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Ghosh A, Delgado-Cunningham K, López T, Green K, Arias CF, DuBois RM. Structure and antigenicity of the divergent human astrovirus VA1 capsid spike. PLoS Pathog 2024; 20:e1012028. [PMID: 38416796 PMCID: PMC10950212 DOI: 10.1371/journal.ppat.1012028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 03/19/2024] [Accepted: 02/05/2024] [Indexed: 03/01/2024] Open
Abstract
Human astrovirus (HAstV) is a known cause of viral gastroenteritis in children worldwide, but HAstV can cause also severe and systemic infections in immunocompromised patients. There are three clades of HAstV: classical, MLB, and VA/HMO. While all three clades are found in gastrointestinal samples, HAstV-VA/HMO is the main clade associated with meningitis and encephalitis in immunocompromised patients. To understand how the HAstV-VA/HMO can infect the central nervous system, we investigated its sequence-divergent capsid spike, which functions in cell attachment and may influence viral tropism. Here we report the high-resolution crystal structures of the HAstV-VA1 capsid spike from strains isolated from patients with gastrointestinal and neuronal disease. The HAstV-VA1 spike forms a dimer and shares a core beta-barrel structure with other astrovirus capsid spikes but is otherwise strikingly different, suggesting that HAstV-VA1 may utilize a different cell receptor, and an infection competition assay supports this hypothesis. Furthermore, by mapping the capsid protease cleavage site onto the structure, the maturation and assembly of the HAstV-VA1 capsid is revealed. Finally, comparison of gastrointestinal and neuronal HAstV-VA1 sequences, structures, and antigenicity suggests that neuronal HAstV-VA1 strains may have acquired immune escape mutations. Overall, our studies on the HAstV-VA1 capsid spike lay a foundation to further investigate the biology of HAstV-VA/HMO and to develop vaccines and therapeutics targeting it.
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Affiliation(s)
- Anisa Ghosh
- Department of Biomolecular Engineering, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Kevin Delgado-Cunningham
- Department of Biomolecular Engineering, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Tomás López
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | - Kassidy Green
- Department of Biomolecular Engineering, University of California Santa Cruz, Santa Cruz, California, United States of America
| | - Carlos F. Arias
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | - Rebecca M. DuBois
- Department of Biomolecular Engineering, University of California Santa Cruz, Santa Cruz, California, United States of America
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2
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Porto PS, Rivera A, Moonrinta R, Wobus CE. Entry and egress of human astroviruses. Adv Virus Res 2023; 117:81-119. [PMID: 37832992 DOI: 10.1016/bs.aivir.2023.08.001] [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] [Indexed: 10/15/2023]
Abstract
Astroviruses encapsidate a positive-sense, single-stranded RNA genome into ∼30nm icosahedral particles that infect a wide range of mammalian and avian species, but their biology is not well understood. Human astroviruses (HAstV) are divided into three clades: classical HAstV serotypes 1-8, and novel or non-classical HAstV of the MLB and VA clades. These viruses are part of two genogroups and phylogenetically cluster with other mammalian astroviruses, highlighting their zoonotic potential. HAstV are a highly prevalent cause of nonbacterial gastroenteritis, primarily in children, the elderly and immunocompromised. Additionally, asymptomatic infections and extraintestinal disease (e.g., encephalitis), are also observed, mostly in immunocompetent or immunocompromised individuals, respectively. While these viruses are highly prevalent, no approved vaccines or antivirals are available to prevent or treat infections. This is in large part due to their understudied nature and the limited understanding of even very basic features of their life cycle and pathogenesis at the cellular and organismal level. This review will summarize molecular features of human astrovirus biology, pathogenesis, and tropism, and then focus on two stages of the viral life cycle, namely entry and egress, since these are proven targets for therapeutic interventions. We will further highlight gaps in knowledge in hopes of stimulating future research into these understudied viruses.
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Affiliation(s)
- Pedro Soares Porto
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, United states
| | - Andres Rivera
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, United states
| | - Rootjikarn Moonrinta
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, United states
| | - Christiane E Wobus
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, MI, United states.
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3
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Razizadeh MH, Pourrostami K, Kachooei A, Zarei M, Asghari M, Hamldar S, Khatami A. An annoying enteric virus: A systematic review and meta‐analysis of human astroviruses and gastrointestinal complications in children. Rev Med Virol 2022; 32:e2389. [DOI: 10.1002/rmv.2389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/22/2022] [Accepted: 07/21/2022] [Indexed: 11/11/2022]
Affiliation(s)
| | - Kumars Pourrostami
- Department of Pediatrics School of Medicine Alborz University of Medical Sciences Karaj Iran
- Dietary Supplements and Probiotic Research Center Alborz University of Medical Sciences Karaj Iran
| | - Atefeh Kachooei
- Department of Virology Faculty of Medicine Iran University of Medical Sciences Tehran Iran
| | - Mohammad Zarei
- Renal Division Harvard Medical School Brigham and Women's Hospital Boston Massachusetts USA
- Harvard T.H. Chan School of Public Health John B. Little Center for Radiation Sciences Boston Massachusetts USA
| | - Milad Asghari
- Department of Microbiology Faculty of Basic Science Tabriz Branch Islamic Azad University Tabriz Iran
| | - Shahrzad Hamldar
- Department of Virology Faculty of Medicine Iran University of Medical Sciences Tehran Iran
| | - Alireza Khatami
- Department of Virology Faculty of Medicine Iran University of Medical Sciences Tehran Iran
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4
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Janowski AB, Owen MC, Dudley H, López T, Espinosa R, Elvin-Lewis M, Colichon A, Arias CF, Burbelo PD, Wang D. High Seropositivity Rate of Neutralizing Antibodies to Astrovirus VA1 in Human Populations. mSphere 2021; 6:e0048421. [PMID: 34468168 PMCID: PMC8550256 DOI: 10.1128/msphere.00484-21] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 08/17/2021] [Indexed: 02/04/2023] Open
Abstract
Astroviruses are common pathogens of the human gastrointestinal tract, but they have been recently identified from cases of fatal meningoencephalitis. Astrovirus VA1 is the most frequently detected astrovirus genotype from cases of human encephalitis, but the prevalence of neutralizing antibodies to VA1 in human sera is unknown. We developed a focus reduction neutralization assay (FRNT) for VA1 and measured the seroprevalence of neutralizing antibodies from two cohorts of adult and pediatric serum samples: (i) an age-stratified cohort from St. Louis, MO, collected from 2007 to 2008 and (ii) a cohort from the Peruvian Amazonian River Basin collected in the late 1990s. In the St. Louis cohort, the lowest seropositivity rate was in children 1 year of age (6.9%), rising to 63.3% by ages 9 to 12, and 76.3% of adults ≥20 years were positive. The Peruvian Amazon cohort showed similar seropositivity rates across all ages, with individuals under age 20 having a rate of 75%, while 78.2% of adults ≥20 years were seropositive. In addition, we also identified the presence neutralizing antibodies to VA1 from commercial lots of intravenous immunoglobulin (IVIG). Our results demonstrate that a majority of humans are exposed to VA1 by adulthood, with the majority of infections occurring between 2 and 9 years of age. In addition, our results indicate that VA1 has been circulating in two geographically and socioeconomically divergent study cohorts over the past 20 years. Nonetheless, a significant proportion of the human population lacks neutralizing immunity and remains at risk for acute infection. IMPORTANCE Astroviruses are human pathogens with emerging disease associations, including the recent recognition of their capacity to cause meningoencephalitis. Astrovirus VA1 is the most commonly identified astrovirus genotype from cases of human encephalitis, but it is unknown what percentage of the human population has neutralizing antibodies to VA1. We found that 76.3 to 78.2% of adult humans ≥20 years of age in two geographically and socioeconomically distinct cohorts are seropositive for VA1, with the majority of infections occurring between 2 and 9 years of age. These results demonstrate that VA1 has been circulating in human populations over the past 2 decades and that most humans develop neutralizing antibodies against this virus by adulthood. However, a subset of humans lack evidence of neutralizing antibodies and are at risk for diseases caused by VA1, including encephalitis.
