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Okuwa T, Himeda T, Utani K, Higuchi M. Generation of a recombinant Saffold Virus expressing UnaG as a marker for the visualization of viral infection. Virol J 2023; 20:175. [PMID: 37550694 PMCID: PMC10408109 DOI: 10.1186/s12985-023-02142-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 07/26/2023] [Indexed: 08/09/2023] Open
Abstract
BACKGROUND Saffold virus (SAFV), which belongs to the genus Cardiovirus of the family Picornaviridae, is associated with acute respiratory or gastrointestinal illnesses in children; it is also suspected to cause severe diseases, such as acute flaccid paralysis and aseptic meningitis. However, the understanding of the mechanism of its pathogenicity is still limited due to the many unknowns about its lifecycle; for example, the cellular receptor for its infection remains to be determined. A system to monitor SAFV infection in vitro and in vivo is required in order to accelerate research on SAFV. RESULTS We generated a recombinant SAFV expressing green fluorescent protein (GFP) or UnaG, a novel fluorescent protein derived from Japanese eel. HeLa cells infected by either GFP or UnaG-expressing SAFV showed a bright green fluorescent signal, enabling convenient monitoring of SAFV infection. However, the expression of GFP but not UnaG was quickly lost during virus passaging due to the difference in genetic stability in the SAFV virus genome; the UnaG gene was stably maintained in the virus genome after at least five passages. CONCLUSIONS SAFV infection of cultured cells can easily be monitored using UnaG-expressing SAFV, which is superior to GFP in terms of genetic stability in the virus genome. This virus could be a useful tool for SAFV research, such as comparing the susceptibility of various cells to SAFV infection and evaluating the effects of antivirals on SAFV infection in high-throughput screening.
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Affiliation(s)
- Takako Okuwa
- Department of Microbiology, Kanazawa Medical University School of Medicine, 1-1 Daigaku, Uchinada, Ishikawa, 920-0293, Japan
| | - Toshiki Himeda
- Department of Microbiology, Kanazawa Medical University School of Medicine, 1-1 Daigaku, Uchinada, Ishikawa, 920-0293, Japan
| | - Koichi Utani
- Department of Microbiology, Kanazawa Medical University School of Medicine, 1-1 Daigaku, Uchinada, Ishikawa, 920-0293, Japan
| | - Masaya Higuchi
- Department of Microbiology, Kanazawa Medical University School of Medicine, 1-1 Daigaku, Uchinada, Ishikawa, 920-0293, Japan.
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Anh NT, Hong NTT, Nhu LNT, Thanh TT, Lau CY, Limmathurotsakul D, Deng X, Rahman M, Chau NVV, van Doorn HR, Thwaites G, Delwart E, Tan LV. Viruses in Vietnamese Patients Presenting with Community-Acquired Sepsis of Unknown Cause. J Clin Microbiol 2019; 57:e00386-19. [PMID: 31217274 PMCID: PMC6711913 DOI: 10.1128/jcm.00386-19] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 06/12/2019] [Indexed: 12/28/2022] Open
Abstract
Community-acquired (CA) sepsis is a major public health problem worldwide, yet the etiology remains unknown for >50% of the patients. Here we applied metagenomic next-generation sequencing (mNGS) to characterize the human virome in 492 clinical samples (384 sera, 92 pooled nasal and throat swabs, 10 stools, and 6 cerebrospinal fluid samples) from 386 patients (213 adults and 173 children) presenting with CA sepsis who were recruited from 6 hospitals across Vietnam between 2013 and 2015. Specific monoplex PCRs were used subsequently to confirm the presence of viral sequences detected by mNGS. We found sequences related to 47 viral species belonging to 21 families in 358 of 386 (93%) patients, including viruses known to cause human infections. After PCR confirmation, human viruses were found in 52 of 386 patients (13.4%); picornavirus (enteroviruses [n = 14], rhinovirus [n = 5], and parechovirus [n = 2]), hepatitis B virus (n = 10), cytomegalovirus (n = 9), Epstein-Barr virus (n = 5), and rotavirus A (n = 3) were the most common viruses detected. Recently discovered viruses were also found (gemycircularvirus [n = 5] and WU polyomavirus, Saffold virus, salivirus, cyclovirus-VN, and human pegivirus 2 [HPgV2] [n, 1 each]), adding to the growing literature about the geographic distribution of these novel viruses. Notably, sequences related to numerous viruses not previously reported in human tissues were also detected. To summarize, we identified 21 viral species known to be infectious to humans in 52 of 386 (13.4%) patients presenting with CA sepsis of unknown cause. The study, however, cannot directly impute sepsis causation to the viruses identified. The results highlight the fact that it remains a challenge to establish the causative agents in CA sepsis patients, especially in tropical settings such as Vietnam.
