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Platen L, Liao BH, Tellenbach M, Cheng CC, Holzmann-Littig C, Christa C, Dächert C, Kappler V, Bester R, Werz ML, Schönhals E, Platen E, Eggerer P, Tréguer L, Küchle C, Schmaderer C, Heemann U, Keppler OT, Renders L, Braunisch MC, Protzer U. Longitudinal SARS-CoV-2 neutralization of Omicron BA.1, BA.5 and BQ.1.1 after four vaccinations and the impact of breakthrough infections in haemodialysis patients. Clin Kidney J 2023; 16:2447-2460. [PMID: 38046025 PMCID: PMC10689143 DOI: 10.1093/ckj/sfad147] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Indexed: 12/05/2023] Open
Abstract
Background Individuals on haemodialysis (HD) are more vulnerable to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection than the general population due to end-stage kidney disease-induced immunosuppression. Methods A total of 26 HD patients experiencing SARS-CoV-2 infection after a third vaccination were matched 1:1 with 26 of 92 SARS-CoV-2-naïve patients by age, sex, dialysis vintage and immunosuppressive drugs receiving a fourth vaccination with a messenger RNA-based vaccine. A competitive surrogate neutralization assay was used to monitor vaccination success. To determine infection neutralization titres, Vero-E6 cells were infected with SARS-CoV-2 variants of concern (VoCs), Omicron sublineage BA.1, BA.5 and BQ.1.1. The 50% inhibitory concentration (IC50, serum dilution factor 1:x) was determined before, 4 weeks after and 6 months after the fourth vaccination. Results A total of 52 HD patients received four coronavirus disease 2019 (COVID-19) vaccinations and were followed up for a median of 6.3 months. Patient characteristics did not differ between the matched cohorts. Patients without a SARS-CoV-2 infection had a significant reduction of real virus neutralization capacity for all Omicron sublineages after 6 months (P < .001 each). Those patients with a virus infection did not experience a reduction in real virus neutralization capacity after 6 months. Compared with the other Omicron VoC, the BQ.1.1 sublineage had the lowest virus neutralization capacity. Conclusions SARS-CoV-2-naïve HD patients had significantly decreased virus neutralization capacity 6 months after the fourth vaccination, whereas patients with a SARS-CoV-2 infection had no change in neutralization capacity. This was independent of age, sex, dialysis vintage and immunosuppression. Therefore, in infection-naïve HD patients a fifth COVID-19 vaccination might be reasonable 6 months after the fourth vaccination.
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Affiliation(s)
- Louise Platen
- Department of Nephrology, University Hospital rechts der Isar, Technical University of Munich, School of Medicine, Munich, Germany
| | - Bo-Hung Liao
- Institute of Virology, Technical University of Munich, School of Medicine, Munich, Germany
| | - Myriam Tellenbach
- Department of Nephrology, University Hospital rechts der Isar, Technical University of Munich, School of Medicine, Munich, Germany
| | - Cho-Chin Cheng
- Institute of Virology, Technical University of Munich, School of Medicine, Munich, Germany
| | - Christopher Holzmann-Littig
- Institute of Virology, Technical University of Munich, School of Medicine, Munich, Germany
- TUM Medical Education Center, Technical University of Munich, School of Medicine, Munich, Germany
| | - Catharina Christa
- Institute of Virology, Technical University of Munich, School of Medicine, Munich, Germany
| | - Christopher Dächert
- Max von Pettenkofer Institute & Gene Center, Virology, Ludwig Maximilian University of Munich, Munich, Germany
| | - Verena Kappler
- Department of Nephrology, University Hospital rechts der Isar, Technical University of Munich, School of Medicine, Munich, Germany
| | - Romina Bester
- Institute of Virology, Technical University of Munich, School of Medicine, Munich, Germany
| | - Maia Lucia Werz
- Department of Nephrology, University Hospital rechts der Isar, Technical University of Munich, School of Medicine, Munich, Germany
| | - Emely Schönhals
- Department of Nephrology, University Hospital rechts der Isar, Technical University of Munich, School of Medicine, Munich, Germany
| | - Eva Platen
