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Morandi MI, Busko P, Ozer-Partuk E, Khan S, Zarfati G, Elbaz-Alon Y, Abou Karam P, Napso Shogan T, Ginini L, Gil Z, Regev-Rudzki N, Avinoam O. Extracellular vesicle fusion visualized by cryo-electron microscopy. PNAS NEXUS 2022; 1:pgac156. [PMID: 36714848 PMCID: PMC9802263 DOI: 10.1093/pnasnexus/pgac156] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 06/30/2022] [Accepted: 08/09/2022] [Indexed: 02/01/2023]
Abstract
Extracellular vesicles (EVs) transfer bioactive molecules between cells in a process reminiscent of enveloped viruses. EV cargo delivery is thought to occur by protein-mediated and pH-dependent membrane fusion of the EV and the cellular membrane. However, there is a lack of methods to identify the fusion proteins and resolve their mechanism. We developed and benchmarked an in vitro biophysical assay to investigate EV membrane fusion. The assay was standardized by directly comparing EV and viral fusion with liposomes. We show that EVs and retroviruses fuse with liposomes mimicking the membrane composition of the late endosome in a pH- and protein-dependent manner. Moreover, we directly visualize the stages of membrane fusion using cryo-electron tomography. We find that, unlike most retroviruses, EVs remain fusogenic after acidification and reneutralization. These results provide novel insights into the EV cargo delivery mechanism and an experimental approach to identify the EV fusion machinery.
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Affiliation(s)
- Mattia I Morandi
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Petro Busko
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Efrat Ozer-Partuk
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Suman Khan
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Giulia Zarfati
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Yael Elbaz-Alon
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Paula Abou Karam
- Department of Biomolecular Sciences, Weizmann Institute of Science, Rehovot 7610001, Israel
| | | | - Lana Ginini
- Faculty of Health, Bar Ilan University, Ramat-Gan 5290002, Israel
| | - Ziv Gil
- Faculty of Health, Bar Ilan University, Ramat-Gan 5290002, Israel,Head and Neck Center, Holy Family Hospital, Nazareth 1641100, Israel
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At Thobari J, Damayanti W, Haposan JH, Nirwati H, Iskandar K, Samad, Fahmi J, Sari RM, Bachtiar NS, Watts E, Bines JE, Soenarto Y. Safety and immunogenicity of human neonatal RV3 rotavirus vaccine (Bio Farma) in adults, children, and neonates in Indonesia: Phase I Trial. Vaccine 2021; 39:4651-4658. [PMID: 34244006 DOI: 10.1016/j.vaccine.2021.06.071] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Revised: 05/09/2021] [Accepted: 06/23/2021] [Indexed: 10/20/2022]
Abstract
BACKGROUND Despite safe and effective WHO prequalified rotavirus vaccines, at least 84 million children remain unvaccinated. A birth dose schedule of the RV3-BB vaccine was reported to be highly efficacious against severe rotavirus disease in Indonesian infants and is under further development at PT Bio Farma, Indonesia. The aim is to develop a rotavirus vaccine starting from birth that could improve the implementation, safety, and effectiveness of vaccines. METHODS A multi-site phase I study of a human neonatal RV3 rotavirus vaccine (Bio Farma) in adults, children, neonates in Indonesia from April 2018 to March 2019. The adult and child cohorts were open-labeled single-dose, while the neonatal cohort was randomized, double-blind, and placebo-controlled three-doses at the age of 0-5 days, 8-10 weeks, and 12-14 weeks. The primary objective was to assess the safety of vaccines with the immunogenicity and vaccine virus fecal shedding as the secondary endpoints in neonates. RESULTS Twenty-five adults, 25 children, and 50 neonates were recruited, and all but one in the neonatal cohort completed all study procedures. Three serious adverse events were reported (1 adult & 2 neonates), but none were assessed related to investigational product (IP). The neonatal vaccine group had a significantly higher positive immune response (cumulative seroconverted SNA and IgA) 28 days after three doses than those in the placebo group (72% vs. 16.7%, respectively). The GMT of serum IgA in the vaccine group was significantly higher at post IP dose 1 (p < 0.05) and post IP dose 3 (p < 0.001) compared to the placebo group. CONCLUSION The trial results show that the RV3 rotavirus vaccine (Bio Farma) is well tolerated in all participant cohorts (adults, children, and neonates). Three doses of this vaccine administered in a neonatal schedule were immunogenic. These promising results support further clinical development of the RV3 rotavirus vaccine (Bio Farma).
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Affiliation(s)
- Jarir At Thobari
- Department of Pharmacology and Therapy, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia; Center for Child Health, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia.
| | - Wahyu Damayanti
- Center for Child Health, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia; Department of Child Health, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada / Dr. Sardjito General Hospital, Yogyakarta, Indonesia
| | - Jonathan Hasian Haposan
- Center for Child Health, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Hera Nirwati
- Center for Child Health, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia; Department of Microbiology, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia
| | - Kristy Iskandar
- Center for Child Health, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia; Universitas Gadjah Mada Academic Hospital, Yogyakarta, Indonesia
| | - Samad
- Department of Pediatrics, dr. Soeradji Tirtonegoro General Hospital, Klaten, Central Java, Indonesia
| | | | | | | | - Emma Watts
- Murdoch Childrens Research Institute (MCRI), Parkville, Victoria, Australia
| | - Julie E Bines
- Murdoch Childrens Research Institute (MCRI), Parkville, Victoria, Australia; Department of Paediatrics, the University of Melbourne, Parkville, Victoria, Australia; Department of Gastroenterology and Clinical Nutrition, Royal Children's Hospital, Parkville, Victoria, Australia
| | - Yati Soenarto
- Center for Child Health, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada, Yogyakarta, Indonesia; Department of Child Health, Faculty of Medicine, Public Health and Nursing, Universitas Gadjah Mada / Dr. Sardjito General Hospital, Yogyakarta, Indonesia
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Zhou L, Niu Z, Jiang X, Zhang Z, Zheng Y, Wang Z, Zhu Y, Gao L, Huang H, Wang X, Sun Q. SARS-CoV-2 Targets by the pscRNA Profiling of ACE2, TMPRSS2 and Furin Proteases. iScience 2020; 23:101744. [PMID: 33134888 PMCID: PMC7591870 DOI: 10.1016/j.isci.2020.101744] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 07/15/2020] [Accepted: 10/26/2020] [Indexed: 02/07/2023] Open
Abstract
The cellular targets of SARS-CoV-2, the novel coronavirus causing the COVID-19 pandemic, is still rudimentary. Here, we incorporated the protein information to analyze the expression of ACE2, the SARS-CoV-2 receptor, together with co-factors, TMPRSS2 and Furin, at single-cell level in situ, which we called protein-proofed single-cell RNA (pscRNA) profiling. Systemic analysis across 36 tissues revealed a rank list of candidate cells potentially vulnerable to SARS-CoV-2. The top targets are lung AT2 cells and macrophages, then cardiomyocytes and adrenal gland stromal cells, followed by stromal cells in testis, ovary, and thyroid, whereas the kidney proximal tubule cells, cholangiocytes, and enterocytes are less likely to be the primary SARS-CoV-2 targets. Actually, the stomach may constitute a physical barrier against SARS-CoV-2 as the acidic environment (pH < 2.0) could completely inactivate SARS-CoV-2 pseudo-viruses. Together, we provide a comprehensive view on the potential SARS-CoV-2 targets by pscRNA profiling.
