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<em>In Vivo</em> Regulation of Murine Cytomegalovirus Infections: The Role of Cell Surface Molecules and Mechanisms of Control by Natural Killer Cells: A DissertationTay, Chin Hun 01 July 1997 (has links)
The overall aim of this thesis was to determine how natural killer (NK) cells regulate virus infections in vivo. Anti-viral mechanisms by which NK cells control murine cytomegalovirus (MCMV) infection in the spleens and livers of adult C57BL/6 mice were first studied, revealing different mechanisms of control in different organs. Three days post-infection, MCMV titers in the spleens of perforin-deficient (perforin 0/0) mice were higher than in wild type controls, but no elevation of liver titers was found in perforin 0/0 mice. NK cell depletion in MCMV-infected perforin 0/0 mice resulted only in an increase in liver viral titers but not in spleen titers. Depletion of IFN-γ in adult C57BL/6 mice by injections with mAbs to IFN-γ resulted in an increase in viral titers in the liver but not in the spleen. Analyses using IFN-γ-receptor-deficient (IFN-γR0/0) mice, rendered chimeric with C57BL/6 bone marrow cells, indicated that even though the donor spleen cells could respond to IFN-γ, the depletion of NK cells in a recipient environment where the host cells could not respond to IFN-γ caused an increase in MCMV titers in the spleens but had little effect in the liver. IFN-γ has the ability to induce a variety of cells to produce nitric oxide (NO), and administrating the nitric oxide synthase (NOS) inhibitor Nω-monomethyl-L-arginine (L-NMA) into MCMV-infected adult C57BL/6 mice resulted in MCMV titer increases in the liver but not in the spleen. These data indicate that in adult C57BL/6 mice, there is a dichotomy in the mechanisms utilized by NK cells in the regulation of MCMV in different organs. In the spleen NK cells exert their effects in a perforin-dependent manner, suggesting a cytotoxic mechanism, whereas in the liver the production of IFN-γ by NK cells may be a predominant mechanism in the regulation of MCMV synthesis. These results may explain why the Cmv-1r (Cmv-1-resistant) locus, which maps closely to genes regulating NK cell cytotoxic function, confers an NK cell-dependent resistance to MCMV infection in the spleen but not in the liver.
The ability of adoptively transferred cells to protect suckling mice from MCMV was another model used to study the mechanisms utilized by NK cells in the regulation of MCMV. Adoptive transfers of 129, C57BL/6 and perforin 0/0 spleen cells or lymphokine-activated killer (LAK) cells into 4 - 6 day old MCMV-infected C57BL/6 suckling mice significantly lowered the splenic MCMV titers in these mice compared to the infected controls. Adoptive transfers of C57BL/6 spleen cells into MCMV-infected 129 suckling mice also decreased the amount of MCMV in the 129 suckling mice, but C57BL/6 spleen cells could not regulate MCMV synthesis when adoptively transferred into 129/IFN-γR0/0 suckling mice. These results suggest that, in the suckling mouse model, the regulation of MCMV by the adoptively transferred NK cells is via an IFN-γ-dependent, perforin-independent, Cmv-1-independent mechanism.
The Cmv-1 gene locus resides within the NK gene complex, in close proximity to the Ly49 NK cell receptor family. Analyses were carried out to determine if any of the 4 known Ly49 NK cell receptors (Ly49A, C, D and G2) played a role in the control of MCMV synthesis by NK cells. Studies comparing the expression of the different Ly49 NK cell subsets in the spleen and the peritoneal cavity revealed that there were differences in the distribution of the Ly49 receptors on NK1.1+ cells. Three days post-MCMV infection, the percentage of NK1.1+- Ly49+ NK cells in the spleen and the peritoneal cavity were different than in naive controls. Within the splenic NK1.1+ population, increases in NK1.1+ -Ly49A+ and NK1.1+-Ly49G2+ cells but decreases in NK1.1+-Ly49C+ and NK1.1+-Ly49D+ cells were observed. These changes in the spleen were accompanied by a concomitant decrease in NK1.1+ - Ly49A+ cells and increases in NK1.1+-Ly49C+, NK1.1+-Ly49D+ and NK1.1+-Ly49G2+ cells within the NK1.1+ population in the peritoneal cavity. These data suggest that 3 days post-MCMV infection, there may be movement of NK cells between the different organs. The role of Ly49 NK cell receptors in the regulation of MCMV was tested using adult C57BL/6 mice depleted of single or multiple Ly49 NK cell subsets. These in vivo depletions did not affect the ability of the residual NK cells to regulate MCMV synthesis. LAK cells sorted into the different Ly49 NK cell subsets and adoptively transferred into C57BL/6 suckling mice lowered the splenic MCMV titers in these mice. Together, these results indicate that even though there is a redistribution of the Ly49 NK cell subsets during MCMV infection, the presence or absence of anyone of the 4 tested Ly49 NK cell receptors does not affect the regulation of MCMV by NK cells. However, there remain a possibility that one of the undefined Ly49 receptors or an untested NK cell receptor may be important in the control ofMCMV.
Most of the cloned NK cell receptors have been shown to bind to MHC class I molecules, and MHC class I antigens have been implicated as modulators of target cell sensitivity to NK cell-mediated lysis. The regulation of virus infections and the fate of NK cells and their natural targets was examined in β2-microglobulin-deficient mice [β2m (-/-)], which have defective MHC class I expression. Infections with either the NK cell-sensitive MCMV or the NK cell-resistant lymphocytic choriomeningitis virus (LCMV) significantly augmented NK cell activity in either C57BL/6 or β2m (-/-) mice. Depletion of NK cells in vivo with antiserum to asialo GM1 markedly enhanced the synthesis of MCMV but had no effect on the synthesis of LCMV in either strain of mouse. Adoptively transferred β2m (-/-) spleen cells lowered splenic MCMV titers in C57BL/6 suckling mice, not unlike adoptively transferred C57BL/6 spleen cells. Analysis of naturally NK cell-sensitive thymocyte targets from these virus-infected β2m (-/-) mice revealed no cell surface expression of class I MHC detectable by conformation-dependent or -independent antibodies, but the virus infections enhanced class I expression on thymocytes from C57BL/6 mice. The sensitivity of C57BL/6 thymocytes to NK cell-mediated lysis was markedly reduced after in vivo poly inosinic:cytidylic (poly I:C) treatment or viral infection; in contrast, the sensitivity of the β2m (-/-) thymocytes was significantly less affected by poly I:C or viral infection. These data indicate that the normal expression of MHC class I antigens on NK cells or their targets is not required for the anti-viral functions of NK cells against an NK-sensitive virus (MCMV) nor do they protect an NK-resistant virus (LCMV) from the anti-viral activity of NK cells.