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Affiliation(s)
- Nguyen To Anh
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | | | | | - Tran Tan Thanh
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | - Chuen-Yen Lau
- Collaborative Clinical Research Branch, Division of Clinical Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Direk Limmathurotsakul
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
- Mahidol Oxford Tropical Research Unit, Bangkok, Thailand
| | - Xutao Deng
- Blood Systems Research Institute, San Francisco, California, USA
- Department of Laboratory Medicine, University of California, San Francisco, California, USA
| | - Motiur Rahman
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
| | | | - H Rogier van Doorn
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Guy Thwaites
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
- Centre for Tropical Medicine and Global Health, Nuffield Department of Medicine, University of Oxford, Oxford, United Kingdom
| | - Eric Delwart
- Blood Systems Research Institute, San Francisco, California, USA
- Department of Laboratory Medicine, University of California, San Francisco, California, USA
| | - Le Van Tan
- Oxford University Clinical Research Unit, Ho Chi Minh City, Vietnam
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Abstract
BACKGROUND Saffold virus (SAFV) is a novel human cardiovirus that was identified in 2007. Recently, SAFV has been isolated from nasal and stool specimens of infants presenting with respiratory and gastrointestinal symptoms and from cerebrospinal fluid (CSF) specimens of children with central nervous system infection. However, little is known regarding clinical characteristics of SAFV in children. METHODS We reviewed 5412 specimens from the database of the infectious agents surveillance system in Niigata prefecture, Japan, between January 2006 and December 2013, and identified SAFV-infected patients. Subsequently, we retrospectively reviewed their medical records and evaluated their clinical characteristics. RESULTS We identified 9 SAFV-infected patients (median age: 5 years; range: 2-16 years). Seven patients were diagnosed with pharyngitis, one with meningitis and one with fever of unknown origin. Dominant symptoms were high fever, appetite loss and headache. The median duration of the fevers was 2 days in patients with pharyngitis; however, the patient with meningitis remained febrile for 5 days. All blood tests available in this case series revealed leukocytosis with a predominance of neutrophils. CSF profiles showed mild lymphocytic pleocytosis. All patients recovered fully without complications. CONCLUSIONS A few clinical characteristics of SAFV infection were clarified, including high fever of short duration in patients with pharyngitis, and neutrophil-dominant leukocytosis. The clinical course and CSF profiles of a case of meningitis were similar to those of other aseptic meningitis. SAFV needs to be included in the differential diagnosis of pharyngitis or meningitis when commonly identified viruses are not identified in such patients.
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Lindner K, Ludwig M, Bootz F, Reber U, Safavieh Z, Eis-Hübinger AM, Herberhold S. Frequent detection of Saffold cardiovirus in adenoids. PLoS One 2019; 14:e0218873. [PMID: 31269055 PMCID: PMC6608973 DOI: 10.1371/journal.pone.0218873] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 06/11/2019] [Indexed: 01/15/2023] Open
Abstract
Saffold virus (SAFV) is classified into the Cardiovirus genus of the Picornaviridae family. Up to now, eleven genotypes have been identified however, their clinical significance remains unclear. Here, we investigated the presence of SAFV in asymptomatic patients admitted for adenoidectomy. A total of 70 adenoid tissue samples were collected from children with clinical symptoms caused by hypertrophy of adenoids but without symptoms of airway infection. Samples were investigated for SAFV by RT-nested PCR and sequence analysis. Eleven of 70 (15.7%) samples were positive for SAFV. Nasopharyngeal swabs were available from 45 children just before surgery. SAFV was rarely found and only in children with SAFV-positive adenoids 2/8. Our findings indicate that the presence of SAFV seems to be more frequent in adenoid tissue than expected. This could support the notion of a longer than previously anticipated persistence of SAFV nucleic acids in the respiratory tract and possibly a chronic infection. Further investigations are necessary to establish the role of SAFV infection in humans.