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Affiliation(s)
- Andrew B. Janowski
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Macee C. Owen
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Holly Dudley
- Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, Ohio, USA
| | - Tomás López
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | - Rafaela Espinosa
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | | | - Alejandro Colichon
- Department of Immunology, Peruvian University Cayetano Heredia, Lima, Peru
| | - Carlos F. Arias
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | - Peter D. Burbelo
- National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland, USA
| | - David Wang
- Department of Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA
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Human Astrovirus 1-8 Seroprevalence Evaluation in a United States Adult Population. Viruses 2021; 13:v13060979. [PMID: 34070419 PMCID: PMC8229645 DOI: 10.3390/v13060979] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Revised: 05/18/2021] [Accepted: 05/24/2021] [Indexed: 12/19/2022] Open
Abstract
Human astroviruses are an important cause of viral gastroenteritis globally, yet few studies have investigated the serostatus of adults to establish rates of previous infection. Here, we applied biolayer interferometry immunosorbent assay (BLI-ISA), a recently developed serosurveillance technique, to measure the presence of blood plasma IgG antibodies directed towards the human astrovirus capsid spikes from serotypes 1-8 in a cross-sectional sample of a United States adult population. The seroprevalence rates of IgG antibodies were 73% for human astrovirus serotype 1, 62% for serotype 3, 52% for serotype 4, 29% for serotype 5, 27% for serotype 8, 22% for serotype 2, 8% for serotype 6, and 8% for serotype 7. Notably, seroprevalence rates for capsid spike antigens correlate with neutralizing antibody rates determined previously. This work is the first seroprevalence study evaluating all eight classical human astrovirus serotypes.
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Human Astroviruses: A Tale of Two Strains. Viruses 2021; 13:v13030376. [PMID: 33673521 PMCID: PMC7997325 DOI: 10.3390/v13030376] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 02/22/2021] [Accepted: 02/24/2021] [Indexed: 12/13/2022] Open
Abstract
Since the 1970s, eight closely related serotypes of classical human astroviruses (HAstV) have been associated with gastrointestinal illness worldwide. In the late 2000s, three genetically unique human astrovirus clades, VA1-VA3, VA2-VA4, and MLB, were described. While the exact disease associated with these clades remains to be defined, VA1 has been associated with central nervous system infections. The discovery that VA1 could be grown in cell culture, supports exciting new studies aimed at understanding viral pathogenesis. Given the association of VA1 with often lethal CNS infections, we tested its susceptibility to the antimicrobial drug, nitazoxanide (NTZ), which we showed could inhibit classical HAstV infections. Our studies demonstrate that NTZ inhibited VA1 replication in Caco2 cells even when added at 12 h post-infection, which is later than in HAstV-1 infection. These data led us to further probe VA1 replication kinetics and cellular responses to infection in Caco-2 cells in comparison to the well-studied HAstV-1 strain. Overall, our studies highlight that VA1 replicates more slowly than HAstV-1 and elicits significantly different cellular responses, including the inability to disrupt cellular junctions and barrier permeability.
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7
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Enteric Viral Co-Infections: Pathogenesis and Perspective. Viruses 2020; 12:v12080904. [PMID: 32824880 PMCID: PMC7472086 DOI: 10.3390/v12080904] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 08/10/2020] [Accepted: 08/14/2020] [Indexed: 02/06/2023] Open
Abstract
Enteric viral co-infections, infections involving more than one virus, have been reported for a diverse group of etiological agents, including rotavirus, norovirus, astrovirus, adenovirus, and enteroviruses. These pathogens are causative agents for acute gastroenteritis and diarrheal disease in immunocompetent and immunocompromised individuals of all ages globally. Despite virus–virus co-infection events in the intestine being increasingly detected, little is known about their impact on disease outcomes or human health. Here, we review what is currently known about the clinical prevalence of virus–virus co-infections and how co-infections may influence vaccine responses. While experimental investigations into enteric virus co-infections have been limited, we highlight in vivo and in vitro models with exciting potential to investigate viral co-infections. Many features of virus–virus co-infection mechanisms in the intestine remain unclear, and further research will be critical.
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Detection of Murine Astrovirus and Myocoptes musculinus in individually ventilated caging systems: Investigations to expose suitable detection methods for routine hygienic monitoring. PLoS One 2019; 14:e0221118. [PMID: 31408494 PMCID: PMC6692027 DOI: 10.1371/journal.pone.0221118] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Accepted: 07/30/2019] [Indexed: 12/26/2022] Open
Abstract
Murine Astrovirus is one of the most prevalent viral agents in laboratory rodent facilities worldwide, but its influence on biomedical research results is poorly examined. Due to possible influence on research results and high seroprevalence rates in mice, it appears useful to include this virus into routine health monitoring programs. In order to establish exhaust air particle PCR as a reliable detection method for Murine Astrovirus infections in mice kept in individually ventilated cages (IVC) and compare the method to sentinel mice monitoring regarding reproducibility and detection limit, we conducted a study with defined Murine Astrovirus cage prevalence. In parallel, the efficacy of both detection strategies (soiled-bedding sentinel (SBS) and exhaust air dust (EAD) analysis) was tested for Myocoptes musculinus. The fur mite was used as a reference organism during the whole study period to ensure the validity of this method. Because some publications already demonstrated successful detection of several pathogens, including murine fur mite species, via EAP-PCR. Detection of Murine Astrovirus infections at low prevalence is possible with both methods tested. Detection by exhaust air particles (EAP) is faster, more sensitive and more reliable compared to soiled bedding sentinels (SBS). Exhaust air particle PCR also detected the reference organism Myocoptes musculinus, which was not detected at all by sentinel mice, not even by high sensitivity fur swab qPCR. In conclusion, Murine Astrovirus can be detected by both exhaust air particle PCR and soiled bedding sentinels. We recommend exhaust air particle PCR as the better detection technique for Murine Astrovirus, because it is more reliable. Environmental samples are the method of choice for detection of Myocoptes musculinus because relying on soiled bedding sentinels harbors a big risk of missing existing infestations.
