The lack of an animal model that recapitulates the prominent features of HIV-1 infection in humans limits the search for preventative and curative strategies against HIV-1. As stated by the National Institutes of Health (NIH), developing highly pathogenic simian-human immunodeficiency viruses (SHIVs) that can establish persistent infections and AIDS progression in rhesus macaques (RMs) remains vital for advancing the field. The HIV-1 envelope (Env) serves as a major target in vaccine studies. SHIVs - which are chimeras of the simian immunodeficiency virus (SIV) backbone and a humanized Env, are utilized for preclinical evaluation of vaccines and therapeutics aimed at targeting the Env glycoprotein. However, SHIVs presently available poorly infect RM due to weak binding interactions between Env and rhesus CD4 (rhCD4). Position 375 (Env375) lies within the rhCD4 binding pocket of HIV-1 Env. Accordingly, substituting the wild-type (WT) amino acid in Env375 for bulky hydrophobic and/or basic amino acids may strengthen Env-rhCD4 interactions. These mutations should increase the pathogenicity of our original SHIV challenge stocks (SHIV162p3 and SHIVAE16) and allow for the development of an animal model that closely mirrors HIV-1 acquisition and chronic AIDS infection in humans. OBJECTIVES: To develop an animal model that recapitulates HIV-1 infection and AIDS progression in humans. MATERIALS AND METHODS: SHIV design involved insertion of human env sequences into a modified SIV backbone (provided by Dr. George Shaw, University of Pennsylvania). Site-directed mutagenesis was employed to introduce amino acid substitutions at Env375 for the following residues: serine, histidine, methionine, tryptophan, tyrosine, and phenylalanine. These constructs were then utilized for transfection of human embryonic kidney cells (293T) with viral supernatants collected 72 hours post-transfection. 293T viral supernatants were then used to infect human and rhesus PBMCs with the resulting supernatant harvested every three days and subjected to ELISA to monitor viral growth. Viruses were further characterized by RT-PCR for quantification and TCID50 assays to determine infectious dose. Resulting SHIVs were then used for challenge studies in rhesus macaques. Sixteen rhesus macaques were divided into groups of four that received the following SHIV challenge stocks: (1) original SHIV162p3, (2) modified SHIV162p3, (3) original SHIVAE16, and (4) modified SHIVAE16. Following infection, animal plasma and sera were collected and subjected to post-challenge analyses such as cellular assays and measurements of plasma viral RNA levels. RESULTS: Several analyses were conducted to study the pathogenicity of the modified SHIV162p3 and SHIVAE16 relative to the original stocks. Regarding SHIV infectivity, several versions of the modified SHIVs exhibited greater in vitro infectivity titers than the original stocks. Additionally, preliminary viral load analyses conducted in vivo indicate that all sixteen RMs challenged with original and modified SHIVs were infected at comparable levels. Furthermore, CD4+ T cell counts were measured and all sixteen animals exhibited declines in CD4+ T cell percentages. CONCLUSION: In sum, the modified SHIVs may improve animal models by closely recapitulating the events of HIV-1 infection in humans and serve better for future studies of preventative and curative treatments against HIV-1. / 2019-07-11T00:00:00Z

Production of an effective vaccine and long-term treatment against human immunodeficiency virus (HIV) is elusive. In this thesis two different techniques were used in an attempt to insert HIV-neutralising monoclonal antibody (IgG1b12) sequences into a simian retroviral gene therapy agent pseudo-typed with vesicular stomatitis virus glycoprotein. Genes were encoded in either a poxvirus split-vector system or a baculovirus expression system. Both systems aim to produce replication incompetent pseudotyped virus like particles with simian origin. It is believed that the resulting non-infectious artificial lentivirus particles enter neighbouring cells, penetrate the nucleus and insert genetic material (the antibody gene) into the mammalian genome. The poxvirus split-vector system used in this project was a Vaccinia Retroviral Hybrid Vector, where recombinant modified vaccinia Ankara (MVA) is used to deliver the simian immunodeficiency virus (SIV) like particles into mammalian cells. However, the MVA system failed to express proteins of interest due to the instability of genetic insertion into the recombinant MVA genome. As an alternative strategy, two different BacMam systems were used to allow the production of VLPs, where mammalian cells are co-transduced with different recombinant baculoviruses (rBVs). VLPs were expressed either under the control of T7 RNA polymerase system or under the cytomegalovirus immediate early gene promoter. The results from the first BacMam system indicated that the T7 RNA polymerase system was not suitable to express detectable levels of proteins. The results indicated that translation of the produced mRNA by T7 promoter is inefficient, most likely because of the absence of RNA 5’ cap structure. To overcome this hybrid BV–T7 system limitation, a different system was developed. Proteins of interest from the second BacMam system were successfully expressed and detected using western blot analysis. VLPs were generated and visualised under electronic microscope. IgG1b12 was secreted in the supernatant of the transduced mammalian cells. Mammalian cells were successfully transduced with multiple different recombinant BVs simultaneously. The study establishes the feasibility of antibody gene transfer, and demonstrates the use of SIV like particles production to transduce mammalian cells using BacMam technology. The technique may have application for use as an immunotherapy of HIV infection as well providing long-acting prevention of HIV infection for those not yet infected with HIV.

