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Jongwe TI, Chapman R, Douglass N, Chetty S, Chege G, Williamson AL. HIV-1 Subtype C Mosaic Gag Expressed by BCG and MVA Elicits Persistent Effector T Cell Responses in a Prime-Boost Regimen in Mice. PLoS One 2016; 11:e0159141. [PMID: 27427967 PMCID: PMC4948879 DOI: 10.1371/journal.pone.0159141] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Accepted: 06/28/2016] [Indexed: 11/18/2022] Open
Abstract
Over 90% of HIV/AIDS positive individuals in sub-Saharan Africa are infected with highly heterogeneous HIV-1 subtype C (HIV-1C) viruses. One of the best ways to reduce the burden of this disease is the development of an affordable and effective prophylactic vaccine. Mosaic immunogens are computationally designed to overcome the hurdle of HIV diversity by maximizing the expression of potential T cell epitopes. Mycobacterium bovis BCG ΔpanCD auxotroph and modified vaccinia Ankara (MVA) vaccines expressing HIV-1C mosaic Gag (GagM) were tested in a prime-boost regimen to demonstrate immunogenicity in a mouse study. The BCG-GagM vaccine was stable and persisted 11.5 weeks post vaccination in BALB/c mice. Priming with BCG-GagM and boosting with MVA-GagM elicited higher Gag-specific IFN-γ ELISPOT responses than the BCG-GagM only and MVA-GagM only homologous vaccination regimens. The heterologous vaccination also generated a more balanced and persistent CD4+ and CD8+ T cell Gag-specific IFN-γ ELISPOT response with a predominant effector memory phenotype. A Th1 bias was induced by the vaccines as determined by the predominant secretion of IFN-γ, TNF-α, and IL-2. This study shows that a low dose of MVA (104 pfu) can effectively boost a BCG prime expressing the same mosaic immunogen, generating strong, cellular immune responses against Gag in mice. Our data warrants further evaluation in non-human primates. A low dose vaccine would be an advantage in the resource limited countries of sub-Saharan Africa and India (where the predominating virus is HIV-1 subtype C).
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Affiliation(s)
- Tsungai Ivai Jongwe
- Institute of Infectious Disease and Molecular Medicine and Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Ros Chapman
- Institute of Infectious Disease and Molecular Medicine and Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- * E-mail:
| | - Nicola Douglass
- Institute of Infectious Disease and Molecular Medicine and Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Shivan Chetty
- Institute of Infectious Disease and Molecular Medicine and Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Gerald Chege
- Institute of Infectious Disease and Molecular Medicine and Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Anna-Lise Williamson
- Institute of Infectious Disease and Molecular Medicine and Division of Medical Virology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- National Health Laboratory Services, Groote Schuur Hospital, Cape Town, South Africa
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Burgers WA, van Harmelen JH, Shephard E, Adams C, Mgwebi T, Bourn W, Hanke T, Williamson AL, Williamson C. Design and preclinical evaluation of a multigene human immunodeficiency virus type 1 subtype C DNA vaccine for clinical trial. J Gen Virol 2006; 87:399-410. [PMID: 16432028 DOI: 10.1099/vir.0.81379-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In this study, the design and preclinical development of a multigene human immunodeficiency virus type 1 (HIV-1) subtype C DNA vaccine are described, developed as part of the South African AIDS Vaccine Initiative (SAAVI). Genetic variation remains a major obstacle in the development of an HIV-1 vaccine and recent strategies have focused on constructing vaccines based on the subtypes dominant in the developing world, where the epidemic is most severe. The vaccine, SAAVI DNA-C, contains an equimolar mixture of two plasmids, pTHr.grttnC and pTHr.gp150CT, which express a polyprotein derived from Gag, reverse transcriptase (RT), Tat and Nef, and a truncated Env, respectively. Genes included in the vaccine were obtained from individuals within 3 months of infection and selection was based on closeness to a South African subtype C consensus sequence. All genes were codon-optimized for increased expression in humans. The genes have been modified for safety, stability and immunogenicity. Tat was inactivated through shuffling of gene fragments, whilst maintaining all potential epitopes; the active site of RT was mutated; 124 aa were removed from the cytoplasmic tail of gp160; and Nef and Gag myristylation sites were inactivated. Following vaccination of BALB/c mice, high levels of cytotoxic T lymphocytes were induced against multiple epitopes and the vaccine stimulated strong CD8+ gamma interferon responses. In addition, high titres of antibodies to gp120 were induced in guinea pigs. This vaccine is the first component of a prime-boost regimen that is scheduled for clinical trials in humans in the USA and South Africa.
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Affiliation(s)
- Wendy A Burgers
- Institute of Infectious Disease and Molecular Medicine (IIDMM) and Division of Medical Virology, University of Cape Town (UCT), Observatory, Cape Town 7925, South Africa
| | - Joanne H van Harmelen
- Institute of Infectious Disease and Molecular Medicine (IIDMM) and Division of Medical Virology, University of Cape Town (UCT), Observatory, Cape Town 7925, South Africa
| | - Enid Shephard
- MRC/UCT Liver Research Centre, UCT, Observatory, Cape Town 7925, South Africa
- Institute of Infectious Disease and Molecular Medicine (IIDMM) and Division of Medical Virology, University of Cape Town (UCT), Observatory, Cape Town 7925, South Africa
| | - Craig Adams
- Institute of Infectious Disease and Molecular Medicine (IIDMM) and Division of Medical Virology, University of Cape Town (UCT), Observatory, Cape Town 7925, South Africa
| | - Thandiswa Mgwebi
- Institute of Infectious Disease and Molecular Medicine (IIDMM) and Division of Medical Virology, University of Cape Town (UCT), Observatory, Cape Town 7925, South Africa
| | - William Bourn
- Institute of Infectious Disease and Molecular Medicine (IIDMM) and Division of Medical Virology, University of Cape Town (UCT), Observatory, Cape Town 7925, South Africa
| | - Tomáš Hanke
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, The John Radcliffe, Oxford, UK
| | - Anna-Lise Williamson
- National Health Laboratory Services, Groote Schuur Hospital, Cape Town, South Africa
- Institute of Infectious Disease and Molecular Medicine (IIDMM) and Division of Medical Virology, University of Cape Town (UCT), Observatory, Cape Town 7925, South Africa
| | - Carolyn Williamson
- Institute of Infectious Disease and Molecular Medicine (IIDMM) and Division of Medical Virology, University of Cape Town (UCT), Observatory, Cape Town 7925, South Africa
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