Safety and Immunogenicity of Novel Recombinant BCG and Modified Vaccinia Virus Ankara Vaccines in Neonate Rhesus Macaques

MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, The John Radcliffe, Oxford, United Kingdom.
Journal of Virology (Impact Factor: 4.44). 08/2010; 84(15):7815-21. DOI: 10.1128/JVI.00726-10
Source: PubMed


Although major inroads into making antiretroviral therapy available in resource-poor countries have been made, there is an urgent need for an effective vaccine administered shortly after birth, which would protect infants from acquiring human immunodeficiency virus type 1 (HIV-1) through breast-feeding. Bacillus Calmette-Guérin (BCG) is given to most infants at birth, and its recombinant form could be used to prime HIV-1-specific responses for a later boost by heterologous vectors delivering the same HIV-1-derived immunogen. Here, two groups of neonate Indian rhesus macaques were immunized with either novel candidate vaccine BCG.HIVA(401) or its parental strain AERAS-401, followed by two doses of recombinant modified vaccinia virus Ankara MVA.HIVA. The HIVA immunogen is derived from African clade A HIV-1. All vaccines were safe, giving local reactions consistent with the expected response at the injection site. No systemic adverse events or gross abnormality was seen at necropsy. Both AERAS-401 and BCG.HIVA(401) induced high frequencies of BCG-specific IFN-gamma-secreting lymphocytes that declined over 23 weeks, but the latter failed to induce detectable HIV-1-specific IFN-gamma responses. MVA.HIVA elicited HIV-1-specific IFN-gamma responses in all eight animals, but, except for one animal, these responses were weak. The HIV-1-specific responses induced in infants were lower compared to historic data generated by the two HIVA vaccines in adult animals but similar to other recombinant poxviruses tested in this model. This is the first time these vaccines were tested in newborn monkeys. These results inform further infant vaccine development and provide comparative data for two human infant vaccine trials of MVA.HIVA.