<p>Problematiken för anskaffning av standardsystem inom en verksamhet kan bli omfattande,</p><p>särskilt ifall företaget tar förhastade beslut, och därmed blir anskaffningen en belastning</p><p>istället för tvärtom. Metodutvecklingen för anskaffningen av standardsystem är ett område</p><p>som inte är utforskat i stor utsträckning. Idag finns det en generell metod som används vid</p><p>anskaffning av standardsystem. Metoden kallas för SIV-metod (Standardsystem i</p><p>verksamheter) och har utvecklats av bl.a. Anders G. Nilsson i samband med ett projekt som</p><p>drevs inom institutet V i Stockholm i början av 1990-talet. SIV-metoden har inte utvecklats</p><p>färdigt och behöver därför prövas i fler praktiska fall. Syftet med denna uppsats är ta fram</p><p>metoden och pröva den i praktiken för att se hur pass användbar den är. Vi har arbetat med</p><p>företaget Koneo i Växjö som är ett IT - relaterat företag och har varit i behov av att</p><p>anskaffa ett standardsystem som i deras fall handlade om ett kundvårdssystem, CRM</p><p>(Customer Relationship Management).</p><p>I vår studie har vi tillämpat SIV-metoden för att se hur användbar den är i praktiken. Efter</p><p>genomgånget projekt kan vi konstatera att metoden är användbar i den mening att den ger</p><p>vägledning och tar vara på de grund delar som ingår i processen vid anskaffning av</p><p>standardsystem.</p> / <p>The problems that occur when obtaining or realising Standardsytem within an organisation,</p><p>can be exhaustive if the enterprise rushes to a desicion. Furthermore, this practical</p><p>application could be a burden instead of an opportunity. The method for obtaining realising</p><p>a standardsystem is an area that has not been studied to any greater extents. In the present,</p><p>the SIV-method (SIV: Standardsystem in business) is a general method used in the</p><p>relization of a standardsystem. The SIV-method has been developed by amongst others,</p><p>Anders G. Nilsson, in a project assigned by the V institute in Stockholm, Sweden. The</p><p>reason for this thesis is that the SIV-method is not considered complete and therefore we</p><p>will attempt to investigate this in a practical case. The purpose of this thesis is to test the</p><p>Siv-method in an organisations process for acquiring a standardsystem.</p><p>This research is co-operated in with the enterprise of Koneo. That is in need of a</p><p>standardsytem that concerns and operates the intergration of a Customer Relation</p><p>Managment system, CRM- system. After accomplishing our project we can establish that</p><p>SIV-method is useful, by means of that it takes into consideration main parts of the process</p><p>when obtaining a standardsystem.</p>

While the human immunodeficiency virus (HIV) can be managed with antiretroviral therapy (ART), there is no cure for the disorder. If ART is discontinued, viral RNA levels rapidly increase in most individuals due to the presence of a cell-mediated hidden replication competent viral burden known as the viral reservoir. In order to successfully cure this disease, a mechanism to eliminate the viral reservoir must be developed. Preliminary research completed using a toll-like-receptor agonist 7 (TLR7) has shown favorable results supporting this goal. In a simian immunodeficiency virus (SIV) model, dosing rhesus macaques (RMs) with TLR7 agonists resulted in the development of controlled viremia. A controlled RM is a SIV positive animal that is able to maintain an undetectable viral load without continued therapeutic intervention. In cases of controlled SIV/HIV, viral RNA no longer replicates despite the discontinuation of all treatment. This implies that the viral reservoir is either completely eliminated or severely reduced. In this study, we quantified expression levels of several immune checkpoint and activation markers including CD69, CD39, CXCR5, TCF7, PD-1, PD-L1, TIGIT, CTLA-4, Tim-3, and Lag-3 on isolated peripheral blood mononuclear immune cells (PBMCs) [including CD4+ T cells, CD8+ T cells, natural killer (NK) cells, and B cells] in both controlled and non-controlled RMs. Our goal was to identify possible mechanisms by which controlled RMs are able to successfully modulate the host immune response after discontinuing TLR7 agonist treatment. The subjects each received one of two different TLR7 agonists (GS-9620 and GS-986). Isolated