Tesis sobre el tema "Retrovirus HTLV"

La variabilite genetique du virus htlv-i a ete etudiee par plusieurs approches complementaires : - les travaux d'epidemiologie moleculaire ont permis d'une part de decrire un nouveau sous-type d'htlv-i (htlv-i d) present en afrique centrale, d'autre part de montrer que la repartition des sous-types viraux presents en afrique est liee au moins a 3 facteurs : a) l'origine geographique des souches virales b) des transmissions singes-hommes repetees, c) l'evolution genetique lente du virus dans des populations isolees. Par ailleurs, un nouveau stlv-i a ete caracterise au niveau moleculaire chez macaca arctoides, singe qui presentait une serologie htlv indeterminee. Ce nouveau virus de la famille des htlv-i/stlv-i est le plus divergent connu actuellement et sa decouverte suggere qu'il devrait exister des virus htlv-i aussi divergents dans certaines populations du sud-est asiatique. Enfin, l'absence de mutation associee a une pathologie donnee (atl ou tsp/ham) a ete confirmee pour une region de la proteine tax. - l'etude des quasiespeces d'htlv-i apres l'infection de singes saimiri sciureus a montre que la faible variabilite genomique observee etait probablement le reflet d'une faible replication virale meme dans cette espece simienne naive pour les stlvs. La stabilite genetique observee chez cet animal serait donc due a la biologie du virus qui ne lui permet pas de se repliquer efficacement et ce quel que soit l'hote infecte. - concernant le mecanisme moleculaire qui regit la faible variabilite genetique d'htlv-i observee in vivo, nous avons montre que la transcriptase inverse d'htlv-i pouvait aussi commettre des erreurs mais a un niveau moindre que celle de vih-1. - la presence d'un virus apparente a htlv-i a ete recherchee dans des populations d'afrique chez lesquelles on trouve frequemment un profil de western-blot indetermine proche de celui retrouve chez les individus infectes par htlv-i. Aucune sequence htlv-i n'a pu etre detectee dans les cellules mononucleees du sang peripherique de ces personnes et nos resultats suggerent que ces profils indetermines pourraient etre dus a des seroreactivites croisees contre certains antigenes palustres qui restent a definir.

Synthetisees dans la cellule infectee, les glycoproteines d'enveloppe des retrovirus gouvernent l'entree virale dans une nouvelle cellule cible. En adoptant les retrovirus htlv comme modeles d'etude, cette these analyse l'oligomerisation des glycoproteines d'enveloppe tout le long de leur existence, depuis leur maturation intracellulaire dans la cellule infectee jusqu'aux evenements qui conduisent a la transmission retrovirale dans une cellule cible. Dans la premiere partie du travail, j'a mis au point un test d'infectivite qui permet d'etudier la transmission des retrovirus htlv au cours d'un seul cycle d'infection. Puis, par mutagenese dirigee, j'ai defini la contribution des differentes regions des proteines d'enveloppe a leur maturation et a leurs fonctions. J'ai ainsi etabli la validite des glycoproteines de htlv comme modeles d'etude des glycoproteines retrovirales. Dans la seconde partie du travail, j'ai combine deux approches experimentales complementaires pour etudier l'oligomerisation des glycoproteines d'enveloppe : des tests fonctionnels qui etudient le caractere transdominant de mutants d'enveloppe, et des tests biochimiques qui mettent en evidence les oligomeres de glycoproteines. D'une part, j'ai montre que l'oligomerisation du precurseur d'enveloppe dans le reticulum endoplasmique requiert l'integrite du domaine n-terminal, et propose que l'assemblage des proteines survient precocement au cours du processus de maturation intracellulaire, ce qui favoriserait le repliement cooperatif de monomeres. D'autre part, j'ai etabli que chacune des etapes du processus d'entree necessite que les glycoproteines d'enveloppe soient sous forme d'oligomeres. Mes resultats suggerent que l'activation de la fusion virale ferait intervenir une transition dans l'ordre d'oligomerisation des glycoproteines, d'une forme dimerique - forme mature mais non-fusiogene presente a la surface de cellules infectees et des virions - a une forme trimerique - effectrice de la fusion.

Thesis (Ph. D.)--Ohio State University, 2005.
Title from first page of PDF file. Document formatted into pages; contains xvii, 216 p.; also includes graphics (some col.). Includes bibliographical references. Available online via OhioLINK's ETD Center

Le travail realise au cours de cette these visait a comprendre le role des proteines gag du retrovirus htlv-1 dans la formation d'un virus infectieux. Comme pour les autres retrovirus, ces proteines forment l'architecture interne du virus, et gouvernent l'assemblage et le bourgeonnement de nouveaux virions depuis la membrane des cellules infectees. Les proteines gag sont synthetisees sous la forme d'une polyproteine, le precurseur gag, qui est ensuite clive par la protease virale en produits matures : matrice, capside et nucleocapside. Afin etudier le trafic intracellulaire du precurseur gag d'htlv-1 depuis son lieu de synthese cytoplasmique jusqu'a la membrane plasmique ou debute le bourgeonnement, nous avons realise une etude systematique de colocalisation avec les compartiments membranaires intracellulaires. Nos resultats indiquent que le transport de gag a la membrane plasmique est independant des membranes intracellulaires mais necessite l'integrite du cytosquelette d'actine. Afin de definir les motifs proteiques qui, dans la matrice de htlv-1, sont necessaires a l'infection, nous avons introduit des mutations dans cette proteine et teste leur effet sur la maturation des proteines gag, la morphogenese et la production des particules virales, et l'infectivite du virus. Nous avons montre que les acides amines basiques de la matrice d'htlv-1 sont necessaires a de multiples fonctions, incluant non seulement la production de particules virales, mais aussi des evenements precoces du cycle viral qui sont requis pour une infection efficace de nouvelles cellules cibles. D'autre part, nous avons etabli que le motif pppy de la matrice d'htlv-1 est implique dans une etape precoce du bourgeonnement. La comparaison de nos resultats

The author’s accepted version (the unedited manuscript) may be deposited into a repository six months after print publication. In this case, authors should cite the publication reference and DOI number on any deposited version, and provide a link from it to the published article on the NPG website.
Kyoto University (京都大学)
0048
新制・課程博士
博士(医学)
甲第19615号
医博第4122号
新制||医||1015(附属図書館)
32651
京都大学大学院医学研究科医学専攻
(主査)教授 生田 宏一, 教授 松田 道行, 教授 高田 穣
学位規則第4条第1項該当

