work, submitted article). (ii) Characterize the molecular determinants involved in the antagonism of HUSH by other lentiviral proteins. First, we wanted to know if different Vpx-related viral proteins, in various simian virus species, had the same capacity to degrade the HUSH complex. This allowed us to reveal a lentiviral species-specificity of HUSH complex antagonism, a major characteristic of restriction factors (contribution to Chougui et al., Nature microbiology, 2018). Secondly, this led me to start studying the viral determinants of these Vpx-related proteins, such as the Vpr proteins from different strains of SIVagm (infecting the African green monkey) that present different phenotypes regarding both SAMHD1 or HUSH degradation (work in progress). All the results allowed us to better characterize the mechanism of HUSH antagonism by Vpx/Vpr lentiviral proteins, and to provide the first molecular tools to differentiate HUSH antagonism from SAMHD1 antagonism in primary cells. In the future, these data may help to better understand how various lentiviral proteins have adapted to their different cellular substrates (and vice versa) along evolution. Finally, targeting HUSH through the identification of interaction or degradation determinants could be interesting for the development of new therapeutic targets
30
Pernot, Eileen. "Etude in vivo du rôle de la 5-phosphatase de phosphoinositides SKIP." Doctoral thesis, Universite Libre de Bruxelles, 2008. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210473.
Abstract:
Les membres de la famille des 5-phosphatases d’inositols polyphosphates et de phosphoinositides sont des enzymes caractérisées par la présence de deux domaines catalytiques conservés qui hydrolysent un phosphate en position 5 sur un noyau inositol. SKIP (Skeletal Muscle and Kidney enriched Inositol Phosphatase), également appelée Pps (Putative PI 5-phosphatase) est un des derniers membres de la famille des 5-phosphatases à avoir été découvert à ce jour. Cette enzyme hydrolyse majoritairement le phosphatidylinositol-4,5-bisphosphate (PtdIns(4,5)P2) et le phosphatidylinositol-3,4,5-trisphosphate (PtdIns(3,4,5)P3). Les phosphoinositides (PtdIns) représentent environ 10% des lipides membranaires et sont impliqués dans de nombreuses cascades de signalisation cellulaire conduisant, entre autres, à la prolifération, l’apoptose, la différenciation, la sécrétion, le trafic vésiculaire et la mobilité cellulaire.Des études de surexpression de SKIP en cellules tendent à montrer que cette protéine pourrait jouer un rôle de régulateur négatif dans la formation du cytosquelette d’actine et/ou dans la voie de signalisation de l’insuline.
Afin d’étudier in vivo la fonction de la protéine SKIP chez la souris, nous avons décidé de générer des souris transgéniques surexprimant cette protéine de manière conditionnelle. Dans ce but, nous avons infecté des embryons murins par des lentivirus porteurs d’un transgène SKIP et avons obtenu, après réimplantation des embryons infectés dans des femelles pseudogestantes, deux lignées de souris transgéniques. Celles-ci ont ensuite été croisées avec des souris exprimant la recombinase Cre de manière ubiquitaire afin de pouvoir activer la transcription de SKIP dans l’ensemble des organes. Des expériences de Western blot, de dosage d’activité 5-phosphatase ainsi que des PCR en temps réel sont venus confirmer la présence de la protéine transgénique et de son activité catalytique.
L’ensemble des expériences qui ont été menées du point de vue phénotypique tend à montrer que dans notre modèle, la surexpression de SKIP ne provoque aucune anomalie évidente du point de vue anatomique, glycémique ou immunologique. Toutefois, des expériences concernant la physiologie rénale ont été réalisées sur base des résultats d’immunohistochimie et nous ont permis de détecter une anomalie dans les mécanismes de réabsorption d’eau ainsi que dans l’expression et la phosphorylation des canaux hydriques AQP2.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
31
Vabret, Nicolas. "Hypothèses sur l'implication du biais nucléotidique des lentivirus dans le développement du SIDA et nouvelles stratégies d'atténuation du VIH-1." Thesis, Lyon, École normale supérieure, 2011. http://www.theses.fr/2011ENSL0649.