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9
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Olortegui MP, Rouhani S, Yori PP, Salas MS, Trigoso DR, Mondal D, Bodhidatta L, Platts-Mills J, Samie A, Kabir F, Lima A, Babji S, Shrestha SK, Mason CJ, Kalam A, Bessong P, Ahmed T, Mduma E, Bhutta ZA, Lima I, Ramdass R, Moulton LH, Lang D, George A, Zaidi AK, Kang G, Houpt ER, Kosek MN. Astrovirus Infection and Diarrhea in 8 Countries. Pediatrics 2018; 141:peds.2017-1326. [PMID: 29259078 PMCID: PMC9923568 DOI: 10.1542/peds.2017-1326] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 10/12/2017] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND AND OBJECTIVES Astroviruses are important drivers of viral gastroenteritis but remain understudied in community settings and low- and middle-income countries. We present data from 8 countries with high prevalence of diarrhea and undernutrition to describe astrovirus epidemiology and assess evidence for protective immunity among children 0 to 2 years of age. METHODS We used 25 898 surveillance stools and 7077 diarrheal stools contributed by 2082 children for enteropathogen testing, and longitudinal statistical analysis to describe incidence, risk factors, and protective immunity. RESULTS Thirty-five percent of children experienced astrovirus infections. Prevalence in diarrheal stools was 5.6%, and severity exceeded all enteropathogens except rotavirus. Incidence of infection and diarrhea were 2.12 and 0.88 episodes per 100 child-months, respectively. Children with astrovirus infection had 2.30 times the odds of experiencing diarrhea after adjustment for covariates (95% confidence interval [CI], 2.01-2.62; P < .001). Undernutrition was a risk factor: odds of infection and diarrhea were reduced by 10% and 13%, respectively, per increase in length-for-age z score (infection: odds ratio, 0.90 [95% CI, 0.85-0.96]; P < .001; diarrhea: odds ratio, 0.87 [95% CI, 0.79-0.96]; P = .006). Some evidence of protective immunity to infection was detected (hazard ratio, 0.84 [95% CI, 0.71-1.00], P = .052), although this was heterogeneous between sites and significant in India and Peru. CONCLUSIONS Astrovirus is an overlooked cause of diarrhea among vulnerable children worldwide. With the evidence presented here, we highlight the need for future research as well as the potential for astrovirus to be a target for vaccine development.
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Affiliation(s)
| | - Saba Rouhani
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Pablo Peñataro Yori
- Asociación Benéfica PRISMA, Iquitos, Peru;,Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | | | | | | | | | - James Platts-Mills
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, Virginia
| | | | | | - Aldo Lima
- Universidade Federal do Ceará, Fortaleza, Brazil
| | | | - Sanjaya Kumar Shrestha
- Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand;,Centre for International Health, University of Bergen, Bergen, Norway
| | - Carl J. Mason
- Armed Forces Research Institute of Medical Sciences, Bangkok, Thailand
| | - Adil Kalam
- Aga Khan University, Naushahro Feroze, Pakistan
| | | | | | | | | | - Ila Lima
- Universidade Federal do Ceará, Fortaleza, Brazil
| | | | - Lawrence H. Moulton
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Dennis Lang
- Fogarty International Center, National Institutes of Health, Bethesda, Maryland; and,Foundation for the National Institutes of Health, Bethesda, Maryland
| | | | | | | | - Eric R. Houpt
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, Virginia
| | - Margaret N. Kosek
- Asociación Benéfica PRISMA, Iquitos, Peru;,Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland;,Address correspondence to Margaret N. Kosek, MD, Department of International Health, Johns Hopkins Bloomberg School of Public Health, 615 N Wolfe St, Baltimore, MD 21205. E-mail
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10
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Cordey S, Vu DL, Zanella MC, Turin L, Mamin A, Kaiser L. Novel and classical human astroviruses in stool and cerebrospinal fluid: comprehensive screening in a tertiary care hospital, Switzerland. Emerg Microbes Infect 2017; 6:e84. [PMID: 28928418 PMCID: PMC5625321 DOI: 10.1038/emi.2017.71] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Revised: 07/03/2017] [Accepted: 07/18/2017] [Indexed: 01/26/2023]
Abstract
Classical human astroviruses (HAstV) are the third most common cause of non-bacterial acute gastroenteritis. Due to the lack of routine molecular assays, novel HAstV are underdiagnosed and the magnitude of their contribution to clinical disease remains unknown. To better understand their prevalence and the susceptible patient profile, we conducted a comprehensive screening of novel and classical HAstV in stool and cerebrospinal fluid (CSF) samples collected for clinical care in a tertiary care hospital using a specially designed rRT-PCR panel for the detection of novel (MLB1-3 and VA1-4) and classical HAstV. Of the 654 stool samples, 20 were positive for HAstV, and the novel (n=10; 3 MLB1, 4 MLB2; 3 VA2) and classical (n=10) serotypes were equally prevalent. None of the 105 CSF samples were positive. Investigating the patient profile, we found a higher prevalence (P=0.0002) of both novel and classical HAstV in pediatric stool samples (3.4% and 3%, respectively) compared with adult stool samples (0.5% and 0.7%, respectively). Furthermore, all novel and classical HAstV-positive pediatric subjects were ≤four years old, demonstrating similar susceptible populations. Forty-five percent of positive patients were immunocompromised (novel: 40%, classical: 50%). A comparison of novel and classical HAstV-positive cases showed a lower viral load for novel HAstV (P=0.0007) with significantly more upper respiratory symptoms (70% of subjects; P=0.02); this observation may suggest a unique pathogenic pathway. This study confirms the clinical and epidemiological relevance of novel HAstV and identifies a target population in which routine screening may yield clinically valuable information.
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Affiliation(s)
- Samuel Cordey
- Laboratory of Virology, Infectious Diseases Service, University Hospitals of Geneva, 1211 Geneva, Switzerland
- University of Geneva Medical School, 1211 Geneva, Switzerland
| | - Diem-Lan Vu
- Laboratory of Virology, Infectious Diseases Service, University Hospitals of Geneva, 1211 Geneva, Switzerland
- University of Geneva Medical School, 1211 Geneva, Switzerland
| | - Marie-Celine Zanella
- Laboratory of Virology, Infectious Diseases Service, University Hospitals of Geneva, 1211 Geneva, Switzerland
- University of Geneva Medical School, 1211 Geneva, Switzerland
| | - Lara Turin
- Laboratory of Virology, Infectious Diseases Service, University Hospitals of Geneva, 1211 Geneva, Switzerland
- University of Geneva Medical School, 1211 Geneva, Switzerland
| | - Aline Mamin
- Laboratory of Virology, Infectious Diseases Service, University Hospitals of Geneva, 1211 Geneva, Switzerland
- University of Geneva Medical School, 1211 Geneva, Switzerland
| | - Laurent Kaiser
- Laboratory of Virology, Infectious Diseases Service, University Hospitals of Geneva, 1211 Geneva, Switzerland
- University of Geneva Medical School, 1211 Geneva, Switzerland
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Propagation of Astrovirus VA1, a Neurotropic Human Astrovirus, in Cell Culture. J Virol 2017; 91:JVI.00740-17. [PMID: 28701405 DOI: 10.1128/jvi.00740-17] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 06/21/2017] [Indexed: 01/11/2023] Open
Abstract
Astrovirus VA1/HMO-C (VA1; mamastrovirus 9) is a recently discovered astrovirus genotype that is divergent from the classic human astroviruses (mamastrovirus 1). The gastrointestinal tract is presumed to be the primary site of infection and pathogenicity for astroviruses. However, VA1 has been independently detected in brain tissue of five cases of human encephalitis. Studies of the pathogenicity of VA1 are currently impossible because there are no reported cell culture systems or in vivo models that support VA1 infection. Here, we describe successful propagation of VA1 in multiple human cell lines. The initial inoculum, a filtered clinical stool sample from the index gastroenteritis case cluster that led to the discovery of VA1, was first passaged in Vero cells. Serial blind passage in Caco-2 cells yielded increasing copies of VA1 RNA, and multistep growth curves demonstrated a >100-fold increase in VA1 RNA 72 h after inoculation. The full-length genomic and subgenomic RNA strands were detected by Northern blotting, and crystalline lattices of viral particles of ∼26-nm diameter were observed by electron microscopy in infected Caco-2 cells. Unlike other human astrovirus cell culture systems, which require addition of exogenous trypsin for continued propagation, VA1 could be propagated equally well with or without the addition of trypsin. Furthermore, VA1 was sensitive to the type I interferon (IFN-I) response, as VA1 RNA levels were reduced by pretreatment of Caco-2 cells with IFN-β1a. The ability to propagate VA1 in cell culture will facilitate studies of the neurotropism and neuropathogenesis of VA1.IMPORTANCE Astroviruses are an emerging cause of central nervous system infections in mammals, and astrovirus VA1/HMO-C is the most prevalent astrovirus in cases of human encephalitis. This virus has not been previously propagated, preventing elucidation of the biology of this virus. We describe the first cell culture system for VA1, a key step necessary for the study of its ability to cause disease.