Together, the data presented in this thesis help to further our understanding of the mechanisms utilized by NK cells in the control ofMCMV in both adult and suckling mice, and also help clarify the roles played by Ly49 NK cell receptors and MHC class I molecules in the regulation of MCMV.
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Incidência e caracterização de cistite hemorrágica em pacientes submetidos a transplante de células-tronco hematopoiéticas alogênico no Hospital de Clínicas de Porto AlegreAmaral, Sheila Nogueira do January 2015 (has links)
Introdução: Cistite Hemorrágica (CH) é uma grave complicação do Transplante de Células-Tronco Hematopoiéticas (TCTH) Alogênico. Sua incidência varia de 12 a 25,5%. A forma precoce desenvolve-se devido aos efeitos tóxicos de certos quimioterápicos usados no regime de condicionamento, especialmente Ciclofosfamida. Já a CH tardia ocorre a partir do terceiro dia após o TCTH e sua etiologia é multifatorial. Vários fatores de risco para o desenvolvimento de CH tardia foram descritos, incluindo Doença do Enxerto Contra o Hospedeiro (DECH) aguda, doador não relacionado, infecções por vírus urotrópicos, sexo masculino e condicionamento mieloablativo. Materiais e Métodos: O presente estudo tem como objetivos descrever a incidência de CH em pacientes adultos e pediátricos submetidos a TCTH alogênico e identificar fatores de risco associados ao desenvolvimento de CH nesta população. Foram analisados dados de prontuário de 347 pacientes submetidos a TCTH Alogênico no Hospital de Clínicas de Porto Alegre no período de Janeiro de 2001 a Dezembro de 2014. Resultados: CH ocorreu em 42 pacientes (12,1%, IC: 8,9 - 16%), em uma média de 53.4 dias após o procedimento (desvio padrão: 28.1 dias). Apenas 1 paciente (2,4%) desenvolveu CH precoce, com início dos sintomas no D+1. Entre os 41 pacientes que desenvolveram CH tardia, BK vírus foi o principal agente viral identificado. CH ocorreu em 12.8% dos pacientes que receberam condicionamento mieloablativo e em 10.5% dos restantes (P = 0,704). Dos 197 pacientes que apresentaram DECH aguda, 35 (17,8%) desenvolveram CH e somente 7 (4,9%) apresentaram CH na ausência de DECH aguda (P < 0,001). CH foi mais frequente também em pacientes do sexo masculino (P = 0,027). Conclusão: A incidência de CH em nossa amostra foi semelhante à encontrada em outros trabalhos. DECH aguda e sexo masculino estiveram associados a um maior risco de desenvolvimento de CH. / Introduction: Hemorrhagic cystitis (HC) is a serious complication of Allogeneic Hematopoietic Stem Cell Transplantation (HSCT) afecting 12 to 25.5% of the patients. The early-onset form of HC develops during or until 72 hours after the conditioning regimen containing high doses of certain chemotherapy drugs such as Busulfan and especially Cyclophosphamide. Late-onset HC occurs from the third day on after HSCT and its etiology is multifactorial. Several risk factors for the late-onset form have been reported including graft-versus-host disease (GVHD), unrelated donor, urotropic infections, male gender and myeloblative conditioning regimen. Methods: This study aims to evaluate the incidence of HC in adult and pediatric patients undergoing Allogeneic HSCT and to identify risk factors associated with the development of HC in this population. Medical records of 347 patients who underwent Allogeneic HSCT at Hospital de Clínicas, Porto Alegre, Brazil, from January 2001 to December 2014 were analyzed. Results: HC occurred in 42 patients (12.1% CI: 8.9 - 16%) at an average of 53.4 days after the procedure (standard deviation: 28.1 days). Only one of them developed early-onset HC, with onset of symptoms on D+1. Among the 41 patients who developed late-onset HC, BKV was the main identified viral agent. HC developed in 12.8% of the patients treated with myeloablative conditioning and in 10.5% of the remaining patients (P = 0.704). Of the 197 patients with acute GVHD, 35 (17.8%) developed HC and only 7 (4.9%) showed HC in the absence of GVHD (P<0.001). HC was also more frequent in males than females (P = 0.027). Conclusion: The incidence of HC in our sample was similar to that found in other studies. In our cohort of patients being male and having acute GVHD increased the risk of developing HC.
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The Role of Human Cytomegalovirus Immediate Early Proteins in Cell Growth Control: A DissertationCastillo, Jonathan Patrick 30 October 2002 (has links)
The proper maintenance of the pathways governing cell growth is critical to ensure cell survival and DNA fidelity. Much of our understanding of how the cell cycle is regulated comes from studies examining the relationship between DNA viruses and the mechanisms of cell proliferation control. There are numerous examples demonstrating that viruses can alter the host cell environment to their advantage. In particular, the small DNA tumor viruses, which include adenovirus, simian-virus 40 (SV-40), and human papillomavirus (HPV), can modulate the host cell cycle to facilitate viral DNA replication. Due to the fact that these viruses infect quiescent, non-cycling cells and lack the necessary enzymes and resources to replicate their DNA (e.g. DNA polymerase), the small DNA tumor viruses must activate the host cell replication machinery in order to expedite viral DNA replication. The capacity of these viruses to perturb normal cell proliferation control is dependent upon their oncogene products, which target p53 and members of the Retinoblastoma (RB) family of proteins and inactivate their respective functions. By targeting these key cell cycle regulatory proteins, the small DNA tumor viruses induce the infected host cells to enter S-phase and activate the components involved with host cell DNA synthesis thereby generating an environment that is conducive to viral DNA replication.
In contrast, the larger, nuclear-replicating DNA viruses such as those from the family Herpesviridae, do not share the same stringent requirement as the small DNA viruses to induce the infected host cell to enter S-phase. The herpesviruses encode many of the components to stimulate nucleotide biosynthesis and the necessary factors to facilitate virus DNA replication including a viral DNA polymerase and other accessory factors. Additionally, many herpesviruses encode gene products that arrest the host cell cycle, in most instances, prior to the G1/S transition point. Inducing cells to growth arrest appears to be a prerequisite for the replication of most herpesviruses.
