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Olvera A, Noguera-Julian M, Kilpelainen A, Romero-Martín L, Prado JG, Brander C. SARS-CoV-2 Consensus-Sequence and Matching Overlapping Peptides Design for COVID19 Immune Studies and Vaccine Development. Vaccines (Basel) 2020; 8:E444. [PMID: 32781672 PMCID: PMC7565482 DOI: 10.3390/vaccines8030444] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 07/28/2020] [Accepted: 07/31/2020] [Indexed: 12/30/2022] Open
Abstract
Synthetic antigens based on consensus sequences that represent circulating viral isolates are sensitive, time saving and cost-effective tools for in vitro immune monitoring and to guide immunogen design. When based on a representative sequence database, such consensus sequences can effectively be used to test immune responses in exposed and infected individuals at the population level. To accelerate immune studies in SARS-CoV-2 infection, we here describe a SARS-CoV-2 2020 consensus sequence (CoV-2-cons) which is based on more than 1700 viral genome entries in NCBI and encompasses all described SARS-CoV-2 open reading frames (ORF), including recently described frame-shifted and length variant ORF. Based on these sequences, we created curated overlapping peptide (OLP) lists containing between 1500 to 3000 peptides of 15 and 18 amino acids in length, overlapping by 10 or 11 residues, as ideal tools for the assessment of SARS-CoV-2-specific T cell immunity. In addition, CoV-2-cons sequence entropy values are presented along with variant sequences to provide increased coverage of the most variable sections of the viral genome. The identification of conserved protein fragments across the coronavirus family and the corresponding OLP facilitate the identification of T cells potentially cross-reactive with related viruses. This new CoV-2-cons sequence, together with the peptides sets, should provide the basis for SARS-CoV-2 antigen synthesis to facilitate comparability between ex-vivo immune analyses and help to accelerate research on SARS-CoV-2 immunity and vaccine development.
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Affiliation(s)
- Alex Olvera
- IrsiCaixa AIDS Research Institute-HIVACAT, Hospital Universitari Germans Trias i Pujol, 08916 Badalona, Spain; (A.O.); (M.N.-J.); (A.K.); (L.R.-M.)
- Faculty of Sciences and Technology, Universitat de Vic-Central de Catalunya (UVic-UCC), 08500 Vic, Spain
| | - Marc Noguera-Julian
- IrsiCaixa AIDS Research Institute-HIVACAT, Hospital Universitari Germans Trias i Pujol, 08916 Badalona, Spain; (A.O.); (M.N.-J.); (A.K.); (L.R.-M.)
- Faculty of Medicine, Universitat de Vic-Central de Catalunya (UVic-UCC), 08500 Vic, Spain
| | - Athina Kilpelainen
- IrsiCaixa AIDS Research Institute-HIVACAT, Hospital Universitari Germans Trias i Pujol, 08916 Badalona, Spain; (A.O.); (M.N.-J.); (A.K.); (L.R.-M.)
| | - Luis Romero-Martín
- IrsiCaixa AIDS Research Institute-HIVACAT, Hospital Universitari Germans Trias i Pujol, 08916 Badalona, Spain; (A.O.); (M.N.-J.); (A.K.); (L.R.-M.)
| | - Julia G. Prado
- IrsiCaixa AIDS Research Institute-HIVACAT, Hospital Universitari Germans Trias i Pujol, 08916 Badalona, Spain; (A.O.); (M.N.-J.); (A.K.); (L.R.-M.)
- Germans Trias i Pujol Research Institute (IGTP), 08196 Barcelona, Spain
| | - Christian Brander
- IrsiCaixa AIDS Research Institute-HIVACAT, Hospital Universitari Germans Trias i Pujol, 08916 Badalona, Spain; (A.O.); (M.N.-J.); (A.K.); (L.R.-M.)
- Faculty of Medicine, Universitat de Vic-Central de Catalunya (UVic-UCC), 08500 Vic, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain
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Arenas M, Araujo NM, Branco C, Castelhano N, Castro-Nallar E, Pérez-Losada M. Mutation and recombination in pathogen evolution: Relevance, methods and controversies. INFECTION GENETICS AND EVOLUTION 2017; 63:295-306. [PMID: 28951202 DOI: 10.1016/j.meegid.2017.09.029] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2017] [Revised: 09/20/2017] [Accepted: 09/21/2017] [Indexed: 02/06/2023]
Abstract
Mutation and recombination drive the evolution of most pathogens by generating the genetic variants upon which selection operates. Those variants can, for example, confer resistance to host immune systems and drug therapies or lead to epidemic outbreaks. Given their importance, diverse evolutionary studies have investigated the abundance and consequences of mutation and recombination in pathogen populations. However, some controversies persist regarding the contribution of each evolutionary force to the development of particular phenotypic observations (e.g., drug resistance). In this study, we revise the importance of mutation and recombination in the evolution of pathogens at both intra-host and inter-host levels. We also describe state-of-the-art analytical methodologies to detect and quantify these two evolutionary forces, including biases that are often ignored in evolutionary studies. Finally, we present some of our former studies involving pathogenic taxa where mutation and recombination played crucial roles in the recovery of pathogenic fitness, the generation of interspecific genetic diversity, or the design of centralized vaccines. This review also illustrates several common controversies and pitfalls in the analysis and in the evaluation and interpretation of mutation and recombination outcomes.
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Affiliation(s)
- Miguel Arenas
- Department of Biochemistry, Genetics and Immunology, University of Vigo, Vigo, Spain; Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, Porto, Portugal; Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Porto, Portugal.
| | - Natalia M Araujo
- Laboratory of Molecular Virology, Oswaldo Cruz Institute, FIOCRUZ, Rio de Janeiro, Brazil.
| | - Catarina Branco
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, Porto, Portugal; Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Porto, Portugal.
| | - Nadine Castelhano
- Instituto de Investigação e Inovação em Saúde (i3S), University of Porto, Porto, Portugal; Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Porto, Portugal.
| | - Eduardo Castro-Nallar
- Universidad Andrés Bello, Center for Bioinformatics and Integrative Biology, Facultad de Ciencias Biológicas, Santiago, Chile.
| | - Marcos Pérez-Losada
- Computational Biology Institute, Milken Institute School of Public Health, George Washington University, Ashburn, VA 20147, Washington, DC, United States; CIBIO-InBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Campus Agrário de Vairão, Vairão 4485-661, Portugal.