Abstract:
Après 30 années de recherche, de nombreux obstacles s'opposent encore à la conception d'un vaccin contre le SIDA. En effet, il n'existe pas de consensus sur les corrélats immunitaires de protection qu'il devra induire ni sur les mécanismes à l'origine de la progression vers le SIDA chez les individus infectés. Dans un premier temps, nous avons cherché à concevoir un virus hybride structuralement semblable au VIH-1 et capable de se répliquer exclusivement dans le cytoplasme des cellules infectées. Dans cet objectif, nous avons développé des nouveaux vecteurs bi et tri-cistroniques dérivés du poliovirus et contenant les séquences des gènes gag et/ou env du VIH-1. Nous avons montré que ces réplicons permettaient l'expression des protéines structurales du VIH-1 sous leur forme mature. Dans un second temps, nous avons mis en évidence une corrélation indiquant que, plus la composition nucléotidique (% A/T/G/C) d'un lentivirus diverge de celle de son hôte, plus la probabilité qu'il soit pathogène est élevée. Nous avons montré que l'optimisation artificielle de la composition nucléotidique de séquences d'ARN lentivirales diminuait leur capacité d'induction d'interféron (IFN-I) après transfection. Nous avons ensuite synthétisé un virus de l'immunodéficience simienne (VIS) dont la séquence a été artificiellement optimisée à la composition nucléotidique moyenne du macaque. Ce virus présente une capacité d'induction d'IFN-I in vitro réduite par rapport au VIS sauvage. Ces données indiquent pour la première fois un lien entre la composition nucléotidique du génome des lentivirus et la progression vers le SIDA. Elles suggèrent de nouvelles stratégies vaccinales d'atténuation du VIH-1After over thirty years of AIDS epidemic, we still need to identify immunological correlates of protection against AIDS and we do not properly understand how HIV causes AIDS in infected individuals. In order to reproduce the protective capacity of live attenuated viruses, we first aimed at generating a hybrid virus structurally similar to HIV-1 and able to replicate exclusively in the cytoplasm of infected cells. We developed new polioviral pluricistronic vectors that contain HIV-1 packaging sequences, gag gene and/or env gene. We then showed that the use of these replicons was compatible with the production of processed and mature HIV structural proteins. Secondly, we investigated the consequences of the lentivirus nucleotide composition (% A/T/G/C) bias on their pathogenicity. We found a correlation, indicating that AIDS results from infection by primate lentiviruses having the most divergent nucleotide composition compared to their hosts, whereas less divergent lentiviruses cause non-pathogenic infections. A strong type I interferon (IFN-I) response during the chronic phase of infection is a typical feature of lentiviral pathogenic infection. We showed that nucleotide optimization of lentiviral RNA sequences dramatically reduce their in vitro capacity to induce IFN-I. We synthesized a simian immunodeficiency virus (SIV), whose genome sequence was artificially optimized to the macaque average nucleotide composition. This virus showed a reduced capacity to stimulate IFN-I in vitro than wt SIV. These data indicate for the first time a link between the nucleotide composition of lentiviruses and their pathogenicity. They suggest new vaccine attenuation strategies against AIDS
32
Inacio, Mamede Joao Filipe. "Interactions de la capside de lentivirus de primates avec les facteurs cellulaires de l’hôte." Thesis, Montpellier 1, 2012. http://www.theses.fr/2012MON13524/document.
Abstract:
Depuis la découverte du virus de l'Immunodéficience humaine, un lentivirus, comme agent pathogène responsable de l'épidémie du SIDA en 1983, beaucoup de progrès sur le sujet ont été réalisés. Il existe deux types de virus différents pouvant infecter l'Homme, le HIV-1 et le HIV-2. Ces deux virus se regroupent en différents groupes et sous-types qui témoignent d'une grande diversité inter et intra individus (notions de quasi-espèces). La découverte de lentivirus infectant naturellement au moins quarante-cinq espèces de primates en Afrique sub-saharienne, a permis un enrichissement des connaissances sur les origines des épidémies lentivirales humaines. Aujourd'hui , il est clairement admis que l'origine des épidémies d'HIV-1 et HIV-2 sont le résultat de transmissions zoonotiques de virus de chimpanzés/gorilles et de mangabeys enfumées, respectivement. La mise en évidence de nombreux SIV circulant chez ces primates non-humains indique bien le risque potentiel de nouvelles zoonoses dans la population humaine exposée, cependant, il peut paraître surprenant que jusqu'à maintenant, deux lignées lentivirales seulement ont été capables de franchir cette barrière d'espèce. Pour pouvoir se répliquer dans les cellules d'un nouvel hôte, un lentivirus doit pouvoir contrecarrer les différents facteurs de restriction exprimés par les cellules cibles tout en exploitant au maximum la machinerie cellulaire. La famille de protéines TRIM5, APOBEC3 et les protéines Tetherin/Bst2 et SAMHD1 sont capables de bloquer une infection rétrovirale. Dans ce travail, le rôle des protéines TRIM5 a été étudié ainsi que celui d'autres protéines interagissant avec des capsides rétrovirales, dans un contexte de transmission inter-espèces de lentivirus de primates. L'étude de TRIM5α humain a montré que cette protéine n'était capable de bloquer aucune des infections par les lentivirus primates testés dans cette