HIV establishes a reservoir comprising long lived, latently infected CD4+ T cells and monocytic cells early during primary infection. This population represents a major barrier to an HIV cure. This thesis aimed to investigate the role of the immunological synapse in the failure of cytotoxic T lymphocytes (CTLs) to eliminate the HIV reservoir and the potential for engineered bispecific <b>I</b>mmune-<b>m</b>obilising <b>m</b>onoclonal <b>T</b> cell receptors <b>A</b>gainst <b>V</b>iruses (ImmTAV) to overcome this by redirecting fully functional CD8+ T cells against viral targets. A primary cell model of latency was used to investigate the expression of HIV Gag on latently infected cells and their susceptibility to ImmTAV-mediated elimination. A subset of cells expressed low levels of Gag without spreading infection and ImmTAV-redirected healthy donor CD8+ T cells were able to eliminate up to 40% of infected cells without latency reversal. CD8+ T cells from chronic HIV infected (CHI) donors showed impaired antiviral activity even with ImmTAV redirection. To investigate this further, confocal microscopy was used to study immunological synapse formation using primary CD8+ T cells from HIV-negative and CHI donors. CD8+ T cells from CHI donors were able to form conjugates with virus-infected cells but exhibited impaired synapse maturation, indicated by reduced Zap70 localisation, delayed microtubule-organising centre polarisation and impaired perforin recruitment to the synapse. ImmTAV redirection partially overcame these defects. Finally, the impact of antiretroviral agents on T cell mitochondrial function was explored. Exposure to zidovudine increased mitochondrial reactive oxygen species production and susceptibility to apoptosis. However, there was no evidence of impaired mitophagy. These data show that defects in CD4+/CD8+ T cell synapse maturation contribute to HIV persistence but nevertheless suggest that a subset of HIV reservoir cells may be susceptible to ImmTAV-mediated elimination. The therapeutic potential of ImmTAVs may depend in part on correction of CD8+ T cell exhaustion.

Acquired immune deficiency syndrome (AIDS) was first discovered in the 1980s, since then, human immunodeficiency virus (HIV) infection and AIDS have become global health, social, and economic concerns. HIV was identified as the cause of AIDS in 1985, and this launched a wide-reaching effort to understand its biology. The knowledge acquired from these vast research efforts contributed to the development of modern therapeutic and preventative treatment strategies. According to recent data from the United Nations Program on HIV/AIDS (UNAIDS), the ratio of infected people to AIDS- related deaths has decreased because of the expanding access to antiretroviral drugs (ARVs). The application of ARVs to HIV+ patients increases patients’ lifespans and improves the quality of life. Remaining as an incurable disease, expanding access to antiretroviral drugs and using prevention strategies are the best options to control the HIV pandemic for now. Treatment strategies with ARVs, however, are not sufficient to adequately address the HIV pandemic. Traditional combinational antiretroviral therapies (cART) for HIV treatment are limited by multiple drawbacks such as possible toxicity, limited drug concentrations, drug resistance, and viral rebound. Additionally, inadequate physicochemical properties of ARVs, such as poor solubility, permeability, and bioavailability, lead to limited absorption and biodistribution, resulting in poor clinical outcomes. Patient compliance and suboptimal efficacy lead to the development of resistant viruses and viral reservoirs. The presence of HIV reservoirs would cause viral rebound two to four weeks after terminating treatments. The complexity of reservoir structure, prolonged cell half-life, and the latent HIV viruses complicate HIV treatments iii targeting viral reservoirs. cART exhibits insufficient efficacy towards reservoir sites because of biological barriers and poor physicochemical properties. These problems highlight an urgent need for novel treatment strategies that are safe and effective to address HIV reservoirs. Innovative and improved delivery systems have been proposed over the years, especially lipid-formulations. Lipid formulations have emerged as promising vehicles owing to their ability to encapsulate molecules with poor solubility and bioavailability, improve active targeting, prolong circulation time, and sustain drug release. Cell-mediated delivery strategy have posed the obstacles of insufficient drug transport and safety. Macrophages, the very same cells that carry the HIV virus, could reach tissues that would otherwise have little or no drug penetration. Macrophages can protect drugs from metabolic degradation with large quantities of drugs for delivery. Activated macrophages express the folate receptor, a potential