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3
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Pérez-Losada M, Arenas M, Galán JC, Palero F, González-Candelas F. Recombination in viruses: mechanisms, methods of study, and evolutionary consequences. INFECTION, GENETICS AND EVOLUTION : JOURNAL OF MOLECULAR EPIDEMIOLOGY AND EVOLUTIONARY GENETICS IN INFECTIOUS DISEASES 2015; 30:296-307. [PMID: 25541518 PMCID: PMC7106159 DOI: 10.1016/j.meegid.2014.12.022] [Citation(s) in RCA: 198] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Revised: 12/15/2014] [Accepted: 12/17/2014] [Indexed: 02/08/2023]
Abstract
Recombination is a pervasive process generating diversity in most viruses. It joins variants that arise independently within the same molecule, creating new opportunities for viruses to overcome selective pressures and to adapt to new environments and hosts. Consequently, the analysis of viral recombination attracts the interest of clinicians, epidemiologists, molecular biologists and evolutionary biologists. In this review we present an overview of three major areas related to viral recombination: (i) the molecular mechanisms that underlie recombination in model viruses, including DNA-viruses (Herpesvirus) and RNA-viruses (Human Influenza Virus and Human Immunodeficiency Virus), (ii) the analytical procedures to detect recombination in viral sequences and to determine the recombination breakpoints, along with the conceptual and methodological tools currently used and a brief overview of the impact of new sequencing technologies on the detection of recombination, and (iii) the major areas in the evolutionary analysis of viral populations on which recombination has an impact. These include the evaluation of selective pressures acting on viral populations, the application of evolutionary reconstructions in the characterization of centralized genes for vaccine design, and the evaluation of linkage disequilibrium and population structure.
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Affiliation(s)
- Marcos Pérez-Losada
- CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Universidade do Porto, Campus Agrário de Vairão, Portugal; Computational Biology Institute, George Washington University, Ashburn, VA 20147, USA
| | - Miguel Arenas
- Centre for Molecular Biology "Severo Ochoa", Consejo Superior de Investigaciones Científicas (CSIC), Madrid, Spain
| | - Juan Carlos Galán
- Servicio de Microbiología, Hospital Ramón y Cajal and Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid, Spain; CIBER en Epidemiología y Salud Pública, Spain
| | - Ferran Palero
- CIBER en Epidemiología y Salud Pública, Spain; Unidad Mixta Infección y Salud Pública, FISABIO-Universitat de València, Valencia, Spain
| | - Fernando González-Candelas
- CIBER en Epidemiología y Salud Pública, Spain; Unidad Mixta Infección y Salud Pública, FISABIO-Universitat de València, Valencia, Spain.
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4
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Tongo M, Burgers WA. Challenges in the design of a T cell vaccine in the context of HIV-1 diversity. Viruses 2014; 6:3968-90. [PMID: 25341662 PMCID: PMC4213573 DOI: 10.3390/v6103968] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 10/15/2014] [Accepted: 10/18/2014] [Indexed: 12/27/2022] Open
Abstract
The extraordinary variability of HIV-1 poses a major obstacle to vaccine development. The effectiveness of a vaccine is likely to vary dramatically in different populations infected with different HIV-1 subtypes, unless innovative vaccine immunogens are developed to protect against the range of HIV-1 diversity. Immunogen design for stimulating neutralizing antibody responses focuses on “breadth” – the targeting of a handful of highly conserved neutralizing determinants on the HIV-1 Envelope protein that can recognize the majority of viruses across all HIV-1 subtypes. An effective vaccine will likely require the generation of both broadly cross-neutralizing antibodies and non-neutralizing antibodies, as well as broadly cross-reactive T cells. Several approaches have been taken to design such broadly-reactive and cross-protective T cell immunogens. Artificial sequences have been designed that reduce the genetic distance between a vaccine strain and contemporary circulating viruses; “mosaic” immunogens extend this concept to contain multiple potential T cell epitope (PTE) variants; and further efforts attempt to focus T cell immunity on highly conserved regions of the HIV-1 genome. Thus far, a number of pre-clinical and early clinical studies have been performed assessing these new immunogens. In this review, the potential use of these new immunogens is explored.
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Affiliation(s)
- Marcel Tongo
- Institute of Infectious Disease and Molecular Medicine, Division of Medical Virology, University of Cape Town, Anzio Road, Observatory 7925, Cape Town, South Africa.
| | - Wendy A Burgers
- Institute of Infectious Disease and Molecular Medicine, Division of Medical Virology, University of Cape Town, Anzio Road, Observatory 7925, Cape Town, South Africa.
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Ruiz-Riol M, Llano A, Ibarrondo J, Zamarreño J, Yusim K, Bach V, Mothe B, Perez-Alvarez S, Fernandez MA, Requena G, Meulbroek M, Pujol F, Leon A, Cobarsi P, Korber BT, Clotet B, Ganoza C, Sanchez J, Coll J, Brander C. Alternative effector-function profiling identifies broad HIV-specific T-cell responses in highly HIV-exposed individuals who remain uninfected. J Infect Dis 2014; 211:936-46. [PMID: 25249264 DOI: 10.1093/infdis/jiu534] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The characterization of host immune responses to human immunodeficiency virus (HIV) in HIV controllers and individuals with high exposure but seronegativity to HIV (HESN) is needed to guide the development of effective preventive and therapeutic vaccine candidates. However, several technical hurdles severely limit the definition of an effective virus-specific T-cell response. By using a toggle-peptide approach, which takes HIV sequence diversity into account, and a novel, boosted cytokine staining/flow cytometry strategy, we here describe new patterns of T-cell responses to HIV that would be missed by standard assays. Importantly, this approach also allows detection of broad and strong virus-specific T-cell responses in HESN individuals that are characterized by a T-helper type 1 cytokine-like effector profile and produce cytokines that have been associated with potential control of HIV infection, including interleukin 10, interleukin 13, and interleukin 22. These results establish a novel approach to improve the current understanding of HIV-specific T-cell immunity and identify cellular immune responses and individual cytokines as potential markers of relative HIV resistance. As such, the findings also help develop similar strategies for more-comprehensive assessments of host immune responses to other human infections and immune-mediated disorders.