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Affiliation(s)
- Kira Lindner
- ENT Department, Head and Neck Surgery, University of Bonn, Bonn, Germany
| | - Michael Ludwig
- Department of Clinical Chemistry and Clinical Pharmacology, University of Bonn, Bonn, Germany
| | - Friedrich Bootz
- ENT Department, Head and Neck Surgery, University of Bonn, Bonn, Germany
| | - Ulrike Reber
- Institute of Virology, University of Bonn Medical Centre, Bonn, Germany
| | | | - Anna Maria Eis-Hübinger
- Institute of Virology, University of Bonn Medical Centre, Bonn, Germany
- * E-mail: (AMEH); (SH)
| | - Stephan Herberhold
- ENT Department, Head and Neck Surgery, University of Bonn, Bonn, Germany
- * E-mail: (AMEH); (SH)
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Ito H, Miyagaki S, Sakaue S, Matsui F, Katsumi Y, Otabe O, Torii J, Itagaki T, Himeda T, Okuwa T, Ohara Y. Saffold Cardiovirus Infection in a 2-Year-Old Boy with Acute Pancreatitis. Jpn J Infect Dis 2017; 70:105-107. [DOI: 10.7883/yoken.jjid.2015.488] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Hisato Ito
- Department of Pediatrics, Nantan General Hospital
| | | | - Satoshi Sakaue
- Department of Pediatrics, Kyoto Prefectural University of Medicine
| | - Fumihiro Matsui
- Department of Pediatrics, North Medical Center Kyoto prefectural University of Medicine
| | - Yoshiki Katsumi
- Department of Pediatrics, Kyoto Prefectural University of Medicine
| | - Osamu Otabe
- Department of Pediatrics, Nantan General Hospital
| | - Jun Torii
- Kyoto Prefectural institute of Public Health and Environment
| | | | - Toshiki Himeda
- Department of Microbiology, Kanazawa Medical University School of Medicine
| | - Takako Okuwa
- Department of Microbiology, Kanazawa Medical University School of Medicine
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Intracerebral Inoculation of Mouse-Passaged Saffold Virus Type 3 Affects Cerebellar Development in Neonatal Mice. J Virol 2016; 90:10007-10021. [PMID: 27581974 DOI: 10.1128/jvi.00864-16] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 08/22/2016] [Indexed: 01/04/2023] Open
Abstract
Saffold virus (SAFV), a human cardiovirus, is occasionally detected in infants with neurological disorders, including meningitis and cerebellitis. We recently reported that SAFV type 3 isolates infect cerebellar glial cells, but not large neurons, in mice. However, the impact of this infection remained unclear. Here, we determined the neuropathogenesis of SAFV type 3 in the cerebella of neonatal ddY mice by using SAFV passaged in the cerebella of neonatal BALB/c mice. The virus titer in the cerebellum increased following the inoculation of each of five passaged strains. The fifth passaged strain harbored amino acid substitutions in the VP2 (H160R and Q239R) and VP3 (K62M) capsid proteins. Molecular modeling of the capsid proteins suggested that the VP2-H160R and VP3-K62M mutations alter the structural dynamics of the receptor binding surface via the formation of a novel hydrophobic interaction between the VP2 puff B and VP3 knob regions. Compared with the original strain, the passaged strain showed altered growth characteristics in human-derived astroglial cell lines and greater replication in the brains of neonatal mice. In addition, the passaged strain was more neurovirulent than the original strain, while both strains infected astroglial and neural progenitor cells in the mouse brain. Intracerebral inoculation of either the original or the passaged strain affected brain Purkinje cell dendrites, and a high titer of the passaged strain induced cerebellar hypoplasia in neonatal mice. Thus, infection by mouse-passaged SAFV affected cerebellar development in neonatal mice. This animal model contributes to the understanding of the neuropathogenicity of SAFV infections in infants. IMPORTANCE Saffold virus (SAFV) is a candidate neuropathogenic agent in infants and children, but the neuropathogenicity of the virus has not been fully elucidated. Recently, we evaluated the pathogenicity of two clinical SAFV isolates in mice. Similar to other neurotropic picornaviruses, these isolates showed mild infectivity of glial and neural progenitor cells, but not of large neurons, in the cerebellum. However, the outcome of this viral infection in the cerebellum has not been clarified. Here, we examined the tropism of SAFV in the cerebellum. We obtained an in vivo-passaged strain from the cerebella of neonatal mice and examined its genome and its neurovirulence in the neonatal mouse brain. The passaged virus showed high infectivity and neurovirulence in the brain, especially the cerebellum, and affected cerebellar development. This unique neonatal mouse model will be helpful for elucidating the neuropathogenesis of SAFV infections occurring early in life.
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Tan SZK, Tan MZY, Prabakaran M. Saffold virus, an emerging human cardiovirus. Rev Med Virol 2016; 27. [PMID: 27723176 PMCID: PMC7169152 DOI: 10.1002/rmv.1908] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 08/23/2016] [Accepted: 08/30/2016] [Indexed: 01/16/2023]
Abstract
Saffold virus (SAFV) is an emerging human cardiovirus that has been shown to be ubiquitous. Initial studies of SAFV focused on respiratory and gastrointestinal infection; however, it has also recently been associated with diverse clinical symptoms including the endocrine, cardiovascular, and neurological systems. Given the systemic nature of SAFV, and its high prevalence, understanding its pathogenicity and clinical impact is of utmost importance. This comprehensive review highlights and discusses recent developments in epidemiology, human pathogenicity, animal, and molecular studies related to SAFV. It also provides detailed insights into the neuropathogenicity of SAFV. We argue that human studies have been confounded by coinfections and therefore require support from robust molecular and animal research. Thereby, we aim to provide foresight into further research to better understand this emerging virus.