targeting moiety. In this study, I intended to develop a novel folate-decorated nanoemulsion (FA- NE) for the delivery of ARVs to HIV infected macrophages. To reach the goal, I focused on two goals: (1) construction of a nanocarrier capable of encapsulating ARV drugs with physiological properties suitable for use in drug delivery and (2) enhancement of delivery to HIV infected macrophages. In Chapter 2, I discuss the rationale for nanoART for HIV treatments. I introduce current HIV treatments and their drawbacks, notably the viral rebound due to limited drug concentration in viral reservoirs. Then I explain why nanotechnology would be a promising strategy for HIV treatment and provide examples of nanomedicine. In all iv cases, however, cell uptake and drug release were limited or complicated by toxicity, which is a significant issue for a validated delivery system that are safe and effective. In chapter 3, I introduce the design and development of the FA-NE. This system includes (1) an oil core to encapsulate antiretroviral drugs that are highly hydrophobic, (2) a lipid monolayer to protect the oil core and to form nanoemulsion (3) folate for target. The system was prepared using the emulsification solvent evaporation method, developed and optimized based on physical properties, including size, PDI, zeta potential, and other in vitro characterizations, such as encapsulation efficacy, drug loading, stability, and drug release. Chapter 4 is a continuation of the work done in Chapter 3 and focuses on the enhancement of cellular uptake with folate overexpression cell models. A lipopolysaccharide (LPS) activated macrophages was built and utilized for intracellular drug release and retention evaluations. In Chapter 5, cytotoxicity and antiretroviral efficacy studies are described. With the conclusion drawn in Chapter 4, I was curious if the enhanced cellular uptake can be translated into improved efficacy. As a result, collaborated with Dr. Kamel Khalili, School of Medicine, Temple University, we evaluated antiretroviral efficacy with an HIV indicator cell and monocyte-derived-macrophages from human donors. Furthermore, I performed cytotoxicity assay to evaluate this nanoemulsion system safety profile. Chapter 6 summarizes the highlights and conclusions of this project and provides suggestions for the future. / Pharmaceutical Sciences

HIV infection represents a major health and socioeconomic challenge worldwide. Despite significant advances in therapy, a cure for HIV continues to be elusive. The design of novel curative strategies will require targeting and elimination of cells that constitute the latent HIV-1 reservoir. However, such an approach is impeded by the inability to distinguish latently HIV-infected cells from uninfected cells. The type-I interferon (IFN-I) response is an integral antiviral defense mechanism, but is impaired at multiple levels during productive HIV infection. Interestingly, similar global impairments in IFN-I signaling have been observed in various human cancers. This led to the development of IFN-sensitive oncolytic viruses, including the recombinant Vesicular Stomatitis Virus (VSV 51) and Maraba virus (MG1), as virotherapy designed to treat various cancers. Based on this, it was hypothesized that IFN-I signaling is impaired in latently HIV-infected cells (as observed in productively infected cells) and that VSV 51 and MG1 may be able to exploit such intracellular defects to target and eliminate latently HIV-infected cells, while sparing healthy cells. First, using cell line models of HIV-1 latency, intracellular defects in IFN-I responses, including impaired IFN / production and expression of IFNAR1, MHC-I, ISG15, and PKR, were demonstrated to represent an important feature of latently HIV-infected cells. Consistent with this, the latently HIV-infected cell lines were observed to have a greater sensitivity to VSV 51 and MG1 infection, and MG1-mediated killing, than the HIV-uninfected parental cells. Next, the ability of oncolytic viruses to kill latently HIV-infected human primary cells was demonstrated using an in vitro resting CD4+ T cell model of latency. Interestingly, while both VSV 51 and MG1 infection resulted in a significant reduction in inducible p24 expression, a dose-dependent decrease in integrated HIV-1 DNA was only observed following MG1 infection. In keeping with this, MG1 infection of memory CD4+ T cells from HIV-1 infected individuals on HAART also resulted in a significant decrease in inducible HIV-1 gag RNA expression. By targeting an intracellular pathway that is impaired in latently HIV-infected cells, the findings presented in this dissertation highlight a novel, proof-of-concept approach to eliminate the latent HIV-1 reservoir. Given that VSV 51 and MG1 are currently being studied in cancer clinical trials, there is significant potential to translate this work to in vivo studies.

