Diss. (sammanfattning) Stockholm : Karol. inst. / Härtill 6 uppsatser.

There are currently an estimated 33.2 million people living with human immunodeficiency virus (HIV) worldwide. For these individuals, long-term use of combination antiretroviral therapy (cART) is not feasible for a variety of reasons including major adverse complications, multi-drug resistance, poor adherence, and high cost. Hence, development of novel therapeutic strategies that can reduce the life-long dependency on cART is highly desired. In order to develop effective therapeutic strategies such as a therapeutic vaccine, we need to have a greater understanding of the immune correlates of viral control in chronic HIV infection. In this thesis, we used treatment interruption (TI) as a tool to test the efficacy of several therapeutic approaches and immune parameters for their association with effective control of viral replication. / In Chapter 2 we showed that cART intensification and Remune vaccination resulted in reduced viral load (VL) plateau during sequential TIs. Although HIV-specific immune responses measured by interferon-gamma (IFN-gamma) enzyme-linked immunospot assay (ELISPOT) increased in the same time frame, neither their breadth nor magnitude correlated with the decrease in VL plateau. In Chapter 3 the effect of ALVAC-vCP1425 plus Remune vaccination on HIV proteome-wide HIV-specific responses was monitored using a dual color IFN-gamma/interleukin-2 (IL-2) ELISPOT assay. We observed an increase in the magnitude of HIV-specific IFN-gamma/IL-2 responses, as well as in the breadth of Gag-specific IFN-gamma responses in the vaccinated groups compared to placebo groups. A shift towards an increased contribution of Gag-specific responses to total HIV-specific vaccine induced immune response was associated with longer delay to viral rebound during TI. In Chapters 4 and 5, we examined baseline pre-TI immune parameters and their association with viral rebound and CD4 count change during TI in HIV-infected individuals in the chronic phase of infection experiencing virologic failure before TI (Chapter 4) or with different levels of VL control while on therapy prior to TI (Chapter 5). We saw that chronic antigen stimulation from persistent viremia as well as co-infections such as with cytomegalovirus are associated with T-cell senescence, which may result in less favourable clinical outcomes during TI. / Consequently, results from this thesis contribute to further understanding of immune correlates of viral control in chronic HIV infection. New therapeutic vaccines and interventions should induce polyfunctional HIV-specific immune responses, broad Gag-specific immune responses, as well as reducing chronic antigen stimulation to prevent irreversible T-cell exhaustion. Taken together, these insights could potentially lead to the development of novel treatment interventions that could effectively control viral replication off cART.

No description available.

Throughout history, human populations have continuously been challenged by new and emerging infectious diseases. For the past 26 years, sub-Saharan Africa and other countries around the world have been dealing with a pandemic caused by a relatively new pathogen called the human immunodeficiency virus (HIV). Although antiretroviral (ARV) therapies effectively reduce morbidity and mortality rates, the long term use in those who have access to treatment inevitably leads to drug-related toxicity and resistance. Even with a strong commitment from governments to expand and finance prevention and treatment programs, transmission rates continue to outpace the benefits of these efforts. Therefore to effectively eradicate the disease, research is focusing on the design of protective and therapeutic vaccines. The first major step in designing these alternative therapies is to define correlates of immune protection. / The research presented in this thesis focuses on characterizing the quantitative and qualitative features of T cell immune responses in individuals who spontaneously control viral replication and exhibit a benign course of disease while remaining off ARV therapy. A comprehensive analysis of HIV-specific IFN-gamma secreting immune responses revealed that neither the breadth nor the magnitude of responses directed against the entire HIV proteome accurately predicts the viral load or rate of CD4 decline. Subsequent analyses showed that the preferential targeting of Gag was associated with reduced rates of CD4 decline and was later confirmed in a cohort of individuals in primary infection whereby the relative breadth and magnitude of Gag p24 was inversely correlated with viral load set point. / The maintenance of polyfunctional immune responses in HIV-infected subjects with a benign course of disease prompted us to develop a method that could comprehensively assess the breadth, magnitude and specificity of three functionally distinct subsets of HIV-specific lymphocytes (single IFN-gamma, single IL-2 and dual IFN-gamma/IL-2 secretors). Survey of immune responses in chronically infected individuals revealed that only the breadth and magnitude of dual IFN-gamma/IL-2 secreting lymphocytes correlated with reduced viral loads and increased CD4 counts suggesting that secretion of IFN-gamma alone was a poor correlate of protection. We also showed that the contribution of polyfunctional lymphocytes to the total response was greater for epitopes restricted by major histocompatibility complex (MHC) class I alleles associated with slow disease progression compared to those restricted by alleles associated with rapid or neutral rates of HIV disease progression. / Taken together, this work supports the view that immune monitoring of infected and vaccinated individuals should include methodologies capable of detecting both IFN-gamma and IL-2 secretion from responding T lymphocytes. The studies presented here have furthered our understanding of what constitutes protection from disease progression emphasizing that both specificity and polyfunctionality are features of effective control of viral replication.