peripheral blood mononuclear cells (PBMCs) were obtained from two controlled RMs and two non-controlled RMs. Samples were analyzed using flow cytometry to identify and quantify levels of markers above. Expression levels of PD-1 and PD-L1 were elevated in PBMCs obtained from non-controlled RMs when compared to levels seen in controlled RMs. In contrast, levels of TIGIT and CTLA4 were downregulated in samples obtained from the controlled RMs. This suggests that immune checkpoint markers responsible for viral control and SIV/HIV pathogenesis have different functional roles. Additionally, the controlled RMs showed high expression of CD69 and CD39 on B cells and increased levels of CXCR5 on CD4+ T cells. This suggests that newly activated B cells likely contribute to the observed improvements in immune function. The results obtained provide favorable support for the potential role of immune checkpoint blockade as an HIV-specific immunotherapy that may contribute to the development of a controlled population. However, it is worthwhile to note that this study was completed using a relatively small sample size (n=4). Thus, interpretations of the findings herein must be replicated with a larger sample prior to forming any definitive conclusions.

Thesis advisor: Welkin E. Johnson / For lentiviruses such as HIV-1, the viral capsid protein (CA) plays a crucial role in replication by facilitating active transport across nuclear pore complexes (NPCs). Nucleoporin Nup358/RanBP2 – a large, multidomain protein that comprises the main component of cytoplasmic NPC filaments – was previously identified as a potential cofactor for HIV-1 nuclear entry, and its C-terminal cyclophilin-like domain (Nup358Cyp) is able to interact with the CA of both HIV-1 and HIV-2. The importance of this interaction to viral replication is unclear though as certain cell-culture experiments suggest CA interaction with Nup358Cyp is dispensable for viral replication, and the CA of several other lentiviruses like SIVmac do not appear to interact with the Nup358Cyp domain. However, we have found that CA interaction with Nup358 is widely conserved among primate lentiviruses and is maintained by natural selection. The exception, SIVmac, likely reflects an evolutionary trade-off allowing escape from rhesus macaque TRIM5Cyp. Together, our observations are strong evidence that the interaction between viral CA and the Nup358Cyp domain must be biologically relevant in vivo. Specifically, by comparing interactions between multiple SIVsm/HIV-2 lineage CAs and several primate orthologs of Nup358, we identified interspecies differences in the Nup358Cyp domain that affect the CA interaction, but only when assayed in conjunction with the preceding Ran-binding domain 4 (Nup358R4). We next found that selection preserves the interaction during cross-species transmission, resulting in adaptation to differences between the Nup358Cyp homologs of the reservoir and spillover hosts. For example, SIVsm CA does not interact with human Nup358R4-Cyp, while HIV-2 CA interacts with both the human and sooty mangabey orthologs. We confirmed these distinct interaction phenotypes in an extended set of SIVsm/HIV-2 CAs, and mapped the difference to a single position – residue 3173 – in the Nup358Cyp domain. The differing ability to interact with human Nup358R4-Cyp is due to residue 85 in the CA 4-5 loops; most SIVsm strains encode a glutamine at position 85, whereas most HIV-2 strains encode an isoleucine. Reciprocal swaps reverse the interaction phenotypes, such that the SIVsm Q85I CA mutant strongly interacts with human Nup358R4-Cyp, while HIV-2 I85Q CA mutant does not. This difference also correlates with differences in single- and multi-cycle infectivity on human cell lines and levels of nuclear import in HeLa cells. Together, these results indicate that HIV-2 adapted to human Nup358 during emergence in humans. We also examined the ability of our CA panel to interact with Cyclophilin A. While all HIV-2 CA interact with CypA, the ability to interact varied among the other SIVsm CA tested, and was absent for SIVpbj. Thus, conservation of CA interaction with Nup358Cyp does not correlate to the ability to interact with CypA, and is not simply a consequence of maintaining the CA-CypA interaction. / Thesis (PhD) — Boston College, 2020. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Biology.