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Affiliation(s)
- Lulin Zhou
- Institute of Biotechnology, 20 Dongda Street, Beijing 100071, P.R. China
- School of Medicine, Nankai University, 94 Weijin Road, Tianjin 300071, P. R. China
| | - Zubiao Niu
- Institute of Biotechnology, 20 Dongda Street, Beijing 100071, P.R. China
| | - Xiaoyi Jiang
- Institute of Biotechnology, 20 Dongda Street, Beijing 100071, P.R. China
- Department of Oncology, Beijing Shijitan Hospital of Capital Medical University, 10 TIEYI Road, Beijing 100038, P. R. China
| | - Zhengrong Zhang
- Institute of Biotechnology, 20 Dongda Street, Beijing 100071, P.R. China
| | - You Zheng
- Institute of Biotechnology, 20 Dongda Street, Beijing 100071, P.R. China
| | - Zhongyi Wang
- Institute of Biotechnology, 20 Dongda Street, Beijing 100071, P.R. China
| | - Yichao Zhu
- Institute of Biotechnology, 20 Dongda Street, Beijing 100071, P.R. China
| | - Lihua Gao
- Institute of Biotechnology, 20 Dongda Street, Beijing 100071, P.R. China
| | - Hongyan Huang
- Department of Oncology, Beijing Shijitan Hospital of Capital Medical University, 10 TIEYI Road, Beijing 100038, P. R. China
| | - Xiaoning Wang
- School of Medicine, Nankai University, 94 Weijin Road, Tianjin 300071, P. R. China
- School of Laboratory Medicine and Biotechnology, Southern Medical University, Guangzhou 510515, P. R. China
- National Clinic Center of Geriatric, the Chinese PLA General Hospital, Beijing 100853, P. R. China
| | - Qiang Sun
- Institute of Biotechnology, 20 Dongda Street, Beijing 100071, P.R. China
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Charpiat B, Bleyzac N, Tod M. Proton Pump Inhibitors are Risk Factors for Viral Infections: Even for COVID-19? Clin Drug Investig 2020; 40:897-899. [PMID: 32779119 PMCID: PMC7417108 DOI: 10.1007/s40261-020-00963-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
During the ongoing pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), more attention should be paid to the balance of risks and benefits associated with proton pump inhibitors for the following reasons. One of the main functions of gastric juice is to inactivate swallowed microorganisms, thereby inhibiting infectious agents from reaching the intestine. Studies have documented that proton pump inhibitors are a risk factor for rotavirus, influenza virus, norovirus, and Middle East respiratory syndrome coronavirus infections, and are associated with an increased risk of acute gastroenteritis during periods of highest circulation of enteric viruses. In light of the evidence for gastrointestinal infection implying a fecal–oral transmission of SARS-CoV-2 and given the magnitude of the SARS-CoV-2/coronavirus disease 2019 pandemic, associated with the widespread misuse of proton pump inhibitors, this suggests that we should not rule out the hypothesis that patients treated with proton pump inhibitors may be more at risk of being infected by SARS-CoV-2.
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Affiliation(s)
- Bruno Charpiat
- Service Pharmacie, Hôpital de La Croix-Rousse, Groupement Hospitalier Nord, Hospices Civils de Lyon, 103 Grande Rue de la Croix-Rousse, 69004, Lyon, France.
| | - Nathalie Bleyzac
- Service Pharmacie, Hôpital de La Croix-Rousse, Groupement Hospitalier Nord, Hospices Civils de Lyon, 103 Grande Rue de la Croix-Rousse, 69004, Lyon, France.,EMR 3738, Ciblage, Thérapeutique en Oncologie, Faculté de Médecine et de Maïeutique Lyon-Sud Charles Mérieux, Université Claude Bernard Lyon 1, Oullins Cedex, France
| | - Michel Tod
- Service Pharmacie, Hôpital de La Croix-Rousse, Groupement Hospitalier Nord, Hospices Civils de Lyon, 103 Grande Rue de la Croix-Rousse, 69004, Lyon, France.,EMR 3738, Ciblage, Thérapeutique en Oncologie, Faculté de Médecine et de Maïeutique Lyon-Sud Charles Mérieux, Université Claude Bernard Lyon 1, Oullins Cedex, France
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Alcohol abrogates human norovirus infectivity in a pH-dependent manner. Sci Rep 2020; 10:15878. [PMID: 32985508 PMCID: PMC7522253 DOI: 10.1038/s41598-020-72609-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 09/03/2020] [Indexed: 02/03/2023] Open
Abstract
Alcohol-based disinfectants are widely used for the sanitization of microorganisms, especially those that cause infectious diseases, including viruses. However, since the germicidal mechanism of alcohol is lipolysis, alcohol-based disinfectants appear to have a minimal effect on non-enveloped viruses, such as noroviruses. Because there is no cultivation method for human norovirus (HuNoV) in vitro, murine norovirus and feline calicivirus have been used as surrogates for HuNoV to analyze the efficacy of disinfectant regents. Therefore, whether these disinfectants and their conditions are effective against HuNoVs remain unknown. In this study, we report that ethanol or isopropanol alone can sufficiently suppress GII.4 genotype HuNoV replication in human iPSC-derived intestinal epithelial cells. Additionally, pH adjustments and salting-out may contribute toward the virucidal effect of alcohol against other HuNoV genotypes and cancel the impediment of organic substance contamination, respectively. Therefore, similar to sodium hypochlorite, alcohol-based disinfectants containing electrolytes can be used for HuNoV inactivation.
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Fuzawa M, Bai H, Shisler JL, Nguyen TH. The Basis of Peracetic Acid Inactivation Mechanisms for Rotavirus and Tulane Virus under Conditions Relevant for Vegetable Sanitation. Appl Environ Microbiol 2020; 86:e01095-20. [PMID: 32709728 PMCID: PMC7499037 DOI: 10.1128/aem.01095-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 07/21/2020] [Indexed: 01/11/2023] Open
Abstract
We determined the disinfection efficacy and inactivation mechanisms of peracetic acid (PAA)-based sanitizer using pH values relevant for vegetable sanitation against rotavirus (RV) and Tulane virus (TV; a human norovirus surrogate). TV was significantly more resistant to PAA disinfection than RV: for a 2-log10 reduction of virus titer, RV required 1 mg/liter PAA for 3.5 min of exposure, while TV required 10 mg/liter PAA for 30 min. The higher resistance of TV can be explained, in part, by significantly more aggregation of TV in PAA solutions. The PAA mechanisms of virus inactivation were explored by quantifying (i) viral genome integrity and replication using reverse transcription-quantitative PCR (RT-qPCR) and (ii) virus-host receptor interactions using a cell-free binding assay with porcine gastric mucin conjugated with magnetic beads (PGM-MBs). We observed that PAA induced damage to both RV and TV genomes and also decreased virus-receptor interactions, with the latter suggesting that PAA damages viral proteins important for binding its host cell receptors. Importantly, the levels of genome-versus-protein damage induced by PAA were different for each virus. PAA inactivation correlated with higher levels of RV genome damage than of RV-receptor interactions. For PAA-treated TV, the opposite trends were observed. Thus, PAA inactivates each of these viruses via different molecular mechanisms. The findings presented here potentially contribute to the design of a robust sanitation strategy for RV and TV using PAA to prevent foodborne disease.IMPORTANCE In this study, we examined the inactivation mechanisms of peracetic acid (PAA), a sanitizer commonly used for postharvest vegetable washing, for two enteric viruses: Tulane virus (TV) as a human norovirus surrogate and rotavirus (RV). PAA disinfection mechanisms for RV were mainly due to genome damage. In contrast, PAA disinfection in TV was due to damage of the proteins important for binding to its host receptor. We also observed that PAA triggered aggregation of TV to a much greater extent than RV. These studies demonstrate that different viruses are inactivated via different PAA mechanisms. This information is important for designing an optimal sanitation practice for postharvest vegetable washing to minimize foodborne viral diseases.
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Affiliation(s)
- Miyu Fuzawa
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Hezi Bai
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Joanna L Shisler
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Institute of Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
| | - Thanh H Nguyen
- Department of Civil and Environmental Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
- Institute of Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois, USA
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Wolff A, Günther T, Albert T, Schilling-Loeffler K, Gadicherla AK, Johne R. Stability of hepatitis E virus at different pH values. Int J Food Microbiol 2020; 325:108625. [PMID: 32361052 DOI: 10.1016/j.ijfoodmicro.2020.108625] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 03/26/2020] [Accepted: 03/30/2020] [Indexed: 12/27/2022]
Abstract
Infection with the hepatitis E virus (HEV) can cause acute and chronic hepatitis in humans. The zoonotic HEV genotype 3 is mainly transmitted by consumption of raw and fermented meat products prepared from infected pigs or wild boars. Lowering of pH during fermentation is one of the microbiological hurdles considered to inhibit growth of certain pathogens. However, no data are currently available on pH stability of HEV. As a reliable and reproducible measurement of HEV infectivity in meat products is not established so far, the stability of the cell culture-adapted HEV genotype 3 strain 47832c was analyzed here in phosphate-buffered saline (PBS) at different pH values. Only a minimal decrease of infectivity (up to 0.6 log10 focus forming units) was found after treatment at pH 2 to 9 for 3 h at room temperature. At pH 10, a decrease of about 3 log10 was evident, whereas no remaining virus (>3.5 log10 decrease) was detected at pH 1. The conditions usually achieved during curing of raw sausages were simulated using D/L-lactic acid added to PBS resulting in pH 4.5 to 6.5. After incubation at 4 °C for 7 days at these conditions, no significant differences as compared to a standard PBS solution at pH 7.7 were evident. At room temperature, a 0.8 log10 decrease was found at pH 4.7 after 7 days incubation compared to pH 7.7, but less at the other pH values. In conclusion, only minimal inactivating effects were found at pH conditions commonly occurring during food processing. Therefore, remaining infectious virus might be present in fermented meat products if HEV-contaminated starting material was used. Additional effects of other factors like high salt concentrations and low aw values should be investigated in future studies.