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Affiliation(s)
- Marta Ruiz-Riol
- HIVACAT, Irsicaixa AIDS Research Institute, Autonomous University of Barcelona
| | - Anuska Llano
- HIVACAT, Irsicaixa AIDS Research Institute, Autonomous University of Barcelona
| | - Javier Ibarrondo
- Center for HIV Prevention Research, University of California-Los Angeles
| | - Jennifer Zamarreño
- HIVACAT, Irsicaixa AIDS Research Institute, Autonomous University of Barcelona
| | | | - Vanessa Bach
- HIVACAT, Irsicaixa AIDS Research Institute, Autonomous University of Barcelona
| | - Beatriz Mothe
- HIVACAT, Irsicaixa AIDS Research Institute, Autonomous University of Barcelona Fundació Lluita Contra La Sida, Hospital Universitari Germans Trias i Pujol University of Vic, Spain
| | | | - Marco A Fernandez
- Flow Cytometry Facility, Health Sciences Research Institute Germans Trias i Pujol, Badalona
| | - Gerard Requena
- Flow Cytometry Facility, Health Sciences Research Institute Germans Trias i Pujol, Badalona
| | | | | | | | - Patricia Cobarsi
- Fundació Lluita Contra La Sida, Hospital Universitari Germans Trias i Pujol
| | | | - Bonaventura Clotet
- HIVACAT, Irsicaixa AIDS Research Institute, Autonomous University of Barcelona Fundació Lluita Contra La Sida, Hospital Universitari Germans Trias i Pujol University of Vic, Spain
| | | | - Jorge Sanchez
- Asociacion Civil Impacta Salud y Educacion, Lima, Peru
| | - Josep Coll
- HIVACAT, Irsicaixa AIDS Research Institute, Autonomous University of Barcelona Fundació Lluita Contra La Sida, Hospital Universitari Germans Trias i Pujol
| | - Christian Brander
- HIVACAT, Irsicaixa AIDS Research Institute, Autonomous University of Barcelona Institució Catalana de Recerca i Estudis Avancats (ICREA), Barcelona University of Vic, Spain
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Tongo M, Zembe L, Ebong E, Roux S, Bekker LG, Williamson C, Mpoudi-Ngole E, Burgers WA. Striking lack of T cell immunodominance in both a multiclade and monoclade HIV-1 epidemic: implications for vaccine development. Vaccine 2014; 32:2328-36. [PMID: 24598726 DOI: 10.1016/j.vaccine.2014.02.063] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2013] [Revised: 02/02/2014] [Accepted: 02/12/2014] [Indexed: 12/16/2022]
Abstract
Understanding the impact of HIV diversity on immunological responses to candidate immunogens is critical for HIV vaccine development. We investigated the reactivity and immunodominance patterns of HIV-1 consensus group M Gag and Nef in (i) Cameroon, where individuals infected with the predominant CRF02_AG clade were compared with those infected with diverse non-CRF02_AG clades; and (ii) in a multiclade epidemic, namely Cameroon, compared with a monoclade C epidemic, South Africa. We analyzed 57 HIV-infected individuals from Cameroon and 44 HIV-infected individuals from South Africa for differences in detecting HIV-1 consensus M Gag and Nef T cell responses using the IFN-γ ELISpot assay. We found no difference in the predicted epitope coverage between CRF02_AG and non-CRF02_AG viruses for either Gag or Nef. There were no differences in the magnitude and breadth of responses for CRF02_AG and non-CRF02_AG-infected individuals. In contrast, the specificity of epitope targeting was markedly different between the two groups, with fewer than one third (11/38) of peptides commonly recognized in Gag. Furthermore, only one peptide was commonly recognized by at least three individuals from both AG and non-AG groups, indicating poor immunodominance. For Nef, more than half of all targeted peptides (14/27) were recognized by both groups, and four peptides were commonly targeted by at least three individuals. Three times more peptides were exclusively targeted in the diverse non-CRF02_AG group compared to the CRF02_AG group (10 vs. 3). Of note, similar results were obtained when South Africa, a monoclade C epidemic, and Cameroon, a multiclade epidemic, were compared. The central nature of HIV-1 consensus M sequences resulted in their broad recognition, but failed to identify highly immunodominant peptides between homogeneous and diverse HIV epidemics.
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Affiliation(s)
- Marcel Tongo
- Division of Medical Virology, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa; Institute of Medical Research and Study of Medicinal Plants, Yaoundé, Cameroon
| | - Lycias Zembe
- Division of Immunology, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa
| | - Eugenie Ebong
- Institute of Medical Research and Study of Medicinal Plants, Yaoundé, Cameroon
| | - Surita Roux
- The Desmond Tutu HIV Centre, Cape Town, South Africa
| | | | - Carolyn Williamson
- Division of Medical Virology, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa; National Health Laboratory Service, Groote Schuur Hospital, Cape Town, South Africa
| | - Eitel Mpoudi-Ngole
- Institute of Medical Research and Study of Medicinal Plants, Yaoundé, Cameroon
| | - Wendy A Burgers
- Division of Medical Virology, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa.
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Performance of a redesigned HIV Selectest enzyme-linked immunosorbent assay optimized to minimize vaccine-induced seropositivity in HIV vaccine trial participants. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2014; 21:391-8. [PMID: 24403525 DOI: 10.1128/cvi.00748-13] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Vaccine-induced seropositivity (VISP) or seroreactivity (VISR), defined as the reaction of antibodies elicited by HIV vaccines with antigens used in HIV diagnostic immunoassays, can result in reactive assay results for vaccinated but uninfected individuals, with subsequent misclassification of their infection status. The eventual licensure of a vaccine will magnify this issue and calls for the development of mitigating solutions in advance. An immunoassay that discriminates between antibodies elicited by vaccine antigens and those elicited by infection has been developed to address this laboratory testing need. The HIV Selectest is based on consensus and clade-specific HIV peptides that are omitted in many HIV vaccine constructs. The assay was redesigned to enhance performance across worldwide clades and to simplify routine use via a standard kit format. The redesigned assay was evaluated with sera from vaccine trial participants, HIV-infected and uninfected individuals, and healthy controls. The HIV Selectest exhibited specificities of 99.5% with sera from uninfected recipients of 6 different HIV vaccines and 100% with sera from normal donors, while detecting HIV-1 infections, including intercurrent infections, with 95 to 100% sensitivity depending on the clade, with the highest sensitivities for clades A and C. HIV Selectest sensitivity decreased in very early seroconversion specimens, which possibly explains the slightly lower sensitivity observed for asymptomatic blood donors than for clinical HIV cases. Thus, the HIV Selectest provides a new laboratory tool for use in vaccine settings to distinguish the immune response to HIV vaccine antigens from that due to true infection.
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8
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Increased sequence coverage through combined targeting of variant and conserved epitopes correlates with control of HIV replication. J Virol 2013; 88:1354-65. [PMID: 24227851 DOI: 10.1128/jvi.02361-13] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A major challenge in the development of an HIV vaccine is that of contending with the extensive sequence variability found in circulating viruses. Induction of HIV-specific T-cell responses targeting conserved regions and induction of HIV-specific T-cell responses recognizing a high number of epitope variants have both been proposed as strategies to overcome this challenge. We addressed the ability of cytotoxic T lymphocytes from 30 untreated HIV-infected subjects with and without control of virus replication to recognize all clade B Gag sequence variants encoded by at least 5% of the sequences in the Los Alamos National Laboratory HIV database (1,300 peptides) using gamma interferon and interleukin-2 (IFN-γ/IL-2) FluoroSpot analysis. While targeting of conserved regions was similar in the two groups (P = 0.47), we found that subjects with control of virus replication demonstrated marginally lower recognition of Gag epitope variants than subjects with normal progression (P = 0.05). In viremic controllers and progressors, we found variant recognition to be associated with viral load (r = 0.62, P = 0.001). Interestingly, we show that increased overall sequence coverage, defined as the overall proportion of HIV database sequences targeted through the Gag-specific repertoire, is inversely associated with viral load (r = -0.38, P = 0.03). Furthermore, we found that sequence coverage, but not variant recognition, correlated with increased recognition of a panel of clade B HIV founder viruses (r = 0.50, P = 0.004). We propose sequence coverage by HIV Gag-specific immune responses as a possible correlate of protection that may contribute to control of virus replication. Additionally, sequence coverage serves as a valuable measure by which to evaluate the protective potential of future vaccination strategies.