However, in addition to encoding factors that inhibit the cell cycle, many herpesviruses encode proteins that can promote cell cycle progression in a manner similar to the small DNA tumor virus oncoproteins. By targeting members of the RB family and p53 protein, the herpesvirus proteins induce S-phase and activate S-phase associated factors that playa role in DNA replication. In this manner, the herpesviruses may promote an environment that is favorable for DNA replication.
Consistent with the other herpesviruses, human cytomegalovirus (HCMV)induces human fibroblasts to growth arrest. However, in other cell types, virus infection causes cells to enter S-phase. In addition, HCMV replication requires several cellular factors that are present only during S-phase. Furthermore, HCMV induces the activation of S-phase-associated events as well as the increased expression of numerous S-phase genes following infection.
HCMV encodes two immediate early (IE) gene products, IE1-72 and IE2-86, which can interact with members of the RB family of proteins. Additionally, the IE2-86 protein can bind to and inhibit p53 protein function. Given the functional resemblance between the HCMV IE proteins and the oncoproteins of the small DNA tumor viruses, we hypothesized that expression of the HCMV IE proteins could modulate cell cycle control.
Specifically, we determined that expression of either IE1-72 or IE2-86 can induce quiescent cells to enter S-phase and delay cell cycle exit following serum withdrawal. Moreover, IE2-86 mediates this effect in the presence or absence of p53, whereas IE1-72 fails to do so in p53-expressing cells. Furthermore, both IE1-72 and IE2-86 induce p53 protein accumulation that is nuclear localized.
Because IE1-72 fails to promote S-phase entry in cells expressing p53 and induces p53 protein levels, the mechanism by which IE1-72 alters p53 levels was examined. IE1-72 elevates p53 protein levels by inducing both p19ARF protein and an ATM-dependent phosphorylation of p53 at Ser15. IE1-72 also promotes p53 nuclear accumulation by abrogating p53 nuclear shuttling. As consequence of this IE1-72-mediated increase in p53 levels, p21 protein is induced leading to a p21-dependent growth arrest in cells expressing IE1-72.
These findings demonstrate that the HCMV IE proteins can alter cell proliferation control and provide further support to the notion that HCMV, through the expression of its IE proteins, induces S-phase and factors associated with S-phase while blocking cell DNA synthesis, to possibly generate an environment that is suitable for viral DNA replication.
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Incidência e caracterização de cistite hemorrágica em pacientes submetidos a transplante de células-tronco hematopoiéticas alogênico no Hospital de Clínicas de Porto AlegreAmaral, Sheila Nogueira do January 2015 (has links)
Introdução: Cistite Hemorrágica (CH) é uma grave complicação do Transplante de Células-Tronco Hematopoiéticas (TCTH) Alogênico. Sua incidência varia de 12 a 25,5%. A forma precoce desenvolve-se devido aos efeitos tóxicos de certos quimioterápicos usados no regime de condicionamento, especialmente Ciclofosfamida. Já a CH tardia ocorre a partir do terceiro dia após o TCTH e sua etiologia é multifatorial. Vários fatores de risco para o desenvolvimento de CH tardia foram descritos, incluindo Doença do Enxerto Contra o Hospedeiro (DECH) aguda, doador não relacionado, infecções por vírus urotrópicos, sexo masculino e condicionamento mieloablativo. Materiais e Métodos: O presente estudo tem como objetivos descrever a incidência de CH em pacientes adultos e pediátricos submetidos a TCTH alogênico e identificar fatores de risco associados ao desenvolvimento de CH nesta população. Foram analisados dados de prontuário de 347 pacientes submetidos a TCTH Alogênico no Hospital de Clínicas de Porto Alegre no período de Janeiro de 2001 a Dezembro de 2014. Resultados: CH ocorreu em 42 pacientes (12,1%, IC: 8,9 - 16%), em uma média de 53.4 dias após o procedimento (desvio padrão: 28.1 dias). Apenas 1 paciente (2,4%) desenvolveu CH precoce, com início dos sintomas no D+1. Entre os 41 pacientes que desenvolveram CH tardia, BK vírus foi o principal agente viral identificado. CH ocorreu em 12.8% dos pacientes que receberam condicionamento mieloablativo e em 10.5% dos restantes (P = 0,704). Dos 197 pacientes que apresentaram DECH aguda, 35 (17,8%) desenvolveram CH e somente 7 (4,9%) apresentaram CH na ausência de DECH aguda (P < 0,001). CH foi mais frequente também em pacientes do sexo masculino (P = 0,027). Conclusão: A incidência de CH em nossa amostra foi semelhante à encontrada em outros trabalhos. DECH aguda e sexo masculino estiveram associados a um maior risco de desenvolvimento de CH. / Introduction: Hemorrhagic cystitis (HC) is a serious complication of Allogeneic Hematopoietic Stem Cell Transplantation (HSCT) afecting 12 to 25.5% of the patients. The early-onset form of HC develops during or until 72 hours after the conditioning regimen containing high doses of certain chemotherapy drugs such as Busulfan and especially Cyclophosphamide. Late-onset HC occurs from the third day on after HSCT and its etiology is multifactorial. Several risk factors for the late-onset form have been reported including graft-versus-host disease (GVHD), unrelated donor, urotropic infections, male gender and myeloblative conditioning regimen. Methods: This study aims to evaluate the incidence of HC in adult and pediatric patients undergoing Allogeneic HSCT and to identify risk factors associated with the development of HC in this population. Medical records of 347 patients who underwent Allogeneic HSCT at Hospital de Clínicas, Porto Alegre, Brazil, from January 2001 to December 2014 were analyzed. Results: HC occurred in 42 patients (12.1% CI: 8.9 - 16%) at an average of 53.4 days after the procedure (standard deviation: 28.1 days). Only one of them developed early-onset HC, with onset of symptoms on D+1. Among the 41 patients who developed late-onset HC, BKV was the main identified viral agent. HC developed in 12.8% of the patients treated with myeloablative conditioning and in 10.5% of the remaining patients (P = 0.704). Of the 197 patients with acute GVHD, 35 (17.8%) developed HC and only 7 (4.9%) showed HC in the absence of GVHD (P<0.001). HC was also more frequent in males than females (P = 0.027). Conclusion: The incidence of HC in our sample was similar to that found in other studies. In our cohort of patients being male and having acute GVHD increased the risk of developing HC.