Le retrovirus htlv-i (human t-cell leukemia virus type i) est associe a deux pathologies graves chez l'homme, la leucemie a cellules t de l'adulte et la paraparesie spastique tropicale. Sa glycoproteine de surface (gp46) est impliquee dans les evenements precoces de l'infection virale. Ce travail s'insere dans le cadre de l'elaboration d'une strategie vaccinale, et propose une double approche d'analyse de la gp46. La structure en solution de fragments peptidiques de synthese est etudiee par dichroisme circulaire et par resonance magnetique nucleaire bidimensionnelle du proton. L'antigenicite de la region immunodominante 239-261 de la gp46 est analysee en fonction de la variabilite de sa sequence proteique ; dans cette region, nous avons defini plusieurs epitopes reconnus par des anticorps contenus dans les serums de patients htlv-i positifs. Les premiers resultats des tests d'immunisation de lapins avec un prototype de vaccin synthetique sont presentes

L'ATL est une prolifération tumorale de cellules lymphoïdes T matures activées ; cette maladie est caractérisée par un mauvais pronostic, du fait d'une resistance importante à la chimiothérapie conventionnelle. L'oncoprotéine TAX joue un rôle primordial dans la prolifération et la transformation des lymphocytes infectées par HTLV-1. Notre équipe a montré que l'arsenic synergise avec l'interferon pour induire dans les cellules leucémiques infectées, un arrêt du cycle cellulaire, une apoptose massive ainsi qu'une dégradation proteosomique spécifique de TAX. Cette dégradation semble être à la base de l'élimination des cellules initiatrices de leucémie (CIL) et l'éradication de l'ATL. Néanmoins, les mécanismes moléculaires du ciblage de TAX par l'arsenic/IFN restaient élusifs. Mon projet de thèse a eu pour objectif d'élucider ces mécanismes. Dans mon travail de thèse, nous avons confirmé, pour la première fois, que la survie des lignées cellulaires dérivées d'ATL est dépendante de l'expression continue de TAX indiquant la contribution majeure de la dégradation de cette oncoprotéine dans la réponse thérapeutique. De plus, la dégradation de TAX sous l'effet de l'arsenic/IFN est due à sa sumoylation et à son ubiquitination séquentielle, médiées par PML et RNF4 respectivement. Ces résultats ont permis de proposer un modèle sur l'effet de l'arsenic/IFN sur les modifications post-traductionnelles de TAX et les enzymes qui y sont impliqués. Par conséquent, le renforcement des CNS suivi par la dégradation des protéines symoylées pathogènes, par un traitement ciblé, pourrait avoir un large intéret thérapeutique
The HTLV-1 TAX Transactivator initiates transformation in adult T-cell leukemia/Lymphoma (ATL), a highly aggressive chemotherapy-resistant malignancy. The arsenic/Interferon combination, which triggers degradation of the tax oncoprotein, selectively precipates apoptosis of ATL cell lines and cures TAX-driven murine ATL. Yet, the role of tax loss in ATL response is disputed and the molecular mechanisms driving degradation remain elusive. Here we demonstrate that ATL-derived cells are addicted to continuous tax expression, implying that tax degradation underlies clinical responses to the arsenic/interferon combination in mice and patients. The latter enforces PML nuclear body (NB) formation and partner protein recruitment. In arsenic/interferon-treated ATL cells, TAX is recruited onto NBS, undergoes PML-dependent hyper-sumoylation by SUMO2/3,but not SUMO1, ubiquitination by RNF4 and proteasome-dependent degradation. Thus arsenic/Interferon is a targeted therapy of ATL, enforcing NB formation by arsenic/Interferon therapy could have broad therapeutic value to destroy pathogenic sumoylated proteins

In this thesis a novel model of gene and protein kinetics of retrovirus Human T-cell Leukemia Virus type 1 (HTLV-1) is proposed. This model is characterized by positive and negative feedback phenomena, similarly to synthetic relaxation oscillators delivered into prokaryotes and able to exhibit limit cycles. To investigate the potential use of the HTLV-1 circuit as a novel oscillator for eukaryotes, the periodic behavior of gene and protein kinetics is analyzed. Techniques to mutate the retroviral genome in order to obtain, practically, oscillations in viral gene and protein expression are discussed. Since, under certain conditions, discreteness and stochasticity may play important roles so that the predictions coming from deterministic differential equations do not accurately describe the system’s true behavior, this latter was tested by Gillespie’s exact stochastic simulations. These showed that: a) stochastic phenomena induce loss of synchronicity in viral expression among clones and b) the expression of the retrovirus transactivator protein Tax can substantially deviate from its deterministic steady state value; in other words, stochastic phenomena can sporadically induce relevant fluctuations of Tax expression, which is the main signal related to retrovirus activation, over the expected level corresponding to the steady state solution. These results suggest mechanisms of viral activation similar to those proposed for HIV by Weinberger et al.1: the virus tends to latency, but stochastic phenomena can induce the persistence of the transactivator protein at expression levels higher than the steady state value, which favors retrovirus activation. However, the steady state level of Tax expression should reasonably be as important, in determining retrovirus HTLV-1 activation, as the noise affecting it and causing stochastic transient expression pulses. To gain a better insight, the characteristics of Tax expression at steady state are investigated in terms of duration of its transient pulses, due to stochastic phenomena, and its Signal-to-Noise ratio (SNR), which combines the protein expression level and the variance of the noise affecting it. As a second step, the system parameters most affecting either Tax SNR or the duration of its transient expression pulses are identified, in order to select candidates for future experiments of selective system perturbation. The rational is that a better understanding of retrovirus regulatory mechanisms, and the identification of system parameters (and corresponding biological processes) affecting them, can open the way for the selection of drug targets to hit in order to avoid retrovirus activation and protract latency.
In questa tesi è proposto un nuovo modello matematico della cinetica di geni e proteine del retrovirus T-cell Leukemia Virus type 1 (HTLV-1). Il modello è dotato di fenomeni di feedback, sia positivi che negativi, al pari dei circuiti genici sintetici noti come relaxation oscillator, introdotti in cellule procariotiche in recenti esperimenti, i quali hanno mostrato cinetiche caratterizzate da cicli limite. Per investigare il potenziale uso del circuito genico di HTLV-1 quale nuovo oscillatore per cellule eucariotiche, i moti periodici caratterizzanti il modello sono stati analizzati. Tecniche biotecnologiche per mutare il genoma retrovirale allo scopo di ottenere oscillazioni nell’espressione di geni e proteine sono poi discusse. Siccome, in certe condizioni, la stocasticità può giocare un ruolo importante cosicché le predizioni provenienti da equazioni differenziali deterministiche non riescono a descrivere accuratamente l’effettivo comportamento del sistema, quest’ultimo è stato testato tramite simulazioni stocastiche esatte di Gillespie. Queste mostrarono che: a) fenomeni stocastici inducono la perdita di sincronicità nell’espressione virale tra cloni e b) l’espressione della protein transattivatrice del retrovirus Tax può deviare in modo sostanziale dal valore deterministico di steady state; in altre parole, fenomeni stocastici possono sporadicamente indurre rilevanti fluttuazioni nell’espressione di Tax, che è il principale segnale legato all’attivazione virale, sopra ilvalore atteso corrispondente alla soluzione di steady state. Queste simulazioni suggeriscono meccanismi di attivazione retrovirale simili a quelli proposti per HIV da Weinberger et al.1: il virus tende alla latenza, ma fenomeni stocastici possono indurre la persistenza della proteina transattivatrice a livelli di espressione superiori al valore di steady state, che favoriscono l’attivazione del retrovirus. Tuttavia, il livello di steady state dell’espressione di Tax dovrebbe ragionevolmente essere altrettanto importante, nel determinare l’attivazione del retrovirus HTLV-1, del rumore che affligge tale espressione e ne causa implulsi transienti di natura stocastica. Al fine di ottentere una migliore comprensione, le caratteristiche dell’espressione di Tax a steady state sono investigate in termini di durata degli i8mpulsi transienti, dovuti a fenomeni stocastici, e del Rapporto Segnale-Rumore (SNR) del circuito genico, che combina il livello di espressione della proteina con la varianza del rumore associato. In secondo luogo, sono stati identificati i parametri di sistema che influenzano di più e in modo esclusivo l’SNR e la durata degli impulsi transienti di espressione, allo scopo di selezionare candidati per futuri esperimenti di perturbazione selettiva del sistema. La ragione è che una migliore comprensione dei meccanismi regolatori del retrovirus, e l’identificazione dei parametri di sistema che li influenzano (assieme ai corrispondenti processi biologici), possono aprire la strada per lo sviluppo di farmaci che mirino ad evitare l’attivazione del retrovirus e a protrarne la latenza.