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9
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Kulkarni V, Rosati M, Valentin A, Ganneru B, Singh AK, Yan J, Rolland M, Alicea C, Beach RK, Zhang GM, Le Gall S, Broderick KE, Sardesai NY, Heckerman D, Mothe B, Brander C, Weiner DB, Mullins JI, Pavlakis GN, Felber BK. HIV-1 p24(gag) derived conserved element DNA vaccine increases the breadth of immune response in mice. PLoS One 2013; 8:e60245. [PMID: 23555935 PMCID: PMC3610668 DOI: 10.1371/journal.pone.0060245] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Accepted: 02/24/2013] [Indexed: 11/18/2022] Open
Abstract
Viral diversity is considered a major impediment to the development of an effective HIV-1 vaccine. Despite this diversity, certain protein segments are nearly invariant across the known HIV-1 Group M sequences. We developed immunogens based on the highly conserved elements from the p24gag region according to two principles: the immunogen must (i) include strictly conserved elements of the virus that cannot mutate readily, and (ii) exclude both HIV regions capable of mutating without limiting virus viability, and also immunodominant epitopes located in variable regions. We engineered two HIV-1 p24gag DNA immunogens that express 7 highly Conserved Elements (CE) of 12–24 amino acids in length and differ by only 1 amino acid in each CE (‘toggle site’), together covering >99% of the HIV-1 Group M sequences. Altering intracellular trafficking of the immunogens changed protein localization, stability, and also the nature of elicited immune responses. Immunization of C57BL/6 mice with p55gag DNA induced poor, CD4+ mediated cellular responses, to only 2 of the 7 CE; in contrast, vaccination with p24CE DNA induced cross-clade reactive, robust T cell responses to 4 of the 7 CE. The responses were multifunctional and composed of both CD4+ and CD8+ T cells with mature cytotoxic phenotype. These findings provide a method to increase immune response to universally conserved Gag epitopes, using the p24CE immunogen. p24CE DNA vaccination induced humoral immune responses similar in magnitude to those induced by p55gag, which recognize the virus encoded p24gag protein. The inclusion of DNA immunogens composed of conserved elements is a promising vaccine strategy to induce broader immunity by CD4+ and CD8+ T cells to additional regions of Gag compared to vaccination with p55gag DNA, achieving maximal cross-clade reactive cellular and humoral responses.
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Affiliation(s)
- Viraj Kulkarni
- Human Retrovirus Pathogenesis Section, Center for Cancer Research, Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States of America
| | - Margherita Rosati
- Human Retrovirus Section, Vaccine Branch, Center for Cancer Research, Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States of America
| | - Antonio Valentin
- Human Retrovirus Section, Vaccine Branch, Center for Cancer Research, Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States of America
| | - Brunda Ganneru
- Human Retrovirus Section, Vaccine Branch, Center for Cancer Research, Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States of America
| | - Ashish K. Singh
- Human Retrovirus Section, Vaccine Branch, Center for Cancer Research, Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States of America
| | - Jian Yan
- University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Morgane Rolland
- Departments of Microbiology Medicine and Laboratory Medicine, University of Washington, Seattle, Washington, United States of America
| | - Candido Alicea
- Human Retrovirus Pathogenesis Section, Center for Cancer Research, Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States of America
| | - Rachel Kelly Beach
- Human Retrovirus Pathogenesis Section, Center for Cancer Research, Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States of America
- Human Retrovirus Section, Vaccine Branch, Center for Cancer Research, Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States of America
| | - Gen-Mu Zhang
- Human Retrovirus Pathogenesis Section, Center for Cancer Research, Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States of America
- Human Retrovirus Section, Vaccine Branch, Center for Cancer Research, Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States of America
| | - Sylvie Le Gall
- Ragon Institute of MGH, MIT and Harvard, Boston, Massachusetts, United States of America
| | - Kate E. Broderick
- Inovio Pharmaceuticals, Inc., Blue Bell, Pennsylvania, United States of America
| | | | - David Heckerman
- Microsoft Research, Redmond, Washington, United States of America
| | - Beatriz Mothe
- IrsiCaixa AIDS Research Institute-HIVACAT, Autonomous University of Barcelona, Barcelona, Spain
| | - Christian Brander
- IrsiCaixa AIDS Research Institute-HIVACAT, Autonomous University of Barcelona, Barcelona, Spain
- Institucio Catalana de Recerca i Estudis Avancats (ICREA), Barcelona, Spain
| | - David B. Weiner
- University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - James I. Mullins
- Departments of Microbiology Medicine and Laboratory Medicine, University of Washington, Seattle, Washington, United States of America
| | - George N. Pavlakis
- Human Retrovirus Section, Vaccine Branch, Center for Cancer Research, Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States of America
- * E-mail: (BKF); (GNP)
| | - Barbara K. Felber
- Human Retrovirus Pathogenesis Section, Center for Cancer Research, Frederick National Laboratory for Cancer Research, Frederick, Maryland, United States of America
- * E-mail: (BKF); (GNP)
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10
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Côrtes FH, Bello G, Vorsatz C, Pilotto JH, Guimarães ML, Grinsztejn B, Veloso VG, Pinto AR, Morgado MG. Higher cross-subtype IFN-γ ELISpot responses to Gag and Nef peptides in Brazilian HIV-1 subtype B- and F1- than in C-infected subjects. Vaccine 2012; 31:1106-12. [PMID: 23261042 DOI: 10.1016/j.vaccine.2012.12.023] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2012] [Revised: 11/19/2012] [Accepted: 12/08/2012] [Indexed: 02/06/2023]
Abstract
HIV-1 diversity has been considered a huge challenge for the HIV-1 vaccine development. To overcome it, immunogens based on centralized sequences, as consensus, have been tested. In Brazil, the co-circulation of three subtypes offers a suitable scenario to test T cell cross-subtype responses to consensus sequences. Furthermore, we included peptides based on closest viral isolates (CVI) from each subtype analyzed to compare with T cell responses detected against the consensus sequences. The study included 32 subjects infected with HIV-1 subtype B (n=13),C (n=11), and F1 (n=8). Gag and Nef-specific T cell responses were evaluated by IFN-γ-ELISpot assay. Peptides based on CVI sequences were similar to consensus in both reducing genetic distance and detecting T cell responses. A high cross-subtype response between B and F1 in both regions was observed in HIV-1 subtype B and F1-infected subjects. We also found no significant difference in responses to subtype B and C consensus peptides among subtype B-infected subjects. In contrast, the magnitude of T cell responses to consensus C peptides in the Gag region was higher than to consensus B peptides among HIV-1 subtype C-infected subjects. Regarding Nef, subtype C-infected subjects showed higher values to consensus C than to consensus F1 peptides. Moreover, subtype F1-infected subjects presented lower responses to subtype C peptides than to subtype F1 and B. A similar level of responses was detected with group M based peptides in subtype B and F1 infected subjects. However, among subtype C infected subjects, this set of peptides detected lower levels of response than consensus C. Overall, the level of cross-subtype response between subtypes B and F1 was higher than between subtype C and B or C and F1. Our data suggests that the barrier of genetic diversity in HIV-1 group M for vaccine design may be dependent on the subtypes involved.