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Cortez V, Meliopoulos VA, Karlsson EA, Hargest V, Johnson C, Schultz-Cherry S. Astrovirus Biology and Pathogenesis. Annu Rev Virol 2017; 4:327-348. [PMID: 28715976 DOI: 10.1146/annurev-virology-101416-041742] [Citation(s) in RCA: 117] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Astroviruses are nonenveloped, positive-sense single-stranded RNA viruses that cause gastrointestinal illness. Although a leading cause of pediatric diarrhea, human astroviruses are among the least characterized enteric RNA viruses. However, by using in vitro methods and animal models to characterize virus-host interactions, researchers have discovered several important properties of astroviruses, including the ability of the astrovirus capsid to act as an enterotoxin, disrupting the gut epithelial barrier. Improved animal models are needed to study this phenomenon, along with the pathogenesis of astroviruses, particularly in those strains that can cause extraintestinal disease. Much like for other enteric viruses, the current dogma states that astroviruses infect in a species-specific manner; however, this assumption is being challenged by growing evidence that these viruses have potential to cross species barriers. This review summarizes these remarkable facets of astrovirus biology, highlighting critical steps toward increasing our understanding of this unique enteric pathogen.
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Affiliation(s)
- Valerie Cortez
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee 38105; , , , , ,
| | - Victoria A Meliopoulos
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee 38105; , , , , ,
| | - Erik A Karlsson
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee 38105; , , , , ,
| | - Virginia Hargest
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee 38105; , , , , , .,Department of Microbiology, Immunology, and Biochemistry, University of Tennessee Health Science Center, Memphis, Tennessee 38163
| | - Cydney Johnson
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee 38105; , , , , ,
| | - Stacey Schultz-Cherry
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee 38105; , , , , ,
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Johnson C, Hargest V, Cortez V, Meliopoulos VA, Schultz-Cherry S. Astrovirus Pathogenesis. Viruses 2017; 9:E22. [PMID: 28117758 PMCID: PMC5294991 DOI: 10.3390/v9010022] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 01/17/2017] [Accepted: 01/17/2017] [Indexed: 12/16/2022] Open
Abstract
Astroviruses are a major cause of diarrhea in the young, elderly, and the immunocompromised. Since the discovery of human astrovirus type 1 (HAstV-1) in 1975, the family Astroviridae has expanded to include two more human clades and numerous mammalian and avian-specific genotypes. Despite this, there is still little known about pathogenesis. The following review highlights the current knowledge of astrovirus pathogenesis, and outlines the critical steps needed to further astrovirus research, including the development of animal models of cell culture systems.
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Affiliation(s)
- Cydney Johnson
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
| | - Virginia Hargest
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
- Department of Microbiology, Immunology, and Biochemistry, University of Tennessee Health Science Center, Memphis, TN 38163, USA.
| | - Valerie Cortez
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
| | - Victoria A Meliopoulos
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
| | - Stacey Schultz-Cherry
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, TN 38105, USA.
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Pérot P, Lecuit M, Eloit M. Astrovirus Diagnostics. Viruses 2017; 9:v9010010. [PMID: 28085120 PMCID: PMC5294979 DOI: 10.3390/v9010010] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 12/23/2016] [Accepted: 12/30/2016] [Indexed: 01/25/2023] Open
Abstract
Various methods exist to detect an astrovirus infection. Current methods include electron microscopy (EM), cell culture, immunoassays, polymerase chain reaction (PCR) and various other molecular approaches that can be applied in the context of diagnostic or in surveillance studies. With the advent of metagenomics, novel human astrovirus (HAstV) strains have been found in immunocompromised individuals in association with central nervous system (CNS) infections. This work reviews the past and current methods for astrovirus detection and their uses in both research laboratories and for medical diagnostic purposes.
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Affiliation(s)
- Philippe Pérot
- Institut Pasteur, Biology of Infection Unit, Inserm U1117, Laboratory of Pathogen Discovery, 75015 Paris, France.
- Institut Pasteur, Centre d'innovation et de Recherche Technologique (Citech), 75015 Paris, France.
| | - Marc Lecuit
- Institut Pasteur, Biology of Infection Unit, Inserm U1117, Laboratory of Pathogen Discovery, 75015 Paris, France.
- Paris Descartes University, Sorbonne Paris Cité, 75005, Paris, France.
- Necker-Enfants Malades University Hospital, Division of Infectious Diseases and Tropical Medicine, 75015 Paris, France.
| | - Marc Eloit
- Institut Pasteur, Biology of Infection Unit, Inserm U1117, Laboratory of Pathogen Discovery, 75015 Paris, France.
- Ecole Nationale Vétérinaire d'Alfort, 94700 Maisons-Alfort, France.
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Vu DL, Cordey S, Brito F, Kaiser L. Novel human astroviruses: Novel human diseases? J Clin Virol 2016; 82:56-63. [PMID: 27434149 DOI: 10.1016/j.jcv.2016.07.004] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Revised: 06/28/2016] [Accepted: 07/10/2016] [Indexed: 10/21/2022]
Abstract
Astroviruses are small, non-enveloped, single-stranded positive RNA viruses that belong to the Astroviridae family. While classical human astroviruses (HAstV) are a well-recognized cause of acute non-bacterial diarrhea among young children worldwide, novel astroviruses, named HAstV-MLB and HAstV-VA/HMO, have been identified recently in humans by molecular assays. They are phylogenetically more related to animal astroviruses than to classical human astroviruses, thus suggesting cross-species transmission. Serological studies demonstrated a surprisingly high seroprevalence in certain populations and highlighted a high infection rate in the early years of life. Although their pathogenic role has not yet been clearly determined, novel astrovirus RNA sequences have been identified in different biological specimens of symptomatic patients, including the feces, plasma, cerebrospinal fluid, and brain biopsies. Thus, there is evidence that they could contribute not only to digestive tract infection, but also to unexpected clinical syndromes, notably encephalitis and meningitis. Severe infections affect mainly immunocompromised patients. These findings indicate that novel astroviruses should be considered in the differential diagnosis of immunocompromised patients with meningitis or encephalitis of unknown origin.
