A molecular study of the immunopathogenesis of TB spondylitis in HIV -infected and -uninfected patients.

Thesis (Ph.D)-University of KwaZulu-Natal, Durban, 2008.Abstract can be viewed in PDF document

BioAfrica's HIV-1 Proteomics Resource: Combining protein data with bioinformatics tools

Most Internet online resources for investigating HIV biology contain either bioinformatics tools, protein information or sequence data. The objective of this study was to develop a comprehensive online proteomics resource that integrates bioinformatics with the latest information on HIV-1 protein structure, gene expression, post-transcriptional/post-translational modification, functional activity, and protein-macromolecule interactions. The BioAfrica HIV-1 Proteomics Resource is a website that contains detailed information about the HIV-1 proteome and protease cleavage sites, as well as data-mining tools that can be used to manipulate and query protein sequence data, a BLAST tool for initiating structural analyses of HIV-1 proteins, and a proteomics tools directory. The Proteome section contains extensive data on each of 19 HIV-1 proteins, including their functional properties, a sample analysis of HIV-1(HXB2), structural models and links to other online resources. The HIV-1 Protease Cleavage Sites section provides information on the position, subtype variation and genetic evolution of Gag, Gag-Pol and Nef cleavage sites. The HIV-1 Protein Data-mining Tool includes a set of 27 group M (subtypes A through K) reference sequences that can be used to assess the influence of genetic variation on immunological and functional domains of the protein. The BLAST Structure Tool identifies proteins with similar, experimentally determined topologies, and the Tools Directory provides a categorized list of websites and relevant software programs. This combined database and software repository is designed to facilitate the capture, retrieval and analysis of HIV-1 protein data, and to convert it into clinically useful information relating to the pathogenesis, transmission and therapeutic response of different HIV-1 variants. The HIV-1 Proteomics Resource is readily accessible through the BioAfrica website at

Drug resistance in children at virological failure in a rural KwaZulu-Natal, South Africa, cohort.

BACKGROUND: Better understanding of drug resistance patterns in HIV-infected children on antiretroviral therapy (ART) is required to inform public health policies in high prevalence settings. The aim of this study was to characterise the acquired drug resistance in HIV-infected children failing first-line ART in a decentralised rural HIV programme. METHODS: Plasma samples were collected from 101 paediatric patients (≤15 yrs of age) identified as failing ART. RNA was extracted from the plasma, reverse transcribed and a 1.3 kb region of the pol gene was amplified and sequenced using Sanger sequencing protocols. Sequences were edited in Geneious and drug resistance mutations were identified using the RegaDB and the Stanford resistance algorithms. The prevalence and frequency of mutations were analysed together with selected clinical and demographic data in STATA v11. RESULTS: A total of 101 children were enrolled and 89 (88%) were successfully genotyped; 73 on a non-nucleoside reverse-transcriptase inhibitor (NNRTI)-based regimen and 16 on a protease inhibitor (PI)-based regimen at the time of genotyping. The majority of patients on an NNRTI regimen (80%) had both nucleoside reverse-transcriptase inhibitor (NRTI) and NNRTI resistance mutations. M184V and K103N were the most common mutations amongst children on NNRTI-based and M184V among children on PI-based regimens. 30.1% had one or more thymidine analogue mutation (TAM) and 6% had ≥3 TAMs. Only one child on a PI-based regimen harboured a major PI resistance mutation. CONCLUSIONS: Whilst the patterns of resistance were largely predictable, the few complex resistance patterns seen with NNRTI-based regimens and the absence of major PI mutations in children failing PI-based regimens suggest the need for wider access to genotypic resistance testing in this setting

HIV serostatus, inflammatory biomarkers and the frailty phenotype among older people in rural KwaZulu-Natal, South Africa.

Objective: We compared the prevalence of frailty by HIV serostatus and related biomarkers to the modified frailty phenotype among older individuals in a rural population in South Africa. Methods: Questionnaire data were from a cohort of people living with HIV (PWH) on antiretroviral therapy (ART) and HIV-uninfected people aged 50 years and older sampled from the Africa Health Research Institute Demographic Health and Surveillance area in northern KwaZulu-Natal. The prevalence of frailty was compared using five categories: (1) physical activity; (2) mobility; (3) fatigue; (4) gait speed; and (5) grip strength, and assessed for demographic, clinical, and inflammatory correlates of frailty. Results: Among 614 individuals in the study, 384 (62.5%) were women. The median age at study enrolment was 64 years [Interquartile range (IQR) (58.6-72.0)]. 292 (47.6%) were PWH. 499 (81%) were classified as either pre-frail or frail. 43 (7%) were frail and HIV positive, 185 (30%) were pre-frail and HIV positive, 57 were frail and HIV negative and 214 (35%) were pre-frail and HIV negative. Frailty was similar for HIV negative and PWH (17.7% vs 14.7%, p = 0.72). Women were more likely to be frail (18.3% vs 13.04%, p = 0.16). The prevalence of frailty increased with age for both HIV groups. In the multivariable analysis, the odds of being frail were higher in those aged 70 years and above than those aged between 50 and 59 years (p < 0.001). Females were less likely to be pre-frail than males (p < 0.001). There was no association between any of the inflammatory biomarkers and frailty and pre-frailty. Conclusion: In this population, the prevalence of frailty is similar for PWH and people without HIV, but higher for women than men. These data suggest that the odds of developing frailty is similar for PWH over the age of 50 years, who survive into older age, as for people without HIV