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Affiliation(s)
- Fernanda Heloise Côrtes
- Laboratório de Aids e Imunologia Molecular, Instituto Oswaldo Cruz, Fundação Oswaldo Cruz, Rio de Janeiro, RJ 21040-360, Brazil
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A 2 amino acid shift in position leads to a substantial difference in the pattern of processing of 2 HIV-1 epitopes. J Acquir Immune Defic Syndr 2012; 59:335-9. [PMID: 22217677 DOI: 10.1097/qai.0b013e318248780c] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND The sequence diversity that exists between HIV-1 strains presents a major obstacle to the design of a vaccine that will be effective on a global scale. Focusing on highly conserved cytotoxic T-lymphocyte epitopes as vaccine targets has been called into question by evidence that variation within epitope flanking regions can affect processing and presentation. METHODS Using epitope-specific T-cell clones tested for recognition of HLA-matched target cells infected with vaccinia viruses expressing HIV-1 nef genes derived from different HIV-1 clades, we examined the efficiency of presentation of an HLA-B*40 restricted HIV-1 nef epitope compared to that of an HLA-B*08 restricted epitope with which it overlaps by 6 amino acides. RESULTS This small shift in epitope position substantially changed the patter or epitope processing and led either to an increase or decrease in antigen generation dependent on the viral sequences present. CONCLUSIONS These data demonstrate the complexity of the antigen presentation pathway and the difficulties associated with selecting CTL epitopes as targets for an HIV-1 vaccine that will be effective in many populations and against several viral strains.
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Serwanga J, Mugaba S, Pimego E, Nanteza B, Lyagoba F, Nakubulwa S, Heath L, Nsubuga RN, Ndembi N, Gotch F, Kaleebu P. Profile of T cell recognition of HIV type 1 consensus group M Gag and Nef peptides in a clade A1- and D-infected Ugandan population. AIDS Res Hum Retroviruses 2012; 28:384-92. [PMID: 21867408 PMCID: PMC3316116 DOI: 10.1089/aid.2011.0175] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Reagents for evaluating non-clade B HIV-specific T cell responses are uncommon. Peptides based on highly conserved HIV-1 consensus group M sequences that are phylogenetically closer to most circulating strains may provide potential alternative reagents in populations with diverse infections, and may be relevant for vaccine design. Recognition of such reagents in clade A1-and D-infected populations has not been previously evaluated. Interferon (IFN)-γ ELISpot assay was used to evaluate T cell recognition of Gag and Nef peptides based on consensus group M sequences in 50 treatment-naive adults predominantly infected with HIV-1 clades A1 and D. Gag-induced T cell responses were correlated with gag sequence diversity. Infecting clades were determined from gag sequences for 45 of the 50 subjects as 40% clade A1 (18/45), 45% clade D (20/45), 2% clade C (1/45), 2% A1/C recombinant (1/45), 2% A1/D (1/45), 7% CRF10_CD (3/45), and 2% U (unclassifiable) (1/45). The mean genetic divergence and diversity of clade A and D gag region compared to group M consensus sequences at synonymous and nonsynonymous nucleotide and amino acid levels were not always significant. Gag peptides were targeted at significantly higher frequency [88% (44/50)] than Nef [64% (32/50)]; p=0.014, although their mean IFN-γ magnitudes were comparable ([3703 (95% CI 2567-4839)] vs. [2120 (95% CI 478-3762)]), respectively. Measurable virus-induced IFN-γ responses were detected in 96% (48/50) individuals, primarily targeting the more conserved Gag p24 and Nef central core regions. Use of these reagents to screen for HIV-specific IFN-γ responses may mitigate the challenge of viral diversity; although this targeting is apparently biased toward a few highly conserved epitopes.
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13
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Castro-Nallar E, Pérez-Losada M, Burton GF, Crandall KA. The evolution of HIV: inferences using phylogenetics. Mol Phylogenet Evol 2012; 62:777-92. [PMID: 22138161 PMCID: PMC3258026 DOI: 10.1016/j.ympev.2011.11.019] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2011] [Revised: 11/17/2011] [Accepted: 11/21/2011] [Indexed: 12/02/2022]
Abstract
Molecular phylogenetics has revolutionized the study of not only evolution but also disparate fields such as genomics, bioinformatics, epidemiology, ecology, microbiology, molecular biology and biochemistry. Particularly significant are its achievements in population genetics as a result of the development of coalescent theory, which have contributed to more accurate model-based parameter estimation and explicit hypothesis testing. The study of the evolution of many microorganisms, and HIV in particular, have benefited from these new methodologies. HIV is well suited for such sophisticated population analyses because of its large population sizes, short generation times, high substitution rates and relatively small genomes. All these factors make HIV an ideal and fascinating model to study molecular evolution in real time. Here we review the significant advances made in HIV evolution through the application of phylogenetic approaches. We first examine the relative roles of mutation and recombination on the molecular evolution of HIV and its adaptive response to drug therapy and tissue allocation. We then review some of the fundamental questions in HIV evolution in relation to its origin and diversification and describe some of the insights gained using phylogenies. Finally, we show how phylogenetic analysis has advanced our knowledge of HIV dynamics (i.e., phylodynamics).
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Affiliation(s)
- Eduardo Castro-Nallar
- Department of Biology, 401 Widtsoe Building, Brigham Young University, Provo, UT 84602-5181, USA.
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14
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Mothe B, Llano A, Ibarrondo J, Daniels M, Miranda C, Zamarreño J, Bach V, Zuniga R, Pérez-Álvarez S, Berger CT, Puertas MC, Martinez-Picado J, Rolland M, Farfan M, Szinger JJ, Hildebrand WH, Yang OO, Sanchez-Merino V, Brumme CJ, Brumme ZL, Heckerman D, Allen TM, Mullins JI, Gómez G, Goulder PJ, Walker BD, Gatell JM, Clotet B, Korber BT, Sanchez J, Brander C. Definition of the viral targets of protective HIV-1-specific T cell responses. J Transl Med 2011; 9:208. [PMID: 22152067 PMCID: PMC3292987 DOI: 10.1186/1479-5876-9-208] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Accepted: 12/07/2011] [Indexed: 02/08/2023] Open
Abstract
Background The efficacy of the CTL component of a future HIV-1 vaccine will depend on the induction of responses with the most potent antiviral activity and broad HLA class I restriction. However, current HIV vaccine designs are largely based on viral sequence alignments only, not incorporating experimental data on T cell function and specificity. Methods Here, 950 untreated HIV-1 clade B or -C infected individuals were tested for responses to sets of 410 overlapping peptides (OLP) spanning the entire HIV-1 proteome. For each OLP, a "protective ratio" (PR) was calculated as the ratio of median viral loads (VL) between OLP non-responders and responders. Results For both clades, there was a negative relationship between the PR and the entropy of the OLP sequence. There was also a significant additive effect of multiple responses to beneficial OLP. Responses to beneficial OLP were of significantly higher functional avidity than responses to non-beneficial OLP. They also had superior in-vitro antiviral activities and, importantly, were at least as predictive of individuals' viral loads than their HLA class I genotypes. Conclusions The data thus identify immunogen sequence candidates for HIV and provide an approach for T cell immunogen design applicable to other viral infections.