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Affiliation(s)
- Diem-Lan Vu
- Laboratory of Virology, Division of Laboratory Medicine and Division of Infectious Diseases, University of Geneva Hospitals, 4 Rue Gabrielle Perret-Gentil, 1211 Geneva 14, Switzerland; University of Geneva Medical School, 1 Rue Michel-Servet, 1211 Geneva 4, Switzerland.
| | - Samuel Cordey
- Laboratory of Virology, Division of Laboratory Medicine and Division of Infectious Diseases, University of Geneva Hospitals, 4 Rue Gabrielle Perret-Gentil, 1211 Geneva 14, Switzerland; University of Geneva Medical School, 1 Rue Michel-Servet, 1211 Geneva 4, Switzerland.
| | - Francisco Brito
- Swiss Institute of Bioinformatics, University of Geneva Medical School, 1 Rue Michel-Servet, 1211 Geneva 4, Switzerland.
| | - Laurent Kaiser
- Laboratory of Virology, Division of Laboratory Medicine and Division of Infectious Diseases, University of Geneva Hospitals, 4 Rue Gabrielle Perret-Gentil, 1211 Geneva 14, Switzerland; University of Geneva Medical School, 1 Rue Michel-Servet, 1211 Geneva 4, Switzerland.
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16
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Ramani S, Atmar RL. Acute Gastroenteritis Viruses. Mucosal Immunol 2015. [DOI: 10.1016/b978-0-12-415847-4.00057-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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17
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Abstract
Human astroviruses (HAtVs) are positive-sense single-stranded RNA viruses that were discovered in 1975. Astroviruses infecting other species, particularly mammalian and avian, were identified and classified into the genera Mamastrovirus and Avastrovirus. Through next-generation sequencing, many new astroviruses infecting different species, including humans, have been described, and the Astroviridae family shows a high diversity and zoonotic potential. Three divergent groups of HAstVs are recognized: the classic (MAstV 1), HAstV-MLB (MAstV 6), and HAstV-VA/HMO (MAstV 8 and MAstV 9) groups. Classic HAstVs contain 8 serotypes and account for 2 to 9% of all acute nonbacterial gastroenteritis in children worldwide. Infections are usually self-limiting but can also spread systemically and cause severe infections in immunocompromised patients. The other groups have also been identified in children with gastroenteritis, but extraintestinal pathologies have been suggested for them as well. Classic HAstVs may be grown in cells, allowing the study of their cell cycle, which is similar to that of caliciviruses. The continuous emergence of new astroviruses with a potential zoonotic transmission highlights the need to gain insights on their biology in order to prevent future health threats. This review focuses on the basic virology, pathogenesis, host response, epidemiology, diagnostic assays, and prevention strategies for HAstVs.
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Affiliation(s)
- Albert Bosch
- Enteric Virus Laboratory, Department of Microbiology and Institute of Nutrition and Food Safety, University of Barcelona, Barcelona, Spain
| | - Rosa M Pintó
- Enteric Virus Laboratory, Department of Microbiology and Institute of Nutrition and Food Safety, University of Barcelona, Barcelona, Spain
| | - Susana Guix
- Enteric Virus Laboratory, Department of Microbiology and Institute of Nutrition and Food Safety, University of Barcelona, Barcelona, Spain
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Tayeb HT, Al-Ahdal MN, Cartear MJ, Al-Qahtani AA, Cruz DMD. Molecular epidemiology of human astrovirus infections in Saudi Arabia pediatric patients. J Med Virol 2010; 82:2038-42. [DOI: 10.1002/jmv.21897] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Abstract
Acute infectious diarrhoea can be linked to various pathogens among which viruses are responsible for more than a half cases. Rotaviruses and caliciviruses are the most frequently encountered, in close to 60 % of viral gastroenteritis. Rotaviruses account for more than 50 % of severe diseases and caliciviruses, especially norovirus are responsible for less severe sporadic gastroenteritis and water-or food- borne epidemics. Astroviruses and adenoviruses are minority, excepted for immunocompromised patients. Viral or Bacterial and viral co- infections are frequent (up to 15 %). To date, the first rotavirus vaccine assays did not reveal any shift from a viral genus to another, such as calicivirus or adenovirus, according to the fact that epidemiologic features of these viruses are quite different. Progress in viral diagnosis and genotyping enabled to analyse viral diversity and to follow viral recombination events, and emergence of new variants that could propagate among various countries. This dynamic evolution that concerns not only Europe but also developing countries should be carefully surveyed at the era of rotavirus vaccination.
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Affiliation(s)
- S Alain
- Service de Bactériologie- Virologie-Hygiène, CHU Dupuytren, 2 av Martin Luther King 87042 Limoges cedex, France.
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Bhattacharya R, Sahoo GC, Nayak MK, Ghosh S, Dutta P, Bhattacharya MK, Mitra U, Gangopadhyay D, Dutta S, Niyogi SK, Saha DR, Naik TN, Bhattacharya SK, Krishnan T. Molecular epidemiology of human astrovirus infections in Kolkata, India. INFECTION GENETICS AND EVOLUTION 2006; 6:425-35. [PMID: 16546454 DOI: 10.1016/j.meegid.2006.02.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2006] [Accepted: 02/13/2006] [Indexed: 11/21/2022]
Abstract
UNLABELLED The study is aimed to determine the seasonal distribution and clinical characteristics of astroviruses associated with acute watery diarrhoea among children in Kolkata and characterize them at the molecular level. METHOD OF STUDY Faecal specimens of acute watery diarrhoea cases (n=857) and non-diarrhoeic samples (n=211) from the hospitals and a nearby field community were screened with IDEIA Astrovirus detection kit; astrovirus co-infections with rotavirus and/or picobirnavirus were detected by RNA-PAGE and silver staining. Further RT-PCR was carried out using specific primers, viz. Mon340 (+) and Mon348 (-) targeting a highly conserved domain of ORF1a (289 bp) of human astroviruses. RESULTS Astrovirus infection was detected in 50 cases (50/857); astroviruses were detected mostly in children aged 6-12 months (50%); all non-diarrhoeic samples (n=211) were negative for astrovirus. In 52% of astrovirus positive cases, the virus was detected as the sole agent; mixed infections were also detected with other diarrhoeic pathogens such as rotavirus (32%), picobirnavirus (2%), rotavirus and picobirnavirus (2%), picobirnavirus and Enterotoxigenic E. coli (ETEC) (2%), rotavirus and ETEC (2%), rotavirus and Enteroaggregative E. coli (EAEC) (2%), Enteropathogenic E. coli (EPEC) (2%), Shigella flexneri type 3a (2%) and Ascaris (2%). RT-PCR and sequencing of amplicons of astroviruses from Kolkata, with specific primers targeted to the conserved domain of ORF1a (289 bp) of the astrovirus genome, showed maximum homology to the astrovirus strain ("5-158") from Seoul (98%). RESULTS AND CONCLUSIONS Clinical characteristics of the diarrhoeic children in Kolkata indicated that astrovirus infections were detected throughout the year and were associated with varying degree of dehydration and acute watery diarrhoea. In-depth molecular epidemiological surveillance of astroviruses in Kolkata is essential for better understanding of their overall genetic nature.
