The use of directed evolution to create a stable and immunogenic recombinant BCG expressing a modified HIV-1 Gag antigen.

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dc.contributor.authorChapman, Rosamunden
dc.contributor.authorBourn, William Ren
dc.contributor.authorShephard, Eniden
dc.contributor.authorStutz, Helenen
dc.contributor.authorDouglass, Nicolaen
dc.contributor.authorMgwebi, Thandien
dc.contributor.authorMeyers, Annen
dc.contributor.authorChin'ombe, Nyashaen
dc.contributor.authorWilliamson, Anna-Liseen
dc.date.accessioned2015-12-15T10:00:32Zen
dc.date.available2015-12-15T10:00:32Zen
dc.date.epub2014-07-25en
dc.date.issued2014-07-25en
dc.description.abstractNumerous features make Mycobacterium bovis BCG an attractive vaccine vector for HIV. It has a good safety profile, it elicits long-lasting cellular immune responses and in addition manufacturing costs are affordable. Despite these advantages it is often difficult to express viral antigens in BCG, which results in genetic instability and low immunogenicity. The aim of this study was to generate stable recombinant BCG (rBCG) that express high levels of HIV antigens, by modification of the HIV genes. A directed evolution process was applied to recombinant mycobacteria that expressed HIV-1 Gag fused to the green fluorescent protein (GFP). Higher growth rates and increased GFP expression were selected for. Through this process a modified Gag antigen was selected. Recombinant BCG that expressed the modified Gag (BCG[pWB106] and BCG[pWB206]) were more stable, produced higher levels of antigen and grew faster than those that expressed the unmodified Gag (BCG[pWB105]). The recombinant BCG that expressed the modified HIV-1 Gag induced 2 to 3 fold higher levels of Gag-specific CD4 T cells than those expressing the unmodified Gag (BCG[pWB105]). Mice primed with 10(7) CFU BCG[pWB206] and then boosted with MVA-Gag developed Gag-specific CD8 T cells with a frequency of 1343±17 SFU/10(6) splenocytes, 16 fold greater than the response induced with MVA-Gag alone. Levels of Gag-specific CD4 T cells were approximately 5 fold higher in mice primed with BCG[pWB206] and boosted with MVA-Gag than in those receiving the MVA-Gag boost alone. In addition mice vaccinated with BCG[pWB206] were protected from a surrogate vaccinia virus challenge.en
dc.description.sponsorshipThis study was supported by the South African AIDS Vaccine Initiative (SAAVI) and National Institute of Health (NIH USA) for funding from the Phased Innovation Awards (PIA R21/R33) in AIDS Vaccine Research: grant number 5R33A173182. This work is also based upon research supported by the South African Research Chairs Initiative of the Department of Science and Technology and National Research Foundation. The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.en
dc.identifier.citationChapman R, Bourn WR, Shephard E, Stutz H, Douglass N, Mgwebi T, Meyers A, Chin'ombe N, Williamson AL. The use of directed evolution to create a stable and immunogenic recombinant BCG expressing a modified HIV-1 gag antigen. PLoS ONE. 2014 July 25;9(7):e103314. DOI: 10.1371/journal.pone.0103314.en
dc.identifier.doi10.1371/journal.pone.0103314en
dc.identifier.issn1932-6203en
dc.identifier.journalPloS Oneen
dc.identifier.pmid25061753en
dc.identifier.urihttp://hdl.handle.net/11288/583900en
dc.internal.reviewer-notePlease remove the number two in the beginning of the "Citation Section".en
dc.language.isoenen
dc.relation.urlhttp://journals.plos.org/plosone/article?id=10.1371/journal.pone.0103314#abstract0en
dc.research.unitGRANTSen
dc.rightsArchived with thanks to PloS oneen
dc.subjectCloningen
dc.subjectCytotoxic T Cellsen
dc.subjectImmune responseen
dc.subjectPlasmid constructionen
dc.subjectRecombinant Proteinen
dc.subjectRecombinant Vaccinesen
dc.subjectT cellsen
dc.subjectVaccinesen
dc.subject.meshAnimalsen
dc.subject.meshCD4-Positive T-Lymphocytesen
dc.subject.meshCD8-Positive T-Lymphocytesen
dc.subject.meshDirected Molecular Evolutionen
dc.subject.meshFemaleen
dc.subject.meshGreen Fluorescent Proteinsen
dc.subject.meshMiceen
dc.subject.meshMice, Inbred BALB Cen
dc.subject.meshMycobacterium bovisen
dc.subject.meshVaccines, Syntheticen
dc.subject.meshgag Gene Products, Human Immunodeficiency Virusen
dc.titleThe use of directed evolution to create a stable and immunogenic recombinant BCG expressing a modified HIV-1 Gag antigen.en
dc.typeArticleen
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