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Affiliation(s)
- A Wolff
- German Federal Institute for Risk Assessment, Department of Biological Safety, Diedersdorfer Weg 1, 12277 Berlin, Germany
| | - T Günther
- German Federal Institute for Risk Assessment, Department of Biological Safety, Diedersdorfer Weg 1, 12277 Berlin, Germany
| | - T Albert
- University of Leipzig, Institute for Food Hygiene, An den Tierkliniken 1, 04103 Leipzig, Germany
| | - K Schilling-Loeffler
- German Federal Institute for Risk Assessment, Department of Biological Safety, Diedersdorfer Weg 1, 12277 Berlin, Germany
| | - A K Gadicherla
- German Federal Institute for Risk Assessment, Department of Biological Safety, Diedersdorfer Weg 1, 12277 Berlin, Germany
| | - R Johne
- German Federal Institute for Risk Assessment, Department of Biological Safety, Diedersdorfer Weg 1, 12277 Berlin, Germany.
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The Phylogeny and Biological Function of Gastric Juice-Microbiological Consequences of Removing Gastric Acid. Int J Mol Sci 2019; 20:ijms20236031. [PMID: 31795477 PMCID: PMC6928904 DOI: 10.3390/ijms20236031] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Revised: 11/24/2019] [Accepted: 11/25/2019] [Indexed: 12/15/2022] Open
Abstract
Gastric juice is a unique combination of hydrochloric acid (HCl), lipase, and pepsin. Acidic gastric juice is found in all vertebrates, and its main function is to inactivate microorganisms. The phylogenetic preservation of this energy-consuming and, at times, hazardous function (acid-related diseases) reflects its biological importance. Proton pump inhibitors (PPIs) are one of the most widely used drugs in the world. Due to the reduced prevalence of Helicobacter pylori infection as well as the increased use of inhibitors of gastric acid secretion, the latter has become the most important cause of gastric hypoacidity. In the present manuscript, we review the microbiological consequences of removing gastric acidity. The resulting susceptibility to infections has not been studied extensively, and focus has mainly been restricted to bacterial and parasitic agents only. The strongest evidence concerning the relationship between hypochlorhydria and predisposition to infections relates to bacterial infections affecting the gastrointestinal tract. However, several other clinical settings with increased susceptibility to infections due to inhibited gastric acidity are discussed. We also discuss the impact of hypochlorhydria on the gut microbiome.
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McCanless A, Hultgren A, Escalante C, Ardt A, Valverde RA. Effect of two digestive enzymes and pH on the dsRNA of endornaviruses of bell pepper and melon under in vitro conditions. ANN MICROBIOL 2019. [DOI: 10.1007/s13213-019-01530-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Abstract
Purpose
The objective of this investigation was to determine the in vitro effect of two common digestive enzymes, amylase and pepsin, and pH on the integrity of the RI dsRNA of bell pepper endornavirus (BPEV) and Cucumis melo endornavirus (CmEV) evaluated by gel electrophoresis and reverse-transcription PCR (RT-PCR).
Methods
We conducted experiments on the in vitro effect of two common digestive enzymes, amylase and pepsin, and pH on the structural integrity of the replicative intermediate (RI) dsRNA of bell pepper endornavirus (BPEV) and Cucumis melo endornavirus (CmEV), evaluated by gel electrophoresis and reverse-transcription polymerase chain reaction.
Result
The effect of the amylase, pepsin, and pH treatments on the dsRNA of both viruses was similar. Amylase did not appear to affect the structural integrity of the dsRNA. In contrast, gel electrophoresis analysis of pepsin-treated dsRNA samples showed an abnormal electrophoretic migration and evidence of partial dsRNA degradation. DsRNAs from both fruits were partially degraded when exposed to a pH value of 2.0 and completely degraded at a pH value of 1.0.
Conclusion
The results of this investigation suggest that when exposed to pepsin and pH values lower than 2.0, the RI of BPEV and CmEV lose their structural integrity. Therefore, when consuming endornavirus-infected bell pepper or melon, our digestive organs are exposed to both fragmented and full RI dsRNA of these two viruses.
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Han X, Bertzbach LD, Veit M. Mimicking the passage of avian influenza viruses through the gastrointestinal tract of chickens. Vet Microbiol 2019; 239:108462. [PMID: 31767100 PMCID: PMC7126190 DOI: 10.1016/j.vetmic.2019.108462] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 10/11/2019] [Accepted: 10/15/2019] [Indexed: 12/27/2022]
Abstract
Avian viruses require neutralization of the gizzard fluid to prevent inactivation. Neutralization uncovers a trypsin-like activity that activates the virus. Viruses grow to high titers in a new epithelial cell line from chicken intestine. Intestinal fluid activate virus particles, but only if diluted. A duck derived virus is better adapted to the fluid compared to fowl plague virus.
In contrast to human influenza viruses that replicate in the respiratory tract and are airborne transmitted, avian viruses also replicate in gut epithelial cells and are transmitted via the fecal-oral route. On this route, the virus is exposed to destructive fluids of the digestive tract, which are acidic and contain the proteases pepsin (gizzard) or chymotrypsin and trypsin (intestine). Only the latter enzyme activates virus by cleaving hemagglutinin (HA) into HA1 and HA2 subunits. We mimicked the passage of viruses through the gastrointestinal tract by treating them with digestive fluids from chicken and determined titers and integrity of HA by western-blot. Gizzard fluid completely inactivated virions and degrades HA even at a high dilution, but only if the pH was kept acidic. If the fluid is diluted with neutral buffer (mimicking virus uptake with seawater) particles were more resistant. Virions containing an uncleaved HA were even activated suggesting that gastric juice contains a trypsin-like protease. Undiluted intestinal fluid inactivated particles and destroyed HA, but diluted fluid activated virions. A virus isolated from the duck´s intestine is more tolerant against intestinal fluid compared to fowl plague virus suggesting that the former is better adapted to grow in the intestine. We also demonstrate that influenza viruses replicate to high titers in a novel chicken epithelial gut cell line. While viruses with a monobasic HA cleavage site require addition of trypsin, these cells effectively process HA with a polybasic cleavage site, which could be blocked with an inhibitor of the cellular furin protease.
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Affiliation(s)
- Xuejiao Han
- Freie Universität Berlin, Faculty of Veterinary Medicine, Institute of Virology, Robert-von-Ostertag-Str. 7-13, Berlin, 14163, Germany
| | - Luca D Bertzbach
- Freie Universität Berlin, Faculty of Veterinary Medicine, Institute of Virology, Robert-von-Ostertag-Str. 7-13, Berlin, 14163, Germany
| | - Michael Veit
- Freie Universität Berlin, Faculty of Veterinary Medicine, Institute of Virology, Robert-von-Ostertag-Str. 7-13, Berlin, 14163, Germany.
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Regla-Nava JA, Viramontes KM, Vozdolska T, Huynh AT, Villani T, Gardner G, Johnson M, Ferro PJ, Shresta S, Kim K. Detection of Zika virus in mouse mammary gland and breast milk. PLoS Negl Trop Dis 2019; 13:e0007080. [PMID: 30742628 PMCID: PMC6386411 DOI: 10.1371/journal.pntd.0007080] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 02/22/2019] [Accepted: 12/14/2018] [Indexed: 12/03/2022] Open
Abstract
Clinical reports of Zika Virus (ZIKV) RNA detection in breast milk have been described, but evidence conflicts as to whether this RNA represents infectious virus. We infected post-parturient AG129 murine dams deficient in type I and II interferon receptors with ZIKV. ZIKV RNA was detected in pup stomach milk clots (SMC) as early as 1 day post maternal infection (dpi) and persisted as late as 7 dpi. In mammary tissues, ZIKV replication was demonstrated by immunohistochemistry in multiple cell types including cells morphologically consistent with myoepithelial cells. No mastitis was seen histopathologically. In the SMC and tissues of the nursing pups, no infectious virus was detected via focus forming assay. However, serial passages of fresh milk supernatant yielded infectious virus, and immunohistochemistry showed ZIKV replication protein associated with degraded cells in SMC. These results suggest that breast milk may contain infectious ZIKV. However, breast milk transmission (BMT) does not occur in this mouse strain that is highly sensitive to ZIKV infection. These results suggest a low risk for breast milk transmission of ZIKV, and provide a platform for investigating ZIKV entry into milk and mechanisms which may prevent or permit BMT.
