Browsing by Author "Williamson, C"

Now showing 1 - 6 of 6
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    Beneficial HLA-mediated viral polymorphisms on the transmitted virus additively influence disease progression in HIV-1, subtype C infection
    (BioMed Central Ltd, 2012) Ntale, R S; Chopera, D R; Ngandu, N K; Abrahams, M; Debra, A; Mlotswa, M; Werner, L; Woodman, Z; Mlisana, K; Karim, S; Gray, CM; Williamson, C; CAPRISA 002 AI Study Team
    Transmitted viral factors have been shown to affect disease progression but whether infection with viruses carrying beneficial HLA-mediated escape polymorphisms affects disease progression in HLA-mismatched participants remains controversial.
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    Characterization of envelope function of transmitted viruses circulating in Mbeya, Tanzania, and its impact on disease progression
    (BioMed Central Ltd, 2012) Nofemela, A; Bandawe, G; Thebus, R; Marais, J; Maboko, L; Hoelscher, M; Williamson, C; Woodman, Z
    An understanding of the biological characteristics of transmitted viruses provides important insights into HIV pathogenesis and informs vaccine development. The aim of the study was to characterize env function of transmitted viruses and its role in disease progression.
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    HIV type 1 subtype C gag and nef diversity in Southern Africa.
    (Mary Ann Liebert, 2007) Bredell, Helba; Martin, Darren P; Van Harmelen Joanne; Varsani, Arvind; Sheppard, Haynes W; Donovan, R; Gray, C; HIVNET028 Study Team; Williamson, C
    Several HIV-1 subtype C-specific gag- and/or nef-based vaccines are currently intended for clinical trial in southern Africa. Here we provide sequences of 64 gag and 45 nef genes sampled in Malawi, Zambia, Zimbabwe, and South Africa and assess the degree of southern African HIV-1 diversity that will confront these vaccines. Whereas reasonable phylogenetic evidence exists for geographical clustering of subtype C gag and nef sequences from various other parts of the world, there is little evidence of similar population founder effects in the southern African epidemic. The entire breadth of subtype C diversity is represented in the southern African genes suggesting there may be no advantage in producing region- or country-specific subtype C vaccines. We do not, however, find much evidence of intersubtype recombination in the Southern African genes, implying that the likelihood of vaccine failure due to the emergence of intersubtype recombinants is probably low.
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    Increased differentiation associates with decreased polyfunctionality for HIV but not CMV-specific CD8+ T cell responses
    (BioMed Central Ltd, 2012) Riou, C; Abrahams, M; Mlisana, K; Koup, R; Roederer, M; Karim, S; de Bruyn, G; Williamson, C; Gray, CM; Burgers, WA
    The generation of polyfunctional CD8+ T cells, in response to vaccination or natural infection, has been associated with improved protective immunity. However, it remains unclear whether the maintenance of polyfunctionality is linked to particular phenotypic characteristics of the cell, such as the differentiation stage of memory T cells. The goal of this study was to investigate the relationship between the memory maturation stage and polyfunctional profiles of antigen-specific CD8+ T cells.
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    The recognition of HIV-1 consensus group M Gag and Nef peptide reagents in mono- and multi-clade epidemics: implications for HIV vaccine design
    (BioMed Central Ltd, 2012) Zembe, L; Tongo, M; Ebong, E; Ngobe, EM; Williamson, C; Burgers, W
    The high level of genetic diversity of HIV-1 poses a major challenge for global vaccine development. Vaccines based on centralized sequences would minimize genetic distances to multiple clades and potentially maximize cross-reactivity. Whether reactivity of these centralized peptide reagents differs in mono- and multi-clade epidemic is unknown.
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    A single dose of SAAVI MVA-C reboosts rhesus macaques after more than 3 years post DNA-MVA prime-boost vaccination
    (BioMed Central Ltd, 2012) Chege, GK; Burgers, W; Muller, T; Shephard, EG; Williamson, C; Williamson, A
    We have previously reported induction of robust immune responses in rhesus macaques following a prime boost immunization with candidate HIV-1 vaccines, SAAVI DNA-C (DNA) and SAAVI MVA-C (MVA). These vaccines are already in clinical evaluation. In the current study, we investigated whether re-boosting these animals with a single MVA inoculation after more than 3 years was sufficient to restore previous magnitudes of HIV-specific immune responses.