1
|
Abstract
Oxygen-sensing mechanisms allow cells to adapt and respond to changes in cellular oxygen tension, including hypoxic conditions. Hypoxia-inducible factor (HIF) is a central mediator in this fundamental adaptive response, and has critical functions in normal and disease physiology. Viruses have been shown to manipulate HIFs during their life cycle to facilitate replication and invasion. Conversely, HIFs are also implicated in the development of the host immune system and response to viral infections. Here, we highlight the recent revelations of host-pathogen interactions that involve the hypoxic response pathway and the role of HIF in emerging viral infectious diseases, as well as discussing potential antiviral therapeutic strategies targeting the HIF signaling axis.
Collapse
Affiliation(s)
- Richard Huang
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Melissa Huestis
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Esther Shuyi Gan
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore
| | - Eng Eong Ooi
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore.,Department of Microbiology and Immunology, National University of Singapore, Singapore, Singapore.,Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore
| | - Michael Ohh
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.,Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| |
Collapse
|
2
|
Gan ES, Tan HC, Le DHT, Huynh TT, Wills B, Seidah NG, Ooi EE, Yacoub S. Dengue virus induces PCSK9 expression to alter antiviral responses and disease outcomes. J Clin Invest 2021; 130:5223-5234. [PMID: 32644974 PMCID: PMC7524462 DOI: 10.1172/jci137536] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 07/01/2020] [Indexed: 12/17/2022] Open
Abstract
Dengue virus (DENV) infection requires cholesterol as a proviral factor, although statin treatment did not show antiviral efficacy in patients with dengue. Here, we show that DENV infection manipulated cholesterol metabolism in cells residing in low-oxygen microenvironments (hypoxia) such as in the liver, spleen, and lymph nodes. DENV infection induced expression of proprotein convertase subtilisin/kexin type 9 (PCSK9), which reduces low-density lipoprotein receptor (LDLR) recycling and hence cholesterol uptake. We found that, whereas LDLR uptake would have distributed cholesterol throughout the various cell compartments, de novo cholesterol synthesis enriched this lipid in the endoplasmic reticulum (ER). With cholesterol enrichment in the ER, ER-resident STING and type I IFN (IFN) activation was repressed during DENV infection. Our in vitro findings were further supported by the detection of elevated plasma PCSK9 levels in patients with dengue with high viremia and increased severity of plasma leakage. Our findings therefore suggest that PCSK9 plays a hitherto unrecognized role in dengue pathogenesis and that PCSK9 inhibitors could be a suitable host-directed treatment for patients with dengue.
Collapse
Affiliation(s)
| | - Hwee Cheng Tan
- Duke-National University of Singapore Medical School, Singapore
| | - Duyen Huynh Thi Le
- Oxford University Clinical Research Unit (OUCRU), Ho Chi Minh City, Vietnam
| | - Trieu Trung Huynh
- Oxford University Clinical Research Unit (OUCRU), Ho Chi Minh City, Vietnam
| | - Bridget Wills
- Oxford University Clinical Research Unit (OUCRU), Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom
| | - Nabil G Seidah
- Laboratory of Biochemical Neuroendocrinology, Montreal Clinical Research Institute, Université de Montréal, Montréal, Québec, Canada
| | - Eng Eong Ooi
- Duke-National University of Singapore Medical School, Singapore.,Saw Swee Hock School of Public Health, National University of Singapore, Singapore.,SingHealth Duke-National University of Singapore Global Health Institute, Singapore.,Antimicrobial Resistance Interdisciplinary Research Group, Singapore MIT Alliance in Research and Technology, Singapore
| | - Sophie Yacoub
- Oxford University Clinical Research Unit (OUCRU), Ho Chi Minh City, Vietnam.,Centre for Tropical Medicine and Global Health, University of Oxford, Oxford, United Kingdom.,Antimicrobial Resistance Interdisciplinary Research Group, Singapore MIT Alliance in Research and Technology, Singapore
| |
Collapse
|
3
|