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Affiliation(s)
- Rittwika Bhattacharya
- Division of Virology, National Institute of Cholera and Enteric Diseases, P 33 CIT Road, Scheme XM, Beliaghata, Kolkata (Calcutta) 700010, India
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Abstract
Astroviruses are one of the leading causes of acute viral enteritis in infants, and are recognized as a clinically important pathogen in the elderly and the immunocompromised. In spite of this, we still know very little about the immune response to astrovirus infection. Clinical observations and human volunteer studies have indicated a role for the humoral response and suggest neutralizing antibodies are important in limiting infection. Studies of human intestinal biopsies have suggested that cellular immunity; specifically CD4(+) T-cells may also be involved in the anti-astrovirus response. Additionally, various animal models have indicated potential roles for the innate immune system in controlling infections. How these various effector arms of the immune system collaborate to result in immunity and resistance to astrovirus infection is still unknown. This review summarizes our current understanding of the immune response to this pathogen and highlights the key concepts that still need to be addressed. Until we understand the role of the immune system in astrovirus infection or other enteric viruses, we will continue to be limited in our ability to treat and control gastrointestinal diseases.
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Affiliation(s)
- Matthew D Koci
- Department of Poultry Science, North Carolina State University, Campus Box 7608, Raleigh, NC 27695, USA.
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22
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Koci MD, Kelley LA, Larsen D, Schultz-Cherry S. Astrovirus-induced synthesis of nitric oxide contributes to virus control during infection. J Virol 2004; 78:1564-74. [PMID: 14722310 PMCID: PMC321379 DOI: 10.1128/jvi.78.3.1564-1574.2004] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2003] [Accepted: 10/09/2003] [Indexed: 11/20/2022] Open
Abstract
Astrovirus is one of the major causes of infant and childhood diarrhea worldwide. Our understanding of astrovirus pathogenesis trails behind our knowledge of its molecular and epidemiologic properties. Using a recently developed small-animal model, we investigated the mechanisms by which astrovirus induces diarrhea and the role of both the adaptive and innate immune responses to turkey astrovirus type-2 (TAstV-2) infection. Astrovirus-infected animals were analyzed for changes in total lymphocyte populations, alterations in CD4(+)/CD8(+) ratios, production of virus-specific antibodies (Abs), and macrophage activation. There were no changes in the numbers of circulating or splenic lymphocytes or in CD4(+)/CD8(+) ratios compared to controls. Additionally, there was only a modest production of virus-specific Abs. However, adherent spleen cells from infected animals produced more nitric oxide (NO) in response to ex vivo stimulation with lipopolysaccharide. In vitro analysis demonstrated that TAstV-2 induced macrophage production of inducible nitric oxide synthase. Studies using NO donors and inhibitors in vivo demonstrated, for the first time, that NO inhibited astrovirus replication. These studies suggest that NO is important in limiting astrovirus replication and are the first, to our knowledge, to describe the potential role of innate immunity in astrovirus infection.
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Affiliation(s)
- Matthew D Koci
- Department of Pathology, University of Georgia, Athens, Georgia 30602, USA
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Le Cann P, Ranarijaona S, Monpoeho S, Le Guyader F, Ferré V. Quantification of human astroviruses in sewage using real-time RT-PCR. Res Microbiol 2004; 155:11-5. [PMID: 14759703 DOI: 10.1016/j.resmic.2003.09.013] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2003] [Accepted: 09/12/2003] [Indexed: 11/30/2022]
Abstract
Human astroviruses constitute a significant cause of acute diarrhea in children. Viral transmission occurs via the fecal-oral route, predominantly person-to-person, but the consumption of fecally contaminated water and shellfish has also been implicated. Viral pathogen detection in water, especially, in wastewater, is difficult and PCR is widely used to detect these viruses. Despite the recent development of real-time quantitative PCR, quantification of astroviruses in sewage had not been available up to now. We have developed a method to quantify astroviruses in sewage. For this purpose, we designed a set of primers and a fluorogenic probe located at the 3' -end of the genome of human astroviruses. The amplified region was cloned and the plasmid was transcribed to generate calibration standards for quantification. After validation of the standards, the method was evaluated in artificially contaminated samples. To validate the method on naturally contaminated samples, raw and treated wastewater samples were collected monthly for one year in a sewage treatment plant. Astrovirus genomes were detected in all samples collected at the entrance to the sewage treatment plant, with a mean value of 4.1 x 10(6) astrovirus genomes for 100 ml. Effluents were less strongly contaminated, with a mean value of 1.01 x 10(4) astrovirus genomes. The high prevalence of astroviruses in sewage treatment plant effluents indicates that these plants are not efficiently eliminating the virus. This is a major public health concern and new techniques of depuration are needed. Our method could be effectively used in evaluating new treatment processes to reduce the viral load in the effluent of treatment plants.
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Affiliation(s)
- Pierre Le Cann
- Laboratoire de Microbiologie, IFREMER, BP 21105, 44311 Nantes cedex 3, France.
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Affiliation(s)
- Douglas K Mitchell
- Center for Pediatric Research, Eastern Virginia Medical School, Children's Hospital of The King's Daughter's, Norfolk, VA, USA
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25
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Guix S, Caballero S, Villena C, Bartolomé R, Latorre C, Rabella N, Simó M, Bosch A, Pintó RM. Molecular epidemiology of astrovirus infection in Barcelona, Spain. J Clin Microbiol 2002; 40:133-9. [PMID: 11773106 PMCID: PMC120088 DOI: 10.1128/jcm.40.1.133-139.2002] [Citation(s) in RCA: 151] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2001] [Accepted: 11/03/2001] [Indexed: 11/20/2022] Open
Abstract
A 3-year study involving 2,347 gastroenteritis samples was conducted to determine the prevalence, time distribution, and medical significance of human astrovirus infection in Barcelona, Spain. The overall incidence of astrovirus was found to be 4.9%. Mixed infections with other enteric agents were detected in 17.2% of all astrovirus-positive samples. During the 3-year period, the highest astrovirus incidence was reported in the winter months, although infections also occurred in summer. The peak detection rate was observed in children between 2 and 4 years of age. Overall, HAstV-1 was the most prevalent type, followed by HAstV-4, HAstV-3, HAstV-8, and HAstV-2. HAstV-5, HAstV-6, and HAstV-7 were not detected during these 3 years. From our serotype data for each age group, we observed that HAstV-1, HAstV-2, and HAstV-3 affected mostly children younger than 3 years of age, while HAstV-4 and HAstV-8 had a greater impact in older children. Genetic variability was analyzed between astroviruses isolated in Barcelona and strains isolated in other parts of the world. A fourth lineage was described for HAstV-1, most likely due to the large number of assayed samples, which may also explain the high level of genetic variability observed in the astrovirus isolates.
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Affiliation(s)
- Susana Guix
- Enteric Virus Laboratory, Department of Microbiology, University of Barcelona, Barcelona, Spain
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Wang QH, Kakizawa J, Wen LY, Shimizu M, Nishio O, Fang ZY, Ushijima H. Genetic analysis of the capsid region of astroviruses. J Med Virol 2001; 64:245-55. [PMID: 11424111 DOI: 10.1002/jmv.1043] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Eight serotypes of human astroviruses (HAstV-1 to HAstV-8) have been described. To date, the entire genomes of HAstV-1 and HAstV-2 as well as the ORF2 sequences of HAstV-1-6 and 8 have been reported. In this study, the ORF2 sequences of seventeen strains of HAstVs originating from different countries were determined, as well as the sequence ORF2 of one porcine astrovirus (PAstV) strain. Afterwards, comparison of the capsid protein precursors encoded by ORF2 of 46 strains of HAstVs, PAstV, and feline astrovirus (FAstV) was carried out. A phylogenetic tree showed eight genogroups of HAstVs that corresponded exactly to the serotypes. HAstV-3 and 7 were the most closely related, whereas HAstVs, FAstV, and PAstV segregated from each other. Compared to a PAstV, a FAstV is closer to HAstVs. Furthermore, the capsid protein precursors were divided into four regions (after amino acid residues 424, 688, and 776, respectively) based on sequence identity. Region I was the most conserved, and FAstV was very close in identity to HAstVs. Two amino acid motifs in region I were predicted to contain the common antigenic epitopes. Region II was relatively variable. Deletions and insertions were characteristic of region III, and region IV was relatively conserved. To our knowledge, this is the first comparative sequence analysis of the capsid protein precursors of eight serotypes of HAstVs as well as two animal astroviruses (FAstV and PAstV).