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Affiliation(s)
- Shawn Zheng Kai Tan
- Temasek Life Science Laboratory, 1 Research Link, National University of Singapore, Singapore, Republic of Singapore
| | - Mark Zheng Yi Tan
- Critical Care Unit, Central Manchester Foundation NHS Trust, Manchester, UK
| | - Mookkan Prabakaran
- Temasek Life Science Laboratory, 1 Research Link, National University of Singapore, Singapore, Republic of Singapore
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Structure and Genome Release Mechanism of the Human Cardiovirus Saffold Virus 3. J Virol 2016; 90:7628-39. [PMID: 27279624 PMCID: PMC4988150 DOI: 10.1128/jvi.00746-16] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 05/31/2016] [Indexed: 12/14/2022] Open
Abstract
In order to initiate an infection, viruses need to deliver their genomes into cells. This involves uncoating the genome and transporting it to the cytoplasm. The process of genome delivery is not well understood for nonenveloped viruses. We address this gap in our current knowledge by studying the uncoating of the nonenveloped human cardiovirus Saffold virus 3 (SAFV-3) of the family Picornaviridae. SAFVs cause diseases ranging from gastrointestinal disorders to meningitis. We present a structure of a native SAFV-3 virion determined to 2.5 Å by X-ray crystallography and an 11-Å-resolution cryo-electron microscopy reconstruction of an “altered” particle that is primed for genome release. The altered particles are expanded relative to the native virus and contain pores in the capsid that might serve as channels for the release of VP4 subunits, N termini of VP1, and the RNA genome. Unlike in the related enteroviruses, pores in SAFV-3 are located roughly between the icosahedral 3- and 5-fold axes at an interface formed by two VP1 and one VP3 subunit. Furthermore, in native conditions many cardioviruses contain a disulfide bond formed by cysteines that are separated by just one residue. The disulfide bond is located in a surface loop of VP3. We determined the structure of the SAFV-3 virion in which the disulfide bonds are reduced. Disruption of the bond had minimal effect on the structure of the loop, but it increased the stability and decreased the infectivity of the virus. Therefore, compounds specifically disrupting or binding to the disulfide bond might limit SAFV infection. IMPORTANCE A capsid assembled from viral proteins protects the virus genome during transmission from one cell to another. However, when a virus enters a cell the virus genome has to be released from the capsid in order to initiate infection. This process is not well understood for nonenveloped viruses. We address this gap in our current knowledge by studying the genome release of Human Saffold virus 3. Saffold viruses cause diseases ranging from gastrointestinal disorders to meningitis. We show that before the genome is released, the Saffold virus 3 particle expands, and holes form in the previously compact capsid. These holes serve as channels for the release of the genome and small capsid proteins VP4 that in related enteroviruses facilitate subsequent transport of the virus genome into the cell cytoplasm.
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Tan SZK, Chua KB, Xu Y, Prabakaran M. The Pathogenesis of Saffold Virus in AG129 Mice and the Effects of Its Truncated L Protein in the Central Nervous System. Viruses 2016; 8:v8020024. [PMID: 26901216 PMCID: PMC4776182 DOI: 10.3390/v8020024] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 01/11/2016] [Accepted: 01/12/2016] [Indexed: 12/03/2022] Open
Abstract
Saffold Virus (SAFV) is a human cardiovirus that has been suggested to cause severe infection of the central nervous system (CNS). Compared to a similar virus, Theiler’s murine encephalomyelitis virus (TMEV), SAFV has a truncated Leader (L) protein, a protein essential in the establishment of persistent CNS infections. In this study, we generated a chimeric SAFV by replacing the L protein of SAFV with that of TMEV. We then compared the replication in cell cultures and pathogenesis in a mouse model. We showed that both SAFV and chimeric SAFV are able to infect Vero and Neuro2a cells well, but only chimeric SAFV was able to infect RAW264.7. We then showed that mice lacking IFN-α/β and IFN-γ receptors provide a good animal model for SAFV infection, and further identified the locality of the infection to the ventral horn of the spine and several locations in the brain. Lastly, we showed that neither SAFV nor chimeric SAFV causes persistence in this model. Overall, our results provide a strong basis on which the mechanisms underlying Saffold virus induced neuropathogenesis can be further studied and, hence, facilitating new information about its pathogenesis.
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Affiliation(s)
- Shawn Zheng Kai Tan
- Temasek Life Science Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore.
| | - Kaw Bing Chua
- Temasek Life Science Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore.
| | - Yishi Xu
- Temasek Life Science Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore.
| | - Mookkan Prabakaran
- Temasek Life Science Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Singapore.
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Kotani O, Naeem A, Suzuki T, Iwata-Yoshikawa N, Sato Y, Nakajima N, Hosomi T, Tsukagoshi H, Kozawa K, Hasegawa H, Taguchi F, Shimizu H, Nagata N. Neuropathogenicity of Two Saffold Virus Type 3 Isolates in Mouse Models. PLoS One 2016; 11:e0148184. [PMID: 26828718 PMCID: PMC4734772 DOI: 10.1371/journal.pone.0148184] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 01/14/2016] [Indexed: 12/11/2022] Open
Abstract
Objective Saffold virus (SAFV), a picornavirus, is occasionally detected in children with acute flaccid paralysis, meningitis, and cerebellitis; however, the neuropathogenicity of SAFV remains undetermined. Methods The virulence of two clinical isolates of SAFV type 3 (SAFV-3) obtained from a patient with aseptic meningitis (AM strain) and acute upper respiratory inflammation (UR strain) was analyzed in neonatal and young mice utilizing virological, pathological, and immunological methods. Results The polyproteins of the strains differed in eight amino acids. Both clinical isolates were infective, exhibited neurotropism, and were mildly neurovirulent in neonatal ddY mice. Both strains pathologically infected neural progenitor cells and glial cells, but not large neurons, with the UR strain also infecting epithelial cells. UR infection resulted in longer inflammation in the brain and spinal cord because of demyelination, while the AM strain showed more infectivity in the cerebellum in neonatal ddY mice. Additionally, young BALB/c mice seroconverted following mucosal inoculation with the UR, but not the AM, strain. Conclusions Both SAFV-3 isolates had neurotropism and mild neurovirulence but showed different cell tropisms in both neonatal and young mouse models. This animal model has the potential to recapitulate the potential neuropathogenicity of SAFV-3.