Yau C, Gan ES, Kwek SS, Tan HC, Ong EZ, Hamis NZ, Rivino L, Chan KR, Watanabe S, Vasudevan SG, Ooi EE. Live vaccine infection burden elicits adaptive humoral and cellular immunity required to prevent Zika virus infection. EBioMedicine 2020; 61:103028. [PMID: 33045466 PMCID: PMC7553235 DOI: 10.1016/j.ebiom.2020.103028] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/31/2020] [Accepted: 09/10/2020] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND The emergence of Zika virus (ZIKV) as an important cause of congenital and childhood developmental disorders presents another challenge to global health. Efforts to develop a Zika vaccine have begun although vaccine development against flaviviruses, of which ZIKV belongs to, has proven to be time-consuming and challenging. Defining the vaccine attributes that elicit adaptive immune response necessary for preventing ZIKV infection could provide an evidence-based guide to Zika vaccine development. METHODS We used a previously described attenuated ZIKV DN-2 strain in a type-I interferon receptor deficient mouse model and tested the hypothesis that duration of vaccine burden rather than peak level of infection, is a determinant of immunogenicity. We quantified both humoral and cellular responses against ZIKV using plaque reduction neutralisation test and flow cytometry with ELISPOT assays, respectively. Vaccinated mice were challenged with wild-type ZIKV (H/PF/2013 strain) to determine the level of protection against infection. FINDINGS We found that the overall vaccine burden is directly correlated with neutralising antibody titres. Reduced duration of vaccine burden lowered neutralising antibody titres that resulted in subclinical infection, despite unchanged peak vaccine viraemia levels. We also found that sterilising immunity is dependant on both neutralising antibody and CD8+T cell responses; depletion of CD8+T cells in vaccinated animals led to wild-type ZIKV infection, especially in the male reproductive tract. INTERPRETATION Our findings indicate that duration of attenuated virus vaccine burden is a determinant of humoral and cellular immunity and also suggest that vaccines that elicit both arms of the adaptive immune response are needed to fully prevent ZIKV transmission. FUNDING This study was supported by the National Medical Research Council through the Clinician-Scientist Award (Senior Investigator) to E.E.O. Salary support for S.W. was from a Competitive Research Programme grant awarded by the National Research Foundation of Singapore.
Collapse
Affiliation(s)
- Clement Yau
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Esther Shuyi Gan
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Swee Sen Kwek
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Hwee Cheng Tan
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Eugenia Z Ong
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore; Viral Research and Experimental Medicine Centre, SingHealth Duke-NUS Academic Medical Centre, Singapore 169857, Singapore
| | - Noor Zayanah Hamis
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Laura Rivino
- School of Cellular and Molecular Medicine, University of Bristol, Bristol BS8 1TD, United Kingdom
| | - Kuan Rong Chan
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Satoru Watanabe
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Subhash G Vasudevan
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore
| | - Eng Eong Ooi
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857, Singapore; Viral Research and Experimental Medicine Centre, SingHealth Duke-NUS Academic Medical Centre, Singapore 169857, Singapore; Saw Swee Hock School of Public health, National University of Singapore, Singapore 117549, Singapore; Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545, Singapore.
| |
Collapse
|
4
|
Abstract
The oxygen levels organ and tissue microenvironments vary depending on the distance of their vasculature from the left ventricle of the heart. For instance, the oxygen levels of lymph nodes and the spleen are significantly lower than that in atmospheric air. Cellular detection of oxygen and their response to low oxygen levels can exert a significant impact on virus infection. Generally, viruses that naturally infect well-oxygenated organs are less able to infect cells under hypoxic conditions. Conversely, viruses that infect organs under lower oxygen tensions thrive under hypoxic conditions. This suggests that in vitro experiments performed exclusively under atmospheric conditions ignores oxygen-induced modifications in both host and viral responses. Here, we review the mechanisms of how cells adapt to low oxygen tensions and its impact on viral infections. With growing evidence supporting the role of oxygen microenvironments in viral infections, this review highlights the importance of factoring oxygen concentrations into in vitro assay conditions. Bridging the gap between in vitro and in vivo oxygen tensions would allow for more physiologically representative insights into viral pathogenesis.