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Affiliation(s)
- Beatriz Mothe
- Irsicaixa AIDS Research Institute-HIVACAT, Badalona, Spain
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15
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Sharp ER, Willberg CB, Kuebler PJ, Abadi J, Fennelly GJ, Dobroszycki J, Wiznia AA, Rosenberg MG, Nixon DF. Immunodominance of HIV-1 specific CD8+ T-cell responses is related to disease progression rate in vertically infected adolescents. PLoS One 2011; 6:e21135. [PMID: 21818255 PMCID: PMC3139570 DOI: 10.1371/journal.pone.0021135] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Accepted: 05/20/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND HIV-1 vertically infected children in the USA are living into adolescence and beyond with the widespread use of antiretroviral drugs. These patients exhibit striking differences in the rate of HIV-1 disease progression which could provide insights into mechanisms of control. We hypothesized that differences in the pattern of immunodomination including breadth, magnitude and polyfunctionality of HIV-1 specific CD8+ T cell response could partially explain differences in progression rate. METHODOLOGY/PRINCIPAL FINDINGS In this study, we mapped, quantified, and assessed the functionality of these responses against individual HIV-1 Gag peptides in 58 HIV-1 vertically infected adolescents. Subjects were divided into two groups depending upon the rate of disease progression: adolescents with a sustained CD4%≥25 were categorized as having no immune suppression (NS), and those with CD4%≤15 categorized as having severe immune suppression (SS). We observed differences in the area of HIV-1-Gag to which the two groups made responses. In addition, subjects who expressed the HLA- B*57 or B*42 alleles were highly likely to restrict their immunodominant response through these alleles. There was a significantly higher frequency of naïve CD8+ T cells in the NS subjects (p = 0.0066) compared to the SS subjects. In contrast, there were no statistically significant differences in any other CD8+ T cell subsets. The differentiation profiles and multifunctionality of Gag-specific CD8+ T cells, regardless of immunodominance, also failed to demonstrate meaningful differences between the two groups. CONCLUSIONS/SIGNIFICANCE Together, these data suggest that, at least in vertically infected adolescents, the region of HIV-1-Gag targeted by CD8+ T cells and the magnitude of that response relative to other responses may have more importance on the rate of disease progression than their qualitative effector functions.
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Affiliation(s)
- Elizabeth R. Sharp
- Division of Experimental Medicine, Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Christian B. Willberg
- Division of Experimental Medicine, Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Peter J. Kuebler
- Division of Experimental Medicine, Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
| | - Jacob Abadi
- Jacobi Medical Center, Bronx, New York, United States of America
| | | | | | - Andrew A. Wiznia
- Jacobi Medical Center, Bronx, New York, United States of America
| | | | - Douglas F. Nixon
- Division of Experimental Medicine, Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
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16
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Ndhlovu ZM, Piechocka-Trocha A, Vine S, McMullen A, Koofhethile KC, Goulder PJR, Ndung'u T, Barouch DH, Walker BD. Mosaic HIV-1 Gag antigens can be processed and presented to human HIV-specific CD8+ T cells. THE JOURNAL OF IMMUNOLOGY 2011; 186:6914-24. [PMID: 21576505 DOI: 10.4049/jimmunol.1004231] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Polyvalent mosaic HIV immunogens offer a potential solution for generating vaccines that can elicit immune responses against genetically diverse viruses. However, it is unclear whether key T cell epitopes can be processed and presented from these synthetic Ags and recognized by epitope-specific human T cells. In this study, we tested the ability of mosaic HIV immunogens expressed by recombinant, replication-incompetent adenovirus serotype 26 vectors to process and present major HIV clade B and clade C CD8 T cell epitopes in human cells. A bivalent mosaic vaccine expressing HIV Gag sequences was used to transduce PBMCs from 12 HIV-1-infected individuals from the United States and 10 HIV-1-infected individuals from South Africa; intracellular cytokine staining, together with tetramer staining, was used to assess the ability of mosaic Gag Ags to stimulate pre-existing memory responses compared with natural clade B and C vectors. Mosaic Gag Ags expressed all eight clade B epitopes tested in 12 United States subjects and all 5 clade C epitopes tested in 10 South African subjects. Overall, the magnitude of cytokine production induced by stimulation with mosaic Ags was comparable to clade B and clade C Ags tested, but the mosaic Ags elicited greater cross-clade recognition. Additionally, mosaic Ags induced HIV-specific CD4 T cell responses. Our studies demonstrate that mosaic Ags express major clade B and clade C viral T cell epitopes in human cells, as well as support the evaluation of mosaic HIV-1 vaccines in humans.
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Affiliation(s)
- Zaza M Ndhlovu
- Ragon Institute of Massachusetts General Hospital, Massachusetts Institute of Technology and Harvard, Charlestown, MA 02129, USA
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17
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The antiviral efficacy of HIV-specific CD8⁺ T-cells to a conserved epitope is heavily dependent on the infecting HIV-1 isolate. PLoS Pathog 2011; 7:e1001341. [PMID: 21589893 PMCID: PMC3093356 DOI: 10.1371/journal.ppat.1001341] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Accepted: 04/11/2011] [Indexed: 01/03/2023] Open
Abstract
A major challenge to developing a successful HIV vaccine is the vast diversity of viral sequences, yet it is generally assumed that an epitope conserved between different strains will be recognised by responding T-cells. We examined whether an invariant HLA-B8 restricted Nef90–97 epitope FL8 shared between five high titre viruses and eight recombinant vaccinia viruses expressing Nef from different viral isolates (clades A–H) could activate antiviral activity in FL8-specific cytotoxic T-lymphocytes (CTL). Surprisingly, despite epitope conservation, we found that CTL antiviral efficacy is dependent on the infecting viral isolate. Only 23% of Nef proteins, expressed by HIV-1 isolates or as recombinant vaccinia-Nef, were optimally recognised by CTL. Recognition of the HIV-1 isolates by CTL was independent of clade-grouping but correlated with virus-specific polymorphisms in the epitope flanking region, which altered immunoproteasomal cleavage resulting in enhanced or impaired epitope generation. The finding that the majority of virus isolates failed to present this conserved epitope highlights the importance of viral variance in CTL epitope flanking regions on the efficiency of antigen processing, which has been considerably underestimated previously. This has important implications for future vaccine design strategies since efficient presentation of conserved viral epitopes is necessary to promote enhanced anti-viral immune responses. One of the greatest challenges to developing an effective HIV vaccine is the ability of HIV to rapidly alter its viral sequence. Such variation in viral sequence enables the virus to frequently evade recognition by the host immune system. To counteract this problem, there has been increasing interest in developing HIV vaccines that target T-cell responses to the regions of the virus that are highly conserved between strains of HIV. However, previous studies have focused on identifying amino acid variation predominantly within a single viral isolate, or have focused on classical within-epitope escape mutation. Our study assessed T-cell recognition of a conserved epitope shared by a total of 13 HIV strains. Strikingly, we show that only a small proportion of the viral strains were effectively recognised and targeted by the T-cells. In contrast, differences in amino acid sequence in the region flanking the epitope impaired the intracellular processing and presentation of epitope in the majority of HIV strains tested. Thus, our findings highlight that a large proportion of HIV strains may evade epitope-specific T-cell recognition despite absolute epitope conservation. This has important implications for both vaccine design and evaluation of vaccine efficacy.