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Affiliation(s)
- Osamu Kotani
- Department of Pathology, National Institute of Infectious Diseases, Tokyo, Japan
- Department of Virology and Viral Infections, Faculty of Veterinary Medicine, Nippon Veterinary and Life Science University, Tokyo, Japan
| | - Asif Naeem
- Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan
| | - Tadaki Suzuki
- Department of Pathology, National Institute of Infectious Diseases, Tokyo, Japan
| | | | - Yuko Sato
- Department of Pathology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Noriko Nakajima
- Department of Pathology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Takushi Hosomi
- The Public Health Institute of Kochi Prefecture, Kochi, Japan
| | - Hiroyuki Tsukagoshi
- Gunma Prefectural Institute of Public Health and Environmental Sciences, Gunma, Japan
| | - Kunihisa Kozawa
- Gunma Prefectural Institute of Public Health and Environmental Sciences, Gunma, Japan
| | - Hideki Hasegawa
- Department of Pathology, National Institute of Infectious Diseases, Tokyo, Japan
| | - Fumihiro Taguchi
- Department of Virology and Viral Infections, Faculty of Veterinary Medicine, Nippon Veterinary and Life Science University, Tokyo, Japan
| | - Hiroyuki Shimizu
- Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan
| | - Noriyo Nagata
- Department of Pathology, National Institute of Infectious Diseases, Tokyo, Japan
- * E-mail:
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Tapia G, Bøås H, de Muinck EJ, Cinek O, Stene LC, Torjesen PA, Rasmussen T, Rønningen KS. Saffold Virus, a Human Cardiovirus, and Risk of Persistent Islet Autoantibodies in the Longitudinal Birth Cohort Study MIDIA. PLoS One 2015; 10:e0136849. [PMID: 26317929 PMCID: PMC4552579 DOI: 10.1371/journal.pone.0136849] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 08/10/2015] [Indexed: 01/27/2023] Open
Abstract
The aim of this study was to describe the frequency and distribution of Saffold virus in longitudinal stool samples from children, and test for association with development of persistent autoantibodies predictive of type 1 diabetes. A cohort of Norwegian children carrying the HLA genotype associated with highest risk of type 1 diabetes (“DR4-DQ8/DR3-DQ2”) was followed with monthly stool samples from 3 to 35 months of age. Blood samples were tested for autoantibodies to insulin, glutamic acid decarboxylase65 and Islet Antigen-2. 2077 stool samples from 27 children with ≥2 repeatedly positive islet autoantibodies (cases), and 53 matched controls were analysed for Saffold virus genomic RNA by semi-quantitative real-time reverse transcriptase PCR. Saffold virus was found in 53 of 2077 (2.6%) samples, with similar proportions between cases (2.5%) and controls (2.6%). The probability of being infected by 3 years of age was 28% (95% CI 0.18–0.40). Viral quantities ranged from <1 to almost 105 copies/μl. Estimated odds ratio between islet autoimmunity and infection episodes prior to seroconversion was 1.98 (95% CI: 0.57–6.91, p = 0.29). Saffold virus had no statistically significant association with islet autoimmunity.