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Affiliation(s)
- Q H Wang
- Department of Developmental Medical Sciences, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
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Eiros Bouza J, Bachiller Luque M, Ortiz de Lejarazu R. Ribovirus emergentes implicados en las gastroenteritis. An Pediatr (Barc) 2001. [PMCID: PMC7129717 DOI: 10.1016/s1695-4033(01)78666-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Los virus se sitúan en un lugar preferente entre los agentes causales de diarrea aguda, en particular en la infancia. En este contexto el papel de los astrovirus, coronavirus, torovirus y picobirnavirus es emergente. Los astrovirus se han detectado en las heces entre el 1,2 y el 20 % de niños con diarrea que requieren atención médica en una gran variedad de localizaciones geográficas. Se han descrito brotes epidémicos en escuelas, guarderías y salas pediátricas, y son más frecuentes entre niños de menos de 3 años. En climas templados se ha demostrado una mayor incidencia invernal, y en climas tropicales ésta es similar en todo el año, siendo su transmisión preferente por vía orofecal. Se han reconocido siete serotipos de astrovirus humanos, de los cuales el más común es el uno. Los viriones pueden eliminarse durante amplios períodos y detectarse mediante microscopia electrónica. En estudios epidemiológicos se emplean técnicas de enzimoinmunoanálisis para detectar el antígeno común de grupo y se han desarrollado también técnicas basadas en la detección de ácidos nucleicos mediante hibridación y amplificación (reacción en cadena de la polimerasa). Los coronavirus entéricos se han asociado con frecuencia con enfermedad gastrointestinal en recién nacidos y niños menores de 12 años. El papel de los torovirus y picobirnavirus como causa de gastroenteritis es también emergente. Se necesitan estudios epidemiológicos para determinar su verdadera frecuencia en la comunidad, identificar sus mecanismos de transmisión y explicar la fisiopatología de los cuadros provocados por estos agentes.
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Traoré O, Belliot G, Mollat C, Piloquet H, Chamoux C, Laveran H, Monroe SS, Billaudel S. RT-PCR identification and typing of astroviruses and Norwalk-like viruses in hospitalized patients with gastroenteritis: evidence of nosocomial infections. J Clin Virol 2000; 17:151-8. [PMID: 10996111 DOI: 10.1016/s1386-6532(00)00088-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Astroviruses (HAstVs) and 'Norwalk-like viruses' (NLV) are frequent causes of gastroenteritis worldwide, though no data on the strains in circulation or their prevalence is available for France. OBJECTIVES We applied molecular methods to detect HAstVs and NLVs by reverse transcription-polymerase chain reaction (RT-PCR) in fecal samples collected during a 2-year period from children and adults hospitalized with gastroenteritis. STUDY DESIGN All samples negative for rotavirus and adenovirus by latex agglutination which contained small (25-40 nm) viral particles observed by electron microscopy (EM) were examined by RT-PCR. RT-PCR products were sequenced to characterize the HAstV and NLV strains present. RESULTS A total of 75 samples were analyzed by RT-PCR, of which 15 were positive for HAstV and 24 for NLV. Several distinct strains of serotype 1 HAstV, the predominant serotype, circulated during the period. Nineteen of the 24 NLVs were of the G2 genogroup including Mexico-like (n=10), Bristol-like (n=8), and Hawaii-like viruses (n=1); two were genogroup 1. Overall, seven (47%) of the 15 HAstV infections and nine (37.5%) of the 24 NLV infections appeared to be nosocomially acquired based on the date of admission in hospital and the date of illness. CONCLUSION This study provides additional evidence of the importance of nosocomial infections caused by NLV and HAstV.
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Affiliation(s)
- O Traoré
- Service and Hygiene Hospitalière, Faculté de Médecine, 28 place Henri Dunant, 63000 Fd Cedex, Clermont, France.
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Sakon N, Yamazaki K, Utagawa E, Okuno Y, Oishi I. Genomic characterization of human astrovirus type 6 Katano virus and the establishment of a rapid and effective reverse transcription-polymerase chain reaction to detect all serotypes of human astrovirus. J Med Virol 2000; 61:125-31. [PMID: 10745244 DOI: 10.1002/(sici)1096-9071(200005)61:1<125::aid-jmv20>3.0.co;2-b] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We previously reported that human astrovirus type 6 (HAstV T6) was the etiologic agent of a large-scale outbreak of acute gastroenteritis that occurred in 1991 in Katano City, Osaka, Japan [Oishi et al., 1994]. The two representative strains, Katano virus K23 and K24, have been analyzed by sequencing the open reading frame 2 (ORF2) region after amplification by reverse transcription-polymerase chain reaction (RT-PCR). The ORF2 region of HAstV T6 strains, including K23, was found to be about 20 bp smaller than those of other types. There was 94% nucleotide sequence identity and 95% amino acid sequence identity between K23 and K24, with the Oxford strains belonging to HAstV T6. The high homology of the ORF2 region between the Katano and Oxford strains shows intratype genomic stability, irrespective of time and place of virus isolation. Comparing sequences of ORF2 of different HAstV serotypes, we established a rapid and highly sensitive detection system for HAstV types using RT-PCR with the AC230/AC1' primer set designed from the 5'-terminal end region of ORF2. This RT-PCR system seems very useful in detecting at least two different viruses in a single PCR test tube using AC230/AC1' in addition to the NV81/82, SM82 primer sets. Thus, our rapid and effective detection system may contribute to the epidemiologic characterization of astrovirus infections as well as Norwalk-like viruses.
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Affiliation(s)
- N Sakon
- Laboratory of Virology, Osaka Prefectural Institute of Public Health, Osaka, Japan.
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Mitchell DK, Matson DO, Cubitt WD, Jackson LJ, Willcocks MM, Pickering LK, Carter MJ. Prevalence of antibodies to astrovirus types 1 and 3 in children and adolescents in Norfolk, Virginia. Pediatr Infect Dis J 1999; 18:249-54. [PMID: 10093946 DOI: 10.1097/00006454-199903000-00008] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To determine the prevalence of antibody to human astrovirus types 1 (HAstV-1) and 3 (HAstV-3) in children. METHODS Sera from children hospitalized in Norfolk, VA, for noninfectious conditions were collected for a 1-month period every 6 months from 1993 to 1996 and tested by enzyme immunoassay for antibody to HAstV-1 and HAstV-3 with the use of baculovirus-expressed recombinant capsid proteins as antigens. RESULTS The seroprevalence of 393 infants and children to HAstV-1 decreased from 67% in infants <3 months of age to 7% by 6 to 8 months of age, consistent with loss of transplacental antibodies. Children acquired HAstV-1 antibody with a peak prevalence of 94% at 6 to 9 years of age (P < 0.001). Antibodies to HAstV-3 exhibited a lower prevalence, with 26% positive at <3 months, 0% at 6 to 11 months and 42% by 6 to 9 years of age. HAstV-1 seroprevalence in children O to 2 months of age decreased from 89% in November, 1993, to 40% in November, 1996 (P = 0.009). CONCLUSIONS Astrovirus type-specific antibody prevalence can be measured by baculovirus-expressed capsid antigens in an enzyme immunoassay. Children developed antibody to HAstV-1 (94%) and to HAstV-3 (42%) by 6 to 9 years of age indicating frequent exposure to these enteric viruses in infancy and early childhood.