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Affiliation(s)
- Jose Angel Regla-Nava
- Division of Inflammation Biology, La Jolla Institute for Allergy & Immunology, La Jolla, California, United States of America
| | - Karla M. Viramontes
- Division of Inflammation Biology, La Jolla Institute for Allergy & Immunology, La Jolla, California, United States of America
| | - Teodora Vozdolska
- Division of Inflammation Biology, La Jolla Institute for Allergy & Immunology, La Jolla, California, United States of America
| | - Anh-Thy Huynh
- Division of Inflammation Biology, La Jolla Institute for Allergy & Immunology, La Jolla, California, United States of America
| | - Tom Villani
- Visikol, New Jersey, United States of America
| | | | | | - Pamela J. Ferro
- Texas Veterinary Medical Diagnostic Laboratory, College Station, TX, United States of America
| | - Sujan Shresta
- Division of Inflammation Biology, La Jolla Institute for Allergy & Immunology, La Jolla, California, United States of America
- Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States of America
| | - Kenneth Kim
- Division of Inflammation Biology, La Jolla Institute for Allergy & Immunology, La Jolla, California, United States of America
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Madan M, Sikriwal D, Sharma G, Shukla N, Mandyal AK, Kale S, Gill D. Rational design of heat stable lyophilized rotavirus vaccine formulations. Hum Vaccin Immunother 2018; 14:2132-2141. [PMID: 29953317 PMCID: PMC6183320 DOI: 10.1080/21645515.2018.1487499] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 05/21/2018] [Accepted: 06/07/2018] [Indexed: 12/20/2022] Open
Abstract
To develop a safe and efficacious heat-stable rotavirus vaccine, new lyophilized formulations were developed using rotavirus serotypes constituting RotaTeq®. A series of formulation compositions, differing in buffering agents, bulking agents, cryoprotectants, amino acids and divalent cations, were screened for their ability to provide stability to rotavirus serotypes during lyophilization and when stored under elevated temperatures for extended periods. Lead formulations and lyophilization cycles were further optimized. Stability profiles of thus optimized formulations showed their ability to retain the potency of rotavirus for > 36 months at 5°C, 20 months at 37°C, and 7 months at 45°C. The heat-stable lyophilized rotavirus formulations developed met the all critical quality attributes for appearance, heat-stability during storage, moisture content as well as pH, viability and stability after reconstitution and has great potential to be used as vaccine candidates for improving access in low-income countries.
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Affiliation(s)
- Madhu Madan
- MSD Wellcome Trust Hilleman Labs Pvt. Ltd, Jamia Hamdard, Hamdard Nagar, New Delhi, India
| | - Deepa Sikriwal
- MSD Wellcome Trust Hilleman Labs Pvt. Ltd, Jamia Hamdard, Hamdard Nagar, New Delhi, India
| | - Gaurav Sharma
- MSD Wellcome Trust Hilleman Labs Pvt. Ltd, Jamia Hamdard, Hamdard Nagar, New Delhi, India
| | - Nidhi Shukla
- MSD Wellcome Trust Hilleman Labs Pvt. Ltd, Jamia Hamdard, Hamdard Nagar, New Delhi, India
| | - Ashwani Kumar Mandyal
- MSD Wellcome Trust Hilleman Labs Pvt. Ltd, Jamia Hamdard, Hamdard Nagar, New Delhi, India
| | - Sachin Kale
- MSD Wellcome Trust Hilleman Labs Pvt. Ltd, Jamia Hamdard, Hamdard Nagar, New Delhi, India
| | - Davinder Gill
- MSD Wellcome Trust Hilleman Labs Pvt. Ltd, Jamia Hamdard, Hamdard Nagar, New Delhi, India
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Ella R, Bobba R, Muralidhar S, Babji S, Vadrevu KM, Bhan MK. A Phase 4, multicentre, randomized, single-blind clinical trial to evaluate the immunogenicity of the live, attenuated, oral rotavirus vaccine (116E), ROTAVAC®, administered simultaneously with or without the buffering agent in healthy infants in India. Hum Vaccin Immunother 2018; 14:1791-1799. [PMID: 29543547 PMCID: PMC6067888 DOI: 10.1080/21645515.2018.1450709] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Revised: 02/16/2018] [Accepted: 03/07/2018] [Indexed: 11/02/2022] Open
Abstract
BACKGROUND The World Health Organization recommends that rotavirus vaccines should be included in all national immunization programs. Some currently licensed oral rotavirus vaccines contain a buffering agent (either as part of a ready-to-use liquid formulation or added during reconstitution) to reduce possible degradation of the vaccine virus in the infant gut, which poses several programmatic challenges (the large dose volume or the reconstitution requirement) during vaccine administration. Because ROTAVAC®, a WHO prequalified vaccine, was derived from the 116E neonatal strain, we evaluated the immunogenicity and safety of ROTAVAC® without buffer and ROTAVAC® with buffer in a phase 4, multicentre, single-blind, randomized clinical trial in healthy infants in India. METHODS 900 infants, approximately 6, 10 and 14 weeks of age, were assigned to 3 groups to receive ROTAVAC® (0.5 mL dose) orally: (i) 2.5 mL of citrate-bicarbonate buffer 5 minutes prior to administration of ROTAVAC® (Group I), (ii) ROTAVAC®, alone, without any buffer (Group II), or (iii) ROTAVAC®, mixed with buffer immediately before administration (Group III). Non-inferiority was compared among the groups for differences in serological responses (detected by serum anti-rotavirus IgA) and safety. RESULTS Geometric mean titers post vaccination at day 84 (28 days after dose 3) were 19.6 (95%CI: 17.0, 22.7), 20.7 (95%CI: 17.9, 24) and 19.2 (95%CI: 16.8, 22.1) for groups I, II and III respectively. Further, seroconversion rates and distribution of adverse events were similar among groups. CONCLUSIONS Administration of ROTAVAC® at a 0.5 mL dose volume without buffering agent was shown to be well tolerated and immunogenic. Given the homologous nature of the strain, it is plausible that ROTAVAC® replicates well and confers immunity even without buffer administration.
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Affiliation(s)
- Raches Ella
- Bharat Biotech International Limited, Genome Valley, Shameerpet, Hyderabad, India
| | - Radhika Bobba
- Bharat Biotech International Limited, Genome Valley, Shameerpet, Hyderabad, India
| | - Sanjay Muralidhar
- Bharat Biotech International Limited, Genome Valley, Shameerpet, Hyderabad, India
| | - Sudhir Babji
- Division of Gastrointestinal Sciences, Christian Medical College, Vellore, Tamil Nadu, India
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14
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Abstract
This narrative review summarises the benefits, risks and appropriate use of acid-suppressing drugs (ASDs), proton pump inhibitors and histamine-2 receptor antagonists, advocating a rationale balanced and individualised approach aimed to minimise any serious adverse consequences. It focuses on current controversies on the potential of ASDs to contribute to infections-bacterial, parasitic, fungal, protozoan and viral, particularly in the elderly, comprehensively and critically discusses the growing body of observational literature linking ASD use to a variety of enteric, respiratory, skin and systemic infectious diseases and complications (Clostridium difficile diarrhoea, pneumonia, spontaneous bacterial peritonitis, septicaemia and other). The proposed pathogenic mechanisms of ASD-associated infections (related and unrelated to the inhibition of gastric acid secretion, alterations of the gut microbiome and immunity), and drug-drug interactions are also described. Both probiotics use and correcting vitamin D status may have a significant protective effect decreasing the incidence of ASD-associated infections, especially in the elderly. Despite the limitations of the existing data, the importance of individualised therapy and caution in long-term ASD use considering the balance of benefits and potential harms, factors that may predispose to and actions that may prevent/attenuate adverse effects is evident. A six-step practical algorithm for ASD therapy based on the best available evidence is presented.
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15
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Zhou J, Li C, Zhao G, Chu H, Wang D, Yan HHN, Poon VKM, Wen L, Wong BHY, Zhao X, Chiu MC, Yang D, Wang Y, Au-Yeung RKH, Chan IHY, Sun S, Chan JFW, To KKW, Memish ZA, Corman VM, Drosten C, Hung IFN, Zhou Y, Leung SY, Yuen KY. Human intestinal tract serves as an alternative infection route for Middle East respiratory syndrome coronavirus. SCIENCE ADVANCES 2017; 3:eaao4966. [PMID: 29152574 PMCID: PMC5687858 DOI: 10.1126/sciadv.aao4966] [Citation(s) in RCA: 273] [Impact Index Per Article: 39.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Accepted: 10/20/2017] [Indexed: 05/08/2023]
Abstract
Middle East respiratory syndrome coronavirus (MERS-CoV) has caused human respiratory infections with a high case fatality rate since 2012. However, the mode of virus transmission is not well understood. The findings of epidemiological and virological studies prompted us to hypothesize that the human gastrointestinal tract could serve as an alternative route to acquire MERS-CoV infection. We demonstrated that human primary intestinal epithelial cells, small intestine explants, and intestinal organoids were highly susceptible to MERS-CoV and can sustain robust viral replication. We also identified the evidence of enteric MERS-CoV infection in the stool specimen of a clinical patient. MERS-CoV was considerably resistant to fed-state gastrointestinal fluids but less tolerant to highly acidic fasted-state gastric fluid. In polarized Caco-2 cells cultured in Transwell inserts, apical MERS-CoV inoculation was more effective in establishing infection than basolateral inoculation. Notably, direct intragastric inoculation of MERS-CoV caused a lethal infection in human DPP4 transgenic mice. Histological examination revealed MERS-CoV enteric infection in all inoculated mice, as shown by the presence of virus-positive cells, progressive inflammation, and epithelial degeneration in small intestines, which were exaggerated in the mice pretreated with the proton pump inhibitor pantoprazole. With the progression of the enteric infection, inflammation, virus-positive cells, and live viruses emerged in the lung tissues, indicating the development of sequential respiratory infection. Taken together, these data suggest that the human intestinal tract may serve as an alternative infection route for MERS-CoV.
