Browsing by Author "Williamson, A"

Now showing 1 - 7 of 7
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    Impact of the innate environment on maintaining memory T-cell numbers in the female genital tract: implications for mucosal vaccine efficacy?
    (BioMed Central Ltd, 2012) Dabee, S; Passmore, J; Williamson, A; Gumbi, P
    Preventative HIV vaccines aim to elicit long-lived protective immune responses at the site of HIV transmission, capable of responding quickly to HIV challenge, but which remain stable at effector sites of the genital mucosa. The genital mucosa is, however, commonly confronted with innate immune modifiers and inflammatory agents including sexually-transmitted infections, behavioural and hygiene practices. We investigated the impact of mucosal inflammation and homeostatic cytokines on local T-cell phenotype, proliferation, exhaustion and activation.
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    Induction of HIV-1 Gag-specific memory T cells in Chacma baboons by MVA prime and VLP boost vaccine regimen
    (BioMed Central Ltd, 2012) Singh, V; Chege, G; Shephard, E; Williamson, A
    We previously reported induction of HIV-specific responses in Chacma baboons following immunization with SAAVI MVA-C (MVA) and HIV-1 Pr55 Gag virus-like particles (VLPs) in a prime-boost vaccination strategy. In the current study, we characterised the vaccine specific memory T cells by flow cytometry.
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    Inflammation in the male genital tract: implications for HIV acquisition and transmission
    (BioMed Central Ltd, 2012) Olivier, Abraham Jacobus; Roberts, L; Coetzee, D; Williamson, A; Passmore, JS; Burgers, WA
    Elevated plasma levels of pro-inflammatory mediators such as TNFα, IL-1β, IL-6 and IL-8, MIP-1α, MIP-1β and RANTES have been demonstrated in HIV-infected individuals and HIV induces higher levels of pro-inflammatory cytokines in the female genital tract. We characterized levels of inflammation in semen, to gain an understanding of factors influencing transmission and acquisition in the male genital tract. Our hypothesis was that infected men would exhibit higher levels of inflammation in semen than uninfected men.
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    P19-53 LB. Priming with recombinant BCG expressing HIV-1 Gag or RT and boosting with recombinant MVA induces an effective immune response in mice
    (BioMed Central Ltd, 2009) Stutz, H; Powles, R; Shephard, EG; Williamson, A
    Mycobacterium bovis BCG (BCG) has a number of characteristics that give it great potential to act as a vehicle for the delivery of recombinant vaccines. However, its success depends on overcoming the challenges of poor antigen expression levels and genetic instability. Our studies using an optimized mycobacterial shuttle vector which utilizes the Mycobacterium tuberculosis mtrA promoter, induced upon infection of macrophages, and the M. tuberculosis 19 kDa signal sequence may overcome these issues. We have used this system to generate a recombinant BCG (rBCG) expressing HIV-1 subtype C full length Gag or reverse transcriptase (RT).
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    A pantothenate suxotroph of BCG rxpressing Gag confers enhanced HIV-specific immunogenicity compared to wildtype and perfingolysin expressing strains
    (BioMed Central Ltd, 2012) Chetty, S; Shephard, E; Bowers, D; Darby, M; Horsnell, W; Chapman, R; Williamson, A
    In tuberculosis vaccine studies, perfingolysin expressing strains (pfo) of recombinant Mycobacterium bovis (rBCG) have been shown to enhance immunogenicity as compared to wildtype strains whilst pantothenate auxotrophic strains (ΔpanCD) have been shown to be safer and more immunogenic. Our group has recently shown that rBCGΔpanCD expressing HIV-1 Gag is more immunogenic than the wildtype Pasteur strain of BCG in the murine model. In this study, a wild type strain, a ΔpanCDstrain, a pfo strain and a ΔpanCD strain expressing perfringolysin (ΔpanCDpfo) of Danish BCG were used as vectors to express HIV-1 subtype C Gag. Gag specific immune responses induced by a prime with each rBCG-Gag vaccine and boost with modified vaccinia Ankara (MVA) were compared.
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    A prime-boost immunization with rBCG expressing HIV-1 Gag, RT and gp120 and SAAVI MVA-C elicits immune responses in blood and MALT of rhesus macaques
    (BioMed Central Ltd, 2012) Chege, GK; Chapman, R; Shephard, EG; Williamson, A
    CG pantothenate auxtroph (ΔpanCD) is safer to use as a live vaccine vector than wild-type BCG. We constructed 3 recombinant BCGΔpanCD candidate vaccines expressing HIV-1 subtype C Gag, RT and Env (gp120). The current study investigated immune responses in rhesus macaques following a prime with a mixture of these rBCG vaccines and a boost with SAAVI MVA-C (MVA).
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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.