Collapse
Affiliation(s)
- Esther Shuyi Gan
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore.
| | - Eng Eong Ooi
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore.,Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore.,Department of Microbiology and Immunology, National University of Singapore, Singapore, Singapore
| |
Collapse
|
5
|
Syenina A, Vijaykrishna D, Gan ES, Tan HC, Choy MM, Siriphanitchakorn T, Cheng C, Vasudevan SG, Ooi EE. Positive epistasis between viral polymerase and the 3' untranslated region of its genome reveals the epidemiologic fitness of dengue virus. Proc Natl Acad Sci U S A 2020; 117:11038-11047. [PMID: 32366663 PMCID: PMC7245076 DOI: 10.1073/pnas.1919287117] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Dengue virus (DENV) is a global health threat, causing repeated epidemics throughout the tropical world. While low herd immunity levels to any one of the four antigenic types of DENV predispose populations to outbreaks, viral genetic determinants that confer greater fitness for epidemic spread is an important but poorly understood contributor of dengue outbreaks. Here we report that positive epistasis between the coding and noncoding regions of the viral genome combined to elicit an epidemiologic fitness phenotype associated with the 1994 DENV2 outbreak in Puerto Rico. We found that five amino acid substitutions in the NS5 protein reduced viral genomic RNA (gRNA) replication rate to achieve a more favorable and relatively more abundant subgenomic flavivirus RNA (sfRNA), a byproduct of host 5'-3' exoribonuclease activity. The resulting increase in sfRNA relative to gRNA levels not only inhibited type I interferon (IFN) expression in infected cells through a previously described mechanism, but also enabled sfRNA to compete with gRNA for packaging into infectious particles. We suggest that delivery of sfRNA to new susceptible cells to inhibit type I IFN induction before gRNA replication and without the need for further de novo sfRNA synthesis could form a "preemptive strike" strategy against DENV.
Collapse
Affiliation(s)
- Ayesa Syenina
- Program in Emerging Infectious Diseases, Duke-National University of Singapore Medical School, 169857 Singapore
- Saw Swee Hock School of Public Health, National University of Singapore, 117549 Singapore
| | - Dhanasekaran Vijaykrishna
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC 3800, Australia
| | - Esther Shuyi Gan
- Program in Emerging Infectious Diseases, Duke-National University of Singapore Medical School, 169857 Singapore
| | - Hwee Cheng Tan
- Program in Emerging Infectious Diseases, Duke-National University of Singapore Medical School, 169857 Singapore
| | - Milly M Choy
- Program in Emerging Infectious Diseases, Duke-National University of Singapore Medical School, 169857 Singapore
| | - Tanamas Siriphanitchakorn
- Program in Emerging Infectious Diseases, Duke-National University of Singapore Medical School, 169857 Singapore
- Department of Biological Sciences, National University of Singapore, 117558 Singapore
| | - Colin Cheng
- Program in Emerging Infectious Diseases, Duke-National University of Singapore Medical School, 169857 Singapore
| | - Subhash G Vasudevan
- Program in Emerging Infectious Diseases, Duke-National University of Singapore Medical School, 169857 Singapore
| | - Eng Eong Ooi
- Program in Emerging Infectious Diseases, Duke-National University of Singapore Medical School, 169857 Singapore;
- Saw Swee Hock School of Public Health, National University of Singapore, 117549 Singapore
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 119228 Singapore
- SingHealth Duke-National University of Singapore Global Health Institute, 169857 Singapore
| |
Collapse
|
6
|
Gan ES, Cheong WF, Chan KR, Ong EZ, Chai X, Tan HC, Ghosh S, Wenk MR, Ooi EE. Hypoxia enhances antibody-dependent dengue virus infection. EMBO J 2017; 36:1348-1363. [PMID: 28320741 PMCID: PMC5430213 DOI: 10.15252/embj.201695642] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Revised: 02/09/2017] [Accepted: 02/17/2017] [Indexed: 11/23/2022] Open
Abstract
Dengue virus (DENV) has been found to replicate in lymphoid organs such as the lymph nodes, spleen, and liver in post‐mortem analysis. These organs are known to have low oxygen levels (~0.5–4.5% O2) due to the vascular anatomy. However, how physiologically low levels of oxygen affect DENV infection via hypoxia‐induced changes in the immune response remains unknown. Here, we show that monocytes adapted to 3% O2 show greater susceptibility to antibody‐dependent enhancement of DENV infection. Low oxygen level induces HIF1α‐dependent upregulation of fragment crystallizable gamma receptor IIA (FcγRIIA) as well as HIF1α‐independent alterations in membrane ether lipid concentrations. The increased FcγRIIA expression operates synergistically with altered membrane composition, possibly through increase membrane fluidity, to increase uptake of DENV immune complexes for enhanced infection. Our findings thus indicate that the increased viral burden associated with secondary DENV infection is antibody‐dependent but hypoxia‐induced and suggest a role for targeting hypoxia‐induced factors for anti‐dengue therapy.