- Kidney Center Eifel Dialyse, Mechernich, Germany
| | - Peter Eggerer
- KfH Kidney Center Harlaching, Munich-Harlaching, Germany
| | - Laëtitia Tréguer
- German Center for Infection Research (DZIF), Partner Site, Munich, Germany
| | - Claudius Küchle
- Department of Nephrology, University Hospital rechts der Isar, Technical University of Munich, School of Medicine, Munich, Germany
| | - Christoph Schmaderer
- Department of Nephrology, University Hospital rechts der Isar, Technical University of Munich, School of Medicine, Munich, Germany
| | - Uwe Heemann
- Department of Nephrology, University Hospital rechts der Isar, Technical University of Munich, School of Medicine, Munich, Germany
- German Center for Infection Research (DZIF), Partner Site, Munich, Germany
| | - Oliver T Keppler
- Max von Pettenkofer Institute & Gene Center, Virology, Ludwig Maximilian University of Munich, Munich, Germany
- German Center for Infection Research (DZIF), Partner Site, Munich, Germany
| | - Lutz Renders
- Department of Nephrology, University Hospital rechts der Isar, Technical University of Munich, School of Medicine, Munich, Germany
- KfH Kidney Center, Traunstein, Germany
| | - Matthias Christoph Braunisch
- Department of Nephrology, University Hospital rechts der Isar, Technical University of Munich, School of Medicine, Munich, Germany
| | - Ulrike Protzer
- Institute of Virology, Technical University of Munich, School of Medicine, Munich, Germany
- German Center for Infection Research (DZIF), Partner Site, Munich, Germany
- Institute of Virology, Helmholtz Munich, Munich, Germany
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Barbey C, Su J, Billmeier M, Stefan N, Bester R, Carnell G, Temperton N, Heeney J, Protzer U, Breunig M, Wagner R, Peterhoff D. Immunogenicity of a silica nanoparticle-based SARS-CoV-2 vaccine in mice. Eur J Pharm Biopharm 2023; 192:41-55. [PMID: 37774890 DOI: 10.1016/j.ejpb.2023.09.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 09/12/2023] [Accepted: 09/26/2023] [Indexed: 10/01/2023]
Abstract
Safe and effective vaccines have been regarded early on as critical in combating the COVID-19 pandemic. Among the deployed vaccine platforms, subunit vaccines have a particularly good safety profile but may suffer from a lower immunogenicity compared to mRNA based or viral vector vaccines. In fact, this phenomenon has also been observed for SARS-CoV-2 subunit vaccines comprising the receptor-binding domain (RBD) of the spike (S) protein. Therefore, RBD-based vaccines have to rely on additional measures to enhance the immune response. It is well accepted that displaying antigens on nanoparticles can improve the quantity and quality of vaccine-mediated both humoral and cell-mediated immune responses. Based on this, we hypothesized that SARS-CoV-2 RBD as immunogen would benefit from being presented to the immune system via silica nanoparticles (SiNPs). Herein we describe the preparation, in vitro characterization, antigenicity and in vivo immunogenicity of SiNPs decorated with properly oriented RBD in mice. We found our RBD-SiNP conjugates show narrow, homogeneous particle distribution with optimal size of about 100 nm for efficient transport to and into the lymph node. The colloidal stability and binding of the antigen was stable for at least 4 months at storage- and in vivo-temperatures. The antigenicity of the RBD was maintained upon binding to the SiNP surface, and the receptor-binding motif was readily accessible due to the spatial orientation of the RBD. The particles were efficiently taken up in vitro by antigen-presenting cells. In a mouse immunization study using an mRNA vaccine and spike protein as benchmarks, we found that the SiNP formulation was able to elicit a stronger RBD-specific humoral response compared to the soluble protein. For the adjuvanted RBD-SiNP we found strong S-specific multifunctional CD4+ T cell responses, a balanced T helper response, improved auto- and heterologous virus neutralization capacity, and increased serum avidity, suggesting increased affinity maturation. In summary, our results provide further evidence for the possibility of optimizing the cellular and humoral immune response through antigen presentation on SiNP.