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Affiliation(s)
- German Tapia
- Department of Genes and Environment, Division of Epidemiology, Norwegian Institute of Public Health, Oslo, Norway
| | - Håkon Bøås
- Department of Genes and Environment, Division of Epidemiology, Norwegian Institute of Public Health, Oslo, Norway
- * E-mail:
| | - Eric J. de Muinck
- Center for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Oslo, Norway
| | - Ondrej Cinek
- Department of Paediatrics, 2nd Faculty of Medicine, Charles University in Prague and University Hospital Motol, Prague, Czech Republic
| | - Lars C. Stene
- Department of Chronic Diseases, Division of Epidemiology, Norwegian Institute of Public Health, Oslo, Norway
| | - Peter A. Torjesen
- Hormone Laboratory, Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
| | - Trond Rasmussen
- Department of IT and e-health, Division of Institute Resources, Norwegian Institute of Public Health, Oslo, Norway
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Kotani O, Iwata‐Yoshikawa N, Suzuki T, Sato Y, Nakajima N, Koike S, Iwasaki T, Sata T, Yamashita T, Minagawa H, Taguchi F, Hasegawa H, Shimizu H, Nagata N. Establishment of a panel of in-house polyclonal antibodies for the diagnosis of enterovirus infections. Neuropathology 2015; 35:107-21. [PMID: 25263613 PMCID: PMC7168124 DOI: 10.1111/neup.12171] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2014] [Accepted: 09/02/2014] [Indexed: 11/30/2022]
Abstract
The aim of this study was to establish a reliable method of virus detection for the diagnosis of critical enterovirus infections such as acute infective encephalitis, encephalomyelitis and myocarditis. Because histopathological and immunohistochemical analyses of paraffin-embedded tissues play an important role in recognizing infectious agents in tissue samples, six in-house polyclonal antibodies raised against three representative enteroviruses using an indirect immunofluorescence assay and immunohistochemistry were examined. This panel of polyclonal antibodies recognized three serotypes of enterovirus. Two of the polyclonal antibodies were raised against denatured virus particles from enterovirus A71, one was raised against the recombinant VP1 protein of coxsackievirus B3, and the other for poliovirus type 1 were raised against denatured virus particles, the recombinant VP1 protein and peptide 2C. Western blot analysis revealed that each of these antibodies recognized the corresponding viral antigen and none cross-reacted with non-enteroviruses within the family Picornaviridae. However, all cross-reacted to some extent with the antigens derived from other serotypes of enterovirus. Indirect immunofluorescence assay and immunohistochemistry revealed that the virus capsid and non-structural proteins were localized in the cytoplasm of affected culture cells, and skeletal muscles and neurons in neonatal mice experimentally-infected with human enterovirus. The antibodies also recognized antigens derived from recent clinical isolates of enterovirus A71, coxsackievirus B3 and poliovirus. In addition, immunohistochemistry revealed that representative antibodies tested showed the same recognition pattern according to each serotype. Thus, the panel of in-house anti-enterovirus polyclonal antibodies described herein will be an important tool for the screening and pathological diagnosis for enterovirus infections, and may be useful for the classification of different enterovirus serotypes, including coxsackieviruses A and B, echoviruses, enterovirus A71 and poliovirus.
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Affiliation(s)
- Osamu Kotani
- Department of PathologyNational Institute of Infectious DiseasesAichiJapan
- Department of Virology and Viral InfectionsFaculty of Veterinary MedicineNippon Veterinary and Life Science UniversityAichiJapan
| | | | - Tadaki Suzuki
- Department of PathologyNational Institute of Infectious DiseasesAichiJapan
| | - Yuko Sato
- Department of PathologyNational Institute of Infectious DiseasesAichiJapan
| | - Noriko Nakajima
- Department of PathologyNational Institute of Infectious DiseasesAichiJapan
| | - Satoshi Koike
- Neurovirology ProjectTokyo Metropolitan Institute of Medical ScienceAichiJapan
| | - Takuya Iwasaki
- Department of PathologyNational Institute of Infectious DiseasesAichiJapan
| | - Tetsutaro Sata
- Department of PathologyNational Institute of Infectious DiseasesAichiJapan
| | - Teruo Yamashita
- Department of Microbiology and Medical ZoologyAichi Prefectural Institute of Public HealthAichiJapan
| | - Hiroko Minagawa
- Department of Microbiology and Medical ZoologyAichi Prefectural Institute of Public HealthAichiJapan
| | - Fumihiro Taguchi
- Department of Virology and Viral InfectionsFaculty of Veterinary MedicineNippon Veterinary and Life Science UniversityAichiJapan
| | - Hideki Hasegawa
- Department of PathologyNational Institute of Infectious DiseasesAichiJapan
| | - Hiroyuki Shimizu
- Department of Virology IINational Institute of Infectious DiseasesAichiJapan
| | - Noriyo Nagata
- Department of PathologyNational Institute of Infectious DiseasesAichiJapan
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Zhang XA, Lu QB, Wo Y, Zhao J, Huang DD, Guo CT, Xu HM, Liu EM, Liu W, Cao WC. Prevalence and genetic characteristics of Saffold cardiovirus in China from 2009 to 2012. Sci Rep 2015; 5:7704. [PMID: 25572936 PMCID: PMC5378990 DOI: 10.1038/srep07704] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2014] [Accepted: 12/08/2014] [Indexed: 12/28/2022] Open
Abstract
The epidemiology and clinical features of the Saffold cardiovirus (SAFV) remain ambiguous. The present study was designed to systematically and intensively investigate the epidemiological features of SAFV in pediatric patients in China. Three cohorts of pediatric patients were recruited from 2009 to 2012. Cohort 1 comprised patients with acute respiratory tract infections. Cohort 2 comprised patients with diarrhea. Cohort 3 comprised hand, foot, and mouth disease (HFMD) patients. A total of 115 patients (1.6%) among 6052 (17/1647, 12/2013, and 86/2392 in cohorts 1, 2, and 3, respectively) were SAFV-positive. The samples from 82 SAFV-positive patients were successfully sequenced, and four genotypes were identified: 8 SAFV-1, 41 SAFV-2, 29 SAFV-3, and 4 SAFV-6. A significantly higher detection rate was found in the HFMD patients than in other two cohorts (both P <0.001). A higher frequency of severe clinical outcome and nervous system manifestation were also observed in the SAFV-positive HFMD patients. Additionally, 6 (3.5%) cerebrospinal fluid and 7 (2.2%) serum samples from the HFMD-associated encephalitis patients were SAFV-positive. Based on the VP1 sequences, all four genotypes displayed distinct geographical clustering. SAFV infection might be associated with a wide clinical spectrum and contribute to HFMD.
