Biology subjects

Esbjornsson, J.

Publications and source records attributed to Esbjornsson, J..

3 recordsLinked to original sources

bioRxiv2018

Characterisation of the HIV-1 Molecular Epidemiology in Nigeria: Origin, Diversity, Demography and Geographic Spread

Nigeria has been reported to have the highest number of AIDS-related deaths in the world. In this study, we aimed to determine the HIV-1 genetic diversity and phylodynamics in Nigeria. We analysed 1442 HIV-1 pol sequences collected 1999-2014 from four geopolitical zones in Nigeria. Phylogenetic analysis showed that the main circulating strains was the circulating recombinant strain (CRF) 02_AG (44% of the analysed sequences), subtype G (8%), and CRF43_02G (16%); and that these were introduced in Nigeria in the 1960s, 1970s and 1980s, respectively. The number of effective infections decreased in Nigeria after the introduction of free antiretroviral treatment in 2006. We also found a significant number of unique recombinant forms (22.7%). The majority of those were recombinants between two or three of the main circulating strains. Seven of those recombinants may represent novel CRFs. Finally, phylogeographic analysis suggested multiple occasions of HIV-1 transmissions between Lagos and Abuja (two of the main cities in Nigeria), that HIV-1 epidemic started in these cities, and then dispersed into rural areas.\n\nIMPORTANCENigeria has the second largest HIV-1 epidemic in the world with the highest number of AIDS-related deaths. The few previous reports have focused on local HIV-1 subtype/CRF distributions in different Nigerian regions, and the molecular epidemiology of HIV-1 in Nigeria as a whole is less well characterized. In this study, we describe the HIV-1 spatiotemporal dynamics of the five dominating transmission clusters representing the main characteristics of the epidemiology. Our results may contribute to inform prevention strategies against further spread of HIV-1 in Nigeria.

microbiology↗

bioRxiv2018

Natural alteration of HIV-1 co-receptor tropism by contemporaneous HIV-2 infection 1

In this study, we show that the pathogenic HIV-1 CXCR4-tropism is more common in HIV-1 single (79%) than in HIV-1 and HIV-2 dual-infected individuals (35%), suggesting that contemporaneous HIV-2 infection can affect HIV-1 co-receptor tropism in late-stage disease. Understanding the underlying mechanisms responsible for this natural alteration by HIV-2 could pave the way towards a deeper understanding of the AIDS pathogenesis.

microbiology↗

bioRxiv2017

Distinct antibody-mediated selection in a narrow-source HIV-1 outbreak among Chinese former plasma donors

The HIV-1 envelope protein mutates rapidly to evade recognition and killing, and is a major target of the humoral immune response and in vaccine development. Identification of common antibody epitopes for vaccine development have been complicated by large variations on both virus (different infecting founder strains) and host genetic levels. We studied HIV-1 envelope gp120 evolution in 12 Chinese former plasma donors infected with a purportedly single founder virus, with the aim of identifying common antibody epitopes under immune selection. We found five amino acid sites to be under significant positive selection in [≥]50% of the patients, and 22 sites housing mutations consistent with antibody-mediated selection. Despite strong selection pressure, some sites housed a limited repertoire of amino acids. Structural modelling revealed that most sites were located on the exposed distal edge of the Gp120 trimer, whilst wholly invariant sites clustered within the centre of the protein complex. Four sites, flanking the V3 hypervariable loop of the Gp120, represent novel antibody epitopes that may be suitable as vaccine candidates.

immunology↗