Le retrovirus htlv-1 est l'agent de la leucemie t de l'adulte (atl) et de la paraparesie spastique tropicale (tsp) chez 5% des individus infectes. Alors que la majorite des retrovirus se replique essentiellement par transcription inverse (rt), la replication de htlv-1 repose essentiellement sur l'expansion clonale des cellules infectees. De par son activite activatrice de la proliferation cellulaire et son potentiel mutagene, la proteine virale tax joue un role clef dans la profileration de la cellule infectee. Htlv-1 se replique donc essentiellement par l'immortalisation de sa cellule hote dans un contexte d'instabilite genetique genere par tax. L'etude du tempo replicatif de htlv-1 chez le singe ecureuil, experimentalement infecte, a permis de montrer que la rt et l'expansion clonale appartenaient a deux etapes distinctes de l'histoire naturelle de l'infection. La replication virale par rt ne constitue en effet qu'une premiere etape transitoire et precoce de l'infection suivie de l'expansion clonale persistante des cellules infectees, l'accroissement de la charge provirale au cours du temps etant correlee au degre de proliferation des cellules infectees et non au nombre de cellules infectees de novo. Chez l'homme, l'etude de la variabilite genetique du provirus a permis de montrer qu'il existait des phenomenes de mutations somatiques (ms) accompagnant la mitose des cellules hotes. Quel que soit le statut clinique des individus, l'essentiel de la variabilite genetique de htlv-1 resulte de ms plutot que de rearrangements lies aux erreurs de rt. La frequence elevee de ces mutations, retrouvee egalement au niveau du genome hote, est correlee au degre de proliferation des cellules infectees. Les clones de grande ampleur etant plus abondant chez les patients atteints d'atl ou de tsp, les ms ont ete plus frequemment detectees chez les sujets symptomatiques. Ces resultats decrivent un nouveau mode de variabilite des retrovirus et suggerent qu'une proliferation accrue des cellules infectees par htlv-1 est susceptible d'entrainer une accumulation de mutations propices a l'acquisition du phenotype malin.

Objetivo del Estudio: comprobar la seroprevalencia de infección por HTLV-1 en pacientes sintomáticos, determinar las enfermedades asociadas y características epidemiológicas. Materiales y Métodos: Estudio retrospectivo, observacional transversal, descriptivo en 591 pacientes a quienes se les sometió a la prueba de HTLV-1 provenientes de hospitalización y consultorio externo durante los años 2008-2012 por sospecha de manifestaciones asociadas; siendo 62 casos positivos con patología asociada con revisión de historias clínicas para evaluar características epidemiológicas. Resultados: La seroprevalencia de HTLV-1 en pacientes con sospecha clínica de enfermedad asociada fue de 10.5% ; la edad promedio de desarrollo de patología asociada a infección por este virus fue la comprendida entre 40-50 años (32.3%); la relación comprendida entre H/M fue de 0.7; como lugar de nacimiento de los casos positivos a infección por HTLV-1 en primer lugar fueron propios de El Callao con un 54.8%; en segundo lugar Lima 14.5%; luego Apurímac 8.1%, Ancash 6.5%, Ayacucho 4.8%. Las patologías asociadas fueron Paraparesia espástica Tropical (HAM/TSP) en un 24.6%; en segundo lugar fue la Tuberculosis (22.6%) siendo la Tuberculosis Pulmonar el 57.1% de estos casos, seguida de Tuberculosis Meníngea (14.3%), Tuberculosis Vertebral (14.3%); la Dermatitis infectiva ocupo el tercer lugar con 16.1%; el Linfoma ATL 14.5%, Estrongiloidiasis 9.7%, Vejiga Neurogenica 6.5%, Sarna Noruega 4.8%, Uveítis 1.6%. La asociación de infección de HTL-1 más VIH fue de 12.9%. Conclusiones: La seroprevalencia de pacientes con infección de HTLV-1 y desarrollo de enfermedades asociadas es alta en relación a estudios previos, el desarrollo de la enfermedad es durante la cuarta a quinta década de vida; más de la mitad de los casos son nacidos en el Callao lo cual indica casos propios de esta región, a diferencia de lo que se creía (casos importados o nacidos en zonas endémicas); la Tuberculosis se asocia a infección por HTLV-1, siendo la T. Pulmonar la más frecuente seguida de T. Meníngea.
Trabajo académico

Thesis (Ph. D.)--Ohio State University, 2004.
Title from first page of PDF file. Document formatted into pages; contains xvii, 250 p.; also includes graphics (some col.) Includes bibliographical references (p. 207-250). Available online via OhioLINK's ETD Center