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18
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Serwanga J, Mugaba S, Betty A, Pimego E, Walker S, Munderi P, Gilks C, Gotch F, Grosskurth H, Kaleebu P. CD8 T-Cell Responses before and after Structured Treatment Interruption in Ugandan Adults Who Initiated ART with CD4 T Cells <200 Cell/μL: The DART Trial STI Substudy. AIDS Res Treat 2011; 2011:875028. [PMID: 21490785 PMCID: PMC3065901 DOI: 10.1155/2011/875028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2010] [Accepted: 12/15/2010] [Indexed: 11/17/2022] Open
Abstract
Objective. To better understand attributes of ART-associated HIV-induced T-cell responses that might be therapeutically harnessed. Methods. CD8(+) T-cell responses were evaluated in some HIV-1 chronically infected participants of the fixed duration STI substudy of the DART trial. Magnitudes, breadths, and functionality of IFN-γ and Perforin responses were compared in STI (n = 42) and continuous treatment (CT) (n = 46) before and after a single STI cycle when the DART STI trial was stopped early due to inferior clinical outcome in STI participants. Results. STI and CT had comparable magnitudes and breadths of monofunctional CD8(+)IFNγ(+) and CD8(+)Perforin(+) responses. However, STI was associated with significant decline in breadth of bi-functional (CD8(+)IFNγ(+)Perforin(+)) responses; P = .02, Mann-Whitney test. Conclusions. STI in individuals initiated onto ART at <200 CD4(+) T-cell counts/μl significantly reduced occurrence of bifunctional CD8(+)IFNγ(+)/Perforin(+) responses. These data add to others that found no evidence to support STI as a strategy to improve HIV-specific immunity during ART.
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Affiliation(s)
- Jennifer Serwanga
- MRC/UVRI Uganda Research Unit on AIDS, 51-59 Nakiwogo Road, Entebbe, Uganda
| | - Susan Mugaba
- MRC/UVRI Uganda Research Unit on AIDS, 51-59 Nakiwogo Road, Entebbe, Uganda
| | - Auma Betty
- MRC/UVRI Uganda Research Unit on AIDS, 51-59 Nakiwogo Road, Entebbe, Uganda
| | - Edward Pimego
- MRC/UVRI Uganda Research Unit on AIDS, 51-59 Nakiwogo Road, Entebbe, Uganda
| | - Sarah Walker
- MRC Clinical Trials Unit, 222 Euston Road, London NW1 2DA, UK
| | - Paula Munderi
- MRC/UVRI Uganda Research Unit on AIDS, 51-59 Nakiwogo Road, Entebbe, Uganda
| | - Charles Gilks
- Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | - Frances Gotch
- Department of Immunology, Imperial College, Chelsea and Westminster Hospital, London SW10 9NH, UK
| | - Heiner Grosskurth
- MRC/UVRI Uganda Research Unit on AIDS, 51-59 Nakiwogo Road, Entebbe, Uganda
- London School of Hygiene & Tropical Medicine, University of London, London WC1E 7HT, UK
| | - Pontiano Kaleebu
- MRC/UVRI Uganda Research Unit on AIDS, 51-59 Nakiwogo Road, Entebbe, Uganda
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19
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Almeida CAM, Roberts SG, Laird R, McKinnon E, Ahmad I, Keane NM, Chopra A, Kadie C, Heckerman D, Mallal S, John M. Exploiting knowledge of immune selection in HIV-1 to detect HIV-specific CD8 T-cell responses. Vaccine 2010; 28:6052-7. [PMID: 20619380 DOI: 10.1016/j.vaccine.2010.06.091] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Revised: 06/23/2010] [Accepted: 06/25/2010] [Indexed: 02/09/2023]
Abstract
Since HLA-restricted cytotoxic T-cell responses select specific polymorphisms in HIV-1 sequences and HLA diversity is relatively static in human populations, we investigated the use of peptide epitopes based on sites of HLA-associated adaptation in HIV-1 sequences to stimulate and detect T-cell responses ex vivo. These "HLA-optimised" peptides captured more HIV-1 Nef-specific responses compared with overlapping peptides of a single consensus sequence, in interferon-gamma enzyme linked immunospot assays. Sites of immune selection can reveal more immunogenic epitopes in HLA-diverse populations and offer insights into the nature of HLA-epitope targeting, which could be applied in vaccine design.
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Affiliation(s)
- Coral-Ann M Almeida
- Centre for Clinical Immunology and Biomedical Statistics, Institute of Immunology and Infectious Diseases, Murdoch University, Perth, Western Australia, Australia
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20
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Progress towards development of an HIV vaccine: report of the AIDS Vaccine 2009 Conference. THE LANCET. INFECTIOUS DISEASES 2010; 10:305-16. [PMID: 20417413 DOI: 10.1016/s1473-3099(10)70069-4] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The search for an HIV/AIDS vaccine is steadily moving ahead, generating and validating new concepts in terms of novel vectors for antigen delivery and presentation, new vaccine and adjuvant strategies, alternative approaches to design HIV-1 antigens for eliciting protective cross-neutralising antibodies, and identification of key mechanisms in HIV infection and modulation of the immune system. All these different perspectives are contributing to the unprecedented challenge of developing a protective HIV-1 vaccine. The high scientific value of this massive effort is its great impact on vaccinology as a whole, providing invaluable scientific information for the current and future development of new preventive vaccine as well as therapeutic knowledge-based infectious-disease and cancer vaccines.
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Abstract
Despite more than 25 years of concerted worldwide research, the development of a safe and effective HIV-1 vaccine remains elusive. Prototype antibody-based and T cell-based HIV-1 vaccines have failed to show efficacy in clinical trials to date. Next-generation HIV-1 vaccine candidates are in various stages of preclinical and clinical development, but key scientific obstacles pose major challenges for the field. Critical hurdles include the enormous global diversity of the virus and the challenges associated with generating broadly reactive neutralizing antibody and cellular immune responses. We review the current state of the HIV-1 vaccine field and outline strategies that are being explored to overcome these roadblocks.
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Affiliation(s)
- Dan H Barouch
- Division of Vaccine Research, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02115, USA.