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Detecção e monitorização da infecção ativa pelo citomegalovirus humano (HCMV) pelas tecnicas de antigenemia, Nested-PCR e Real-time PCR em pacientes submetidos a transplante alogenico de celulas tronco hematopoeticas / Detection and monitoring of active human cytomegalovirus infectio (HCMV) by antigenemia, Nested-PCR and Real-time PCR assays in allogenic hematopoietic stem cell transplantation patientsPeres, Renata Maria Borges 14 August 2018 (has links)
Orientador: Sandra Cecilia Botelho Costa / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-14T05:42:16Z (GMT). No. of bitstreams: 1
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Previous issue date: 2009 / Resumo: O citomegalovírus humano (HCMV) é um vírus cosmopolita pertencente à família Herpesviridae, subfamília Betaherpesvirinae. É amplamente disseminado na população, com soroprevalência entre 40 e 100%. Sua transmissão se dá através do contato direto com secreções contendo o vírus como: sêmen, secreção cervical, urina, saliva, leite materno, hemoderivados e também através de transplante de órgãos e tecidos. Durante a infecção primária o HCMV apresenta intensa replicação e em seguida estabelece um estágio de latência no hospedeiro. Periódicas reativações ocorrem em situações de estresse, imunossupressão, doenças auto-imunes e uso de quimioterápicos. O impacto desta infecção em receptores de Transplante de Células Tronco Hematopoéticas (TCTH) é grande podendo causar pneumonia intersticial, doença no trato gastrointestinal, hepatite, mielossupressão, retinite, nefrite, encefalite, atraso da pega medular, doença do enxerto contra hospedeiro, infecções por outros organismos oportunistas, aceleração da perda do enxerto e óbito. Por este motivo, é de suma importância o uso de técnicas laboratoriais, suficientemente sensíveis e específicas, capazes de fazer o diagnóstico precoce da infecção ativa pelo HCMV e estudos mais aprofundados sobre a real relação e correlação clínica que estas técnicas apresentam a fim de prevenir o aparecimento da doença pelo HCMV e demais complicações associadas ao HCMV. Neste estudo foram monitorizados semanalmente, 30 pacientes submetidos a TCTH do tipo alogênico desde o dia do transplante até o dia 150 pós-transplante pelas técnicas de antigenemia, Nested-PCR e Real-time PCR. O tratamento precoce com medicamento antiviral foi iniciado a partir dos seguintes resultados: = 1 célula pp65 positiva/3x105 leucócitos e/ou 2 ou mais Nested-PCR positivas consecutivas. O cut-off da Real-time PCR para a infecção ativa pelo HCMV foi padronizado neste estudo, sendo de 418,39 cópias virais/104 leucócitos periféricos. Vinte e sete pacientes (90%) apresentaram infecção ativa pelo HCMV, com maior incidência durante o segundo mês pós-TCTH. Destes 27 pacientes, 21 (77,78%) foram submetidos ao tratamento precoce com Ganciclovir, 18 (66,67%) apresentaram infecções oportunistas, 11 (40,74%) tiveram DECH aguda, 9 pacientes (33,33%) tiveram infecção ativa recorrente pelo HCMV, 5 (18,52%) tiveram rejeição crônica do enxerto, 2 (7,4%) desenvolveram doença pelo HCMV e 11 (40,47%) evoluíram a óbito, sendo 1 (3,7%) por doença por HCMV associado a DECH aguda e infecção bacteriana. O teste mais precoce para o diagnóstico da infecção ativa pelo HCMV foi a Nested-PCR com mediana de 33 dias pós-TCTH, seguido pela Real-time PCR e antigenemia, ambas com mediana de 40 dias pós-TCTH. A Real-time PCR foi o teste mais sensível (S=92,3%) e que apresentou melhor valor preditivo negativo (VPN=85,71%) para o diagnóstico da infecção ativa pelo HCMV. Já a antigenemia foi o teste mais específico (E=77,77%) e que apresentou melhor valor preditivo positivo (VPP=84,61%) para este diagnóstico. Os testes utilizados no estudo foram eficazes no monitoramento da infecção ativa pelo HCMV, pois somente 2 (7,4%) dos 27 pacientes que apresentaram infecção ativa pelo HCMV desenvolveram doença por HCMV. / Abstract: Human cytomegalovirus (HCMV) is a member of the Herpesviridae family and Betaherpesvirinae subfamily. HCMV is distributed worldwide, with prevalence of HCMV-positive antibodies of 40% to 100%. Transmission occurs during close personal contact with secretions of infected persons such as: semen, cervical secretions, urine, saliva, breast milk, blood products and transplanted organs and hematopoietic stem cell. During primary infection occurs intense replication followed by latent infection in host. Periodic reactivations occur in stress situations, immunosuppression, autoimmune diseases and use of chemotherapy. The impact of HCMV infection on recipients HSCT is large and can cause pneumonitis, gastrointestinal diseases, hepatitis, marrowsuppression, retinitis, nephritis, encephalitis, delay of bone marrow engraftment, severe acute graft-versus host disease (GVHD), opportunistic infections, chronic rejection and death. For this reason it is extremely important the use of sensitive and specific methods for early diagnostic of active HCMV infection and deeper studies about the real clinical relation and correlation these techniques show in order to prevent the disease through HCMV and further complications connected to HCMV. In this study 30 patients recipients of allogenic HSCT were monitored at weekly intervals from D+0 to D+150 post-transplant by antigenemia, Nested-PCR and Real-time PCR. Antiviral preemptive therapy was initiated upon a result = 1 positive pp65 cell/3x105 of PML and/or two or more consecutive positive Nested-PCR. The optimal cut-off value by Real-time PCR for active HCMV infection was 418,39 copies/104 of PBL. Twenty seven (90%) patients had active HCMV infection, with the highest incidence occurring during the second month after HSCT. Twenty one (77,78%) of the 27 patients who had active HCMV infection received preemptive antiviral therapy with Ganciclovir, 18 (66,67%) had opportunist infection, 11 (40,74%) had acute graft-versus host disease (GVHD), 9 (33,33%) had recurrence of HCMV infection, 5 (18,51%) had chronic rejection, 2 (7,4%) developed HCMV disease and 11 (40,47%) died, one (3,7%) by HCMV disease associated with GVHD and bacterial infection. The most precocious test for diagnostic of active HCMV was Nested-PCR after a median of 33 days after HSCT followed by Real-time PCR and antigenemia, both with a median of 40 days after HSCT. Real-time PCR was the most sensitive (Sensitive=92,3%) and with the best predictive negative value (PNV=85,71%) for diagnostic of active HCMV infection. Antigenemia was the most specific (Specific=77,77%) and with the best predictive positive value (PPV=84,61%) for this diagnostic. The three assays utilized in this study were effective in active HCMV infection surveillance because only 2 (7,4%) of 27 patients that had active HCMV infection had HCMV disease. / Universidade Estadual de Campi / Ciencias Basicas / Mestre em Clinica Medica
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Citomegalovírus, herpesvírus humano 6, herpesvírus humano 7 e perfil imunofenotípico do infiltrado inflamatório na periodontite crônica marginal / Cytomegalovirus, human herpesvirus 6, human herpesvirus 7 and immunophenotypic profile of inflammatory infiltrate in marginal chronic periodontitisThomasini, Ronaldo Luís, 1978- 11 April 2011 (has links)