Monócitos podem ser classificados em três subgrupos de acordo com o nível de expressão dos marcadores CD14 e CD16. Monócitos clássicos são os mais abundantes no sangue. Eles expressam um fenótipo CD14+CD16-CCR2+, conferindo a eles a habilidade de migrar rapidamente a sítios inflamatórios, através da resposta à quimiocina CCL2 (CC chemokine ligand 2). Aqui apresentamos a identificação e caracterização de uma expansão de um novo subgrupo de monócitos durante a infecção por SIV e HIV. Essas células são indistinguíveis dos monócitos clássicos quanto à expressão de CD14 e CD16; porém não expressam CCR2 de superfície. A análise do transcriptoma de células selecionadas confirmou que elas representam uma subpopulação distinta que expressa níveis mais baixos de citocinas inflamatórias e marcadores de ativação que as CCR2+. Elas exibem fagocitose alterada e quimiotaxia deficiente em resposta a CCL2 e CCL7, além de serem refratárias à infecção por SIV e apresentarem atividade antiproliferativa. Nós as denominamos monócitos clássicos atípicos CCR2- (ACC monocytes), e acreditamos que elas têm um papel importante na patogenia da AIDS, possivelmente refletindo uma resposta anti-inflamatória contra a excessiva imunoativação observada durante a infecção por SIV e HIV. Tratamento antirretroviral leva a um declínio dessa subpopulação tanto em macacos como seres humanos, sugerindo que a replicação viral é capaz de induzir esse fenótipo atípico / Monocytes have been categorized in three main subpopulations based on CD14 and CD16 surface expression. Classical monocytes are the most abundant subset in the blood. They express a CD14+CD16-CCR2+ phenotype, which confers on them the ability to migrate to inflammatory sites by quickly responding to CC chemokine ligand 2 (CCL2) signaling. Here we identified and characterized the surge and expansion of a novel monocyte subset during SIV and HIV infection. They were undistinguishable from classical monocytes regarding CD14 and CD16 expression, but did not express surface CCR2. Transcriptome analysis of sorted cells confirmed that they represent a distinct subpopulation that expresses lower levels of inflammatory cytokines and activation markers than their CCR2+ counterparts. They exhibited impaired phagocytosis and deficient chemotaxis in response to CCL2 and CCL7, besides being refractory to SIV infection and showing antiproliferative activity. We named these cells atypical CCR2- classical (ACC) monocytes, and believe they play an important role in AIDS pathogenesis, possibly reflecting an anti-inflammatory response against the extreme immune activation observed during SIV and HIV infection. Antiretroviral therapy caused this population to decline in both macaque and human subjects, suggesting that this atypical phenotype may be induced by viral replication

Monócitos podem ser classificados em três subgrupos de acordo com o nível de expressão dos marcadores CD14 e CD16. Monócitos clássicos são os mais abundantes no sangue. Eles expressam um fenótipo CD14+CD16-CCR2+, conferindo a eles a habilidade de migrar rapidamente a sítios inflamatórios, através da resposta à quimiocina CCL2 (CC chemokine ligand 2). Aqui apresentamos a identificação e caracterização de uma expansão de um novo subgrupo de monócitos durante a infecção por SIV e HIV. Essas células são indistinguíveis dos monócitos clássicos quanto à expressão de CD14 e CD16; porém não expressam CCR2 de superfície. A análise do transcriptoma de células selecionadas confirmou que elas representam uma subpopulação distinta que expressa níveis mais baixos de citocinas inflamatórias e marcadores de ativação que as CCR2+. Elas exibem fagocitose alterada e quimiotaxia deficiente em resposta a CCL2 e CCL7, além de serem refratárias à infecção por SIV e apresentarem atividade antiproliferativa. Nós as denominamos monócitos clássicos atípicos CCR2- (ACC monocytes), e acreditamos que elas têm um papel importante na patogenia da AIDS, possivelmente refletindo uma resposta