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Affiliation(s)
- Jie Zhou
- State Key Laboratory of Emerging Infectious Diseases, University of Hong Kong, Hong Kong, China
- Department of Microbiology, University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong, China
- Research Centre of Infection and Immunology, University of Hong Kong, Hong Kong, China
| | - Cun Li
- Department of Microbiology, University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong, China
| | - Guangyu Zhao
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Hin Chu
- State Key Laboratory of Emerging Infectious Diseases, University of Hong Kong, Hong Kong, China
- Department of Microbiology, University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong, China
- Research Centre of Infection and Immunology, University of Hong Kong, Hong Kong, China
| | - Dong Wang
- Department of Microbiology, University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong, China
| | - Helen Hoi-Ning Yan
- Department of Pathology, University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong, China
| | - Vincent Kwok-Man Poon
- Department of Microbiology, University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong, China
| | - Lei Wen
- Department of Microbiology, University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong, China
| | - Bosco Ho-Yin Wong
- Department of Microbiology, University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong, China
| | - Xiaoyu Zhao
- Department of Microbiology, University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong, China
| | - Man Chun Chiu
- Department of Microbiology, University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong, China
| | - Dong Yang
- Department of Microbiology, University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong, China
| | - Yixin Wang
- Department of Microbiology, University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong, China
| | - Rex K. H. Au-Yeung
- Department of Pathology, University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong, China
| | | | - Shihui Sun
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Jasper Fuk-Woo Chan
- State Key Laboratory of Emerging Infectious Diseases, University of Hong Kong, Hong Kong, China
- Department of Microbiology, University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong, China
- Research Centre of Infection and Immunology, University of Hong Kong, Hong Kong, China
- Carol Yu Centre for Infection, University of Hong Kong, Hong Kong, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, University of Hong Kong, Hong Kong, China
| | - Kelvin Kai-Wang To
- State Key Laboratory of Emerging Infectious Diseases, University of Hong Kong, Hong Kong, China
- Department of Microbiology, University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong, China
- Research Centre of Infection and Immunology, University of Hong Kong, Hong Kong, China
- Carol Yu Centre for Infection, University of Hong Kong, Hong Kong, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, University of Hong Kong, Hong Kong, China
| | - Ziad A. Memish
- Ministry of Health and College of Medicine, Alfaisal University, Riyadh, Kingdom of Saudi Arabia
- Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA
| | - Victor M. Corman
- Institute of Virology, Charité–Universitätsmedizin Berlin, Berlin, Germany
- German Centre for Infection Research (DZIF), Berlin, Germany
| | - Christian Drosten
- Institute of Virology, Charité–Universitätsmedizin Berlin, Berlin, Germany
- German Centre for Infection Research (DZIF), Berlin, Germany
| | - Ivan Fan-Ngai Hung
- Department of Medicine, University of Hong Kong, Queen Mary Hospital, Hong Kong, China
| | - Yusen Zhou
- State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Suet Yi Leung
- Department of Pathology, University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong, China
| | - Kwok-Yung Yuen
- State Key Laboratory of Emerging Infectious Diseases, University of Hong Kong, Hong Kong, China
- Department of Microbiology, University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong, China
- Research Centre of Infection and Immunology, University of Hong Kong, Hong Kong, China
- Carol Yu Centre for Infection, University of Hong Kong, Hong Kong, China
- Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, University of Hong Kong, Hong Kong, China
- Corresponding author.
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16
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Abstract
The actin cytoskeleton and its network of associated proteins constitute a physical barrier that viruses must circumvent to gain entry into cells for productive infection. The mechanisms by which the physical signals of infection are sensed by the host to activate an innate immune response are not well understood. The antiviral endoribonuclease RNase L is ubiquitously expressed in a latent form and activated upon binding 2-5A, a unique oligoadenylate produced during viral infections. We provide evidence that RNase L in its inactive form interacts with the actin-binding protein Filamin A to modulate the actin cytoskeleton and inhibit virus entry. Cells lacking either RNase L or Filamin A displayed increased virus entry which was exacerbated in cells lacking both proteins. RNase L deletion mutants that reduced Filamin A interaction displayed a compromised ability to restrict virus entry, supporting the idea of an important role for the RNase L-Filamin A complex in barrier function. Remarkably, both the wild type and a catalytically inactive RNase L mutant were competent to reduce virus entry when transfected into RNase L-deficient cells, indicating that this novel function of RNase L is independent of its enzymatic activity. Virus infection and RNase L activation disrupt its association with Filamin A and release RNase L to mediate its canonical nuclease-dependent antiviral activities. The dual functions of RNase L as a constitutive component of the actin cytoskeleton and as an induced mediator of antiviral signaling and effector functions provide insights into its mechanisms of antiviral activity and opportunities for the development of novel antiviral agents. Cells constantly face and sample pathogens on their outer surface. The actin cytoskeleton and interacting proteins associate with the cell membrane and constitute a barrier to infection. Disruption of the actin cytoskeleton allows viruses to enter the cell and induces innate immune responses to clear infections. The molecular mechanisms that link virus-induced physical perturbations to host defense pathways remain unclear. Our studies identified a novel interaction between the antiviral endoribonuclease RNase L and the actin-binding protein Filamin A that enhances host defense by preventing viral entry into naive cells. This role for RNase L is independent of its enzymatic function. Virus infection alters actin dynamics, disrupts the RNase L-Filamin A complex, and releases RNase L to mediate antiviral signaling and effector functions via its established nucleolytic activities. These dual roles for RNase L provide an efficient strategy to protect cells from infection and rapidly respond upon pathogen exposure.
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Queiroz DMM, Rocha AMC, Crabtree JE. Unintended consequences of Helicobacter pylori infection in children in developing countries: iron deficiency, diarrhea, and growth retardation. Gut Microbes 2013; 4:494-504. [PMID: 23988829 PMCID: PMC3928161 DOI: 10.4161/gmic.26277] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Helicobacter pylori infection is predominantly acquired early in life. The prevalence of the infection in childhood is low in developed countries, whereas in developing countries most children are infected by 10 y of age. In poor resource settings, where malnutrition, parasitic/enteropathogen and H. pylori infection co-exist in young children, H. pylori might have potentially more diverse clinical outcomes. This paper reviews the impact of childhood H. pylori infection in developing countries that should now be the urgent focus of future research. The extra-gastric manifestations in early H. pylori infection in infants in poor resource settings might be a consequence of the infection associated initial hypochlorhydria. The potential role of H. pylori infection on iron deficiency, growth impairment, diarrheal disease, malabsorption and cognitive function is discussed in this review.
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Affiliation(s)
- Dulciene MM Queiroz
- Laboratory of Research in Bacteriology; Faculdade de Medicina; Universidade Federal de Minas Gerais; Belo Horizonte, Brazil
| | - Andreia MC Rocha
- Laboratory of Research in Bacteriology; Faculdade de Medicina; Universidade Federal de Minas Gerais; Belo Horizonte, Brazil
| | - Jean E Crabtree
- Leeds Institute Molecular Medicine; St. James’s University Hospital; University of Leeds; Leeds, UK,Correspondence to: Jean E Crabtree,
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Caricati CP, Oliveira‐Nascimento L, Yoshida JT, Stephano MA, Caricati ATP, Raw I. Safety of snake antivenom immunoglobulins: efficacy of viral inactivation in a complete downstream process. Biotechnol Prog 2013; 29:972-9. [PMID: 23804299 PMCID: PMC7161767 DOI: 10.1002/btpr.1758] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Revised: 05/14/2013] [Indexed: 12/26/2022]
Abstract
Viral safety remains a challenge when processing a plasma-derived product. A variety of pathogens might be present in the starting material, which requires a downstream process capable of broad viral reduction. In this article, we used a wide panel of viruses to assess viral removal/inactivation of our downstream process for Snake Antivenom Immunoglobulin (SAI). First, we screened and excluded equine plasma that cross-reacted with any model virus, a procedure not published before for antivenoms. In addition, we evaluated for the first time the virucidal capacity of phenol applied to SAI products. Among the steps analyzed in the process, phenol addition was the most effective one, followed by heat, caprylic acid, and pepsin. All viruses were fully inactivated only by phenol treatment; heat, the second most effective step, did not inactivate the rotavirus and the adenovirus used. We therefore present a SAI downstream method that is cost-effective and eliminates viruses to the extent required by WHO for a safe product.