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Affiliation(s)
- Clara Barbey
- Department of Pharmaceutical Technology, University of Regensburg, Regensburg, Germany
| | - Jinpeng Su
- Institute of Virology, Technical University of Munich / Helmholtz Munich, Munich, Germany
| | - Martina Billmeier
- Institute of Medical Microbiology and Hygiene, University of Regensburg, Regensburg, Germany
| | - Nadine Stefan
- Institute of Medical Microbiology and Hygiene, University of Regensburg, Regensburg, Germany
| | - Romina Bester
- Institute of Virology, Technical University of Munich / Helmholtz Munich, Munich, Germany
| | - George Carnell
- Lab of Viral Zoonotics, Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Nigel Temperton
- Viral Pseudotype Unit, Medway School of Pharmacy, The Universities of Greenwich and Kent at Medway, Chatham ME4 4BF, United Kingdom
| | - Jonathan Heeney
- Lab of Viral Zoonotics, Department of Veterinary Medicine, University of Cambridge, Cambridge, United Kingdom
| | - Ulrike Protzer
- Institute of Virology, Technical University of Munich / Helmholtz Munich, Munich, Germany; German Center for Infection Research (DZIF), Munich Partner Site, Germany
| | - Miriam Breunig
- Department of Pharmaceutical Technology, University of Regensburg, Regensburg, Germany
| | - Ralf Wagner
- Institute of Medical Microbiology and Hygiene, University of Regensburg, Regensburg, Germany; Institute of Clinical Microbiology and Hygiene, University Hospital Regensburg, Regensburg, Germany
| | - David Peterhoff
- Institute of Medical Microbiology and Hygiene, University of Regensburg, Regensburg, Germany; Institute of Clinical Microbiology and Hygiene, University Hospital Regensburg, Regensburg, Germany.
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Nieborak A, Lukauskas S, Capellades J, Heyn P, Santos GS, Motzler K, Zeigerer A, Bester R, Protzer U, Schelter F, Wagner M, Carell T, Hruscha A, Schmid B, Yanes O, Schneider R. Depletion of pyruvate kinase (PK) activity causes glycolytic intermediate imbalances and reveals a PK-TXNIP regulatory axis. Mol Metab 2023:101748. [PMID: 37290673 DOI: 10.1016/j.molmet.2023.101748] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 05/14/2023] [Accepted: 05/31/2023] [Indexed: 06/10/2023] Open
Abstract
OBJECTIVE Cancer cells convert more glucose into lactate than healthy cells, what results in their growth advantage. Pyruvate kinase (PK) is a key rate limiting enzyme in this process, what makes it a promising potential therapeutic target. However, currently it is still unclear what consequences the inhibition of PK has on cellular processes. Here, we systematically investigate the consequences of PK depletion for gene expression, histone modifications and metabolism. METHODS Epigenetic, transcriptional and metabolic targets were analysed in different cellular and animal models with stable knockdown or knockout of PK. RESULTS Depleting PK activity reduces the glycolytic flux and causes accumulation of glucose-6-phosphate (G6P). Such metabolic perturbation results in stimulation of the activity of a heterodimeric pair of transcription factors MondoA and MLX but not in a major reprogramming of the global H3K9ac and H3K4me3 histone modification landscape. The MondoA:MLX heterodimer upregulates expression of thioredoxin-interacting protein (TXNIP) - a tumour suppressor with multifaceted anticancer activity. This effect of TXNIP upregulation extends beyond immortalised cancer cell lines and is applicable to multiple cellular and animal models. CONCLUSIONS Our work shows that actions of often pro-tumorigenic PK and anti-tumorigenic TXNIP are tightly linked via a glycolytic intermediate. We suggest that PK depletion stimulates the activity of MondoA:MLX transcription factor heterodimers and subsequently, increases cellular TXNIP levels. TXNIP-mediated inhibition of thioredoxin (TXN) can reduce the ability of cells to scavenge reactive oxygen species (ROS) leading to the oxidative damage of cellular structures including DNA. These findings highlight an important regulatory axis affecting tumour suppression mechanisms and provide an attractive opportunity for combination cancer therapies targeting glycolytic activity and ROS-generating pathways.