Le génome des rétrovirus existe sous deux formes différentes : sous forme d'ARN simple brin, qui est traduit ou encapsidé, ou sous forme d'ADN double brin intégré dans le génome de la cellule hôte infectée. Cette dernière forme, l'ADN proviral, est indispensable à la production de tous les ARNm viraux nécessaires à la synthèse des protéines virales, qui en retour agissent sur la région promotrice située au niveau du LTR 5'. Cependant, l'ADN proviral possède un second LTR à son extrémité 3', capable de réguler une transcription antisens, orientée dans la direction opposée à celle contrôlée par le LTR 5'. L'ADN proviral a donc deux brins codants, ce qui offre au virus un plus grand potentiel de synthèse protéique. Dans le cas du Virus de l'immunodéficience Humaine de type 1 (VIH-1), la transcription antisens permet la production d'une protéine, appelée ASP (Antisense Protein). Dans ce manuscrit, nous démontrons que cette activité transcriptionnelle antisens s'exprime préférentiellement dans les cellules d'origine monocytaire, en particulier les cellules dendritiques ; une localisation membranaire de la protéine ASP a par ailleurs été mise en évidence dans ce type cellulaire. Nos résultats suggèrent également que la transcription antisens du VIH-1 est indépendante de la protéine Tat, et que par ailleurs les deux types de transcriptions ne sont pas exprimés simultanément au sein d'une même cellule. En outre, nos données soulignent que la séquence codante de la protéine ASP est très fortement conservée parmi les différents isolats viraux. Sur la base de l'ensemble de ces résultats, notre hypothèse est que la protéine ASP du VIH-1 possède des fonctions cruciales dans le cycle réplicatif des rétrovirus, indépendantes de la production virale
Genome of retroviruses exists in two different forms: as single-stranded RNA that is translated or packaged, or as double-stranded DNA integrated into the genome of the infected host cell. The latter form, the proviral DNA, is essential for the production of all viral mRNAs required for the synthesis of viral proteins, which in turn act on the promoter region located at the 5 '-LTR. However, the proviral DNA has a second LTR at its 3 '-end, capable of regulating antisense transcription oriented in the opposite direction to that controlled by the 5'-LTR. The proviral DNA has then two coding strands, which gives the virus a greater potential for protein synthesis. In the case of the Human Immunodeficiency Virus type 1 (HIV-1), antisense transcription allows the production of a protein called ASP (Antisense Protein). In this manuscript, we demonstrate that this antisense transcriptional activity is preferentially expressed in cells of the monocyte lineage, in particular dendritic cells; a membrane localization of the ASP protein was also observed in this cell type. Our results also suggest that the antisense transcription of HIV-1 is Tat-independent, and what's more that the two types of transcription are not expressed simultaneously within the same cell. In addition, our data highlight that the ASP protein coding sequence is highly conserved among different viral isolates. Based on these results, our hypothesis is that the ASP protein of HIV-1 has critical functions in the replicative cycle of retroviruses, distinct from viral production

L'infection par le retrovirus htlv-i entraine divers syndromes proliferatifs et degeneratifs chez l'homme. La proteine tax1, produite par le virus, possede des activites transactivatrices et oncogeniques qui sont en grande partie responsables des pathologies associees a htlv-i. Les etudes que nous avons engagees ont permis de caracteriser plusieurs proteines qui interagissent avec tax1 dans la cellule. Des etudes effectuees in vivo et in vitro montrent que tax1 favorise la premiere etape de la mise en place du complexe d'initiation de la transcription, en recrutant directement tfiid. Par ailleurs, le systeme du simple hybride dans la levure a permis d'identifier 3 facteurs de transcription, creb, crem et atf1, capables de cooperer in vivo avec tax1 sur le motif tre1 du promoteur htlv-i. Dans un deuxieme temps, nous avons recherche d'autres partenaires cellulaires de tax1 par un criblage avec le systeme des deux hybrides dans la levure. Deux sous-unites du proteasome, hc9 et hsn3, ont ete ainsi isolees. Une etude fonctionnelle suggere que tax1 favorise l'association de p105 avec le proteasome et accelere ainsi le clivage de p105 en p50 dans la voie nf-b. Lors de ce criblage, nous avons egalement isole l'homologue humain de la proteine de souris int-6 impliquee dans la proliferation cellulaire. En interagissant avec hint-6, tax1 altere sa localisation nucleaire en points. Ce mecanisme pourrait modifier la fonction d'hint-6 et donc participer au processus de transformation cellulaire induit par tax1. Enfin, six nouvelles proteines contenant des domaines pdz ont ete isolees. Leur interaction avec tax1 est assuree par l'extremite c-terminale de la proteine virale, qui possede le motif consensus x-t/s-x-v-cooh implique dans l'interaction avec les domaines pdz. De part les fonctions des proteines de cette famille dans la cellule, il est possible que ces interactions soient a l'origine de certains desordres proliferatifs et degeneratifs qui sont associes a htlv-i.

Thesis (M.S. in Biological Sciences)--S.M.U., 2007.
Title from PDF title page (viewed Mar. 18, 2008). Source: Masters Abstracts International, Volume: 45-02, page: 0743. Adviser: Robert Harrod. Includes bibliographical references.

In this thesis, we examine epidemiological models of two different retroviruses, which infect the human body. The two viruses under study are HIV or the human immunodefiency virus and HTLV-I, which is the human T lymphotropic virus type I. A retrovirus is a virus, which injects its RNA into the host, rather than it's DNA. We will study each of the different mathematical models for each of the viruses separately. Then we use MATLAB-SIMULINK to analyze the models by studying the reproductive numbers in each case and the disease progression by examining the graphs. In Chapter 1, we mention basic ideas associated with HIV and HTLV-I. In Chapter 2 some of the basic mathematical model of epidemiology is presented. Chapter 3 is devoted to a model describing the intra-host dynamics of HIV. Here, we take into account how HIV infects and replicates in the CD4+ T cells. The model studied in this thesis examines the difference between cells, which are susceptible to the virus, and cells, which are not susceptible. Through the graphs associated with this model, we are able to see how this difference affects disease progression. In Chapter 4, we examine the effect of HTLV-I virus on human body. The HTLV-I virus causes a chronic infection in humans and may eventually lead to other diseases. In particular, the development of Adult T-cell Leukemia or ATL is studied in this thesis. The T-cell dynamics and progression to ATL is described using a mathematical model with coupled differential equations. Using mathematical analysis and SIMULINK, we obtain results on stability, asymptotic stability and the manner of progression of the disease. In Chapter 5 and appendices, we mention our inference and the MATLAB-SIMULINK codes used in this thesis, so that a reader can verify the details of the work carried out in this thesis.
M.S.
Department of Mathematics
Sciences
Mathematical Science MS

Thesis (Ph. D.)--Ohio State University, 2004.
Document formatted into pages; contains 237 p. Includes bibliographical references. Abstract available online via OhioLINK's ETD Center; full text release delayed at author's request until 2005 Aug. 13.

Systemic Lupus Erythematosus (SLE) is a complex autoimmune disease. HTLV-1 Related Endogenous Sequence (HRES-1), a human endogenous retrovirus, produces 2 retroviral-like Gag capsid proteins (p8 and p15) that share significant sequence homology to the U1-subunit of the small ribonucleoprotein complex (U1sn-RNP), an autoantigen of lupus. The central hypothesis is that molecular mimicry between HRES-1 and U1sn-RNP serves as a priming event in SLE via the production of cross-reactive autoantibodies. Anti-HRES-1/U1sn-RNP serological responses in subjects with SLE and comparison populations were characterized. An overlapping peptide set mapping the HRES-1 p8 and p15 proteins was used. SLE subjects produce IgG to several regions of HRES-1. Healthy subjects or those with RA, HIV-1 infection, or HTLV-1-infection produced no significant anti-HRES-1 IgG. Anti-HRES-1 antibodies deposited in the kidneys of patients with SLE glomerulonephritis were identified. Our data suggests that HRES-1 plays a role in SLE by means of a molecular mimicry mechanism with U1sn-RNP.