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Affiliation(s)
| | | | - J. T. Yoshida
- Faculdade de Ciências FarmacêuticasUniversidade de Sao Paulo (USP)Sao PauloSPBrazil
| | - M. A. Stephano
- Faculdade de Ciências FarmacêuticasUniversidade de Sao Paulo (USP)Sao PauloSPBrazil
| | | | - I. Raw
- Instituto ButantanSao PauloSPBrazil
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19
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Smith GW, Ahmed AF, Constable PD. Effect of orally administered electrolyte solution formulation on abomasal luminal pH and emptying rate in dairy calves. J Am Vet Med Assoc 2013; 241:1075-82. [PMID: 23039985 DOI: 10.2460/javma.241.8.1075] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To determine the effects of 3 commercially available, orally administered electrolyte solutions (OAEs) on abomasal luminal pH and emptying rate in dairy calves, compared with the effect of orally administered milk replacer. DESIGN Randomized crossover study. ANIMALS 6 male dairy calves (age, 12 to 31 days). PROCEDURES Calves were surgically instrumented with an abomasal cannula and were administered 4 treatments in randomized order: all-milk protein milk replacer, high-glucose high-bicarbonate OAE, high-glucose high-bicarbonate OAE containing glycine, and low-glucose OAE containing acetate and propionate. Abomasal luminal pH was measured with a miniature glass pH electrode prior to treatment administration and every second afterward for 24 hours. RESULTS Feeding of orally administered milk replacer resulted in a rapid increase in mean abomasal luminal pH from 1.3 to 5.8, followed by a gradual decrease to preprandial values by 8 hours afterward (mean 24-hour pH, 3.2). High-glucose high-bicarbonate OAEs caused a large and sustained increase from 1.3 to 7.5 (mean 24-hour pH, 4.1 for the solution without glycine and 3.5 for the solution with glycine). In contrast, feeding of the acetate-containing OAE was followed by only a mild and transient increase (mean 24-hour pH, 2.1); luminal pH returned to preprandial values by 3 hours after ingestion. CONCLUSIONS AND CLINICAL RELEVANCE Ingestion of a bicarbonate-containing OAE resulted in sustained abomasal alkalinization in dairy calves. Because persistently high abomasal luminal pH may facilitate growth of enteropathogenic bacteria, administration of OAEs containing a high bicarbonate concentration (> 70mM) is not recommended for calves with diarrhea.
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Affiliation(s)
- Geof W Smith
- Department of Population Health and Pathobiology, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606, USA.
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20
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Fossmark R, Waldum H. The distressing overuse of gastric acid inhibitors. Dig Dis Sci 2013; 58:600-1. [PMID: 23306853 DOI: 10.1007/s10620-012-2532-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Accepted: 12/18/2012] [Indexed: 12/09/2022]
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21
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Lipson SM, Ozen FS, Karthikeyan L, Gordon RE. Effect of pH on anti-rotavirus activity by comestible juices and proanthocyanidins in a cell-free assay system. FOOD AND ENVIRONMENTAL VIROLOGY 2012; 4:168-78. [PMID: 23412889 DOI: 10.1007/s12560-012-9086-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2012] [Accepted: 08/30/2012] [Indexed: 05/25/2023]
Abstract
Cranberry (Vaccinium macrocarpon) and grape (Vitis labrusca) juices, and these species' secondary plant metabolites [i.e., proanthocyanidins (PACs)] possess antiviral activity. An understanding of the mechanism(s) responsible for these juices and their polyphenolic constituents' direct effect on enteric virus integrity, however, remains poorly defined. Using the rotavirus (RTV) as a model enteric virus system, the direct effect of manufacturer-supplied and commercially purchased juices [Ocean Spray Pure Cranberry 100 % Unsweetened Juice (CJ), Welch's 100 % Grape Juice (GJ), 100 % Concord (PG) and 100 % Niagara juices (NG)] and these species' cranberry (C-PACs) and grape PACs (G-PACs) was investigated. Loss of viral capsid integrity in cell-free suspension by juices and their PACs, and as a factor of pH, was identified by an antigen (RTV) capture enzyme-linked immunosorbent assay. At native and an artificially increased suspension at or near pH 7, loss of viral infectivity occurred after 5 min, in the order CJ > NG = GJ > PG, and PG > GJ = NG = CJ, respectively. Antiviral activity of CJ was inversely related to pH. Grape, but not cranberry PACs, displayed a comparatively greater anti-RTV activity at a suspension pH of 6.7. Anti-RTV activity of C-PACs was regained upon reduction of RTV-cranberry PAC suspensions to pH 4. An alteration or modification of Type A PAC (of V. macrocarpon) structural integrity at or near physiologic pH is suggested to have impacted on this molecule's antivirus activity. Type B PACs (of V. labrusca) were refractive to alternations of pH. Significantly, findings from pure system RTV-PAC testing paralleled and in turn, supported those RTV-juice antiviral studies. Electron microscopy showed an enshroudment by PACs of RTV particles, suggesting a blockage of viral antigenic binding determinants. The implications of our work are significant, especially in the interpretation of PAC (and PAC-containing food)-RTV interactions in the differing [pH] conditions of the gastrointestinal tract.
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Affiliation(s)
- Steven M Lipson
- Department of Biology and Health Promotion, St. Francis College, 180 Remsen Street, Brooklyn Heights, NY 11201, USA.
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22
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Baert L, Debevere J, Uyttendaele M. The efficacy of preservation methods to inactivate foodborne viruses. Int J Food Microbiol 2009; 131:83-94. [DOI: 10.1016/j.ijfoodmicro.2009.03.007] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2008] [Revised: 01/26/2009] [Accepted: 03/13/2009] [Indexed: 10/21/2022]
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23
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Lipson SM, Sethi L, Cohen P, Gordon RE, Tan IP, Burdowski A, Stotzky G. Antiviral effects on bacteriophages and rotavirus by cranberry juice. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2007; 14:23-30. [PMID: 17140784 PMCID: PMC7125675 DOI: 10.1016/j.phymed.2006.11.009] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Studies were undertaken to investigate the antiviral effects of comestible juices, especially cranberry juice, on non-related viral species. After exposure of bacteriophage T2 to a commercially available cranberry (Vaccinium macrocarpon) juice cocktail (CJ), virus infectivity titer was no longer detectible. After a 60-min exposure to orange (OJ) and grapefruit juices (GJ), phage infectivity was reduced to 25-35% of control, respectively. Similar data were observed for the bacteriophage T4. CJ inactivation of phage T4 was rapid, dose-dependent, and occurred at either 4 or 23 degrees C. Neither pH nor differences in sugar/carbohydrate levels among the juices may be ascribed to the recognized antiviral effects. Further studies were performed to identify the occurrence of antiviral activity by CJ to a mammalian enteric virus. The treatment of the simian rotavirus SA-11 with a 20% CJ suspension was sufficient to inhibit hemagglutination. Under scanning and transmission electron microscopy, CJ was observed to inhibit the adsorption of phage T4 to its bacterial host cells and prevented the replication of rotavirus in its monkey kidney (MA-104) host cells, respectively. The data suggest, for the first time, a non-specific antiviral effect towards unrelated viral species (viz., bacteriophages T2 and T4 and the simian rotavirus SA-11) by a commercially available cranberry fruit juice drink.
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Affiliation(s)
- S M Lipson
- Biology Department, St. Francis College, 180 Remsen Street, Brooklyn Heights, NY 11201, USA.