étude, ni par les autres SIV. Nous avons pu mettre en évidence que la dépendance de la liaison à la Cyclophiline A pour l'infection des différents SIV était variable en fonction de la capside testée. Ainsi, si cette interaction est largement répandue parmi les différentes lignées de SIV, elle n'est toutefois pas universelle. La sensibilité des SIV à la déplétion de nucléoporines qui sont connues pour affecter l'infection par HIV-1, était également variable pour différents SIV, et la même diversité a été observée concernant les déplétions de RanBP2 et Nup153. De plus, nous avons découvert une capside de SIV soumise à une forte restriction de son infection dans les cellules humaines, ce phénotype a été nommé Ref2.Il a été suggéré qu'il existait une possible corrélation entre des variations de la capside de HIV-2 et la progression vers le SIDA, nous avons donc élaboré une étude afin de déterminer si les protéines TRIM5 étaient impliquées dans ce phénotype. La conclusion est que TRIM5α humaine ne restreint fortement aucune des capsides de HIV-2 testées provenant d'une cohorte d'individus à “progression rapide“ ou “lente“ vers le SIDA. Cependant nous avons observé une capacité d'infection qui corrélait avec la pathogénicité. Il est intéressant de noter que toutes les capsides d'HIV-2 testées étaient dépendantes de la présence de Cyclophiline A pour leur infection. Toutes ces capsides étaient sensibles à la déplétion de RanBP2, et l'interaction est très probablement médiée par le motif C-ter de RanBP2 qui a une forte homologie avec la Cyclophiline A. En conclusion, il est très probable que des SIV infectant naturellement des singes puissent utiliser les mêmes protéines que HIV-1, pour un éventuel passage inter-espèces. TRIM5α ne semble pas être une barrière efficace aux différents SIV, et l'interaction avec la Cyclophiline A est probablement très conservée par les lentivirus primatesEver since HIV has been discovered to be the pathogenic agent that causes AIDS in 1983, much progress has been made in the field. Two different viruses are now known to infect humans, HIV-1 and HIV-2. These two distinct viruses have many sub-types and clades representing a high diversity inter and intra-individuals (quasi-species). The finding of HIV simian counterparts, the Simian Immunodeficiency Viruses (SIVs), has broadened the knowledge of primate lentiviruses and to date forty-five species of non-human primates are known to be infected with SIVs in sub-saharan Africa. It is now clear that HIV-1 and HIV-2 epidemics are the result of zoonosis from chimpanzees/gorillas and sooty mangabeys, respectively. With such a big diversity of SIVs in the wild and a frequent contact of SIV infected monkey species with humans, it is interesting that so far, only two lineages breached the species barrier and infected human populations. To be able to correctly infect a cell, a lentivirus has to overcome the installed cellular barriers known as restriction factors while at the same time correctly exploiting the established host cellular machinery. Proteins such as TRIM5, APOBEC3, Tetherin/Bst2, SAMHD1 are able to restrict retroviral infections in certain conditions. In this thesis, it has been evaluated the role of TRIM5 proteins and other capsid interacting proteins with a scope to the eventuality of a cross-species transmission infection. The results showed that human TRIM5alpha does not restrict any of the primate lentiviruses tested, and so far, no primate lentivirus is known to be restricted by it. Cyclophilin A binding and dependence is variable depending on the SIV capsid; this interaction is widespread among the primate lentiviruses phylogenetic tree but not a universal phenotype. Different capsids from SIVs have been tested for the sensitivity to the depletion of nucleoporins that are known to be used by HIV-1 in its infection; it has been concluded that the same diversity applies to the interaction with RanBP2 and Nup153. Additionally, we identified a SIV capsid that is highly restricted in human cells; this phenotype was called Ref2. With the report of a possible correlation between HIV-2 capsid variations and different levels of progression to AIDS, we devised a study aiming to identify if TRIM5 proteins were involved in this phenotype. We concluded that human TRIM5alpha does not restrict any HIV-2 capsid obtained from a HIV-2 cohort, in which individuals were presenting different levels of progression to AIDS. However, we observed a different viral fitness that correlated with pathogenicity. Moreover, Cyclophilin A dependence seems ubiquitous among all of the tested HIV-2 capsids. All of these capsids are sensitive to RanBP2 depletion and the interaction is much likely mediated by RanBP2's C-terminal motif that shares a high homology with Cyclophilin A. Summing up, it is much likely that some SIVs that still circulate in the wild can hijack the same specific cellular co-factors as HIV-1 to produce a new epidemic in humans. TRIM5α does not seem to be a potent barrier to an eventual cross-species transmission from lower primates to humans, and Cyclophilin A interaction seems to play a major role to the infection of some SIVs
33
Baup, Delphine. "Identification de gènes préférentiellement exprimés par les cellules dendritiques et évaluation critique d'une approche de transgenèse lentivirale afin d'en étudier la fonction biologique in vivo." Doctoral thesis, Universite Libre de Bruxelles, 2009. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/210209.