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Affiliation(s)
- Anna Nieborak
- Institute of Functional Epigenetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Saulius Lukauskas
- Institute of Functional Epigenetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Jordi Capellades
- Universitat Rovira i Virgili, Department of Electronic Engineering, IISPV, Tarragona, Spain; CIBER on Diabetes and Associated Metabolic Diseases (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
| | - Patricia Heyn
- Institute of Functional Epigenetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Gabriela Silva Santos
- Institute of Functional Epigenetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany
| | - Karsten Motzler
- Institute for Diabetes and Cancer, Helmholtz Center Munich, 85764 Neuherberg, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany; Joint Heidelberg-IDC Translational Diabetes Program, Inner Medicine 1, Heidelberg University Hospital, Heidelberg, Germany
| | - Anja Zeigerer
- Institute for Diabetes and Cancer, Helmholtz Center Munich, 85764 Neuherberg, Germany; German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany; Joint Heidelberg-IDC Translational Diabetes Program, Inner Medicine 1, Heidelberg University Hospital, Heidelberg, Germany
| | - Romina Bester
- Institute of Virology, Technical University of Munich, School of Medicine / Helmholtz Munich, Trogerstr. 30, 81675 Munich, Germany
| | - Ulrike Protzer
- Institute of Virology, Technical University of Munich, School of Medicine / Helmholtz Munich, Trogerstr. 30, 81675 Munich, Germany
| | - Florian Schelter
- Ludwig-Maximilians-Universität München, Institute for Chemical Epigenetics Munich, Butenandtstr. 5-13, 81377 Munich, Germany
| | - Mirko Wagner
- Ludwig-Maximilians-Universität München, Institute for Chemical Epigenetics Munich, Butenandtstr. 5-13, 81377 Munich, Germany
| | - Thomas Carell
- Ludwig-Maximilians-Universität München, Institute for Chemical Epigenetics Munich, Butenandtstr. 5-13, 81377 Munich, Germany
| | - Alexander Hruscha
- German Center for Neurodegenerative Diseases (DZNE) Munich, 81377 Munich, Germany
| | - Bettina Schmid
- German Center for Neurodegenerative Diseases (DZNE) Munich, 81377 Munich, Germany
| | - Oscar Yanes
- Universitat Rovira i Virgili, Department of Electronic Engineering, IISPV, Tarragona, Spain; CIBER on Diabetes and Associated Metabolic Diseases (CIBERDEM), Instituto de Salud Carlos III, Madrid, Spain
| | - Robert Schneider
- Institute of Functional Epigenetics, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Faculty of Biology, Ludwig-Maximilians-Universität München, 82152 Planegg-Martinsried, Germany.
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Cheng CC, Platen L, Christa C, Tellenbach M, Kappler V, Bester R, Liao BH, Holzmann-Littig C, Werz M, Schönhals E, Platen E, Eggerer P, Tréguer L, Küchle C, Schmaderer C, Heemann U, Renders L, Protzer U, Braunisch MC. Improved SARS-CoV-2 Neutralization of Delta and Omicron BA.1 Variants of Concern after Fourth Vaccination in Hemodialysis Patients. Vaccines (Basel) 2022; 10:vaccines10081328. [PMID: 36016216 PMCID: PMC9415993 DOI: 10.3390/vaccines10081328] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 08/11/2022] [Accepted: 08/13/2022] [Indexed: 12/21/2022] Open
Abstract
Hemodialysis patients are exposed to a markedly increased risk when infected with SARS-CoV-2. To date, it is unclear if hemodialysis patients benefit from four vaccinations. A total of 142 hemodialysis patients received four COVID-19 vaccinations until March 2022. RDB binding antibody titers were determined in a competitive surrogate neutralization assay. Vero-E6 cells were infected with SARS-CoV-2 variants of concern (VoC), Delta (B.1.617.2), or Omicron (B.1.1.529, sub-lineage BA.1) to determine serum infection neutralization capacity. Four weeks after the fourth vaccination, serum infection neutralization capacity significantly increased from a 50% inhibitory concentration (IC50, serum dilution factor 1:x) of 247.0 (46.3−1560.8) to 2560.0 (1174.0−2560.0) for the Delta VoC, and from 37.5 (20.0−198.8) to 668.5 (182.2−2560.0) for the Omicron VoC (each p < 0.001) compared to four months after the third vaccination. A significant increase in the neutralization capacity was even observed for patients with high antibody titers after three vaccinations (p < 0.001). Ten patients with SARS-CoV-2 breakthrough infection after the first blood sampling had by trend lower prior neutralization capacity for Omicron (p = 0.051). Our findings suggest that hemodialysis patients benefit from a fourth vaccination in particular in the light of the highly infectious SARS-CoV-2 Omicron-variants. A routinely applied four-time vaccination seems to broaden immunity against variants and would be recommended in hemodialysis patients.