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Affiliation(s)
- D K Mitchell
- Center for Pediatric Research, Children's Hospital of The King's Daughters, Eastern Virginia Medical School, Norfolk, USA
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Shastri S, Doane AM, Gonzales J, Upadhyayula U, Bass DM. Prevalence of astroviruses in a children's hospital. J Clin Microbiol 1998; 36:2571-4. [PMID: 9705394 PMCID: PMC105164 DOI: 10.1128/jcm.36.9.2571-2574.1998] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
An enzyme immunoassay for astrovirus was used to screen 357 stool samples from 267 symptomatic inpatients at a tertiary-care children's hospital. Thirty stool samples from 26 patients contained astrovirus antigen, while rotavirus was found in 34 samples and Clostridium difficile toxin was found in 40. Half of the astrovirus infections were nosocomial. Additional pathogens were identified in six of the astrovirus antigen-positive stool samples. Most (80%) of the astroviruses recovered were of serotype 1. Astrovirus infections were significantly more common than rotavirus or C. difficile infections in very young infants and in those with surgical short-bowel syndrome.
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Affiliation(s)
- S Shastri
- Department of Pediatrics and Center for Digestive Disease, Stanford University, Stanford, California 94305-5208, USA
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Molberg O, Nilsen EM, Sollid LM, Scott H, Brandtzaeg P, Thorsby E, Lundin KE. CD4+ T cells with specific reactivity against astrovirus isolated from normal human small intestine. Gastroenterology 1998; 114:115-22. [PMID: 9428225 DOI: 10.1016/s0016-5085(98)70639-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND & AIMS The gut is the largest immunologic organ in the human body, but little is known about the antigen specificity of mucosal T cells. This study sought to determine whether T cells resident in the duodenal mucosa could recognize astrovirus, a common and clinically important gastroenteritis virus. Serum antibodies against astrovirus are prevalent, indicating frequent viral exposure and postinfectious induction of systemic immune responses. Mucosal immune responses may conceivably mediate protection on astroviral reinfections. METHODS Small intestinal biopsy specimens with normal histology were obtained from 8 adults and challenged in an organ culture system with inactivated human astrovirus. T cells activated by the viral challenge were isolated either by immunomagnetic positive selection of mucosal resident cells or by collecting cells emigrating into the culture supernatant. RESULTS Astrovirus-specific, mucosal T-cell lines were isolated from all 8 subjects. Analysis of 29 CD4+ T-cell clones from 3 subjects showed predominant HLA-DR restriction of astrovirus responses. Most of the T-cell clones showed a Th1-like cytokine profile when restimulated with astrovirus. CONCLUSIONS Helper T cells residing in normal, duodenal mucosa of adult subjects recognize a common enteropathogenic virus. These mucosal CD4+ T cells are presumably important in mucosal defense against recurrent astroviral infections.
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Affiliation(s)
- O Molberg
- Institute of Transplantation Immunology, Rikshospitalet, Oslo, Norway.
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Koopmans MP, Bijen MH, Monroe SS, Vinjé J. Age-stratified seroprevalence of neutralizing antibodies to astrovirus types 1 to 7 in humans in The Netherlands. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 1998; 5:33-7. [PMID: 9455876 PMCID: PMC121387 DOI: 10.1128/cdli.5.1.33-37.1998] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Astroviruses are a new family of positive-stranded RNA viruses that cause gastroenteritis in a wide range of animals and in humans. Seven types of astrovirus, tentatively considered serotypes, have been distinguished by enzyme-linked immunosorbent assays (ELISA) or immunoelectron microscopy, but it is unclear whether the serotype designation is used properly. To test human sera for the presence of neutralizing antibodies and to type field strains, neutralization tests (NT) using CaCo2 tissue-culture-adapted astrovirus strains 1 to 7 and the corresponding rabbit reference sera were developed. In rabbits, neutralizing antibodies were predominantly serotype specific, with the exception of low-level cross-reactivity in astrovirus serotype 4 reference serum with astrovirus serotype 1 virus. Similarly, in humans, no evidence of cross-reactivity was found for the serotype combinations tested (all except the combination 1 and 7 and the combination 6 and 7). Typing by NT was concordant with typing by ELISA and genotyping, with one exception. The seroprevalence rates of neutralizing antibodies in an age-stratified sample of the population in Utrecht Province (n = 242) were 91% for astrovirus serotype 1, 69% for astrovirus serotype 3, 56% for astrovirus serotype 4, 36% for astrovirus serotype 5, 31% for astrovirus serotype 2, 16% for astrovirus serotype 6, and 10% for astrovirus serotype 7. Acquisition of antibodies was slower among persons seropositive for astrovirus serotype 5 than among those seropositive for astrovirus serotypes 1 to 4, suggesting that the epidemiology of serotype 5 astrovirus is different from that of astrovirus serotypes 1 to 4.
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Affiliation(s)
- M P Koopmans
- Research Laboratory for Infectious Diseases, National Institute for Public Health and the Environment (RIVM), Bilthoven, The Netherlands.
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Abstract
Astroviruses are important agents of pediatric gastroenteritis. To better understand astrovirus antigenic structure and the basis of protective immunity, monoclonal antibodies (MAbs) were produced against serotype 1 human astrovirus. Four MAbs were generated. One MAb (8G4) was nonneutralizing but reacted to all seven serotypes of astrovirus by enzyme-linked immunosorbentassay (ELISA) and immunoperoxidase staining of infected cells. Three MAbs were found to have potent neutralizing activity against astrovirus. The first (5B7) was serotype 1 specific, another (7C2) neutralized all seven human astrovirus serotypes, while the third (3B2) neutralized serotypes 1 and 7. Immunoprecipitation of radiolabeled astrovirus proteins from supernatants of astrovirus-infected cells showed that all three neutralizing antibodies reacted with VP29. MAb 5B7 also reacted strongly with VP26. A competition ELISA showed that all three neutralizing antibodies competed with each other for binding to purified astrovirus virions, suggesting that their epitopes were topographically in close proximity. None of the neutralizing MAbs competed with nonneutralizing MAb 8G4. The neutralizing MAbs were used to select antigenic variant astroviruses, which were then studied in neutralization assays. These assays also suggested a close relationship between the respective epitopes. All three neutralizing MAbs were able to prevent attachment of radiolabeled astrovirus particles to human Caco 2 intestinal cell monolayers. Taken together, these data suggest that the astrovirus capsid protein VP29 may be important in viral neutralization, heterotypic immunity, and virus attachment to target cells.
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Affiliation(s)
- D M Bass
- Department of Pediatrics and Center for Digestive Disease, Stanford University, California 94305-5119, USA.
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