La primo-infection est un moment critique de l’établissement du réservoir justifiant de l’initiation d’un traitement précoce. Nous avons initié un essai randomisé évaluant l’impact de deux ans d’un traitement antirétroviral intense (essai ANRS147 OPTIPRIM, trithérapie versus pentathérapie) sur le réservoir et avons initié des études physiopathologiques au cours de cet essai. Nous montrons ainsi la faible diversité génétique des virus en primo-infection dans les compartiments sanguins et rectaux. Le réservoir s’établit dès le premier mois de l’infection par diffusion d’un cluster viral homogène au sein des lymphocytaires T CD4 naïfs (TN) et mémoires centrales (TCM), transitionnelles (TTM), effectrices (TEM) quiescents. Il en résulte une perturbation de l’homéostasie lymphocytaire associée à une faible contribution au réservoir des cellules peu différenciées à longue demi-vie, TN et TCM. Par ailleurs nous montrons que la majorité des patients au moment de leur primo-infection n’ont pas la capacité de développer des réponses T CD8 à même de supprimer la réplication virale comme chez les patients HIV Controllers. Après deux ans de traitement, nous observons que la diversité virale n’a pas évolué, par contre la taille du réservoir est fortement réduite. Les anomalies de l’homéostasie lymphocytaire T CD4 persistent, par contre le traitement très précoce a permis de protéger les TN et TCM. Il n’y a pas de bénéfice additionnel d’une pentathérapie mais nous avons validé le concept qu’un traitement précoce permet d’induire un contrôle virologique au long cours après arrêt de traitement. Nos résultats indiquent qu’un traitement plus long que deux ans permettrait de renforcer la diminution du réservoir. Ces résultats seront à prendre en compte pour l’élaboration de futurs essais en primo-infection visant à réduire le réservoir pour une rémission au long cours. / HIV primary infection is a critical period in the establishment of the reservoirs that justifies the initiation of an early treatment. We started a randomised trial to assess the impact of a two-year intense HAART (ANRS147 OPTIPRIM trial: five-drug therapy versus. three-drug therapy) on the blood reservoir; within this this trial, we included some pathophysiological studies. Thus, we show that during the primary infection, viruses have a low genetic diversity in blood and rectal compartments. The reservoir establishes itself as early as the first month of the infection by spreading a homogeneous viral cluster in CD4 T cells subsets, naive T cells (TN), central memories (TCM), transitional memories (TTM), effector memories (TEM), and resting T cells. This results in a disruption of the lymphocyte homeostasis, linked to the low contribution to the reservoir of TN and TCM, which are little differentiated cells with long half-lives. Moreover, we show that, at the time of the primary infection, the majority of patients do not have the ability to develop CD8 T cells responses that could suppress the viral replication, as HIV Controllers patients do. After two years of treatment, we observe that there is no evolution of the viral diversity, but the size of the reservoir is significantly reduced. The abnormalities of the CD4 T cells lymphocyte homeostasis remain, but the very early treatment was able to protect the TN and TCM. The five-drug therapy does not have any additional benefit, but we confirm the idea that early treatment can induce long-term virological control after the discontinuation of the treatment. Our results show that a treatment lasting more than two years would be able to reinforce the reduction of the reservoir. These results should be taken into account in the development of future trials aiming to reduce the reservoir in patients treated at the time of primary infection for a sustainable remission.

HIV/AIDS is raging and causing millions of deaths around the world. The major challenge in treating HIV/AIDS is the establishment of HIV reservoirs where the viruse escapes both drug and immune system attempts at eradication. Throughout the course of HIV/AIDS, productive HIV infection occurs primarily in the lymphoid follicles or germinal centers (GC) surrounding follicular dendritic cells (FDC). In the GCs, FDCs trap and maintain infectious HIV for years and provide these infectious viruses to the host cells. FDCs also attract B and T cells into the GCs and increase the ability of CD4+ T cells to be infected. Additionally, FDCs also mediate the increase of HIV replication in HIV-infected CD4+ T cells. Recently, several clinical cases and in vitro studies suggest that alpha-1-antitrypsin (AAT) might inhibit HIV infection and replication. Therefore, I hypothesized that AAT inhibited both the infection and replication of HIV in primary CD4+ T cells. I also postulated that AAT inhibited the FDC-mediated contributions that potentiate HIV infection and replication. To test whether AAT inhibited HIV infection in lymphocytes, CD4+ T cells were pretreated with AAT and then incubated with HIV to detect HIV infection. To exam whether AAT inhibited HIV replication, infected CD4+ T cells were cultured with AAT to detect the replication of HIV. To determine whether AAT blocked the FDC-mediated contributions to HIV pathogenesis, activated or resting FDCs were treated with AAT to detect the trapping and maintenance of HIV. The results suggested that AAT inhibited HIV entry into CD4+ T cells by directly interacting with gp41 and thereby inhibiting the interaction between HIV and CD4+ T cells. AAT also inhibited HIV replication in infected CD4+ T cells. Further study revealed that AAT interacted with low-density lipoprotein-receptor related protein to mediate the internalization of AAT through a clathrin-dependent endocytic process in CD4+ T cells. Subsequently, internalized AAT was transported from the endosome to the lysosome and then released into the cytosol. In the cytosol, AAT directly interacted with IκBα to block its polyubiquitinylation at lysine residue 48, which resulted in the accumulation of phosphorylated/ubiqutinylated IκBα in the cytosol. In turn, the dissociation of IκBα from NF-κB was blocked, which thereby inhibited the nuclear translocation and activation of NF-κB. Additionally, AAT also down-regulated FDC-CD32 and FDC-CD21 expression, which are regulated by NF-kB, thereby inhibiting the trapping and maintenance of HIV on FDCs. Hence, AAT not only suppresses HIV replication, but also blocks HIV replication in CD4+ T cells. Moreover, AAT also inhibits the activation of FDCs thereby affecting the trapping and maintenance of HIV.