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24
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De Martel C, Ratanasopa S, Passaro D, Parsonnet J. Validation of the blood quininium resin test for assessing gastric hypochlorhydria. Dig Dis Sci 2006; 51:84-8. [PMID: 16416217 DOI: 10.1007/s10620-006-3089-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2005] [Accepted: 04/28/2005] [Indexed: 12/09/2022]
Abstract
Although gastric hypochlorhydria is a risk factor for gastroenteritis and for gastric cancer, no reliable, inexpensive, noninvasive test exists for screening or epidemiologic studies. We aimed to evaluate the sensitivity and specificity of the blood quininium resin test (bQRT) for hypochlorhydria, against pH monitoring. Twelve fasting adult volunteers-seven with and five without H. pylori infection-ingested 80 mg/kg of quininium resin twice, once with and once without acid suppression. Gastric pH was monitored for 75 minutes; serum samples were obtained at times 0 and 75 minutes. The bQRT levels were compared to gastric pH, controlling for omeprazole use and H. pylori infection. Subjects with a median recorded pH > or =3.5 were considered hypochlorhydric. Using a bQRT level of 10 as a cutoff for hypochlorhydria, the sensitivity and specificity of the bQRT were 100% and 37.5%, respectively. The bQRT predicted omeprazole use more accurately than pH monitoring. In conclusions, The bQRT has a high sensitivity for hypochlorhydria, making it potentially useful in populations with a high prevalence of hypochlorhydria. In its current formulation, the bQRT's low specificity makes it less useful in low-risk population.
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Affiliation(s)
- Catherine De Martel
- Departments of Health Research and Policy, Stanford University School of Medicine, Stanford, California 94305, USA.
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25
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Abstract
All vertebrates produce gastric acid. Its main function is inactivation of ingested microorganisms. The majority of microbiological pathogens ingested never reaches the intestine because of the gastric barrier. Although gastric hypochlorhydria is fairly common due to atrophic gastritis, gastric surgery or use of inhibitors of gastric acid secretion, the resulting susceptibility to infection has not been studied extensively. Drug-induced blockade of acid secretion leads to gastrointestinal bacterial overgrowth; the clinical significance of this is still controversial. Gastric acidity is known to protect against non-typhoid salmonellosis and cholera and it is suspected that it protects against several parasitic diseases as giardiasis and strongyloides. There is a lack of studies focusing on the impact of the gastric acidic barrier on viral infections. Concerning prion infections only a single study has been performed, demonstrating a possible role of gastric acidity in the protection against foodborne prion disease in mice. The combination of malnutrition and hypochlorhydria may contribute to the high prevalence of gastrointestinal infections in developing countries. Further studies are needed to evaluate the clinical consequences of impaired gastric acidity with respect to susceptibility to infections.
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Affiliation(s)
- Tom C Martinsen
- Department of Cancer Research and Molecular Medicine, Children's and Women's Health, Norwegian University of Science and Technology and University Hospital of Trondheim, Norway.
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26
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Favier AL, Burmeister WP, Chroboczek J. Unique physicochemical properties of human enteric Ad41 responsible for its survival and replication in the gastrointestinal tract. Virology 2004; 322:93-104. [PMID: 15063120 PMCID: PMC7172780 DOI: 10.1016/j.virol.2004.01.020] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2003] [Revised: 12/08/2003] [Accepted: 01/13/2004] [Indexed: 01/30/2023]
Abstract
Human enteric adenovirus Ad41 is associated with children gastroenteritis. To infect gastrointestinal cells, the invading virus must be acid-stable and resistant to inactivation by bile salts and proteases. In addition, it has to cross the mucus barrier before it infects mucosa cells. We show that Ad41 infectivity is not diminished by acid exposure, a condition limiting the infectivity of the respiratory Ad. This feature can be attributed to a large extent to the global basic charge of enteric Ad virions and to the stability of Ad41 fiber, a viral protein mediating virus attachment. Upon exposure to pH shock, the respiratory Ad2 loses its ability to interact with lipids while enteric Ad41 still binds to the major phospholipids of gastric and intestine mucus. In addition, contrary to respiratory Ad, enteric Ad41 interacts with several sphingolipid components of plasma membranes. These results show that the molecular bases of the Ad41 enteric tropism stem from its particular physicochemical properties.
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Affiliation(s)
| | - Wilhelm P Burmeister
- Virologie Moléculaire et Structurale, UFR de Pharmacie, Université Joseph Fourier, et EMBL, Grenoble, France
| | - Jadwiga Chroboczek
- Institut de Biologie Structurale, 38027 Grenoble Cedex 1, France
- Corresponding author. Institut de Biologie Structurale, 41, rue Jules Horowitz, 38027 Grenoble Cedex 1, France. Fax: +33-4-38-78-54-94.
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Clark HF, Burke CJ, Volkin DB, Offit P, Ward RL, Bresee JS, Dennehy P, Gooch WM, Malacaman E, Matson D, Walter E, Watson B, Krah DL, Dallas MJ, Schödel F, Kaplan KM, Heaton P. Safety, immunogenicity and efficacy in healthy infants of G1 and G2 human reassortant rotavirus vaccine in a new stabilizer/buffer liquid formulation. Pediatr Infect Dis J 2003; 22:914-20. [PMID: 14551493 DOI: 10.1097/01.inf.0000091887.48999.77] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND A refrigerator-stable rotavirus (RV) vaccine that withstands gastric acid is anticipated to permit more widespread use of RV vaccine. OBJECTIVE We investigated for the first time in infants an oral, liquid formulation of G1 and G2 human bovine reassortant rotavirus vaccine (HRRV) with a new stabilizer/buffer (S/B) containing sucrose, sodium phosphate and sodium citrate. METHODS During 1997 through 1998, 731 healthy infants approximately 2 to 4 months of age were enrolled at 19 US sites to receive 3 HRRV or placebo doses approximately 6 to 8 weeks apart in a partially double blinded study. Infants were randomized to: (1) HRRV with no S/B but with prefeeding; (2) HRRV plus 1 of 3 different concentrations/volumes of S/B; or (3) placebo. RESULTS No serious vaccine-related adverse experiences or intussusception cases were reported. No statistically significant differences were observed between vaccine and placebo recipients for fever (> or =38.1 degrees C) 0 to 7 days after any dose, irritability, vomiting or diarrhea incidence 0 to 42 days after any dose. Vaccine virus shedding among vaccine recipients was uncommon. Among S/B vaccine groups, proportions of infants with a > or =3-fold titer rise from baseline to Postdose 3 for G1 serum-neutralizing antibody (SNA), G2 SNA, WC3 SNA, serum anti-RV IgA, serum anti-RV IgG and stool anti-RV IgA were generally similar to those of the prefed non-S/B group. CONCLUSIONS HRRV with a new S/B was generally well-tolerated; immunogenicity was generally similar to the prefed non-S/B group. No intussusception cases were reported, but the small sample size precluded a definitive conclusion. A large international clinical study is under way to address safety and efficacy of an S/B formulation of a pentavalent version of HRRV.
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Affiliation(s)
- H Fred Clark
- University of Pennsylvania School of Medicine, Philadelphia, USA
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28
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Smith JL. The role of gastric acid in preventing foodborne disease and how bacteria overcome acid conditions. J Food Prot 2003; 66:1292-303. [PMID: 12870767 DOI: 10.4315/0362-028x-66.7.1292] [Citation(s) in RCA: 137] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The secretion of hydrochloric acid by the stomach plays an important role in protecting the body against pathogens ingested with food or water. A gastric fluid pH of 1 to 2 is deleterious to many microbial pathogens; however, the neutralization of gastric acid by antacids or the inhibition of acid secretion by various drugs may increase the risk of food- or waterborne illnesses. Peptic ulcer disease is often treated by decreasing or eliminating gastric acid secretion, and such treatment blocks the protective antibacterial action of gastric fluid. The majority of peptic ulcer disease cases originate from Helicobacter pylori infections. Treatment of H. pylori-induced peptic ulcers with antibiotics reduces the need for drugs that inhibit gastric acid secretion and thereby diminishes the risk of food- and waterborne illness for peptic ulcer disease patients. Many bacterial pathogens, such as Escherichia coli, Salmonella Typhimurium, and H. pylori, can circumvent the acid conditions of the stomach by developing adaptive mechanisms that allow these bacteria to survive in acid environments. As a consequence, these bacteria can survive acidic stomach conditions and pass into the intestinal tract, where they can induce gastroenteritis.
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Affiliation(s)
- James L Smith
- U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, 600 East Mermaid Lane, Wyndmoor, Pennsylvania 19038, USA.