Thesis (Ph. D.)--Ohio State University, 2004.
Title from first page of PDF file. Document formatted into pages; contains xiii, 111 p.; also includes graphics Includes bibliographical references (p. 102-111). Available online via OhioLINK's ETD Center

Le virus HTLV-1 est l’agent étiologique de la leucémie T de l’adulte. L’oncoprotéine virale Tax contribue à la transformation cellulaire en provoquant entre autres une activation constitutive de la voie NF-κB et des dysfonctions du centrosome. Afin de mieux comprendre les mécanismes moléculaires sous-jacents à ces activités, notre équipe cherche à identifier et analyser fonctionnellement les partenaires cellulaires ciblés par Tax. Le premier objectif de ce projet est de développer au sein de l’équipe une approche de protéomique innovante basée sur la biotinylation de proximité in situ (BioID). Tax est fusionnée à BirA*, une forme modifiée d’une biotine ligase d’E. coli. Après expression de BirA*-Tax en cellules, l’analyse par spectrométrie de masse des protéines biotinylées permet d’identifier de potentiels partenaires de proximité de Tax. Par le biais de cette technique, le second objectif est d’identifier spécifiquement de nouveaux partenaires centrosomaux de Tax, puis de caractériser leur implication dans les dysfonctions oncogènes du centrosome induites par Tax. Nous validons ici la pertinence de la stratégie de BioID appliquée à Tax et présentons les résultats de protéomique obtenus. Parmi les partenaires identifiés, nous avons validé l’interaction de Tax avec la protéine p62, un récepteur autophagique impliqué dans l’activation de la voie NF-κB. Nous avons également validé l’interaction de Tax avec la protéine centrosomale Cep63 impliquée dans le cycle de duplication du centrosome. Nous discutons enfin des autres partenaires centrosomaux potentiels identifiés par BioID, ainsi que de la pertinence d’étendre cette approche à d’autres virus oncogènes tels qu’EBV et HPV. De manière générale, ces travaux offrent de nouvelles perspectives quant à la caractérisation des mécanismes moléculaires dérégulés au cours de l’oncogenèse viro-induite
The HTLV-1 retrovirus is the etiological agent of adult T-cell leukemia. The Tax oncoprotein contributes to cellular transformation by inducing, among other processes, a constitutive activation of the NF-κB pathway and centrosomal dysfunctions. In order to better understand the underlying mechanisms leading to these dysfunctions, we aim at identifying new partners targeted by Tax and analysing their functional alterations. The first aim of this project is to develop in the team an innovative proteomic strategy based on in situ biotinylation (BioID). Tax is fused to BirA*, a modified biotin ligase from E. coli. After expression of BirA*-Tax in cells, mass spectrometry analysis of biotinylated proteins allow us to identify potential partners of Tax. The second aim is to specifically identify Tax centrosomal partners and then characterize their implication in the oncogenic dysfunctions of the centrosome. Here, we validate the BioID technology applied to Tax and present the results obtained from the proteomic analysis. Among the potential partners identified by BioID, we validate the interaction of Tax with p62, an autophagic receptor involved in the activation of NF-κB signalling. We also validate the interaction of Tax with the centrosomal protein Cep63 involved in the centrosome duplication cycle. We discuss the other potential centrosomal partners identified by BioID, as well as the opportunity to extend this study to other oncogenic viruses such as EBV and HPV. This study open new perspectives on the characterization of molecular mechanisms deregulated during viral-induced oncogenesis

Les rétrovirus sont un enjeu de santé publique, aussi bien humaine qu'animale. La compréhension des déterminants structuraux sous-jacents à la fonction de leurs protéines constitue une étape essentielle dans le développement de stratégies antirétrovirales efficaces.Ce manuscrit porte sur l'étude des bases structurales des mécanismes moléculaires impliqués dans les fonctions clés des rétrovirus que sont i) la régulation de l'expression des protéines de rétrovirus complexes et ii) l'assemblage des particules virales, à travers l'étude de deux protéines rétrovirales d'intérêt thérapeutique : la protéine Tax du virus T-lymphotrope humain (HTLV) et la protéine de capside du virus de l'immunodéficience féline (FIV). L'étude structurale de ces deux protéines d'intérêt et la compréhension des mécanismes moléculaires nécessaires à leurs fonctions permettraient d'ouvrir la voie à la conception de nouvelles stratégies antirétrovirales.Malgré de nombreux tests d'expression et de purification, l'étude structurale de la protéine Tax du HTLV n'a pu être réalisée, en raison de son insolubité. Cependant, ce travail doctoral a permis de résoudre, pour la première fois, la structure cristallographique de la protéine de capside entière du FIV. Bien que cette dernière adopte un repliement similaire aux autres capsides rétrovirales dont la structure est connue, elle présente également des spécificités structurales dont les conséquences fonctionnelles seront discutées
Retroviruses are a major concern of public health in humans but also in animals. A better understanding of the structural determinants underlying the functions of retroviral proteins is a crucial step for the development of efficient antiretroviral therapies.This manuscript studies the structural basis of the molecular mechanisms implicated in key functions of retroviruses such as, i) the regulation of complex retroviruses protein expression and ii) the assembly of viral particles, through the study of two retroviral proteins of therapeutic interest: the human T-lymphotropic virus (HTLV) Tax protein and the feline immunodeficiency virus (FIV) capsid protein. The functional and structural studies of these two proteins and the understanding of the molecular mechanisms required for their functions will pave the way to the conception of new antiretroviral therapeutic strategies.Despite several expression and purification assays, no structural studies could be performed for the HLTV Tax protein. However, this study allowed the resolution of the first structure for the full-length FIV capsid protein by X-ray crystallography. Although the FIV capsid protein displays a standard a-helical topology like other retroviral CAs, it also harbors original features whose functional consequences will be discussed