Abstract:
A chaque instant notre organisme est confronté à des agents pathogènes de nature très variable. Pourtant, malgré toutes les agressions rencontrées, il maintient une certaine intégrité. Cette dernière résulte de la mise en place d’un système de défense perfectionné, fruit de la collaboration étroite de diverses cellules :le système immunitaire. Parmi toutes les cellules qui le composent, les cellules dendritiques jouent un rôle prépondérant. Disséminées dans la plupart de nos organes et tissus, elles surveillent, en alerte du moindre danger. Elles orchestrent la réponse immune :elles sont capables d'initier et polariser une réponse immune ou d'instaurer la tolérance. De nombreux traitements thérapeutiques tentent d’exploiter leurs capacités intrinsèques. Ces cellules présentent en effet un grand potentiel dans la vaccination anti-tumorale et antivirale, dans l’acceptation de greffes et le contrôle de maladies auto-immunes. Toutefois, de nombreux éclaircissements restent encore à apporter que ce soit sur l’ontogénie des cellules dendritiques, leur rôle ou leur propre biologie. Aussi, le dessein de ce travail était d’approfondir nos connaissances fondamentales sur les propriétés moléculaires et la biologie des cellules dendritiques afin de mieux appréhender la nature et l’amplitude des réponses qu’elles induisent. A cette fin, nous avons identifié deux nouveaux gènes qu’elles expriment préférentiellement et nous avons essayé de caractériser leur fonction. L’avènement de l’utilisation de la technique d’ARN interférence dans les systèmes de mammifères et le développement des vecteurs lentiviraux nous sont apparus comme des outils présentant un réel potentiel pour répondre à nos questions. Nous avons donc généré des souris qui sur- ou sous- expriment le gène d’intérêt, par infection lentivirale d’embryons, pour tenter de cerner son rôle in vivo. Cette méthode de transgénèse était très prometteuse car rapide, efficace, peu onéreuse et sollicitait peu de compétences pour la manipulation des embryons. Cependant, l’approche s’est révélée plus laborieuse que prévu. Nous avons en effet rencontré de nombreux phénomènes de variégation et de « silencing » qui a rendu plus ardue l’utilisation des souris transgéniques. Néanmoins, nous pensons aujourd’hui être à même d’élaborer une stratégie de sélection des souris générées par transgénèse lentivirale qui ne développeraient probablement pas les problèmes rencontrés. Au cours de l’étude, nous avons également observé une fluctuation de l’activité du promoteur CAG pendant le développement thymique, pointant l’importance du choix d’un promoteur optimal en fonction du projet de recherche. Enfin, l’analyse des souris, bien que préliminaire, suggère un rôle potentiel d’un des gènes examinés dans la différenciation, la mobilisation ou la survie des cellules dendritiques, des macrophages et des lymphocytes B.
Doctorat en Sciences
info:eu-repo/semantics/nonPublished
34
Lee, Wei-Cheng. "Studies on lentivirus infection of macrophages." Thesis, University of Edinburgh, 1994. http://hdl.handle.net/1842/29845.
Abstract:
Several aspects of the interaction of macrophages and maedi visna virus (MVV) were undertaken: viral replication, phenotype, phagocytosis and antigen presenting function of macrophages after MVV (EV1) infection. MVV replication in monocyte-derived-macrophages (MDM) showed viral budding sites both at cytoplasmic and vesicular membranes. In contrast, viral budding sites predominantly occurred at the cytoplasmic membrane of skin fibroblasts, whilst virus accumulated in vesicular lumens of MVV-infected alveolar macrophages (AM). Many intracytoplasmic type A (ICA) particles accumulated in the cytoplasm of MDM and AM infected with EV1. Expression of MHC class II, MHC class I, CD4, CD8, LFA-1 and VPM32 antigen on MDM infected in vitro was unaltered by 5 days after MVV infection (P>0.05). In vivo MHC class I, class II (DQ & DR) and LFA-1 expression on AM from MVV infected sheep with lung lesions was greatly increased to uninfected sheep (P<0.05). A significant decrease in the CD4:CD8 ratio in bronchoalveolar lymphocytes was also found in the same group. The phagocytic activity of macrophages after MVV infection was also studied both in vivo and in vitro. There was a decrease in the phagocytic activity for RBC (P<0.05) and yeast by MVV-infected MDM after 5 days post infection, but the FcR expression of MDM assayed by erythrocyte rosetting (ER) did not show a significant difference between MVV and mock infected MDM. In vivo, there was no significant difference in ER, phagocytosis of RBC and P. hemolytica by monocytes between MVV-infected and control sheep. However surface binding and phagocytosis of opsonized P. hemolytica by AM from MVV infected sheep without lung lesions was significantly increased compared to uninfected sheep (P<0.05), but this increase was not seen in ER and phagocytosis of RBC by AM in the same group. In contrast the ER, phagocytosis of RBC and P. hemolytica by AM from sheep with lung lesions was slightly lower, but not significantly different from uninfected sheep.
35
Starling, Isabella. "Mechanisms and specificity of lentivirus neurotoxicity." Thesis, University of Edinburgh, 1998. http://webex.lib.ed.ac.uk/abstracts/starli01.pdf.
36
Burkala, Evan Jon. "Investigations of the Australian bovine lentivirus." Thesis, Burkala, Evan Jon (2001) Investigations of the Australian bovine lentivirus. PhD thesis, Murdoch University, 2001. https://researchrepository.murdoch.edu.au/id/eprint/41607/.