No description available.

Understanding the host response immediately following mucosal HIV-1 infection will be pivotal in determining whether the immune response induced by a vaccine will successfully sense and control viral replication. In order for effective vaccine strategies and modalities to be developed, these earliest immunological events must be fully assessed in a non-biased manner. Nonhuman primates (NHP), specifically Rhesus macaques (RM), serve as a model to investigate the immunological landscape immediately post-challenge and to define the spatiotemporal path of simian immunodeficiency virus (SIV). SIV infection of RM serves as a model of human HIV infection as it recapitulates many of the virological, immunological, and pathological features of HIV infection in the human host. In this thesis I will test the hypothesis whether transcriptional analysis will allow a sensitive measure of the early innate immune responses that accompany detection of the SIV virus in the periphery. I have determined that an early inflammatory profile arises early in tissues proximal to the challenge site that precedes widespread immune activation and the systemic antiviral interferon response. This study defines in detail the spatiotemporal relationship between virus and host immune response and may be a valuable resource in guiding future vaccine design strategies. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

Pacientes infectados pelo HIV apresentam resposta de imunogenicidade menor àquela obtida pela população geral com a imunização de rotina. A vacina meningocócica C conjugada é indicada para essa população, não existindo pesquisas prévias que avaliassem a imunogenicidade desta, para esse grupo específico. O estudo realizou essa avaliação comparando a resposta vacinal entre os pacientes infectados e não infectados pelo HIV, as relações dessa resposta com parâmetros clínicos e laboratoriais da infecção pelo vírus e os eventos adversos à vacinação. Utilizou-se as técnicas ensaios de anticorpos bactericidas séricos ou ação bactericida no soro (SBA) e o enzyme-linked immunosorbent assay (ELISA). Tratou-se de um ensaio clínico, envolvendo 92 pacientes, com idades entre 10-20 anos, sendo 43 infectados e 49 não infectados pelo HIV. Após a vacinação, 72,1% do grupo HIV+ e 100% do grupo HIV- foram considerados protegidos. Os pacientes do grupo HIV+ não respondedores à vacinação foram revacinados, tendo sido respondedores a essa nova dose 40% destes. Portanto, 81,4% dos pacientes infectados pelo HIV adquiriram proteção com a vacina (após uma ou duas doses). Foi encontrada correlação da resposta vacinal com o número de esquemas antirretrovirais previamente utilizados e carga viral pré-vacinação, não havendo outras associações com os demais parâmetros clínicos e laboratoriais da infecção pelo HIV. Pacientes com adequada resposta vacinal tenderam a ser os de menor idade. Efeitos colaterais ocorreram em 16,3% no grupo HIV+ e em 44% no HIV-. Conclui-se que a vacina meningocócica C conjugada é segura e efetiva para uso em adolescentes e adultos jovens com aids, embora a resposta de anticorpos seja menor do que a observada em indivíduos saudáveis. Isso indica a necessidade de discussão de novos esquemas de imunização em infectados pelo HIV, objetivando uma proteção mais efetiva contra doença meningocócica / Children and adolescents infected with HIV typically have a weaker response to immunization in comparison with the healthy population. The meningococcal C conjugate vaccine is routinely recommended for those individuals. No studies, however, have evaluated the antibody response to this vaccine in HIV-infected patients yet. In this study, we compared the antibody response to the meningococcal C conjugate vaccine between HIV-infected and HIV-uninfected patients using the serum bactericidal antibody assay (SBA) and the enzyme-linked immunoabsorbent assay (ELISA). Additional objectives were to determine whether the acquired immunity correlated with clinical and laboratory features of HIV infection, and to evaluate the vaccine side effects in this population. This clinical trial included 92 patients aged 10 to 20 years old: 43 HIV-infected and 49 HIV-uninfected patients. After one single dose of the vaccine, 72.1% of the HIV-infected and 100% of the HIV-uninfected patients were considered protected. Of the HIV-infected patients (non-responders in first dose) who received a second dose of the vaccine, only 40% reached protective antibody levels. Overall, 81.4% of the HIV-infected patients reached protective antibody titres (after one or two doses of the vaccine). The antibody response in HIV-infected patients correlated with the number of prior antiretroviral therapy schedules and with the pre-vaccination viral load, but with no other clinical features or laboratory tests. Patients with adequate vaccinal response tended to be younger. Side effects occurred in 16.3% and 44% of the HIV-infected and HIV-uninfected groups, respectively. In conclusion, the meningococcal serogroup C conjugate vaccine proved to be safe and effective in HIV-infected adolescents and young adults, although their antibody response was weaker than that of HIV-uninfected patients. These results suggest that the immunization schedule for HIV-infected patients should be re-evaluated, in order to assure more effective protection against the meningococcal disease in this population