anti-inflamatória contra a excessiva imunoativação observada durante a infecção por SIV e HIV. Tratamento antirretroviral leva a um declínio dessa subpopulação tanto em macacos como seres humanos, sugerindo que a replicação viral é capaz de induzir esse fenótipo atípico / Monocytes have been categorized in three main subpopulations based on CD14 and CD16 surface expression. Classical monocytes are the most abundant subset in the blood. They express a CD14+CD16-CCR2+ phenotype, which confers on them the ability to migrate to inflammatory sites by quickly responding to CC chemokine ligand 2 (CCL2) signaling. Here we identified and characterized the surge and expansion of a novel monocyte subset during SIV and HIV infection. They were undistinguishable from classical monocytes regarding CD14 and CD16 expression, but did not express surface CCR2. Transcriptome analysis of sorted cells confirmed that they represent a distinct subpopulation that expresses lower levels of inflammatory cytokines and activation markers than their CCR2+ counterparts. They exhibited impaired phagocytosis and deficient chemotaxis in response to CCL2 and CCL7, besides being refractory to SIV infection and showing antiproliferative activity. We named these cells atypical CCR2- classical (ACC) monocytes, and believe they play an important role in AIDS pathogenesis, possibly reflecting an anti-inflammatory response against the extreme immune activation observed during SIV and HIV infection. Antiretroviral therapy caused this population to decline in both macaque and human subjects, suggesting that this atypical phenotype may be induced by viral replication

Les Virus de l'Immunodéficience Humaine (VIH) sont le résultat de plusieurs transmissions inter-espèces de SIV (Virus de l'Immunodéficience Simienne) de Primates Non Humains (PNH) à l'Homme. Les SIV les plus proches du VIH-1 sont le SIVcpz et le SIVgor qui infectent naturellement les chimpanzés et les gorilles. Les SIVsmm retrouvés chez les mangabés enfumés d'Afrique de l'Ouest sont les plus proches du VIH-2. Actuellement, au moins 13 transmissions du singe à l'Homme ont été documentées, 4 à l'origine des 4 groupes du VIH-1 (groupe M, N, O et P) et 9 pour le 9 VIH-2 (A-I). La question du réservoir à l'origine du VIH-1 chez l'Homme est partiellement résolue. Les chimpanzés, Pan troglodytes troglodytes, du sud-est et centre sud du Cameroun sont respectivement les réservoirs du VIH-1 M pandémique chez l'Homme ainsi que du VIH-1 groupe N. En ce qui concerne les groupes O et P, il n'y a actuellement pas de réponse définitive. Les SIVgor sont bien les virus les plus proches phylogénétiquement des VIH-1 O et P. Cependant, de plus amples recherches sont nécessaires pour identifier les ancêtres directs des variants O et P. Ces recherches supplémentaires aideront aussi à élucider l'origine du SIVgor chez les gorilles, et à savoir si ce sont les gorilles qui ont transmis les virus O et/ou P à l'Homme, ou s'il existe toujours un réservoir des ancêtres O et P chez les chimpanzés. Des études supplémentaires sont aussi nécessaires afin de mieux comprendre les mécanismes d'adaptation à un nouvel hôte et l'impact des infections SIV chez les grands singes. Dans ce but, l'étude du récepteur accessoire pour le VIH, l'intégrine α4β7, pourrait aussi jouer un rôle pour l'infection du SIV/VIH. Cette intégrine facilite également la migration du virus vers l'intestin. Une étude récente a montré des substitutions d'acides aminés chez les Primates du Nouveau Monde (PNM) qui empêche l'adhérence du liant. Ainsi, les polymorphismes de cette intégrine et son rôle dans l'infection SIV chez les Primates de l'Ancien Monde (PdAM) sont encore inconnus. L'objectif majeur de cette thèse était de mieux documenter et mieux comprendre l'infection SIV chez les gorilles sauvages en Afrique Centrale. Sur plus de 6.000 échantillons testés, nous avons constaté que seuls les gorilles (Gorilla gorilla gorilla) du sud Cameroun sont infectés par le SIVgor. Parmi eux, nous avons