Abstract:
The bovine lentiviruses (BL), Bovine immunodeficiency virus (BIV) and Jembrana disease virus (JDV) are two relatively unknown lentiviruses that produce remarkably different disease syndromes. BIV typically causes a mild and transient lymphocytosis with associated lymphadenopathy in Bos taurus cattle with some suggested mild immune suppression. JDV, on the other hand, is an acutely pathogenic lentivirus causing marked leucopoenia with associated lymphadenopathy and splenomegaly and has an experimental mortality rate of approximately 20%.
Recombinant antigens of both bovine lentivirus including the immunodominant viral proteins, capsid (CA or p26) and transmembrane (TM or p42) envelope proteins were developed using a glutathione-s-transferase fusion protein expressed m a heterologous Escherichia coli expression system. The recombinant proteins were recognised by antisera from experimentally infected animals of the respective viruses but also showed significant cross-reactivity.
The recombinant proteins were used as antigens to develop western immunoblot and ELISA serological assays to identify cattle with antibody to bovine lentivirus with high specificity and sensitivity. An antigenically-related bovine lentivirus was identified in Australian cattle including the states of Queensland, South Australia and Western Austnilia. Sera from random cattle provided by the local agricultural department (AgWA) showed reactivity to BIV and JDV CA antigens with only slight reactivity to TM proteins. Interestingly, serum samples varied in specificity for the BIV or JDV antigens indicating exposure to antigenically variable viruses. Of the 690 Dairy cattle in Western Australia surveyed, approximately 16% by western immunoblot (WIB) and 4% by ELISA were found to have been exposed to an antigenically-related bovine lentivirus. A high percentage (74% by ELISA and 61% by WIB) of WA dairy properties were also found to have at least one animal with bovine lentivirus antibody. Subsequent investigation concluded that bovine lentivirus infection is endemic to Australian cattle herds.
Several herds in Queensland, South Australia and Western Australia with a history of immune suppressive disorders of unknown aetiology were also investigated for the seroprevalence of bovine lentivirus. There was high level of correlation of bovine lentivirus antigen reactivity and the presence of the immune suppressive disease in IX these problem herds. However, the role of bovine lentivirus infection in the cause of the condition was unclear but unlikely to be the cause of such diseases.
A PCR assay was developed that could identify .bovine lentiviruses. Many sets of published PCR primers for the identification of BIV were examined for specificity and sensitivity. Specific primer sets that could identify both of the known bovine lentiviruses and also differentiate between JDV and BIV were determined. The sensitivity of the PCR assay was adequate but showed high specificity to the target.
Attempts to further investigate the Australian bovine lentivirus by in vitro culture and nucleotide sequencing from antibody-positive cattle were unsuccessful. There was an indication that a very low number of lymphocytes contain bovine lentivirus genetic material and most probably contains a divergent nucleotide sequence to that known for the US isolate. In addition, co-culture of peripheral blood mononuclear cells from antibody-positive animals with primary foetal bovine lung cells did not show any significant evidence of BIV replication. For these reasons, it concluded that the PCR assay for BIV based upon US isolates was not applicable to the Australian bovine lentivirus, possibly due to low specificity and sensitivity.
Experimental infection with blood from seropositive cattle commonly caused a mild transient lymphocytosis and mild lymphadenopathy but had no association with apparent clinical disease. Individual animals responded differently to experimental infection ranging from a marked persistent lymphocytosis to a mild and transient lymphocytosis.
As a direct result of this research, there is an increased understanding of the extent of bovine lentivirus infection in Australia and a possible association with immune suppressive disorders present. This study has produced information about the Australian bovine lentivirus that will be the foundation of bovine lentivirus research to determine the effect it may have on the cattle industry in Australia and Indonesia. This study has been valuable for the reagents developed that will be used for the specific surveillance of JDV in Indonesia and vaccination for JDV in Indonesian cattle.
37
Camacho, Emely. "Optimization of Lentivirus Production for Cancer Therapy." Thesis, Uppsala universitet, Institutionen för medicinsk biokemi och mikrobiologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-164715.
Abstract:
Vectors based on lentivirus backbones have revolutionized our ability to transfer genesinto many cell types. Lentiviral vectors integrate into the chromatin of target cells and do not transfer any viral genes causing vector replication. Both of these features arecommonly used in gene therapy and have been used clinically in individuals sufferingfrom cancer, infections and genetic diseases. It has been discovered that T-cells can be genetically modified to be used as effective weapons against cancer: therefore virus mustbe produced to deliver the gene of interest into the T-cells. In this project, lentiviralvectors have been produced to transfer the gene coding for a chimeric antigen receptor(CAR) which is directed to CD19 on B-cells. The vectors will, hence, be used to generateCD19 retargeted T-cells in purpose to kill CD19 cells such as B-cell lymphoma andleukemia. We have evaluated two production protocols to determine a feasible method toculture these vectors. We have also stimulate T-cells with two different antibodies (anti-CD3 and anti-CD28) and transduced T-cells. Our results demonstrate that theconcentration of virus was higher after prolonged incubation in 4˚C, which can not beexplained. The stimulation demonstrated that bound anti-CD3 was the best stimulator,and moreover the FACS-analysis showed that addition of anti-CD28 gave a highertransduction level. In conclusion, the viral vectors may be kept in 4˚C for two days beforeconcentrating the virus, and bound anti-CD3 is a better choice than soluble anti-CD3 forstimulation of T-cells.