Pacientes infectados pelo HIV apresentam resposta de imunogenicidade menor àquela obtida pela população geral com a imunização de rotina. A vacina meningocócica C conjugada é indicada para essa população, não existindo pesquisas prévias que avaliassem a imunogenicidade desta, para esse grupo específico. O estudo realizou essa avaliação comparando a resposta vacinal entre os pacientes infectados e não infectados pelo HIV, as relações dessa resposta com parâmetros clínicos e laboratoriais da infecção pelo vírus e os eventos adversos à vacinação. Utilizou-se as técnicas ensaios de anticorpos bactericidas séricos ou ação bactericida no soro (SBA) e o enzyme-linked immunosorbent assay (ELISA). Tratou-se de um ensaio clínico, envolvendo 92 pacientes, com idades entre 10-20 anos, sendo 43 infectados e 49 não infectados pelo HIV. Após a vacinação, 72,1% do grupo HIV+ e 100% do grupo HIV- foram considerados protegidos. Os pacientes do grupo HIV+ não respondedores à vacinação foram revacinados, tendo sido respondedores a essa nova dose 40% destes. Portanto, 81,4% dos pacientes infectados pelo HIV adquiriram proteção com a vacina (após uma ou duas doses). Foi encontrada correlação da resposta vacinal com o número de esquemas antirretrovirais previamente utilizados e carga viral pré-vacinação, não havendo outras associações com os demais parâmetros clínicos e laboratoriais da infecção pelo HIV. Pacientes com adequada resposta vacinal tenderam a ser os de menor idade. Efeitos colaterais ocorreram em 16,3% no grupo HIV+ e em 44% no HIV-. Conclui-se que a vacina meningocócica C conjugada é segura e efetiva para uso em adolescentes e adultos jovens com aids, embora a resposta de anticorpos seja menor do que a observada em indivíduos saudáveis. Isso indica a necessidade de discussão de novos esquemas de imunização em infectados pelo HIV, objetivando uma proteção mais efetiva contra doença meningocócica / Children and adolescents infected with HIV typically have a weaker response to immunization in comparison with the healthy population. The meningococcal C conjugate vaccine is routinely recommended for those individuals. No studies, however, have evaluated the antibody response to this vaccine in HIV-infected patients yet. In this study, we compared the antibody response to the meningococcal C conjugate vaccine between HIV-infected and HIV-uninfected patients using the serum bactericidal antibody assay (SBA) and the enzyme-linked immunoabsorbent assay (ELISA). Additional objectives were to determine whether the acquired immunity correlated with clinical and laboratory features of HIV infection, and to evaluate the vaccine side effects in this population. This clinical trial included 92 patients aged 10 to 20 years old: 43 HIV-infected and 49 HIV-uninfected patients. After one single dose of the vaccine, 72.1% of the HIV-infected and 100% of the HIV-uninfected patients were considered protected. Of the HIV-infected patients (non-responders in first dose) who received a second dose of the vaccine, only 40% reached protective antibody levels. Overall, 81.4% of the HIV-infected patients reached protective antibody titres (after one or two doses of the vaccine). The antibody response in HIV-infected patients correlated with the number of prior antiretroviral therapy schedules and with the pre-vaccination viral load, but with no other clinical features or laboratory tests. Patients with adequate vaccinal response tended to be younger. Side effects occurred in 16.3% and 44% of the HIV-infected and HIV-uninfected groups, respectively. In conclusion, the meningococcal serogroup C conjugate vaccine proved to be safe and effective in HIV-infected adolescents and young adults, although their antibody response was weaker than that of HIV-uninfected patients. These results suggest that the immunization schedule for HIV-infected patients should be re-evaluated, in order to assure more effective protection against the meningococcal disease in this population