Analysis of dominant HIV quasispecies suggests independent viral evolution within spinal granulomas coinfected with mycobacterium tuberculosis and HIV-1 Subtype C

Extrapulmonary tuberculosis (TB) is a significant public health challenge in South Africa and worldwide, largely fuelled by the HIV epidemic. In spinal TB, Mycobacteria infect the spinal column without dissemination to the spinal cord. The immune microenvironment, target cell characteristics, and other evolutionary forces within granulomas during HIV/TB coinfection are poorly characterized. We investigated whether spinal TB granulomas represent a sequestered anatomical site where independent HIV evolution occurs, and assessed the role of macrophages as a target cell for both HIV and mycobacteria. RNA was extracted from plasma and granulomatous tissue from six antiretroviral-naive HIV-1/spinal TB-coinfected patients, RT-PCR amplified, and the C2-V5 env segment was cloned and sequenced. Analysis of genetic diversity, phylogeny and coalescence patterns was performed on clonal sequences. To investigate their role in HIV sequestration, macrophages and the HIV-1 p24 protein were immune localized and ultrastructural features were studied. Intercompartment diversity measurements and phylogenetic reconstruction revealed anatomically distinct monophyletic HIV-1 clusters in four of six patients. Genotypic CCR5-tropic variants were predominant (98.9%) with conservation of putative N-linked glycosylation sites in both compartments. CD68+ reactivity was associated with higher tissue viral load (r = 1.0; p 0.05). Ultrastructural imaging revealed the presence of bacterial and virus-like particles within membrane-bound intracellular compartments of macrophages. Spinal tuberculosis granulomas may form anatomically discreet sites of divergent viral evolution. Macrophages in these granulomas harbored both pathogens, suggesting that they may facilitate the process of viral sequestration within this compartment.This work was funded by a Wellcome Trust Grant. T. Ndung'u is funded through the South African DST/NRF Research Chair in Systems Biology of HIV/AIDS, the Victor Daitz Chair in HIV/TB Research, and an International Early Career Scientist Award from the Howard Hughes Medical Institute.http://online.liebertpub.com/aid2017-03-31hb2017Immunolog

Evidence of Long-Lived Founder Virus in Mother-to-Child HIV Transmission

<div><p>Exposure of the infant’s gut to cell-associated and cell-free HIV-1 trafficking in breast milk (BM) remains a primary cause of mother-to-child transmission (MTCT). The mammary gland represents a unique environment for HIV-1 replication and host-virus interplay. We aimed to explore the origin of the virus transmitted during breastfeeding, and the link with quasi-species found in acellular and cellular fractions of breast-milk (BM) and in maternal plasma. The C2–V5 region of the env gene was amplified, cloned and sequenced from the RNA and DNA of BM, the RNA from the mother’s plasma (PLA) and the DNA from infant’s dried blood spot (DBS) in 11 post-natal mother-infant pairs. Sequences were assembled in Geneious, aligned in ClustalX, manually edited in SeAL and phylogenetic reconstruction was undertaken in PhyML and MrBayes. We estimated the timing of transmission (ETT) and reconstructed the time for the most recent common ancestor (TMRCA) of the infant in BEAST. Transmission of single quasi-species was observed in 9 of 11 cases. Phylogenetic analysis illustrated a BM transmission event by cell-free virus in 4 cases, and by cell-associated virus in 2 cases but could not be identified in the remaining 5 cases. Molecular clock estimates, of the infant ETT and TMRCA, corresponded well with the timing of transmission estimated by sequential infant DNA PCR in 10 of 11 children. The TMRCA of BM variants were estimated to emerge during gestation in 8 cases. We hypothesize that in the remaining cases, the breast was seeded with a long-lived lineage latently infecting resting T-cells. Our analysis illustrated the role of DNA and RNA virus in MTCT. We postulate that DNA archived viruses stem from latently infected quiescent T-cells within breast tissue and MTCT can be expected to continue, albeit at low levels, should interventions not effectively target these cells.</p></div

Sample size of VTS cohort.

<p>An illustration of the number of patients in the post-natal vertical transmission study and the subsequent number of cases, comprising mother-infant pairs, selected for this analysis.</p