碩士
國立陽明大學
公共衛生研究所
90
Decoy receptor 3 (DcR3) is a member of the TNF receptor superfamily. Since DcR3 lacks a transmembrane domain, it can be secreted from the cells. DcR3 can neutralize the biological effects of FasL and LIGHT and inhibit the cells from undergoing apoptosis. In addition, DcR3 can repress the maturation of dendritic cells and inactivate the phagocytosis function of macrophage. Previously, it has been shown that some of lung cancer and colon cancer patients had elevated plasma levels of DcR3. Besides, lymphoma caused by EBV or HTLV-I infection also had higher mRNA levels of DcR3. Therefore, the goals of this proposal were 1. to study the association of the plasma levels of DcR3 and different disease progression or manifestation of HIV-1 and HTLV-I infection; and 2. to elucidate the mechanism of the activation of DcR3 in virus infected cells. We selected 37 HIV/AIDS patients which including 2 slow progressors (CD4 cell counts > 500 per μl at least for 2 years), 18 medium progressors (CD4 cell counts between 200 to 500 per μl) and 17 fast progressors (CD4 cell counts < 200 per μl) from a longitudal follow-up cohort (each patients required to be followed up at least 2 years with 11 time points of plasma collection) and analyzed their plasma levels of DcR3 by using EIA. The results showed that the levels of DcR3 in slow progressors were significantly higher than that of the medium and fast progressors (ANOVA，p = 0.0019，Scheffe’s test). Among fast progressors, the levels of DcR3 of patients infected with HIV-1 subtype B were significantly higher than that of patients infected with subtype A/E (Student t test，p = 0.004). Among patients infected with HIV-1 subtype A/E, the levels of DcR3 of patients who had higher CD4 counts were significantly higher than that of patients who had lower CD4 counts (Student t test，p < 0.0001). Generalized Estimating Equation model was employed to analyze the correlation between levels of DcR3 and other factors related with AIDS disease progression. After adjusted sex, age, CD4, CD8 and HIV viral load, the levels of DcR3 in slow progressors were still significantly higher than that in the medium progressors (p = 0.0212) and fast progressors (p = 0.0759). To elucidate the interaction between HIV-1 Tat protein and the DcR3 gene expression, plasmid pSV-Tat-exon2 was constructed. Jurkat cells were transfected with pSV-Tat (exon 1 & exon 2) or pSV-Tat-exon2 plasmids and their expression of DcR3 was evaluated using flow cytometry. The results showed that the DcR3 levels in the Jurkat cells which expressed Tat or only exon 2 of Tat were not activated. The DcR3 levels were also compared in the following 4 groups of patients: 50 HTLV-I healthy carriers, 47 adult T-cell leukemia patients, 44 HAM/TSP patients and 95 HTLV-I negative controls. The results showed that the DcR3 levels in above 3 groups of HTLV-I-infected patients were significantly higher than that in the HTLV-I negative controls (ANOVA, p = 0.002). In this study, we found that the DcR3 levels are associated with human retroviruses infection. In addition, DcR3 levls had negative correlation with the AIDS disease progression and it may be affected by different HIV-1 subtypes. Finally, preliminary results indicated that HIV-1 Tat (exon 2 peptide of Tat) can’t activate DcR3 expression. This may contribute to the understanding of the mechanisms that HIV-1 Tat induces apoptosis of T cells.

Le premier membre de la famille des rétrovirus humains HTLV (Virus T-lymphotropique Humain), HTLV-1, a été découvert en 1980 et l’on estime aujourd’hui à plus de 10 millions le nombre d’individus infectés à travers le monde. Après une période de latence d’environ 40 ans, 5% des individus infectés développent des leucémies, des lymphomes adultes de lymphocytes T (ATLL) ou encore une myélopathie associée à HTLV-1/ paraparésie spastique tropicale (HAM/TSP). L’apparition de la maladie serait en grande partie orchestrée par deux protéines virales, soit Tax et HTLV-1 bZIP factor (HBZ). L’expression du génome viral se fait à partir d’un transcrit sens de pleine longueur suite à un épissage alternatif, à l’exception du gène HBZ. HBZ est produite à partir d’un transcrit antisens initié dans la séquence terminale longue répétée (LTR)’3. Elle a été décrite comme étant capable de réguler négativement la transcription virale dépendante de Tax en se dimérisant avec des facteurs de transcription cellulaires tels que CREB-2 et certains membres de la famille Jun. HBZ a aussi un pouvoir prolifératif et bien que nous ne sachions toujours pas le mécanisme moléculaire menant à l’oncogenèse par HBZ, nous savons qu’elle module une multitude de voies de transduction de signaux, dont AP-1. Nous avons récemment mis en évidence un transcrit antisens nommé Antisense Protein of HTLV-2 (APH-2) chez HTLV-2 qui n’est associé qu’à une myélopathie apparentée au HAM/TSP. Ce n’est qu’en 2005 que HTLV-3 et HTLV-4 se sont rajoutés au groupe HTLV. Cependant, aucune corrélation avec le développement d’une quelconque maladie n’a été montrée jusqu’à ce jour. Le premier volet de ce projet de doctorat avait pour objectif de détecter et caractériser les transcrits antisens produits par HTLV-3 et HTLV-4 et d’étudier les protéines traduites à partir de ces transcrits pour ainsi évaluer leurs similitudes et/ou différences avec HBZ et APH-2. Nos études de localisation cellulaire réalisées par microscopie confocale ont montré que APH-3 et APH-4 sont des protéines nucléaires, se retrouvant sous la forme de granules et, dans le cas d’APH-3, partiellement cytoplasmique. Ces granules co-localisent en partie avec HBZ. Les analyses à l’aide d’un gène rapporteur luciférase contenant le LTR 5’ de HTLV-1 ont montré que APH-3 et APH-4 peuvent aussi inhiber la transactivation du LTR 5’ par Tax. Aussi, des études faisant appel au gène rapporteur précédé d’un promoteur de collagénase (site AP-1), ont montré que ces deux protéines, contrairement à HBZ, activent la transcription dépendante de tous les membres des facteurs de transcription de la famille Jun. De plus, les mutants ont montré que le motif fermeture éclair (LZ) atypique de ces protéines est impliqué dans cette régulation. En effet, APH-3 et APH-4 modulent la voie Jun-dépendante en se dimérisant via leur LZ atypique avec la famille Jun et semblent activer la voie par un mécanisme ne faisant pas par d’un domaine activateur autonome. Dans un deuxième volet, nous avions comme objectif d’approfondir nos connaissances sur la localisation nucléolaire de HBZ. Lors de nos analyses, nous avons identifié deux nouveaux partenaires d’interaction, B23 et la nucléoline, qui semblent être associés à sa localisation nucléolaire. En effet, ces interactions sont plus fortes suivant une délétion des domaines AD et bZIP de HBZ qui dans ce cas est localisée strictement au nucléole. De plus, bien que APH-3 et APH-4 puissent se localiser aux nucléoles, HBZ est la seule protéine traduite à partir d’un transcrit antisens pouvant interagir avec B23. Finalement, ces travaux ont clairement mis en évidence que HTLV-3 et HTLV-4 permettent la production de transcrits antisens comme chez d’autres rétrovirus. Les protéines traduites à partir de ces transcrits antisens jouent d’importants rôles dans la réplication rétrovirale mais semblent avoir des fonctions différentes de celles de HBZ au niveau de la régulation de la transcription de la voie Jun. HBZ semble aussi jouer un rôle unique dans le nucléole en ciblant les protéines nucléolaires de la cellule. Ces études démontrent que les protéines produites à partir de transcrits antisens chez les rétrovirus HTLV partagent plusieurs ressemblances, mais démontrent aussi des différences. Ainsi, les APH pourraient, en tant qu’outil comparatif, aider à mieux cibler les mécanismes moléculaires importants utilisés par HBZ pour induire la pathogénèse associée à une infection par HTLV.
The first human T-cell lymphotropic virus (HTLV) family member was discovered in 1980 and it is estimated that approximately 10 million people are infected with HTLV-1 worldwide. After about 40 years, 5% of infected individuals will develop an adult T-cell leukemia/lymphoma (ATLL) while another 4% will develop HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). It is believed that two viral proteins, Tax and HBZ, together orchestrate the oncogenic process. The viral proteins are expressed from an alternatively spliced sense transcript except for the HBZ gene. HBZ is translated from an antisense transcript initiated in the long terminal repeat (LTR)’3. This viral protein is capable of inhibiting Tax transactivation of the LTR5’ by dimerizing with cellular transcription factors such as CREB-2 and c-Jun. HBZ also has proliferating capacities and while the molecular mechanisms leading to the disease still need to be elucidated, it is well known that HBZ can modulate a multitude of signal transduction pathways like AP-1. We have recently discovered an antisense transcript termed Antisense Protein of HTLV-2 (APH-2) produced in HTLV-2. HTLV-2 is only associated to myelopathies resembling HAM/TSP. HTLV-3 and HTLV-4 were discovered in 2005 and have not been associated with any type of disease thus far. The first goal of this PhD project was hence to detect and characterize the antisense transcripts produced in HTLV-3 and HTLV-4, to study the functions of these translated proteins and to evaluate their similarities and/or differences shared with HBZ and APH-2. Our localization studies using confocal microscopy demonstrated that APH-3 and APH-4 are found in the nucleus as speckles, and for APH-3, also partially cytoplasmic. These two proteins can also partially colocalize with HBZ. Using a luciferase reporter plasmid bearing the HTLV-1 LTR5’, we demonstrated that APH-3 and APH-4 could inhibit Tax transactivation of the LTR5’. We also used a luciferase reporter plasmid bearing the collagenase promoter, which bears an AP-1 site, and demonstrated that both viral proteins could activate transcription in the presence of any of the Jun family of transcription factors. We generated several mutants and the atypical leucine zipper (LZ) found in APH-3 and APH-4 is crucial for this regulation. In fact, APH-3 and APH-4 using their atypical LZ dimerize with Jun family members and activate this pathway using a mechanism other than an autonomous activation domain. Our next goal was to investigate the significance of the HBZ nucleolar localization. During this project, we identified two new interacting partners, B23 and nucleolin, which seem to be associated with its nucleolar localization. In fact, these interactions are stronger when HBZ is deleted of its AD and bZIP domains and hence when HBZ demonstrates a stronger nucleolar distribution. Moreover, while APH-3 and APH-4 are also found in the nucleolus, HBZ is the only antisense protein able to interact with B23. Finally, this work clearly demonstrates that HTLV-3 and HTLV-4 can produce an antisense transcript alike other retroviruses. The encoded proteins play an important role in retroviral replication and seem to regulate Jun-dependant transcription differently than HBZ. HBZ also seems to have a unique role in the nucleoli by targeting specific cellular nucleolar proteins. Similarities but also differences are shared between the antisense proteins. Thus, the APH proteins represent a good comparative tool in order to better understand the molecular mechanisms involved in HTLV induced diseases.