identifié les ancêtres du VIH-1 P chez des populations du sud-ouest Cameroun. Nous avons aussi mis en évidence que les gorilles sont à l'origine du VIH-1 groupe O. Les analyses fonctionnelles du facteur de restriction APOBEC3G ont montré que celui-ci protège les gorilles des infections SIVcpz, expliquant en partie la faible prévalence de SIVgor. Nous avons évalué une nouvelle technologie sérologique, le Luminex®, en utilisant des antigènes spécifiques de la lignée SIVgor. Ces résultats ont été comparés avec ceux que nous pouvons obtenir avec l'INNO-LIATM qui est une technique de référence basée sur des réactions croisées entre anticorps SIV et antigènes VIH-1. Nous avons aussi évalué la faisabilité de la technologie de séquençage de deuxième génération Illumina® pour étudier les viromes de deux gorilles. Nous n'avons pas pu obtenir la séquence du SIVgor dans l'échantillon de l'individu infecté. Cependant, en comparant les résultats obtenus entre les deux gorilles étudiés, nous avons pu constater un probable déséquilibre de la réplication des virus entériques seulement pour le gorille infecté par le SIVgor. Enfin, nous avons décrit la diversité de la sous-unité α4 de l'intégrine α4β7 chez les PdAM. En conclusion, ces travaux de thèse ont apporté de nouvelles connaissances majeures sur l'infection SIV chez les gorilles et ont contribués à élucider l'origine des quatre groupes VIH-1. / Human Immunodeficiency Viruses (HIV) are the result of numerous interspecies transmissions of different SIV (Simian Immunodeficiency Virus) from Non-Human Primates (NHP) to humans. SIVcpz and SIVgor from chimpanzees and gorillas are most closely related to HIV-1, and SIVsmm from sooty mangabeys in West Africa to HIV-2. At least 13 cross-species transmissions from NHP to humans have been reported, 4 leading to the 4 HIV-1 group (M, N, O and P) and 9 for the 9 HIV-2 groups (A-I). Today the origin of HIV-1 group M and N is elucidated and their simian ancestors, have been identified in chimpanzee (Pan troglodytes troglodytes) populations in southeast and south-central Cameroon, respectively. HIV-1 group O and P are most closely related to SIVgor from gorillas but their direct ancestors have not been identified yet. More studies are thus needed to clarify the origin of HIV-1 group O and P in humans as well as on the origin of SIVgor in gorillas. These studies will also elucidate whether HIV-1 group O and P have been transmitted by chimpanzees or gorillas and whether simian ancestors of these HIV groups and the ancestor of SIVgor still circulates in today's chimpanzee populations. More studies are also needed to understand viral and host factors related adaptation in the new host and the impact of SIV infection in general in apes. As such, α4β7 integrin has been recently described as a new HIV-1 receptor that facilitates virus migration to the Gut-Associated Lymphoid Tissue (GALT). In a recent study, amino acid substitutions were observed in the α4 binding site in New World Primates (NWP), that can reduce the activity of this receptor. The impact of the genetic diversity of this integrin in Old World Primates (OWP) and its role in SIV infection is still unknown. Therefore, characterizing the polymorphisms profiles in OWP could bring new insights into progression of the pathogenic and non pathogenic SIV infections. The main objective of this thesis was to better characterize and understand SIV infection in wild gorillas in Central Africa. On more than 6,000 fecal samples from gorillas collected across Central Africa, we showed that only gorillas from southern Cameroon are infected with SIVgor and we identified the ancestors of HIV1 group P in gorilla populations from southwest Cameroon. We also provided evidence that gorillas are at the origin of HIV-1 group O in humans. Functional analysis of the restriction factor APOBEC3G showed that its protects gorillas from SIVcpz infections and can explain the low prevalence in gorillas. We evaluated a new antibody detection approach