Orientador: Sandra Cecília Botelho Costa / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-19T10:22:52Z (GMT). No. of bitstreams: 1
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Previous issue date: 2011 / Resumo: Periodontite humana crônica é um processo inflamatório caracterizado por denso acúmulo de células imunes no tecido periodontal. A periodontite pode levar a perda do dente no paciente e a patogênese desta doença não é completamente conhecida. Este estudo testou a hipótese de que as células do infiltrado inflamatório podem abrigar betaherpesviruses e estes vírus estão ligados á subpopulação específicas de linfócitos. Fragmentos de tecido periodontal foram obtidas de pacientes afetados por periodontite e de indivíduos saudáveis. Imuno-histoquímica foi realizada para a contagem de células CD19+, céulas CD3+ e células CD4+ e CD8+. Reação em cadeia da polimerase e imuno-histoquímica foram realizados para detectar citomegalovírus, herpesvirus humanos 6 e 7 nas amostras. Como esperado, os tecidos coletados de indivíduos saudáveis não apresentaram nível significativo de infiltrado inflamatório e, portanto, foram excluídos dos procedimentos de imunofenotipagem. Os resultados mostraram que células CD19+ foram discretamente predomiantes sobre as células CD3+ no tecido periodontal afetado, mas estatisticamente não significativo. A subpopulação CD4+ de linfócitos estava significativamente em maior número que a subpopulação CD8+ de linfócitos (P=0,004), nas amostras. Citomegalovírus e herpesvírus humano 7 foram encontrados em locais afetados, mas não no tecido coletado de indivíduos saudáveis (P=0,04 e P=0,04, respectivamente). Herpesvirus humano 6 foi raramente detectado. Foi encontrado correlação entre citomegalovírus com menor relação de CD19+/CD3+ (P=0,003) e herpesvirus humano 7 com menor relação CD19+/CD3+ (P=0,003) e maior relação de CD4+/CD8+ ( P=0,002). Imuno-histoquímica foi negativa para citomegalovírus, herpesvirus humano 6 e herpesvirus humano 7 em todas as amostras. Este estudo mostra que citomegalovírus e herpesvírus humano 7 podem estar presentes em regiões afetadas pela periodontite, mas são incomuns em regiões saudáveis. Além disso, este estudo sugere que citomegalovírus pode ser relacionado ao infiltrado inflamatório, com predomínio de células CD3+ e, herpesvirus humano 7 pode estar relacionado ao infiltrado inflamatório com predomínio de células CD4+. Os dados sugerem que citomegalovírus e herpesvírus humano 7 podem estar presentes no infiltrado inflamatório, em estado de latência. No entanto, outros métodos deveriam ser realizados para confirmar esta hipótese / Abstract: Human chronic periodontitis is an inflammatory process characterized by dense accumulation of immune cells in the periodontal tissue. The periodontitis can lead to loss of teeth in the patient and the pathogenesis of this disease is not completely known. This study tested the hypothesis that cells within inflammatory infiltrate can harbor betaherpesviruses and these viruses are linked to specific lymphocyte subpopulation. Biopsies of periodontal tissue were taken from periodontitis affected and from healthy subjects. Immunohistochemistry was performed to count CD19+ cells, CD3+ cells, CD4+ and CD8+ cell subsets. Polymerase chain reaction and immunohistochemistry were performed to detected cytomegalovirus, human herpesvirus 6 and 7 in the samples. As expected, tissues collected from healthy subjects presented no significant level of inflammatory infiltration and therefore were excluded from immunostaining procedures. The results showed that CD19+ cells had discrete predominance over CD3+ cells in the periodontitis affected tissue but not statistically significant. CD4+ lymphocyte subset were significantly higher then CD8+ lymphocyte subset (P=0.004) in the samples. Cytomegalovirus and human herpesvirus 7 were found in affected sites but not in tissue collected from healthy subjects (P=0.04 and P=0.04, respectively). Human herpesvirus 6 was rarely detected. We found a correlation between cytomegalovirus with lower CD19+/CD3+ ratios (P=0.003) and human herpesvirus 7 with lower CD19+/CD3+ ratio (P=0.003) and higher CD4+/CD8+ ratios (P=0.002). Imunohistochemistry was negative for cytomegalovirus, human herpesvirus 6 and human herpesvirus 7 in the total of samples. This study shows that cytomegalovirus and human herpesvirus 7 can be present in periodontitis affected sites but are uncommon in healthy sites. Moreover, this study suggests that cytomegalovirus can be related to inflammatory infiltrate with predominance of CD3+ cells and, human herpesvirus 7 can be related to inflammatory infiltrate with predominance of CD4+. The data suggest that cytomegalovirus and human herpesvirus 7 could be present in the inflammatory infiltrate in latent state. However, different methods should be performed to confirm this hypothesis / Doutorado / Ciencias Basicas / Doutor em Clínica Médica
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Diagnostico e genotipagem de citomegalovirus humano (HCMV) em receptores pediatrico de transplante de rim ou celulas tronco hematopoeticas / Diagnosis and genotyping of Human Cytomegalovirus in renal or haematopoetic stem cell pediatric transplant recipientsDieamant, Debora de Campos 23 August 2006 (has links)
Orientador: Sandra Cecilia Botelho Costa / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas / Made available in DSpace on 2018-08-07T12:27:03Z (GMT). No. of bitstreams: 1
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Previous issue date: 2006 / Resumo: A partir de 1960, com a evolução nos processos cirúrgicos para transplante, a infecção pelo HCMV começa a ser reconhecida como uma doença de importância clínica, sendo considerado o principal agente patogênico em hospedeiros com o sistema imunológico comprometido. Foi iniciada, em 1980, a utilização de medidas para o controle do vírus com agentes antivirais e intervenções imunológicas, e atualmente, os avanços para a compreensão dessa virose estão relacionados aos aspectos moleculares da infecção e controle clínico, principalmente nos grupos de risco. Sabendo-se da importância do diagnóstico precoce da infecção ativa e da identificação das linhagens de HCMV em pacientes transplantados por sua possível relação com a infectividade e apresentação clínica, este trabalho teve como objetivos principais: (1)Diagnosticar e monitorizar a infecção ativa por HCMV em receptores pediátricos de transplante de rim ou medula óssea em seguimento no Hospital de Clínicas da UNICAMP e no Centro Infantil Boldrini;(2)Determinar a prevalência dos subtipos gB de HCMV na população estudada;(3)Avaliar a relação de uma determinada linhagem com o quadro clínico, apresentado pelos pacientes estudados, durante a infecção ativa e doença por HCMV. Para o diagnóstico da infecção ativa por HCMV, foram analisadas amostras de sangue de 42 pacientes transplantados pediátricos, atendidos no Hospital de Clínicas da UNICAMP e Centro Infantil Boldrini, com idade entre 2 a 18 anos, sendo que 19 deles eram receptores de transplante renal e os outros 23, receptores de transplante de medula óssea. Foram utilizadas técnicas rápidas e precoces de diagnóstico: Antigenemia e Nested-PCR A identificação das diferentes cêpas do HCMV foi feita a partir do DNA de pacientes que apresentaram