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22
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Malhotra U, Nolin J, Horton H, Li F, Corey L, Mullins JI, McElrath MJ. Functional properties and epitope characteristics of T-cells recognizing natural HIV-1 variants. Vaccine 2009; 27:6678-87. [PMID: 19747576 DOI: 10.1016/j.vaccine.2009.08.093] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2009] [Revised: 08/17/2009] [Accepted: 08/26/2009] [Indexed: 11/18/2022]
Abstract
To understand how broad recognition of HIV-1 variants may be achieved we examined T-cell reactivity in newly infected persons as well as vaccine recipients to a broad spectrum of potential T-cell epitope (PTE) variants containing conservative, semi-conservative and non-conservative amino acid substitutions. Among early infected persons T-cells recognized epitope variants with one substitution at a significantly higher frequency versus those with two (P=0.0098) and three (P=0.0125) substitutions. Furthermore T-cells recognized variants containing conservative substitutions at a higher frequency versus those containing semi-conservative (P=0.0029) and non-conservative (P<0.0001) substitutions. Similar effects were observed on recognition of variants by vaccine-induced T-cells. Moreover even when variants were recognized, the IFN-gamma and granzyme B responses as well as T-cell proliferation were of lower magnitude. Finally, we show that epitope distribution is strongly influenced by both processing preferences and amino acid entropy. We conclude that induction of broad immunity is likely to require immunogen sequences that encompass multiple variants. However, cost-effective design of peptide and sequence based vaccine immunogens that provide maximal coverage of circulating sequences may be achieved through emphasis on virus domains likely to be T-cell targets.
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Affiliation(s)
- U Malhotra
- Fred Hutchinson Cancer Research Center, Seattle, WA, USA.
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23
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T-cell vaccine strategies for human immunodeficiency virus, the virus with a thousand faces. J Virol 2009; 83:8300-14. [PMID: 19439471 DOI: 10.1128/jvi.00114-09] [Citation(s) in RCA: 118] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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Yerly D, Heckerman D, Allen T, Suscovich TJ, Jojic N, Kadie C, Pichler WJ, Cerny A, Brander C. Design, expression, and processing of epitomized hepatitis C virus-encoded CTL epitopes. THE JOURNAL OF IMMUNOLOGY 2009; 181:6361-70. [PMID: 18941227 DOI: 10.4049/jimmunol.181.9.6361] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Hepatitis C virus (HCV) vaccine efficacy may crucially depend on immunogen length and coverage of viral sequence diversity. However, covering a considerable proportion of the circulating viral sequence variants would likely require long immunogens, which for the conserved portions of the viral genome, would contain unnecessarily redundant sequence information. In this study, we present the design and in vitro performance analysis of a novel "epitome" approach that compresses frequent immune targets of the cellular immune response against HCV into a shorter immunogen sequence. Compression of immunological information is achieved by partial overlapping shared sequence motifs between individual epitopes. At the same time, sequence diversity coverage is provided by taking advantage of emerging cross-reactivity patterns among epitope variants so that epitope variants associated with the broadest variant cross-recognition are preferentially included. The processing and presentation analysis of specific epitopes included in such a compressed, in vitro-expressed HCV epitome indicated effective processing of a majority of tested epitopes, although re-presentation of some epitopes may require refined sequence design. Together, the present study establishes the epitome approach as a potential powerful tool for vaccine immunogen design, especially suitable for the induction of cellular immune responses against highly variable pathogens.
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Affiliation(s)
- Daniel Yerly
- Clinic for Rheumatology and Clinical Immunology, University of Bern, Bern, Switzerland
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Expanded breadth of the T-cell response to mosaic human immunodeficiency virus type 1 envelope DNA vaccination. J Virol 2008; 83:2201-15. [PMID: 19109395 DOI: 10.1128/jvi.02256-08] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
An effective AIDS vaccine must control highly diverse circulating strains of human immunodeficiency virus type 1 (HIV-1). Among HIV-1 gene products, the envelope (Env) protein contains variable as well as conserved regions. In this report, an informatic approach to the design of T-cell vaccines directed to HIV-1 Env M group global sequences was tested. Synthetic Env antigens were designed to express mosaics that maximize the inclusion of common potential T-cell epitope (PTE) 9-mers and minimize the inclusion of rare epitopes likely to elicit strain-specific responses. DNA vaccines were evaluated using intracellular cytokine staining in inbred mice with a standardized panel of highly conserved 15-mer PTE peptides. One-, two-, and three-mosaic sets that increased theoretical epitope coverage were developed. The breadth and magnitude of T-cell immunity stimulated by these vaccines were compared to those for natural strain Envs; additional comparisons were performed on mutant Envs, including gp160 or gp145 with or without V regions and gp41 deletions. Among them, the two- or three-mosaic Env sets elicited the optimal CD4 and CD8 responses. These responses were most evident in CD8 T cells; the three-mosaic set elicited responses to an average of eight peptide pools, compared to two pools for a set of three natural Envs. Synthetic mosaic HIV-1 antigens can therefore induce T-cell responses with expanded breadth and may facilitate the development of effective T-cell-based HIV-1 vaccines.
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Rousseau CM, Daniels MG, Carlson JM, Kadie C, Crawford H, Prendergast A, Matthews P, Payne R, Rolland M, Raugi DN, Maust BS, Learn GH, Nickle DC, Coovadia H, Ndung'u T, Frahm N, Brander C, Walker BD, Goulder PJR, Bhattacharya T, Heckerman DE, Korber BT, Mullins JI. HLA class I-driven evolution of human immunodeficiency virus type 1 subtype c proteome: immune escape and viral load. J Virol 2008; 82:6434-46. [PMID: 18434400 PMCID: PMC2447109 DOI: 10.1128/jvi.02455-07] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Accepted: 04/11/2008] [Indexed: 01/02/2023] Open
Abstract
Human immunodeficiency virus type 1 (HIV-1) mutations that confer escape from cytotoxic T-lymphocyte (CTL) recognition can sometimes result in lower viral fitness. These mutations can then revert upon transmission to a new host in the absence of CTL-mediated immune selection pressure restricted by the HLA alleles of the prior host. To identify these potentially critical recognition points on the virus, we assessed HLA-driven viral evolution using three phylogenetic correction methods across full HIV-1 subtype C proteomes from a cohort of 261 South Africans and identified amino acids conferring either susceptibility or resistance to CTLs. A total of 558 CTL-susceptible and -resistant HLA-amino acid associations were identified and organized into 310 immunological sets (groups of individual associations related to a single HLA/epitope combination). Mutations away from seven susceptible residues, including four in Gag, were associated with lower plasma viral-RNA loads (q < 0.2 [where q is the expected false-discovery rate]) in individuals with the corresponding HLA alleles. The ratio of susceptible to resistant residues among those without the corresponding HLA alleles varied in the order Vpr > Gag > Rev > Pol > Nef > Vif > Tat > Env > Vpu (Fisher's exact test; P < or = 0.0009 for each comparison), suggesting the same ranking of fitness costs by genes associated with CTL escape. Significantly more HLA-B (chi(2); P = 3.59 x 10(-5)) and HLA-C (chi(2); P = 4.71 x 10(-6)) alleles were associated with amino acid changes than HLA-A, highlighting their importance in driving viral evolution. In conclusion, specific HIV-1 residues (enriched in Vpr, Gag, and Rev) and HLA alleles (particularly B and C) confer susceptibility to the CTL response and are likely to be important in the development of vaccines targeted to decrease the viral load.
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Affiliation(s)
- Christine M Rousseau
- Department of Microbiology, University of Washington, 1959 NE Pacific Street, Box 358070, Seattle, WA 98195-8070, USA.
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