Collapse
Affiliation(s)
- Esther Shuyi Gan
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore
| | - Wei Fun Cheong
- Department of Biochemistry, National University of Singapore, Singapore, Singapore
| | - Kuan Rong Chan
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore
| | - Eugenia Ziying Ong
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore
| | - Xiaoran Chai
- Program in Cardiovascular & Metabolic Disorders and Centre for Computational Biology, Duke-NUS Medical School, Singapore, Singapore
| | - Hwee Cheng Tan
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore
| | - Sujoy Ghosh
- Program in Cardiovascular & Metabolic Disorders and Centre for Computational Biology, Duke-NUS Medical School, Singapore, Singapore
| | - Markus R Wenk
- Department of Biochemistry, National University of Singapore, Singapore, Singapore
| | - Eng Eong Ooi
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore .,Department of Microbiology and Immunology, National University of Singapore, Singapore, Singapore.,Saw Swee Hock School of Public Health, National University of Singapore, Singapore, Singapore.,Infectious Diseases Interdisciplinary Research Group, Singapore MIT Alliance Research and Technology CREATE Campus, Singapore, Singapore
| |
Collapse
|
7
|
Abstract
INTRODUCTION Dengue is a prevalent disease in tropical and subtropical countries with an estimated 400 million people infected annually. While significant advancement has been made in the chase for an effective dengue vaccine, the recently licensed Sanofi vaccine was, in contrast to in vitro data, only partially protective. Areas covered: This suggests that our understanding of the serological correlates for dengue is currently inadequate. With growing evidence supporting the role of fragment crystalizable gamma receptors (FcγRs) in antibody-mediated neutralization or antibody-dependent enhancement (ADE) of dengue virus (DENV) infection, FcγR-expressing cells have been increasingly used for measuring neutralizing antibody responses elicited by dengue vaccines. Here, we review the mechanisms of how FcγRs modulates both DENV neutralization and enhanced infections via its interactions with antibodies. Expert commentary: This review provides insights on the importance of factoring FcγRs for in vitro neutralization assays. Bridging the gap between in vitro and clinical observations would allow researchers to more accurately predict in vivo vaccine efficacy.
Collapse
Affiliation(s)
- Esther Shuyi Gan
- a Program in Emerging Infectious Diseases , Duke-NUS Medical School , Singapore , Singapore
| | - Donald Heng Rong Ting
- b Department of Microbiology and Immunology, Yong Loo Lin School of Medicine , National University of Singapore , Singapore , Singapore
| | - Kuan Rong Chan
- a Program in Emerging Infectious Diseases , Duke-NUS Medical School , Singapore , Singapore
| |
Collapse
|
8
|
Chan KR, Wang X, Saron WAA, Gan ES, Tan HC, Mok DZL, Zhang SLX, Lee YH, Liang C, Wijaya L, Ghosh S, Cheung YB, Tannenbaum SR, Abraham SN, St John AL, Low JGH, Ooi EE. Cross-reactive antibodies enhance live attenuated virus infection for increased immunogenicity. Nat Microbiol 2016; 1:16164. [PMID: 27642668 PMCID: PMC7097525 DOI: 10.1038/nmicrobiol.2016.164] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 08/08/2016] [Indexed: 01/10/2023]
Abstract
Vaccination has achieved remarkable successes in the control of childhood viral diseases. To control emerging infections, however, vaccines will need to be delivered to older individuals who, unlike infants, probably have had prior infection or vaccination with related viruses and thus have cross-reactive antibodies against the vaccines. Whether and how these cross-reactive antibodies impact live attenuated vaccination efficacy is unclear. Using an open-label randomized trial design, we show that subjects with a specific range of cross-reactive antibody titres from a prior inactivated Japanese encephalitis vaccination enhanced yellow fever (YF) immunogenicity upon YF vaccination. Enhancing titres of cross-reactive antibodies prolonged YF vaccine viraemia, provoked greater pro-inflammatory responses, and induced adhesion molecules intrinsic to the activating Fc-receptor signalling pathway, namely immune semaphorins, facilitating immune cell interactions and trafficking. Our findings clinically demonstrate antibody-enhanced infection and suggest that vaccine efficacy could be improved by exploiting cross-reactive antibodies.