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Passaro DJ, Hurwitz A, Triadafilopoulos G, Parsonnet J. A modification of the quininium resin test for assessing gastric acidity. Aliment Pharmacol Ther 2002; 16:875-80. [PMID: 11966494 DOI: 10.1046/j.1365-2036.2002.01258.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/08/2022]
Abstract
BACKGROUND Gastric acid is an important defence against enteric infection. Studies investigating the relationship between hypochlorhydria and enteric infections or gastric malignancy have been limited by difficulties in the non-invasive measurement of gastric acidity. AIM To develop a blood test for hypochlorhydria based on the quininium resin test. METHODS Quininium resin dissociates to liberate free quinine at pH <or= 3.5. Ten fasting adult volunteers ingested 100 mg/kg of quininium resin twice: once before (control) and once after acid suppression with rabeprazole (10 mg b.d. for 3 days). Blood and serum samples were collected at baseline and 45, 60, 75, 90 and 120 min after ingestion. Quinine levels were measured fluorometrically from 100 microL samples after simple extraction. Results obtained by the quininium resin test were compared with gastric juice pH measurements. RESULTS After quininium resin ingestion, mean quinine levels were lower in the acid-suppressed than in the control condition at all times (P < 0.001). Optimized cut-off values at 90 min post-ingestion yielded 95% accuracy rates in both serum and blood. Quininium resin was well tolerated. CONCLUSIONS Using blood or serum, the quininium resin test identifies hypochlorhydria accurately and non-invasively. This test may be useful in screening for gastric atrophy and in studies investigating hypochlorhydria.
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Affiliation(s)
- D J Passaro
- Department of Medicine, Stanford University Medical Center, Stanford, CA, USA.
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Passaro DJ, Taylor DN, Meza R, Cabrera L, Gilman RH, Parsonnet J. Acute Helicobacter pylori infection is followed by an increase in diarrheal disease among Peruvian children. Pediatrics 2001; 108:E87. [PMID: 11694671 DOI: 10.1542/peds.108.5.e87] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Cohort and case-crossover studies were conducted to evaluate whether new Helicobacter pylori infections are followed by increased diarrhea. METHODS Participants were 6-month-old to 12-year-old shantytown residents living near Lima, Peru. Baseline data were collected from community households. Health interviews were completed daily, and sera, drawn every 4 months, were tested for H pylori immunoglobulin G. Diarrhea rates among newly H pylori-infected (seroconverting) children were compared with rates among persistently uninfected and infected children using cohort and case-crossover analyses. RESULTS Sera were obtained from 345 children from January 1, 1995, through September 1, 1997. H pylori incidence was 12% per year (36 H pylori infections in 109 866 seronegative days). In adjusted cohort analyses, seroconverters had more diarrhea days (rate ratio: 2.0; 95% confidence interval: 1.6-2.4), episodes, and sick days in the year after infection than did uninfected children; and more diarrhea days and sick days than did persistently infected children. This effect was strongest in the first 2 months. Case-crossover analyses supported these findings. CONCLUSION Preventing H pylori infection may help reduce pediatric diarrheal disease.
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Affiliation(s)
- D J Passaro
- Division of Infectious Diseases and Geographic Medicine, Stanford University Medical Center, Stanford, California, USA.
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31
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Affiliation(s)
- I J Seymour
- Campden & Chorleywood Food Research Association, Chipping Campden, Gloucestershire, UK
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32
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Ruiz MC, Charpilienne A, Liprandi F, Gajardo R, Michelangeli F, Cohen J. The concentration of Ca2+ that solubilizes outer capsid proteins from rotavirus particles is dependent on the strain. J Virol 1996; 70:4877-83. [PMID: 8763990 PMCID: PMC190437 DOI: 10.1128/jvi.70.8.4877-4883.1996] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
It has been previously shown that rotavirus maturation and stability of the outer capsid are calcium-dependent processes. More recently, it has been hypothesized that penetration of the cell membrane is also affected by conformational changes of the capsid induced by Ca2+. In this study, we determined quantitatively the critical concentration of calcium ion that leads to solubilization of the outer capsid proteins VP4 and VP7. Since this critical concentration is below or close to trace levels of Ca2+, we have used buffered solutions based on ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) and Ca-EGTA. This method allowed us to show a very high variability of the free [Ca2+] needed to stabilize, at room temperature, the outer capsid of several rotavirus strains. This concentration is about 600 nM for the two bovine strains tested (RF and UK), 100 nM for the porcine strain OSU, and only 10 to 20 nM for the simian strain SA11. Titration of viral infectivity after incubation in buffer of defined [Ca2+] confirmed that the loss of infectivity occurs at different [Ca2+] for these three strains. For the bovine strain, the cleavage of VP4 by trypsin has no significant effect on the [Ca2+] that solubilizes outer shell proteins. The outer layer (VP7) of virus-like particles (VLP) made of recombinant proteins VP2, VP6, and VP7 (VLP2/6/7) was also solubilized by lowering the [Ca2+]. The critical concentration of Ca2+ needed to solubilize VP7 from VLP2/6/7 made of protein from the bovine strain is close to the concentration needed for the corresponding virus. Genetic analysis of this phenotype in a set of reassortant viruses from two parental strains having the phenotypes of strains OSU (porcine) and UK (bovine) confirmed that this property of viral particles is probably associated with the gene coding for VP7. The analysis of VLP by reverse genetics might allow the identification of the region(s) essential for calcium binding.
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Affiliation(s)
- M C Ruiz
- Laboratorio de Fisiologia Gastrointestinal, Instituto Venezolano de Investigaciones Cientificas, Caracas, Venezuela
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Abstract
Human rotaviruses, discovered nearly 20 years ago, have been proven to be major cause of paediatric diarrhoeal disease morbidity and mortality. The clinical significance of these viruses stimulated basic studies on their biology, molecular and antigenic properties and epidemiology. General features, clinical relevance, epidemiologic pattern and laboratory diagnosis of human rotavirus infections are here reviewed.
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Affiliation(s)
- G Donelli
- Laboratorio di Ultrastrutture, Istituto Superiore di Sanità, Roma, Italy
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Salim AF, Phillips AD, Farthing MJ. Pathogenesis of gut virus infection. BAILLIERE'S CLINICAL GASTROENTEROLOGY 1990; 4:593-607. [PMID: 1962725 PMCID: PMC7172617 DOI: 10.1016/0950-3528(90)90051-h] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In summary, the pathogenesis of many gut virus infections remains uncertain. However, human and animal studies indicate that the majority of gut viruses infect villous enterocytes. Viruses appear to have different affinities for enterocytes at different sites on the villus. Infection of enterocytes leads to cell death, extrusion into the lumen, and villous atrophy when the rate of cell production in the crypts cannot keep pace with the rate of enterocyte loss. This results in a reduced surface area as well as impairment of digestive and absorptive functions. This may also result in a net secretory state. All these changes, along with others such as reduced enzymatic activity and reduced epithelial integrity, may contribute to the induction of an acute but transient malabsorptive diarrhoea which may persist until the digestive/absorptive functions of the enterocyte are restored. However, if colonic compensation is sufficient to handle the increased fluid load, diarrhoea may not be evident. The roles of villous ischaemia, altered countercurrent exchanger of altered immune responses still remain uncertain and require further investigation.
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Abstract
During the last 15 years, several different groups of fastidious viruses that are responsible for a large proportion of acute viral gastroenteritis cases have been discovered by the electron microscopic examination of stool specimens. This disease is one of the most prevalent and serious clinical syndromes seen around the world, especially in children. Rotaviruses, in the family Reoviridae, and fastidious fecal adenoviruses account for much of the viral gastroenteritis in infants and young children, whereas the small caliciviruses and unclassified astroviruses, and possibly enteric coronaviruses, are responsible for significantly fewer cases overall. In addition to electron microscopy, enzyme immunoassays and other rapid antigen detection systems have been developed to detect rotaviruses and fastidious fecal adenoviruses in the stool specimens of both nonhospitalized patients and those hospitalized for dehydration and electrolyte imbalance. Experimental rotavirus vaccines have also been developed, due to the prevalence and seriousness of rotavirus infection. The small, unclassified Norwalk virus and morphologically similar viruses are responsible for large and small outbreaks of acute gastroenteritis in older children, adolescents, and adults. Hospitalization of older patients infected with these viruses is usually not required, and their laboratory diagnoses have been limited primarily to research laboratories.
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Affiliation(s)
- M L Christensen
- Department of Pathology, Northwestern University Medical School, Chicago, Illinois 60611
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36
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Abstract
We studied the minimal infective dose of the gastroenteritis virus, rotavirus. Increasingly lower doses [10(4), 10(3), 10(1), 1, 10(-2) plaque forming units (PFU)] of the OSU strain of porcine rotavirus were administered to highly susceptible (colostrum deprived, cesarean derived) newborn miniature swine piglets. In vitro studies showed that virus infectivity was inactivated in piglet gastric juice, both by low pH and by pH- and concentration-dependent factor(s). These factors remain unidentified, but to prevent intragastric viral inactivation, sodium bicarbonate was administered prior to oral virus inoculation of piglets with virulent (non-tissue culture passaged) virus. The lowest dose of virus to induce clinical illness or to demonstrate viral replication by recovery of significantly more infectious virus than was administered, or both, was 1 PFU. These results should help establish standards for virus contamination of water and recommendations for evaluating disinfection procedures for rotaviruses.
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