38
Parker, Douglas George Anthony, and park0290@flinders edu au. "Lentivirus-mediated gene expression in corneal endothelium." Flinders University. Medicine, 2008. http://catalogue.flinders.edu.au./local/adt/public/adt-SFU20081204.094431.
Abstract:
Modulation of corneal transplant rejection using gene therapy shows promise in experimental models but the most appropriate vector for gene transfer is yet to be determined. The overarching aim of the thesis was to evaluate the potential of a lentiviral vector for use in human corneal transplantation. Specific aims were: (i) to assess the ability of an HIV-1-based lentiviral vector to mediate expression of the enhanced yellow fluorescent protein (eYFP), and a model secreted protein interleukin-10 (IL10), in ovine and human corneal endothelium; and (ii) to examine the influence of lentivirus-mediated IL10 expression on the survival of ovine corneal allografts.
Four lentiviral vectors expressing eYFP under the control of different promoters, were tested: the simian virus type-40 (SV40) early promoter, the phosphoglycerate kinase (PGK) promoter, the elongation factor-1alpha (EF) promoter, and the cytomegalovirus (CMV) promoter. Two lentiviral vectors expressing IL10 were tested: one containing the SV40 promoter and another containing a steroid-inducible promoter (GRE5). Lentivirus-mediated expression in transduced ovine and human corneal endothelium was assessed by fluorescence microscopy, real-time quantitative RT-PCR and ELISA, following alterations of transduction period duration (224 hr) and vector dose, as well as in the presence or absence of polybrene or dexamethasone (GRE5 vector). It was also compared to expression mediated by adenoviral vectors. Orthotopic transplantation of ex vivo transduced donor corneas was performed in outbred sheep. Allografts were reviewed daily for vascularisation and signs of immunological rejection.
Lentivirus-mediated eYFP expression was delayed in ovine corneal endothelium compared to human. However, in both species the final transduction rate was greater than 80% and expression was stable for at least 14 d in vitro. Lentivirus-mediated expression in ovine and human corneal endothelium was higher with the viral promoters in comparison to the mammalian promoters. A 24 h transduction of ovine corneal endothelium with the lentiviral vector encoding IL10 resulted in expression levels which were increasing after 15 d of organ culture but logarithmically lower than those achieved by adenovirus. Shortening the lentiviral transduction period to 2 h led to a reduction in expression, but the addition of polybrene (40 micrograms / ml) to the transduction mixture restored expression to levels comparable to those attained after a 24 h transduction period. Lentivirus-mediated IL10 expression was higher and more rapid in human corneal endothelium compared to ovine corneas. Dexamethasone-responsive transgene expression was observed in both ovine and human corneal endothelium using the lentiviral vector containing the GRE5 promoter. Lentivirus-mediated expression in ovine corneal endothelium was stable for 28 d in vivo. A modest prolongation of ovine corneal allograft survival (median of 7 d) was achieved by transduction of donor corneas for 23 h with the lentivirus expressing IL10. Attempts to increase the expression of IL10 by the addition of polybrene (40 micrograms / ml) to the transduction mixture, resulted in a toxic effect on corneal allografts which abrogated the beneficial effect of IL10.
The lentiviral vector shows potential for the stable expression of therapeutic transgenes in human corneal transplantation. However, the mechanisms underlying the species-specific differences in HIV-1-mediated transgene expression will need to be elucidated and overcome if the ovine preclinical model is to provide justification for a clinical trial.
39
MAZARIN, VERONIQUE. "Etude d'un gene precoce du lentivirus visna." Aix-Marseille 2, 1989. http://www.theses.fr/1989AIX22964.
40
Vink, C. A. "A hybrid lentivirus-transposon vector for safer gene therapy." Thesis, University College London (University of London), 2010. http://discovery.ucl.ac.uk/19233/.
Abstract:
Gene therapy vectors based on the HIV-1 lentivirus are an attractive option for clinical applications because they enter a broad range of target cells efficiently and deliver stable gene expression through integration into host chromosomes. However, lentiviral vectors are known to integrate preferentially within actively transcribing genes. Leukaemia-like expansions observed in gene therapy trials using gammaretroviral vectors and are thought to have been caused by disruption of host proto-oncogenes at or close to the vector integration site, and the safety of these vectors may be related to the pattern of vector integration with respect to genes. The safety of integrating gammaretroviral and lentiviral vectors is therefore a significant concern with respect to their use in gene therapy. In this study, this problem was addressed by developing a novel hybrid vector which combines the efficient cell and nuclear entry properties of lentiviral vectors with chromosomal integration by the Sleeping Beauty transposase. Unlike the HIV-1 integrase enyme, Sleeping Beauty transposase does not exhibit a preference for integration within active genes. Nonintegrating lentiviral vectors were developed to carry Sleeping Beauty transposon and transposase expression cassettes. These were able to deliver transient transposase expression to target cells, and episomal lentiviral DNA was found to be a suitable substrate for integration by Sleeping Beauty transposase. Importantly, integration with this novel vector was found to occur significantly less frequently within active genes than a standard lentiviral vector. Finally, it was shown that the transposase protein can be incorporated into lentiviral vector particles in a manner analogous to HIV-1 integrase. The development of vectors with safer integration patterns may lead to better clinical outcomes for patients treated with gene therapy.