in faecal samples, based on Luminex® technology that use SIVgor specific antigens, comparing with the actual serological test INNO-LIATM HIV confirmatory assay, based on cross-reactive SIV antibodies with HIV antigens. We also evaluated the feasibility of virus sequencing in faecal samples with the Illumina® technology to study viromes of gorillas. We studied two samples, one of a SIVgor infected individual and one from an uninfected gorilla. Although the SIVgor sequence was not retrieved from the infected individual, we observed a tendency to enteric virus replication disorder in the infected animal that has not been seen in the uninfected one. Finally, we also documented here the genetic diversity of the α4 subunit from OWP. In this thesis we documented more in detail different aspects of SIV infection in gorillas and contributed to elucidate the origin of all HIV-1 groups.

Thesis advisor: Kenneth C. Williams / Elucidating the mechanisms through which viral infection and persistence in CNS occurs is critical to understanding the development and progression of neurological disease. To date, no study has demonstrated that monocyte traffic in HIV and SIV infection directly results in neuronal injury. The central hypothesis in this thesis is that continuous trafficking of monocytes into tissues is essential for pathogenesis with viral infection. In the dissertation work presented here, two studies addressed this hypothesis. In Chapter 2, experiments examining the role of peripheral monocyte activation in the development of neuroAIDS using the tetracycline antibiotic minocycline will be described. We hypothesized that decreased monocyte activation with minocycline treatment would play a neuroprotective role in the context of rapid SIV infection with a high incidence of SIV encephalitis (SIVE). We observed a reversal of neuronal injury within days of minocycline treatment that correlated with loss of monocyte activation. From these findings we concluded that decreased activation of monocytes results in lower CNS traffic. However this effect may have occurred due to lower plasma virus, decreased SIV infection of monocytes, or the ability of minocycline to cross the BBB and modulate changes within the CNS directly. In Chapter 3 of this thesis, we hypothesized that continuous traffic of activated monocytes from the periphery into the CNS is required for neuronal injury with AIDS, and that by effectively stopping monocyte accumulation, CNS pathology can be blocked or reversed. We also hypothesized that monocyte trafficking is necessary for the seeding of brain and small intestine with cell-associated virus. In order to test these hypotheses, we utilized the anti-α4 blocking antibody natalizumab (Tysabri; Biogen Idec), which selectively binds to the α4 subunit of α4β1 (VLA-4) and α4β7 integrins, preventing the interaction between α4 and its various ligands. To address the first hypothesis, natalizumab was administered after four weeks of infection once significant neuronal damage had already occurred. We found that preventing cell traffic with natalizumab is sufficient to stabilize neuronal injury and loss, demonstrating conclusively that stopping monocyte traffic stabilizes CNS disease. To address the second hypothesis, rhesus macaques were treated with natalizumab on the day of SIV infection. Natalizumab treatment completely blocked SIV infection in the brain, and virus traffic to the small intestine was significantly suppressed. Overall, these studies demonstrate that continuous traffic of monocytes is required for neuronal injury and the formation of CNS lesions, and that early trafficking of leukocytes is critical for seeding of the CNS and contributes to seeding of the small intestine with virus. / Thesis (PhD) — Boston College, 2014. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Biology.

Thesis (Ph. D.)--Ohio State University, 2009. / Title from first page of PDF file. Includes vita. Includes bibliographical references (p. 217-241).