Browsing by Author "Thebus, Ruwayhida."

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Decreased incidence of dual infections in South African subtype C-infected women compared to a cohort ten years earlier.
(Mary Ann Liebert., 2011) Woodman, Zenda.; Mlisana, Koleka Patience.; Treurnicht, Florette K.; Abrahams, Melissa-Rose.; Thebus, Ruwayhida.; Abdool Karim, Salim Safurdeen.; Williamson, Carolyn.
Previously, we determined the incidence of dual infections in a South African cohort and its association with higher viral setpoint. Ten years later, we compare the incidence and impact of dual infections at transmission on viral setpoint in a geographically similar cohort (n=46) making use of both the heteroduplex mobility assay (HMA) and the more recent single genome amplification (SGA) approach. HIV incidence was lower in this cohort (7% compared to 18%), and we find a similar reduction in the number of dual infections (9% compared to 19%). Unlike the previous study, there was no association between either dual infection (n=4) or multivariant transmission (n=7) and disease progression. This study emphasized the importance of monitoring changes in the HIV epidemic as it may have important ramifications on our understanding of the natural history of disease.
Differences in HIV-1 neutralization breadth in two geographically distinct cohorts in Africa.
(Oxford University Press., 2015) Bandawe, Gama P.; Moore, Penelope L.; Werner, Lise.; Gray, Elin Solomonovna.; Sheward, Daniel J.; Madiga, Maphuti C.; Nofemela, Andile.; Thebus, Ruwayhida.; Marais, Jinny C.; Maboko, Leonard.; Abdool Karim, Salim Safurdeen.; Hoelscher, Michael.; Morris, Lynn.; Williamson, Carolyn.
Abstract available in pdf.
Features of recently transmitted HIV-1 clade C viruses that impact antibody recognition : implications for active and passive immunization.
(Public Library of Science., 2016) Rademeyer, Cecilia.; Korber, Bette T. M.; Seaman, Michael S.; Giorgi, Elena E.; Thebus, Ruwayhida.; Robles, Alexander.; Sheward, Daniel J.; Wagh, Kshitij.; Garrity, Jetta.; Carey, Brittany R.; Gao, Hongmei.; Greene, Kelli M.; Tang, Haili.; Bandawe, Gama P.; Marais, Jinny C.; Diphoko, Thabo E.; Hraber, Peter.; Tumba, Nancy Lola.; Moore, Penelope L.; Gray, Glenda Elizabeth.; Kublin, James.; McElrath, Margaret Juliana.; Vermeulen, Marion.; Middelkoop, Keren.; Bekker, Linda-Gail.; Hoelscher, Michael.; Maboko, Leonard.; Makhema, Joseph.; Robb, Merlin L.; Abdool Karim, Salim Safurdeen.; Abdool Karim, Quarraisha.; Kim, Jerome H.; Hahn, Beatrice H.; Gao, Feng.; Swanstrom, Ronald.; Morris, Lynn.; Montefiori, David Charles.; Williamson, Carolyn.
Abstract available in PDF file.
Quantitating the multiplicity of infection with human immunodeficiency virus type 1 subtype C reveals a non-poisson distribution of transmitted variants.
(American Society for Microbiology., 2008) Abrahams, Melissa-Rose.; Anderson, Jeffrey A.; Giorgi, Elena E.; Seoighe, Cathal.; Mlisana, Koleka Patience.; Liu, Pinghuang.; Athreya, G. S.; Treurnicht, Florette K.; Keele, Brandon F.; Wood, N.; Salazar-Gonzalez, Jesus F.; Bhattacharya, Tanmoy.; Chu, Haitao.; Hoffman, Irving F.; Galvin, S.; Mapanje, Clement.; Kazembe, P.; Thebus, Ruwayhida.; Fiscus, Susan A.; Hide, Winston.; Cohen, Myron S.; Abdool Karim, Salim Safurdeen.; Haynes, Barton F.; Shaw, George M.; Hahn, Beatrice H.; Korber, Bette T. M.; Swanstrom, Ronald.; Williamson, Carolyn.
Identifying the specific genetic characteristics of successfully transmitted variants may prove central to the development of effective vaccine and microbicide interventions. Although human immunodeficiency virus transmission is associated with a population bottleneck, the extent to which different factors influence the diversity of transmitted viruses is unclear. We estimate here the number of transmitted variants in 69 heterosexual men and women with primary subtype C infections. From 1,505 env sequences obtained using a single genome amplification approach we show that 78% of infections involved single variant transmission and 22% involved multiple variant transmissions (median of 3). We found evidence for mutations selected for cytotoxic-T-lymphocyte or antibody escape and a high prevalence of recombination in individuals infected with multiple variants representing another potential escape pathway in these individuals. In a combined analysis of 171 subtype B and C transmission events, we found that infection with more than one variant does not follow a Poisson distribution, indicating that transmission of individual virions cannot be seen as independent events, each occurring with low probability. While most transmissions resulted from a single infectious unit, multiple variant transmissions represent a significant fraction of transmission events, suggesting that there may be important mechanistic differences between these groups that are not yet understood.
Rapid, complex adaption of transmitted HIV-1 full-length genomes in subtype C-infected individuals with differing disease progression.
(Wolters Kluwer Health., 2013) Abrahams, Melissa-Rose.; Treurnicht, Florette K.; Ngandu, Nobubelo K.; Goodier, Sarah A.; Marais, Jinny C.; Bredell, Helba.; Thebus, Ruwayhida.; de Assis Rosa, Debra.; Seoighe, Cathal.; Abdool Karim, Salim Safurdeen.; Gray, Clive M.; Williamson, Carolyn.; Mlisana, Koleka Patience.
Objective(s): There is limited information on full-length genome sequences and the early evolution of transmitted HIV-1 subtype C viruses, which constitute the majority of viruses spread in Africa. The purpose of this study was to characterize the earliest changes across the genome of subtype C viruses following transmission, to better understand early control of viremia. Design: We derived the near full-length genome sequence responsible for clinical infection from five HIV subtype C-infected individuals with different disease progression profiles and tracked adaptation to immune responses in the first 6 months of infection. Methods: Near full-length genomes were generated by single genome amplification and direct sequencing. Sequences were analyzed for amino acid mutations associated with cytotoxic T lymphocyte (CTL) or antibody-mediated immune pressure, and for reversion. Results: Fifty-five sequence changes associated with adaptation to the new host were identified, with 38% attributed to CTL pressure, 35% to antibody pressure, 16% to reversions and the remainder were unclassified. Mutations in CTL epitopes were most frequent in the first 5 weeks of infection, with the frequency declining over time with the decline in viral load. CTL escape predominantly occurred in nef, followed by pol and env. Shuffling/toggling of mutations was identified in 81% of CTL epitopes, with only 7% reaching fixation within the 6-month period. Conclusion: There was rapid virus adaptation following transmission, predominantly driven by CTL pressure, with most changes occurring during high viremia. Rapid escape and complex escape pathways provide further challenges for vaccine protection.