41
Lerondelle, Catherine. "Les infections mammaires à lentivirus chez les petits ruminants." Lyon 1, 1992. http://www.theses.fr/1992LYO10210.
Abstract:
La mammite a lentivirus se manifeste sous deux formes: une forme clinique aigue lors de la mise-bas puis une forme subclinique chronique, la plus frequente. Dans les deux cas, la production est diminuee, voire annulee et le lait reste d'aspect normal. La numeration cellulaire, un mois apres la mise-bas, est peu modifiee. Le virus est mis en evidence a partir des cellules du lait. Les lesions de mammite interstitielle sont observees meme chez les chevrettes de trois mois et les agnelles de 100 jours. Dans les explants de tissu mammaire, la presence du virus est suspectee dans les cellules epitheliales mammaires par apparition de formations syncitiales. Le virus s'exprime dans les macrophages du lait au moment de la mise-bas. L'induction de lactation par injections d'hormones steroides permet de reproduire cette excretion virale dans les cellules du lait. Chez une brebis seropositive, le virus peut etre excrete dans les macrophages du lait d'une demi-mamelle et pas de la seconde. Lors de l'expression du virus, a la mise-bas, le lait contient plus de leucocytes, plus de lymphocytes et en particulier plus de lymphocytes cd8. L'augmentation du nombre de lymphocytes est plus precoce chez les brebis multipares que chez les primipares
42
Bodungen, Uta von. "Immunohistology of the early course of lentivirus-induced arthritis /." [S.l.] : [s.n.], 1996. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.
43
He, Jin. "Lentiviral vectors mechanisms of transgene silencing and functional characterization of novel genes /." [Gainesville, Fla.] : University of Florida, 2004. http://purl.fcla.edu/fcla/etd/UFE0006628.
Abstract:
Thesis (Ph.D.)--University of Florida, 2004.Typescript. Title from title page of source document. Document formatted into pages; contains 143 pages. Includes Vita. Includes bibliographical references.
44
Chettab, Abdelkamel. "Utilisation de constructions plasmidiques pour l'investigation des interactions entre les lentivirus des petits ruminants et leurs hôtes in vivo et in vitro." Lyon 1, 1997. http://www.theses.fr/1997LYO1T107.
45
Rolland, Morgane. "Etude des relations phylogénétiques entre les lentivirus des petits ruminants." Bordeaux 2, 2003. http://www.theses.fr/2003BOR21029.
Abstract:
Les lentivirus des petits ruminants ou SRLV ("small ruminant lentivirus") correspondent au virus mae͏̈di visna ou MVV, qui infecte les moutons, et au virus de l'arthrite-encéphalite caprine ou CAEV ("caprine arthritis-encephalitis Virus"), qui infecte les chèvres. Pour faciliter l'étude des SRLV, nous avons immortalisé des cellules GSM ("goat synovial membrane") par l'expression ectopique de la télomérase. La lignée cellulaire GSM T a proliféré à un rythme constant avec plus de 160 passages en culture, tout en conservaNt la morphologie des cellules GSM primaires. De plus, les cellules GSM T peuvent être infectées soit par le CAEV soit par le MVV et elles reproduisent des phénotypes cytopathiques différents de la souche virale infectante. En parallèle, nous avons optimisé des protocoles de PCR qui permettent d'amplifier l'intégralité de génomes SRLV d'origines caprine et ovine. Pour étudier les relations entre les SRLV à l'échelle mondiale, nous avons effectué des analyses phylogénétiques extensives en ajoutant aux séquences disponibles celles que nous avons caractérisées en Irlande et en Espagne. Le lentivirus irlandais, bien qu'isolé chez une chèvre, est plus proche des souches ovines MVV prototypes. Les séquences des quare lentivirus ovins espagnols se répartissent en trois clades, ce qui reflète la diversité génétique majeure des SRLV observées en Espagne. Les analyses phylogénétiques dans les régions gag, pol et env ont permis de reconsidérer la classification des SRLV, qui se répartissent en cinq clades au lieu des six précédemment décrites. Comme les SRLV ne peuvent pas être distingués phylogénétiquement en fonction de leur hôte, nous proposons d'abandonner la classification MVV/CAEV et de regrouper les lentivirus d'origines caprine et ovine sous le seul terme de SRLVTo facilitate the study of SRLV, we established a GSM T ("goat synovial membrane") cell line by the ectopic expression of telomerase. Cultures of GSM T cells have been passaged over 160 times without showing any phenotypic difference from the original primary GSM cells. Moreover, the immortalized GSM T cells were susceptible to infection by both CAEV and MVV and were able to propagate these viruses. We also optimized a PCR protocol to amplify the SRLV genome as a whole or with two overlapping fragments. To address the genetic diversity and relatedness among SRLV strains worldwide, we applied extensive phylogenetic methods to the sequences available together with our newly characterized sequences from Ireland and Spain. The Irish lentivirus strain, which was isolated from a goat, was more closely related to the lentivirus that infects sheep : MVV. The four Spanish ovine isolates fell in three distinct clusters, which clearly depicted the major genetic variability seen in Spain. Based on the phylogenetic analyses in the gag, pol and env regions, we revise the classification of the SRLV, which could be confidently classified into five clades rather than six as it was previously suggested. Furthermore, we observed that MVV and CAEV sequences could not be phylogenetically distinguished according to their host. Therefore, we propose to group the two viruses more appropriately as SRLV
46
Gourdou, Isabelle. "Le lentivirus Visna : étude de ses gènes de régulation précoces." Aix-Marseille 1, 1990. http://www.theses.fr/1990AIX11291.