Background Human T cell Lymphotropic Virus Type I (HTLV-I) associated infective dermatitis, first described by Sweet in Jamaican children, is a pattern of eczema characterized by exudation, crusting around the nostrils, ears and scalp with eventual appearance of a generalized fine papular rash. More recently LeGranade and co-workers have proposed major and minor criteria in establishing the diagnosis of HTLV-I associated infective dermatitis (HAID). HTLV-I has been aetiologically linked to Adult T cell leukaemia/lymphoma (ATLL) and tropical spastic paraparesis (TSP). HAID is not only a marker of childhood infection with HTLV-I but may be a harbinger of more serious HTLV-I associated diseases later on in life such as ATLL or TSP. The pathogenesis of HAID is poorly understood so are the histopathological features of this entity. The effects of co-infection with human immunodeficiency virus- 1 (HIV-1) are inconclusive. HAID is described in Sub Saharan Africa, Senegal but no data is published on this entity in Southern Africa, characterizing the clinical, laboratory features and the histopathology of this entity. Aims and Objectives 1) To describe the clinical and histological features of HTLV-I associated infective dermatitis in KZN, South Africa 2) To determine the virological characteristics of HTLV-I in KZN, South Africa 3) To assess for HTLV-I / HIV co-infection Methods This was a prospective study of all patients with HAID who presented to King Edward VIII hospital (KEH), outpatient department over a period of 42 months. These were patients who fulfilled the clinical criteria of HAID. Enrolled patients were subjected to a confirmatory HTLV-I serology testing. Demographic data was obtained from all HTLV-I seropositive patients. Their clinical examination included dermatological, neurological and pathological examination. A blood count, immunoglobulin levels, serum protein electrophoresis measuring albumin levels and globulin fractions were measured. For bacteriological assessment skin swabs were taken from the affected sites with stool samples examined for parasites, ova and cysts. The HIV-1 status together with HIV-1 viral load were determined on those enrolled. The CD4 count, CD8 counts and CD4/CD8 ratio were also calculated. Skin biopsies were taken for histological examination. PCR for HTLV subtyping was performed on a subset of the cohort. Results Demography Of the 60 patients recruited, 33 fulfilled criteria for HAID. The majority of patients fell between age categories of 6 to lOyears. The male to female ratio was 1:1. There were more females in the adult group than there were within the childhood group. All of the patients in our cohort were African. Clinical features The lesions were erythematous, scaly, exudative, and crusted in all cases. The distribution of lesions was as follows: scalp (77.4%), retroauricular areas (71%), the axilla (65%) and paranasal areas (58%) were the sites more commonly affected. Nasal crusting was not a significant feature in this series. Bacteriology Culture was positive for Staphylococcus aureus (S. aureus) in 90%, with streptococcal group of organisms found in 68% of the skin swabs taken from the lesional skin. Haematological Our patients were mildly anaemic as has been shown in previous studies. They had a mean Hb of 11.5g/dl. In 12 of the 14 patients tested, the erythrocyte sedimentation rate (ESR) was elevated. Serum protein electrophoresis and levels of Immunoglobulin A, G and M were raised. The mean CD4 count in the entire group was elevated at 1730 cells/fil, CD8 was 1299 cells/ul Histopathology The major histological findings were as follows: 38% demonstrated a superficial and deep perivascular inflammatory infiltrate, 28% had a superficial and deep perivascular inflammatory infiltrate together with a lichenoid dermatitis, 12.9% had features of superficial and deep inflammatory infiltrate with an interface dermatitis, 6.4% revealed features of seborrhoeic dermatitis. Genotyping Our patients were infected with the strains belonging to the Cosmopolitan, A Subtype (HTLV-Ia). Complications Complications were low in this series with the commonest being scabies in 6(18.1%), corneal opacities in 3(8.6%), 2(6 %) with HAM/TSP. No parasitic worm infestations were isolated. HIV/HTLV-I co-infection Of the 33 patients, 9 (30 %) were co-infected with HIV. The mean viral load in this group was 52 000 copies/ml. Their mean CD4 count was also elevated at 1505cells/^il with a CD8 of 1704 cells/Mi and a CD4/CD8 ratio of 1.15. Discussion Thirty three of the 60 patients enrolled met the diagnosis for HAID according to the established criteria. The mean age in this series was 17 years (range: 8 months-46 years)however; almost a third (30.3%) were children under 12 years, reinforcing the entity as a childhood infective condition. There was an equal male female distribution in the childhood group and a female predominance in the adult group. Clinically patients presented with infected erythematous, scaly lesions mainly on the scalp, neck and post- auricular area. The clinical features were in keeping with other series worldwide. The complication rate was low in our cohort. S. aureus was the predominant organism in both anterior nares and lesional skin. The most common histological pattern was superficial and deep perivascular inflammatory infiltrate. The subtype in our series was the Cosmopolitan Subtype A (HTLV-Ia) as opposed to subtype B in Japan. We share with Brazil a common subtype. A subset of our patients (30%) was co-infected with HIV. The CD4 cell count in this subgroup was lower than the entire group but this was not statistically significant. The histological patterns found in this subgroup infected with HIV were similar to the rest of the group except for a more intense eosinophilic infiltrate in these skin biopsy specimens. Conclusion HTLV-I associated infective dermatitis is distinct entity which affects the African population of KwaZulu Natal, South Africa. It is predominantly a disease of childhood with an equal female to male ratio in children. The clinical features are an exudative, erythematous scaly rash most commonly found involving the scalp, axillae, paranasal and retroauricular areas. HTLV-I positivity is essential for the diagnosis; the Cosmopolitan Subtype A is commonest in South Africa. The commonest histological pattern is a superficial and deep perivascular infiltrate in 38%. A subset, 30%, was co-infected with HIV.
Thesis (M.Med.)-University of KwaZulu-Natal, Durban, 2008.