Collapse
Affiliation(s)
- Kuan Rong Chan
- Program in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857
| | - Xiaohui Wang
- Program in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857
| | - Wilfried A A Saron
- Program in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857
| | - Esther Shuyi Gan
- Program in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857
| | - Hwee Cheng Tan
- Program in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857
| | - Darren Z L Mok
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597
| | - Summer Li-Xin Zhang
- Program in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857
| | - Yie Hou Lee
- Interdisciplinary Research Group in Infectious Diseases, Singapore-MIT Alliance for Research & Technology (SMART), Singapore 138602.,KK Research Centre, KK Women's and Children's Hospital, Singapore 229899
| | - Cui Liang
- Interdisciplinary Research Group in Infectious Diseases, Singapore-MIT Alliance for Research & Technology (SMART), Singapore 138602
| | - Limin Wijaya
- Department of Infectious Diseases, Singapore General Hospital, Singapore 169856
| | - Sujoy Ghosh
- Centre for Computational Biology, Duke-NUS Medical School, Singapore 169857
| | - Yin Bun Cheung
- Center for Quantitative Medicine, Duke-NUS Medical School, Singapore 169857.,Department for International Health, University of Tampere, 33100 Finland
| | - Steven R Tannenbaum
- Interdisciplinary Research Group in Infectious Diseases, Singapore-MIT Alliance for Research & Technology (SMART), Singapore 138602.,Department of Biological Engineering and Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Soman N Abraham
- Program in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857.,Department of Immunology and the Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, North Carolina 27710, USA
| | - Ashley L St John
- Program in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857
| | - Jenny G H Low
- Department of Infectious Diseases, Singapore General Hospital, Singapore 169856
| | - Eng Eong Ooi
- Program in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore 169857.,Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597.,Interdisciplinary Research Group in Infectious Diseases, Singapore-MIT Alliance for Research & Technology (SMART), Singapore 138602
| |
Collapse
|
9
|
Goh KCM, Tang CK, Norton DC, Gan ES, Tan HC, Sun B, Syenina A, Yousuf A, Ong XM, Kamaraj US, Cheung YB, Gubler DJ, Davidson A, St John AL, Sessions OM, Ooi EE. Molecular determinants of plaque size as an indicator of dengue virus attenuation. Sci Rep 2016; 6:26100. [PMID: 27185466 PMCID: PMC4868997 DOI: 10.1038/srep26100] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 04/27/2016] [Indexed: 12/12/2022] Open
Abstract
The development of live viral vaccines relies on empirically derived phenotypic criteria, especially small plaque sizes, to indicate attenuation. However, while some candidate vaccines successfully translated into licensed applications, others have failed safety trials, placing vaccine development on a hit-or-miss trajectory. We examined the determinants of small plaque phenotype in two dengue virus (DENV) vaccine candidates, DENV-3 PGMK30FRhL3, which produced acute febrile illness in vaccine recipients, and DENV-2 PDK53, which has a good clinical safety profile. The reasons behind the failure of PGMK30FRhL3 during phase 1 clinical trial, despite meeting the empirically derived criteria of attenuation, have never been systematically investigated. Using in vitro, in vivo and functional genomics approaches, we examined infections by the vaccine and wild-type DENVs, in order to ascertain the different determinants of plaque size. We show that PGMK30FRhL3 produces small plaques on BHK-21 cells due to its slow in vitro growth rate. In contrast, PDK53 replicates rapidly, but is unable to evade antiviral responses that constrain its spread hence also giving rise to small plaques. Therefore, at least two different molecular mechanisms govern the plaque phenotype; determining which mechanism operates to constrain plaque size may be more informative on the safety of live-attenuated vaccines.
Collapse
Affiliation(s)
| | | | | | | | | | - Bo Sun
- Duke University School of Medicine, Durham, North Carolina 27710, USA
| | - Ayesa Syenina
- Duke-NUS Medical School, Singapore 169857, Singapore
| | | | - Xin Mei Ong
- Duke-NUS Medical School, Singapore 169857, Singapore
| | | | | | | | | | | | | | - Eng Eong Ooi
- Duke-NUS Medical School, Singapore 169857, Singapore
| |
Collapse
|