Abstract:
Le cycle replicatif du virus visna in vitro comprend une phase precoce de 24 h, au cours de laquelle seuls les arnm sous-genomiques de 1,4 kb et 1,7 kb sont synthetises, et une phase tardive (qui s'acheve 3 jours apres l'infection) ou tous les arnm viraux sont presents. Cette regulation temporelle de l'expression virale est fonction de la presence, dans le genome proviral, de genes supplementaires par rapport aux trois genes de structure retroviraux gag, pol, env. Ainsi, les arnm precoces de 1,4 kb et 1,7 kb portent les genes additionnels tat et rev, dont les produits (tat et rev) trans-activent l'expression des genes viraux via les regions promotrices des sequences ltrs. La proteine rev, synthetisee au temps precoce du cycle lytique, est accumulee dans le compartiment cytoplasmique de la cellule infectee et est aussi associee aux particules virales. La proteine tat possede au niveau de sa sequence, une region homologue a la region riche en cysteines de la proteine tat de hiv-1. Des peptides synthetiques representatifs de ces deux sequences homologues sont chacun, apres injection intracerebroventriculaire (icv) chez la souris, responsables tres rapidement de la mort de l'animal. La proteine native tat de hiv-1, testee par icv, est egalement toxique
47
Puissant, Bénédicte. "Etude de facteurs génétiques susceptibles d'influencer l'infection par les lentivirus." Toulouse 3, 2005. http://www.theses.fr/2005TOU30036.
Abstract:
Chez l'homme et les primates, les facteurs génétiques de l'hôte influencent fortement la sévérité de l'immunodéficience provoquée par les lentivirus VIH humains ou SIV simiens. Notre étude du polymorphisme des gènes de chémokines et de leurs récepteurs chez l'homme révèle que ces gènes n'influencent peu ou pas l'évolution de la maladie traitée. Ces gènes sont polymorphes dans les huit espèces de primates que nous avons étudiées. En dehors des gènes de chémokines et de leurs récepteurs, nous avons étudié, chez l'homme, l'impact du polymorphisme des glycosyltranférases de groupes sanguins et découvert que la fréquence des sujets Lewis positifs était abaissée chez les patients VIH+ par rapport aux témoins, suggérant un rôle protecteur des antigènes Lewis vis-à-vis de l'infection par le VIH. Enfin, la comparaison de la modulation de la transcription génique entre les lymphoblastes CD4+ d'homme et de chimpanzé soumis à l'infection par le VIH-1 nous a permis d'identifier des gènes candidats susceptibles d'être impliqués dans la résistance du chimpanzé à la progression vers l'immunodéficience induite par les VIHHost genetic factors greatly influence the disease progression in human and primates infected with HIV (Human Immunodeficiency Virus) or SIV (Simian Immunodeficiency Virus). We studied the polymorphism of chemokine genes and chemokine receptor genes in human and we showed that these polymorphisms did not influence the virological response to antiretroviral treatment. We also showed that these genes are polymorphic in the eight primate species we studied. We analyzed the polymorphism of blood group glycosyltransferases in HIV-infected patients and we observed that the frequency of Lewis positive individuals was lower among HIV-infected patients than among healthy controls. This could suggest a protective effect of Lewis antigens against HIV infection. Finally, we analyzed the gene expression of human and chimpanzee CD4 T cells infected in vitro by HIV and we identified genes that could explain the resistance of chimpanzee to HIV induced disease
48
Barban, Véronique. "Etude du contenu génétique et de l'expression des lentivirus animaux." Grenoble 2 : ANRT, 1986. http://catalogue.bnf.fr/ark:/12148/cb37595704k.
49
Yoon, Soonsang. "Functional analysis of accessory proteins in equine infectious anaemia virus." Thesis, University of Oxford, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.325550.
50
Haziza, Brice. "Assemblage du lentivirus CAEV et approches vaccinales dans le modèle caprintitre." Aix-Marseille 2, 2000. http://www.theses.fr/2000AIX22033.