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L’obstacle majeur à l’éradication du VIH est l’existence de réservoirs cellulaires du VIH, qui échappent au traitement et à la réponse immunitaire de l’hôte. Ce réservoir s’établit très tôt dans l’infection, menant typiquement à la destruction d’un grand nombre de lymphocytes T CD4+. Cependant, une faible proportion de ces cellules retourne à l’état quiescent en ayant intégré le génome viral. La taille et l’évolution du réservoir chez l’adulte ont été bien élucidées. Cependant, on en sait moins sur la taille et la distribution du réservoir du VIH, et sur l’impact de l’initiation précoce de la thérapie antirétrovirale combinée (TARc) sur ces dernières dans la population infantile. Cet essai s’inscrit dans le cadre de l’étude prospective multicentrique EPIC4 (Early Pediatric Initiation, Canada Child Cure Cohort Study), qui a recruté 221 enfants infectés par la voie verticale dans neuf centres pédiatriques canadiens. Nous soumettons l’hypothèse que l'initiation très précoce de la TARc chez l’enfant infecté par le VIH permettrait de réduire le réservoir à ses plus bas niveaux, menant à un meilleur contrôle de la réplication virale suite à une éventuelle interruption de traitement. Nous avons obtenu des corrélations positives entre la taille du réservoir viral lymphocytaire sanguin du VIH-1 et l'âge de l’initiation de la TARc et l'âge à la suppression virale soutenue (SVS). Les niveaux des réservoirs sont négativement corrélés à la proportion de la vie sous TARc efficace et à la proportion de la vie sous SVS et au compte de lymphocytes T CD4+. Nous avons montré également qu’un traitement initié précocement dans les premiers six mois de vie serait un facteur de prédictions d’une suppression virale plus rapide et plus soutenue. Nos résultats confirment que l’initiation précoce de la TARc et le maintien à long terme de la suppression virale stable sont des facteurs clés conduisant à une taille limitée du réservoir viral. Par ailleurs, nous démontrons pour la première fois que la taille du réservoir inductible du VIH-1 mesurée dans les lymphocytes T CD4+ du sang périphérique après stimulation avec un analogue de prostratine corrèle significativement avec celle mesurée en ADN proviral. Ainsi, nous avons validé une nouvelle technique de mesure de réservoir inductible qui est rapide et moins coûteuse et surtout requiert un faible volume de sang donc semble très prometteuse pour des études sur le VIH-1 pédiatrique. / The major barrier to eradicating HIV is the existence of cellular reservoirs of HIV, which escape the treatment and immune response of the host. This reservoir is established very early in the infection, typically leading to the destruction of a large number of CD4+ T cells. However, a small proportion of these cells return to quiescent state after integrating the viral genome. The size and evolution of the reservoir in adults have been well understood. However, we know less about the size and distribution of the HIV reservoir, and the impact of early initiation of combination antiretroviral therapy (cART) on it in the infant population. Our study is a part of the Early Pediatric Initiation Canada, Child Cure Cohort (EPIC4); a prospective, multicenter study, which enrolled 221 vertically HIV-1 infected children in nine Canadian pediatric centers. We hypothesize that very early initiation of cART in HIV-infected children would reduce the reservoir to its lowest levels, leading to better control of viral replication following a possible interruption of treatment. A strong positive correlation was observed between reservoir size in peripheral blood and both the age at initiation of cART and the age at which sustained viral suppression (SVS) was achieved. We found a strong negative correlation between the size of the viral reservoir and the proportion of life spent on effective cART or the proportion of life with SVS and CD4+ T lymphocytes count. This study shows that starting cART within 6 months from birth is a predictor of faster and more sustained virological suppression in infants. Our findings suggest that early cART initiation in infants and long-term viral suppression are key factors leading to limited viral reservoir size. Furthermore, we established for the first time that the size of the inducible HIV-1 reservoir in peripheral blood CD4+ T lymphocytes of children, quantified by the prostratin analogue stimulation test, correlates with the size obtained using proviral DNA measurement. Thus, we have validated a new inducible reservoir measurement technique that is fast, less expensive, and, importantly requires a lower blood volume. This assay could be very promissing for evaluating inducible HIV-1 reservoirs in pediatric HIV-1 studies.