antigenemia e/ou 2 ¿Nested PCR¿ consecutivos positivos para a região IE do vírus. Para a genotipagem também foi utilizada a Nested-PCR para a amplificação da glicoproteína B seguida da análise de restrição com as enzimas Rsa I e Hinf I para que fosse possível a identificação da linhagem viral.A infecção ativa por HCMV foi diagnosticada em 20 (47,6%) dos 42 pacientes estudados, sendo 5/20 (21,7%) receptores de células tronco hemeatopoética e 15/20 (79%) receptores de transplante de rim. Deste pacientes que apresentaram infecção ativa pelo HCMV fizemos a genotipagem através de uma amostra positiva de sangue. Para os pacientes que apresentaram recorrência da infecção (5/20) a análise do genótipo viral foi feita nos dois períodos da infecção, caracterizando, em todos os casos, reatiavação viral. Como resultados da genotipagem tivemos uma prevalência do genótipo 1, encontrado em 45% (9/20) dos pacientes infectados pelo HCMV, sendo 7/15 receptores de rim e 2/5 receptores de células tronco hemetopoéticas. O Genótipo 2 também teve uma frequência considerável entre este pacientes apresentando uma prevalência de 25% (5/20) e sugeriu estar relacionado com um quadro clínico mais grave e reativação viral após tratamento. A mistura de linhagens também foi encontrada em 30% (6/20) dos pacientes estudados, gB1gB2 (3/6), gB1gB4 (2/6) e gB2gB3 (1/6). Os pacientes que apresentaram como linhagem viral a mistura de linhagens apresentaram melhor prognóstico da infecção ativa pelo HCMV. Os genótipos 3 e 4 não foram encontrados isoladamente em nenhuma amostra genotipada dos pacientes estudados / Abstract: Human cytomegalovirus (HCMV) remains the most important cause of serious viral infections in pediatric transplant recipients. In these patients, early diagnosis of active HCMV infection is important since the development of HCMV disease may be prevented. Ganciclovir has been established as an effective treatment agent for active infection by HCMV. HCMV disease can occur from infection acquired by the transplanted organ or from re-activation of latent infection. The risk is highest within 2 months of transplantation. Several risk factors for disease have been identified and include: HCMV-positive donor, HCMV-negative recipient, lack of anti-viral prophylaxis, and receipt of cadaveric kidney or type of bone marrow transplant. Intense immunosuppression has also been implicated. For discriminate patients with active infection from those without such infection, tests that include the pp65 antigenemia assay (AGM) and DNA detection methods are describle. The polymarase chain reaction (PCR) is a sensitive method for detection of HCMV DNA and active infection. The HCMV antigenemia assay is a rapid and quantitative method widely used as a guideline for starting treatment with ganciclovir. Genetic variability of functionally important genes among different virus strains may influence clinical manifestations of HCMV infections. These variabilities, mainly of the glycoprotein B (gB) gene of the viral envelope, appear to be of clinical relevance because they are assumed to play an essential role in the induction of immune response and in viral entry into host cells, and it has been considered as a potential marker for viral virulence. Based on the restriction analysis of PCR products (PCR-RFLP), the HCMV genotypes were determined previously, and it may possibly be helpful in predicting the clinical outcome of HCMV infection. The aim of this study were detect and monitoring active HCMV infection in pediatric patients recipients of renal or bone marrow transplantation using DNA detection and antigenemia tests and to study the prevalence of subtypes gB-HCMV in this patients and the clinical impact. Twenty patients (47.6%) were infected during the monitoring with N-PCR and/or AGM. Recurrent infection occurred in five out of 20 patients(25%). One of these patient (20%) had done bone marrow transplantation and four patients (80%) had renal transplant. The median time of the recurrent infection was 122 days (89-134). The patients that received ganciclovir prophylaxis had active HCMV infection and probable HCMV disease. Fourteen out of 20 patients (70%) developed probable HCMV disease. Three out of (21.4%) these patients were recipients of bone marrow transplantation and eleven (78.6%) were recipients of renal transplant. T he symptoms more frequent in these patients were fever, diarrhea and vomit. This symptoms associate with active HCMV infection were considered probable HCMV disease. Nested-PCR amplification and restriction enzyme digestion of the HCMV gene were performed in 20 patients with active HCMV infection and results in differentiation of four digestion patterns as previously demostrated (Chou and Dennison, 1991). The genotypes founds were: nine patients (45%) were compatible with the gB1 genotype; five (25%) were gB2 and six patients were mixture of gB types. In the patients that demostrated mixture of gB types, 3 (50%) were compatible with the gB1gB2; two (33.3%) were compatible with gB1gB4 and one (16.7%) were compatible with gB2 gB3. No found isolated gB3 and gB4 genotype in the patients studied. / Mestrado / Mestre em Farmacologia
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Two strategies for prevention of cytomegalovirus infections after liver transplantationSimon, Philipp, Sasse, Max, Laudi, Sven, Petroff, David, Bartels, Michael, Kaisers, Udo X., Bercker, Sven January 2016 (has links)
Aim: To analyze differences in patients’ clinical course, we compared two regimes of either preemptive therapy or prophylaxis after liver transplantation. Methods: This retrospective study was reviewed and approved by the institutional review board of the University of Leipzig. Cytomegalovirus (CMV) prophylaxis with valganciclovir hydrochloride for liver transplant recipients was replaced by a preemptive strategy in October 2009. We retrospectively compared liver transplant recipients 2 years before and after October 2009. During the first period, all patients
received valganciclovir daily. During the second period all patients included in the analysis were treated following a preemptive strategy. Outcomes included one year survival and therapeutic intervention due to CMV viremia or infection. Results: Between 2007 and 2010 n = 226 patients underwent liver transplantation in our center. n = 55 patients were D+/R- high risk recipients and were excluded from further analysis. A further 43 patients had to be excluded since CMV prophylaxis/preemptive strategy was not followed although there was no clinical reason for the deviation. Of the remaining 128 patients whose data were analyzed, 60 received prophylaxis and 68 were treated following a preemptive strategy. The difference in overall mortality was not significant, nor was it significant for one-year mortality
where it was 10% (95%CI: 8%-28%, P = 0.31) higher for the preemptive group. No significant differences in blood count abnormalities or the incidence of sepsis and infections were observed other than CMV. In total, 19 patients (14.7%) received ganciclovir due
to CMV viremia and/or infections. Patients who were treated according to the preemptive algorithm had a significantly higher rate risk of therapeutic intervention with ganciclovir [n = 16 (23.5%) vs n = 3 (4.9%), P = 0.003)].