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Affiliation(s)
- Xiao-Ai Zhang
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 100071, Beijing, P. R. China
| | - Qing-Bin Lu
- School of Public Health, Peking University, 100191, Beijing, P. R. China
| | - Ying Wo
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 100071, Beijing, P. R. China
| | - Jin Zhao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 100071, Beijing, P. R. China
| | - Dou-Dou Huang
- 1] State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 100071, Beijing, P. R. China [2] Graduate School of Anhui Medical University, 230032, Hefei, P. R. China
| | - Chen-Tao Guo
- 1] State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 100071, Beijing, P. R. China [2] Graduate School of Anhui Medical University, 230032, Hefei, P. R. China
| | - Hong-Mei Xu
- Children's Hospital of Chongqing Medical University, 400014, Chongqing, P. R. China
| | - En-Mei Liu
- Children's Hospital of Chongqing Medical University, 400014, Chongqing, P. R. China
| | - Wei Liu
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 100071, Beijing, P. R. China
| | - Wu-Chun Cao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, 100071, Beijing, P. R. China
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14
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Naeem A, Hosomi T, Nishimura Y, Alam MM, Oka T, Zaidi SSZ, Shimizu H. Genetic diversity of circulating Saffold viruses in Pakistan and Afghanistan. J Gen Virol 2014; 95:1945-1957. [PMID: 24899154 DOI: 10.1099/vir.0.066498-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Human cardioviruses or Saffold viruses (SAFVs) of the family Picornaviridae are newly emerging viruses whose genetic and phenotypic diversity are poorly understood. We report here the full genome sequence of 11 SAFV genotypes from Pakistan and Afghanistan, along with a re-evaluation of their genetic diversity and recombination. We detected 88 SAFV from stool samples of 943 acute flaccid paralysis cases using reverse transcriptase-PCR targeting the 5' untranslated region (UTR). Further characterization based on complete VP1 analysis revealed 71 SAFVs belonging to 11 genotypes, including three previously unidentified genotypes. SAFV showed high genetic diversity and recombination based on phylogenetic, pairwise distance distributions and recombination mapping analyses performed herein. Phylogenies based on non-structural and UTRs were highly incongruent indicating frequent recombination events among SAFVs. We improved the SAFV genotyping classification criteria by determining new VP1 thresholds based on the principles used for the classification of enteroviruses. For genotype assignment, we propose a threshold of 23 and 10 % divergence for VP1 nucleotide and amino acid sequences, respectively. Other members of the species Theilovirus, such as Thera virus and Theiler's murine encephalomyelitis virus, are difficult to classify in the same species as SAFV, because they are genetically distinct from SAFV, with 41-56 % aa pairwise distances. The new genetic information obtained in this study will improve our understanding of the evolution and classification of SAFV.
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Affiliation(s)
- Asif Naeem
- Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan
| | - Takushi Hosomi
- The Meat Inspection Center of Kochi Prefecture, Kochi, Japan
| | - Yorihiro Nishimura
- Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan
| | | | - Tomoichiro Oka
- Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan
| | | | - Hiroyuki Shimizu
- Department of Virology II, National Institute of Infectious Diseases, Tokyo, Japan
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15
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Saffold virus is able to productively infect primate and rodent cell lines and induces apoptosis in these cells. Emerg Microbes Infect 2014; 3:e15. [PMID: 26038510 PMCID: PMC3944122 DOI: 10.1038/emi.2014.15] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Revised: 12/17/2013] [Accepted: 12/24/2013] [Indexed: 01/07/2023]
Abstract
Saffold virus (SAFV), a newly discovered human cardiovirus of the Picornaviridae family, causes widespread infection among children, as shown by previous seroprevalence studies. To determine the host cell range of SAFV and its cytopathogenicity, eight mammalian cell lines that were available in the laboratory were screened for productive SAFV infection by a laboratory-adapted SAFV of genotype 3. Five of the cell lines (Neuro2A, CHO-K1, NIH/3T3, Vero and HEp-2) were found to be permissible. The time required for SAFV to induce complete lysis as a cytopathic effect (CPE) in these permissibly infected cells and the resultant end point virus titer differed for each cell type. HEp-2 exhibited the shortest time frame to reach full CPE compared to the others. All infected cell lines produced a high virus titer at 72 h post-infection. In addition to causing lytic cell death, SAFV also induced apoptotic cell death in host cells through both extrinsic and intrinsic pathways, although the apoptotic events in HEp-2 cells appeared to have been blocked between the early and late stages. In conclusion, laboratory-adapted SAFV is able to productively infect a number of mammalian cell lines and induce apoptosis in the infected host cells. However, apoptosis in HEp-2 cells is blocked before the end stage.