MA (Psychology)
Department of Psychology
Background: An estimated 70% of people in Sub-Saharan Africa out of 25 million are living with HIV. HIV is a debilitating disease, however, antiretroviral treatment helps promote effective viral suppression, reduces the risk of transmission and prevents death (WHO, 2013). To ensure positive treatment outcomes, high levels of Anti-Retroviral Therapy (ART) adherence, 95%, is necessary, however, research indicates that 23% of Africans are achieving less than 80% adherence, potentially impacting negatively on prognosis. Aim: The aim of this study was to determine adherence, explore perceptions and behaviour of patients on Antiretroviral Therapy attending Thohoyandou Health Centre, in Vhembe District, Limpopo, South Africa. Methodology: This was a mixed method which employed both quantitative and qualitative research approaches. In quantitative, triangulation was utilised through a questionnaire and patients’ file, simple random sampling was used to select 105 male and female patients aged 18-60 who are on ART at Thohoyandou Health Centre; data were collected and SPSSversion 25 was used to analyse the data through descriptive, cross tabulation and inferential statistics using Chi-square.Qualitative phase – phenomelogical research design was utilised, twenty participants were purposively sampled and individually interviewed, ATLAS. ti program was used to analyse the data collected. Results: 67% of respondents were females, 34% of the respondents’ age range was 50-60 years, 44.8% were single, 48.6% had tertiary education and 69.5% were unemployed. The self-report of ART adherence of 87.6% among patients was indicated, with 19.6% who reported defaulting ART, 14.3% admitted to missing medical appointments. The reasons for missing medical appointments were: forgetfulness, not a convenient time, patient feeling better, transportation challenges and being too sick to attend. The objective evaluation of patients’ CD4 count at baseline revealed that 40.9% of patients had a CD4 count of <200c/mm3, out of 40.9% respondents (15.2%) were those aged between 41-50 years, 31.4% of respondents did not know their CD4 count for various reasons (defaulted on treatment, missed appointments). CD4 count follow-up data after six months revealed that 33% of patients had a CD4 count <200c/mm3 and 39% accounted for unknown CD4 count. vi Three themes emerged from the data, namely: Knowledge of HIV were respondents presented a negaitive and positive perception of ths diagnosis; barriers to ART adherence where sub-themes included discrimination, strigma, rejection, inadequate knowledge about the diagnosis and treatment, side effects; coping strategies where acceptance, religion and social support serve as corner stones for patients. Association was examined and findings did not reveal any significant association between gender, marital status, education, occupation; however, age was significantly associated with non-adherence to ART with X2 = 3.69, df = 1, p = < .002. Recommendations: The study recommends intensification of health education campaign against stigma, discrimination, rejection and other barriers to enhance positive attitude towards HIV patients that wil consequently stimulate adherence and alleviate the burden associated with taking treatment unswervingly. Given the high percentage of infected older respondents, government must also focus its resources to educate illiterate and older people about HIV, adherence and management in order to achieve the golden standardrate of 95% adherence. Strategies to facilitate and normalise adherence among males is indicated.
NRF

MA (Psychology)
Department of Psychology
Background: Given that there is 57.7 million HIV-diagnosed people living in South Africa and the government has established the largest public antiretroviral programme in the whole world but only 53% are adhering. Adherence remains a challenge, due to presence of mental health issues among HIV diagnosed. Aim: The aim of this study was to investigate adherence to antiretroviral therapy and mental health of HIV-diagnosed patients in Vhembe District, Limpopo Province. Methods: This was a mixed method study using a combination of quantitative and qualitative research approaches. In the quantitative approach, triangulation was utilised in the form of a questionnaire and patients records. Simple random sampling was used to select 134, descriptive analysis using SPSS version 25. For the qualitative approach, a phenomenological research designs was considered and convenience sampling was used to select fifteen participants (15). Data was collected using semi-structured interview; responses were analysed using a computer-aided program called, ATLAS ti. Results: The self-report of adherence was 94.8 %, objectively 39.6% of CD4 count <200c/mm3 at baseline and 34.3% CD4 count after six months was found. 16.5% of females and 2% of males defaulted treatment and 14.9% of missed medical appointments 1-6 times. This study also revealed the mental health issues that HIV-diagnosed patients are struggling with after the diagnosis include the stages of grief, stress, depression, anxiety, mistrust, shame, stigma and discrimination. Recommendation: Effective strategies need to be enhanced and tailor made in effort to encourage patients to take ART diligently. The healthcare providers, community members and the government should be made aware of mental health issues.
NRF