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Rôles des kinases IKK et IKK-related dans les maladies inflammatoires chroniques : implications dans l’athérosclérose et la réponse hypoxiqueGravel, Simon-Pierre 12 1900 (has links)
L’inflammation est un procédé complexe qui vise l’élimination de l’agent causal de dommages tissulaires en vue de faciliter la réparation du tissu affecté. La persistance de l’agent causal ou l’incapacité à résoudre l’inflammation mène à un dérèglement homéostatique chronique qui peut avoir une incidence sur la morbidité et la mortalité. L’athérosclérose est une condition inflammatoire chronique des vaisseaux sanguins dont l’origine est multifactorielle. L’hypertension et l’état infectieux représentent respectivement des facteurs de risque classiques et émergents du développement de cette maladie. Les fondements initiaux de l’inflammation font intervenir l’immunité innée, la première ligne de défense dont disposent les cellules pour répondre à un signal de danger. Le but de cette thèse est d’examiner le rôle pro-inflammatoire d’une famille de kinases essentielles à l’immunité innée, soit celle des kinases de IkappaB (IKK) et des kinases IKK-related. Les kinases IKKalpha et IKKbeta forment le complexe IKK avec la molécule adaptatrice NEMO/IKKgamma. Ce complexe est chargé d’effectuer la phosphorylation de l’inhibiteur de NF-kappaB, IkappaBalpha, ce qui mène à sa dégradation et à la libération du facteur de transcription NF-kappaB. Nous montrons que le peptide vasoactif angiotensine II (AngII) induit l’activité phosphotransférase d’IKKbeta dans les VSMC par immunoprécipitation de NEMO puis essai kinase in vitro. Grâce à une approche ARN interférence (ARNi) dirigée contre IKK, nous montrons que cette kinase est responsable de la phosphorylation de p65/RelA. Nous montrons que le mécanisme d’induction de NF-kappaB par l’AngII est atypique, puisqu’il ne module pas IkappaBalpha, et montrons à l’aide d’inhibiteurs pharmacologiques que l’activation de p65 est indépendante des voies MEK-ERK-RSK, PI3K et de la transactivation du récepteur de l’EGF. Les kinases IKK-related Tank-binding kinase 1 (TBK1) et IKK-i sont quant à elles principalement activées suite à une infection bactérienne ou virale. Ces kinases phosphorylent directement le facteur de transcription interferon regulatory factor (IRF)-3. Nous montrons que le cytomégalovirus humain, un pathogène associé à l’athérosclérose, a la capacité d’induire l’activation de TBK1 dans les VSMC. L’usage d’ARNi dirigé contre TBK1 et IKKi montre que les 2 kinases sont impliquées dans l’activation d’IRF-3. De plus, nous montrons à l’aide d’une lignée de VSMC exprimant une version dominante négative d’IRF-3 que ce dernier est essentiel à la synthèse des chimiokines RANTES et IP-10, tel qu’analysé par RT-PCR. Par ailleurs, il a récemment été montré que les kinases IKK-related étaient étroitement liées à la transformation oncogénique, et que TBK1 était pro-angiogénique. Or, l’angiogenèse est le plus souvent modulée par la réponse hypoxique qui est d’ailleurs commune à la majorité des processus inflammatoires. Le facteur de transcription hypoxia inducible factor (HIF)-1 module l’angiogenèse, l’inflammation et la survie cellulaire. Nous montrons à l’aide de cellules Tbk1 et Ikbke -/- et d’une approche lentivirale que TBK1 est spécifiquement impliquée dans l’induction traductionnelle de HIF-1alpha en condition de stress hypoxique. L’expression de TBK1 est induite sous ces conditions, et cette kinase module la phosphorylation de ERK, RSK, Akt et TSC1. Les résultats originaux présentés dans cette thèse montrent donc que les kinases IKK et IKK-related exercent leurs actions pro-inflammatoires par des mécanismes distincts. / Inflammation is a complex process that allows elimination of tissular damaging agents and thus facilitates wound repair. Persistance of a damaging agent or the incapacity to resolve the inflammatory state leads to chronic homeostatic deregulation with putative incidence on morbidity and mortality. Atherosclerosis is an inflammatory state of blood vessels which origins are multifactorial. Hypertension and the infectious state represent classical and emerging factors of atherosclerosis development, respectively. The innate immune response takes place in the initial steps of inflammation, and represents the first cellular line of defense against danger signals. The goal of this thesis is to examine the pro-inflammatory roles of the IkB kinases (IKK) and the IKK-related kinases, which are essential innate immune response protein kinases. IKKalpha and IKKbeta form, together with NEMO/IKKgamma, the IKK complex. This complex is responsible of the phosphorylation of the inhibitor of NF-kappaB, IkappaBalpha, a process that leads to its degradation and NF-kappaB release. By immunoprecipitation of NEMO and assessment of the IKK complex activity in vitro, we show that the vasoactive peptide angiotensin II (AngII) induces IKKbeta phosphotransferase activity in vascular smooth muscle cells (VSMC). The use of RNA interference (RNAi) against IKKbeta reveals that this kinase is responsible for p65/RelA phosphorylation. AngII modulation of NF-kappaB is atypical since it does not modulate IkappaB. Moreover, the use of pharmacological inhibitors shows that p65 induction is independent of both MEK-ERK-RSK and PI3K pathways, and that it does not involve EGF receptor transactivation. IKK-related kinases Tank-binding kinase 1 (TBK1) and IKK-i are known to be induced by bacterial and