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16
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Himeda T, Hosomi T, Okuwa T, Muraki Y, Ohara Y. Saffold virus type 3 (SAFV-3) persists in HeLa cells. PLoS One 2013; 8:e53194. [PMID: 23308162 PMCID: PMC3537732 DOI: 10.1371/journal.pone.0053194] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 11/27/2012] [Indexed: 01/17/2023] Open
Abstract
Saffold virus (SAFV) was identified as a human cardiovirus in 2007. Although several epidemiological studies have been reported, they have failed to provide a clear picture of the relationship between SAFV and human diseases. SAFV genotype 3 has been isolated from the cerebrospinal fluid specimen of patient with aseptic meningitis. This finding is of interest since Theiler’s murine encephalomyelitis virus (TMEV), which is the closely related virus, is known to cause a multiple sclerosis-like syndrome in mice. TMEV persistently infects in mouse macrophage cells in vivo and in vitro, and the viral persistence is essential in TMEV-induced demyelinating disease. The precise mechanism(s) of SAFV infection still remain unclear. In order to clarify the SAFV pathogenicity, in the present study, we studied the possibilities of the in vitro persistent infection of SAFV. The two distinct phenotypes of HeLa cells, HeLa-N and HeLa-R, were identified. In these cells, the type of SAFV-3 infection was clearly different. HeLa-N cells were lyticly infected with SAFV-3 and the host suitable for the efficient growth. On the other hand, HeLa-R cells were persistently infected with SAFV-3. In addition, the SAFV persistence in HeLa-R cells is independent of type I IFN response of host cells although the TMEV persistence in mouse macrophage cells depends on the response. Furthermore, it was suggested that SAFV persistence may be influenced by the expression of receptor(s) for SAFV infection on the host cells. The present findings on SAFV persistence will provide the important information to encourage the research of SAFV pathogenicity.
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Affiliation(s)
- Toshiki Himeda
- Department of Microbiology, Kanazawa Medical University School of Medicine, Ishikawa, Japan
| | - Takushi Hosomi
- The Public Health Institute of Kochi Prefecture, Kochi, Japan
| | - Takako Okuwa
- Department of Microbiology, Kanazawa Medical University School of Medicine, Ishikawa, Japan
| | - Yasushi Muraki
- Department of Microbiology, Kanazawa Medical University School of Medicine, Ishikawa, Japan
| | - Yoshiro Ohara
- Department of Microbiology, Kanazawa Medical University School of Medicine, Ishikawa, Japan
- * E-mail:
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17
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Three clusters of Saffold viruses circulating in children with diarrhea in Japan. INFECTION GENETICS AND EVOLUTION 2013. [DOI: 10.1016/j.meegid.2012.11.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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18
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Wang CYT, Greer RM, Delwart E, Sloots TP, Mackay IM. A newly designed real-time RT-PCR for SAFV detects SAFV-2 and SAFV-3 in the respiratory tracts of ill children during 2011. J Clin Virol 2012; 55:173-6. [PMID: 22832058 PMCID: PMC7108345 DOI: 10.1016/j.jcv.2012.06.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Revised: 06/28/2012] [Accepted: 06/29/2012] [Indexed: 01/06/2023]
Affiliation(s)
- C Y T Wang
- Queensland Paediatric Infectious Diseases Laboratory, Queensland Children's Medical Research Institute, Sir Albert Sakzewski Virus Research Centre, Children's Health Services, The University of Queensland, Australia
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Abstract
Although cardioviruses have been thought to mainly infect rodents, a novel human cardiovirus, designated Saffold virus (SAFV), was identified in 2007. SAFV is grouped with Theiler-like rat virus and Theiler's murine encephalomyelitis virus (TMEV) in the species Theilovirus of the genus Cardiovirus of the family Picornaviridae. Eight genotypes of SAFV have now been identified. SAFV has been isolated from nasal and stool specimens from infants presenting with respiratory and gastrointestinal symptoms as well as from children with nonpolio acute flaccid paralysis; however, the relationship of SAFV to this symptomatology remains unclear. Of note, the virus has also been isolated from the cerebrospinal fluid specimens of patients with aseptic meningitis. This finding is of interest since TMEV is known to cause a multiple sclerosis-like syndrome in mice. The involvement of SAFV in various diseases (e.g., respiratory illness, gastrointestinal illness, neurological diseases, and type I diabetes) is presently under investigation. In order to clarify the pathogenicity of SAFV, additional epidemiological studies are required. Furthermore, identification of the SAFV cellular receptor will help establish an animal model for SAFV infection and help clarify the pathogenesis of SAFV-related diseases. In addition, investigation of the tissue-specific expression of the receptor may facilitate development of a novel picornavirus vector, which could be a useful tool in gene therapy for humans. The study of viral factors involved in viral pathogenicity using a reverse genetics technique will also be important.
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