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    • "These characteristics make BCG an attractive vaccine vector for the expression of heterologous immunogens with the goal of a combined vaccine with efficacy against both TB and other pathogens [4] [5]. Several research groups have developed vaccine vectors expressing HIV or SIV proteins in recombinant forms of either BCG or attenuated M. tuberculosis [6] [7] [8] [9] [10] [11] [12] [13] [14]. However, prior anti-vector immunity has the potential to impact the effectiveness of rBCG vaccine vectors since BCG shares antigens with other mycobacterial species. "
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    ABSTRACT: A recombinant Mycobacterium bovis BCG (rBCG) vector expressing HIV transgenes is an attractive candidate as a dual vaccine against HIV and TB. However, pre-existing immune responses to mycobacteria may influence immune responses to rBCG. We analyzed data from a rhesus rBCG trial to determine the effect of pre-existing mycobacterial immune responses on the vaccine-induced responses to the vector and expressed transgene. Indian-origin rhesus macaques were primed with rBCG expressing simian immunodeficiency virus (SIV) Gag and boosted with attenuated vaccinia NYVAC gag-pol. Mycobacteria responses were measured by Mycobacterium tuberculosis (Mtb) purified protein derivative (PPD) interferon-γ ELISpot and Mtb whole cell lysate (WCL) ELISA. SIV Gag responses were measured by SIV Gag ELISpot and by p11C tetramer binding. Baseline Mtb PPD ELISpot responses and Mtb WCL antibody responses in rhesus macaques overlapped those in human populations. Cellular and antibody responses boosted sharply 4 weeks after rBCG vaccination. Mtb WCL antibody titers at 4 weeks correlated with baseline titers. Primates vaccinated with rBCG developed strong SIV Gag ELISpot and p11C tetramer responses after rBCG prime and NYVAC boost. There were no correlations between the pre-existing mycobacterial immune responses and the SIV Gag T cell responses after vaccination. Rhesus immune responses to SIV Gag expressed by rBCG vectors were independent from pre-existing anti-mycobacterial immunity. Rhesus macaques may serve as a surrogate for investigations of pre-existing anti-mycobacterial immunity in humans. Copyright © 2015. Published by Elsevier Ltd.
    Full-text · Article · Jul 2015 · Vaccine
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    • "In 2007 when the PedVacc 001 trial was conceived, we envisaged a strategy administering MVA.HIVA boost to 20-week-old infants who have been primed at birth with HIVA-expressing Mycobacterium bovis bacillus Calmette-Guérin (BCG) [49,50]. Moreover, encouraged by then promising results of candidate TB vaccine MVA85A [51], there was a possibility to develop the BGC-MVA regimen into a dual HIV-TB vaccine platform [24,25,52-56]. Since the commencement of PedVacc 001, both the immunogen design and vector delivery evolved. "
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    ABSTRACT: A vaccine to decrease transmission of human immunodeficiency virus type 1 (HIV-1) during breast-feeding would complement efforts to eliminate infant HIV-1 infection by antiretroviral therapy. Relative to adults, infants have distinct immune development, potentially high-risk of transmission when exposed to HIV-1 and rapid progression to AIDS when infected. To date, there have been only three published HIV-1 vaccine trials in infants. We conducted a randomized phase I clinical trial PedVacc 001 assessing the feasibility, safety and immunogenicity of a single dose of candidate vaccine MVA.HIVA administered intramuscularly to 20-week-old infants born to HIV-1-negative mothers in The Gambia. Infants were followed to 9 months of age with assessment of safety, immunogenicity and interference with Expanded Program on Immunization (EPI) vaccines. The trial is the first stage of developing more complex prime-boost vaccination strategies against breast milk transmission of HIV-1. From March to October 2010, 48 infants (24 vaccine and 24 no-treatment) were enrolled with 100% retention. The MVA.HIVA vaccine was safe with no difference in adverse events between vaccinees and untreated infants. Two vaccine recipients (9%) and no controls had positive ex vivo interferon-γ ELISPOT assay responses. Antibody levels elicited to the EPI vaccines, which included diphtheria, tetanus, whole-cell pertussis, hepatitis B virus, Haemophilus influenzae type b and oral poliovirus, reached protective levels for the vast majority and were similar between the two arms. A single low-dose of MVA.HIVA administered to 20-week-old infants in The Gambia was found to be safe and without interference with the induction of protective antibody levels by EPI vaccines, but did not alone induce sufficient HIV-1-specific responses. These data support the use of MVA carrying other transgenes as a boosting vector within more complex prime-boost vaccine strategies against transmission of HIV-1 and/or other infections in this age group. NCT00982579 The Pan African Clinical Trials Registry PACTR2008120000904116.
    Full-text · Article · Oct 2013 · PLoS ONE
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    • "We observed in newborn mice a lower level of HIV-1 specific T-cell immune responses compared with adult mice. Rosario et al. [59] have assessed the immunogenicity of the BCG.HIVA222 prime and MVA.HIVA boost regimen in newborn rhesus macaques and made similar observation. On the other hand, we suggest that additional experiments should be performed in newborn mice inoculating the rBCG expressing HIV-1 antigens by different routes and different doses, because the route and dose of neonatal vaccination may provide different levels of immune activation, which may affect the efficacy of the vaccine. "
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    ABSTRACT: In the past, we proposed to develop a heterologous recombinant BCG prime-recombinant modified vaccinia virus Ankara (MVA) boost dual pediatric vaccine platform against transmission of breast milk HIV-1 and Mycobacterium tuberculosis (Mtb). In this study, we assembled an E. coli-mycobacterial shuttle plasmid pJH222.HIVA(CAT) expressing HIV-1 clade A immunogen HIVA. This shuttle vector employs an antibiotic resistance-free mechanism based on Operator-Repressor Titration (ORT) system for plasmid selection and maintenance in E. coli and lysine complementation in mycobacteria. This shuttle plasmid was electroporated into parental lysine auxotroph (safer) strain of BCG to generate vaccine BCG.HIVA(CAT). All procedures complied with Good Laboratory Practices (GLPs). We demonstrated that the episomal plasmid pJH222.HIVA(CAT) was stable in vivo over a 20-week period, and genetically and phenotypically characterized the BCG.HIVA(CAT) vaccine strain. The BCG.HIVA(CAT) vaccine in combination with MVA.HIVA induced HIV-1- and Mtb-specific interferon γ-producing T-cell responses in newborn and adult BALB/c mice. On the other hand, when adult mice were primed with BCG.HIVA(CAT) and boosted with MVA.HIVA.85A, HIV-1-specific CD8(+) T-cells producing IFN-γ, TNF-α, IL-2 and CD107a were induced. To assess the biosafety profile of BCG.HIVA(CAT)-MVA.HIVA regimen, body mass loss of newborn mice was monitored regularly throughout the vaccination experiment and no difference was observed between the vaccinated and naïve groups of animals. Thus, we demonstrated T-cell immunogenicity of a novel, safer, GLP-compatible BCG-vectored vaccine using prototype immunogen HIVA. Second generation immunogens derived from HIV-1 as well as other major pediatric pathogens can be constructed in a similar fashion to prime protective responses soon after birth.
    Full-text · Article · Aug 2012 · PLoS ONE
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