viral infections. These kinases are able to phosphorylate directly interferon regulatory factor (IRF)-3 transcription factor. Human cytomegalovirus (HCMV) seropositivity was shown to be linked to atherosclerosis development. We show that TBK1 activity is induced in HCMV-infected VSMC. RNAi directed against TBK1 and IKK-i reveals that both kinases are required for IRF-3 activation. The use of a VSMC line that express a dominant negative version if IRF-3 shows that this transcription factor is involved in the induction of RANTES and IP-10 chemokines, as assessed by RT-PCR. In addition, IKK-related kinases were recently shown to be implicated in oncogenic transformation. TBK1 was also shown to be pro-angiogenic. Angiogenesis is known to be regulated by the hypoxic response, a common condition of inflammatory processes. Hypoxia-inducible factor (HIF)-1 is a transcription factor that modulates angiogenesis, inflammation and cell survival. We show with the use of Tbk1 and Ikbke -/- cells combined with the use of a lentiviral approach that TBK1 is specifically involved in HIF-1alpha translational induction under hypoxic stress. We also show that TBK1 expression is enhanced under theses conditions, and that this kinase modulates the phosphorylation of ERK, RSK, Akt and TSC1. In conclusion, the results presented in this thesis show that the IKK and IKK-related kinases are both pro-inflammatory, and exert their actions by distinct mechanisms.
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Influence of HCMV proteins pUL71 and pUL77 on viral maturationMeissner, Christina Sylvia 01 December 2011 (has links)
Die Bildung infektiöser Viruspartikel des humanen Zytomegalievirus (HCMV) ist ein mehr-stufiger Prozess. Sie beginnt mit der Verpackung der DNA in die Kapside im Kern, gefolgt von weiterer Reifung während des Transports durch das Zytoplasma und der abschließenden Freisetzung aus der Zelle. Im Zuge dieser Arbeit wurden zwei Proteine, die Einfluss auf die ebengenannten Prozesse haben, analysiert. Der erste Teil der Arbeit befasst sich mit der funktionellen Charakterisierung des HCMV Pro-teins pUL77. Es ist bekannt, dass das homologe Protein pUL25 in alpha-Herpesvirinae essentiell für die DNA-Verpackung ist. Zunächst konnte das Protein als Kapsid-assoziiertes strukturelles Protein identifiziert werden. Es wurden Interaktionen von pUL77 mit DNA-Verpackungs- und Kapsidproteinen gezeigt. Weiterhin wurde die DNA-Bindungsfähigkeit von pUL77 in verschiedenen „in vitro“-Experimenten untersucht. Zusammengefasst weisen unsere Ergebnisse auf eine Funktion von HCMV pUL77 bei der DNA-Verpackung hin. Im zweiten Teil der Arbeit wurde das HCMV Protein pUL71 charakterisiert, das in allen Herpesviren konserviert vorkommt, dessen Funktion jedoch nicht charakterisiert ist. Zunächst wurde das Protein als strukturelles Tegumentprotein mit “earlylate“ Expressionskinetik klassifiziert. Weiterhin wurden die subzelluläre Lokalisation sowie virale und zelluläre Interaktionspartner untersucht. Die Ergebnisse weisen auf eine Funktion von HCMV pUL71 bei der Reifung und beim Transport der Virionen im Zytoplasma hin. „In silico“-Vorhersagen zeigten ein „Leuzin Zipper“-Motiv in pUL71, das als mögliche Oligomerisationsdomäne dienen könnte. Mutationen wurden in dieses Motiv eingebracht und die resultierenden Proteine auf ihre Oligomerisationsfähigkeit mit „in vitro“-Methoden und in rekombinanten Viren untersucht. Zusammenfassend konnten wir zeigen, dass das „Leuzin Zipper“-Motiv wichtig für die Funktion von pUL71 ist und diese mit einer unbeeinträchtigten Oligomerisation des Proteins zusammen hängt. / The morphogenesis of Human cytomegalovirus (HCMV) virions starts with the capsid assem-bly and DNA insertion in the nucleus followed by maturation during transport through the cytoplasm prior to release of virus progeny. In this study we are functionally characterising two proteins that are involved in those steps. The function of essential HCMV protein pUL77 is characterised in the first part of the study. HCMV pUL77 was shown to be a structural protein associated with capsids. Furthermore, our experiments demonstrated that HCMV pUL77 interacts with DNA packaging motor compo-nents and capsid proteins. The ability of HCMV pUL77 to bind double-stranded DNA was studied in “in vitro” assays designed for this study. The homologue α-Herpesvirinae protein pUL25 is described to be involved in processes connected with DNA packaging. Data ob-tained in this study demonstrates that HCMV pUL77 might serve a similar function. In the second part of the study HCMV pUL71, conserved throughout the Herpesvirus family but to date unclassified, was functionally characterised. HCMV pUL71 was defined a struc-tural tegument protein with early-late expression kinetics. We studied the sub-cellular local-isation and interactions of pUL71 with a subset of cellular and viral proteins. Thereby we could show that HCMV pUL71 function might be connected with processes of viral egress. By in silico analyses we identified a leucine zipper motif in pUL71 that might serve as a puta-tive oligomerisation domain. In order to investigate the function of the leucine zipper motif, we performed in vitro assays and investigated the alterations of the motif in the viral context. Taken together we can conclude that (i) an intact leucine zipper motif is crucial for the func-tion of pUL71 and (ii) this function is dependent upon undisturbed oligomerisation of the pro-tein.
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