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Affiliation(s)
- Cho-Chin Cheng
- Institute of Virology, School of Medicine, Technical University of Munich, 81675 Munich, Germany
| | - Louise Platen
- Department of Nephrology, School of Medicine, Technical University of Munich, Klinikum Rechts der Isar, 81675 Munich, Germany
| | - Catharina Christa
- Institute of Virology, School of Medicine, Technical University of Munich, 81675 Munich, Germany
| | - Myriam Tellenbach
- Department of Nephrology, School of Medicine, Technical University of Munich, Klinikum Rechts der Isar, 81675 Munich, Germany
| | - Verena Kappler
- Department of Nephrology, School of Medicine, Technical University of Munich, Klinikum Rechts der Isar, 81675 Munich, Germany
| | - Romina Bester
- Institute of Virology, School of Medicine, Technical University of Munich, 81675 Munich, Germany
| | - Bo-Hung Liao
- Institute of Virology, School of Medicine, Technical University of Munich, 81675 Munich, Germany
| | - Christopher Holzmann-Littig
- Department of Nephrology, School of Medicine, Technical University of Munich, Klinikum Rechts der Isar, 81675 Munich, Germany
- TUM Medical Education Center, School of Medicine, Technical University of Munich, 81675 Munich, Germany
| | - Maia Werz
- Department of Nephrology, School of Medicine, Technical University of Munich, Klinikum Rechts der Isar, 81675 Munich, Germany
| | - Emely Schönhals
- Department of Nephrology, School of Medicine, Technical University of Munich, Klinikum Rechts der Isar, 81675 Munich, Germany
| | - Eva Platen
- Kidney Center Eifel Dialyse, 53894 Mechernich, Germany
| | - Peter Eggerer
- KfH Kidney Center Harlaching, Munich-Harlaching, 81545 Munich, Germany
| | | | - Claudius Küchle
- Department of Nephrology, School of Medicine, Technical University of Munich, Klinikum Rechts der Isar, 81675 Munich, Germany
| | - Christoph Schmaderer
- Department of Nephrology, School of Medicine, Technical University of Munich, Klinikum Rechts der Isar, 81675 Munich, Germany
| | - Uwe Heemann
- Department of Nephrology, School of Medicine, Technical University of Munich, Klinikum Rechts der Isar, 81675 Munich, Germany
| | - Lutz Renders
- Department of Nephrology, School of Medicine, Technical University of Munich, Klinikum Rechts der Isar, 81675 Munich, Germany
- German Center for Infection Research (DZIF), Partner Site, 81675 Munich, Germany
| | - Ulrike Protzer
- Institute of Virology, School of Medicine, Technical University of Munich, 81675 Munich, Germany
- German Center for Infection Research (DZIF), Partner Site, 81675 Munich, Germany
- Institute of Virology, Helmholtz Munich, 85764 Munich, Germany
- Correspondence: (U.P.); (M.C.B.); Tel.: +0049-(0)-89-4140-6863 (U.P.); +0049-(0)-89-4140-2231 (M.C.B.); Fax: +0049-(0)-89-4140-6823 (U.P.); +0049-(0)-89-4140-7734 (M.C.B.)
| | - Matthias Christoph Braunisch
- Department of Nephrology, School of Medicine, Technical University of Munich, Klinikum Rechts der Isar, 81675 Munich, Germany
- Correspondence: (U.P.); (M.C.B.); Tel.: +0049-(0)-89-4140-6863 (U.P.); +0049-(0)-89-4140-2231 (M.C.B.); Fax: +0049-(0)-89-4140-6823 (U.P.); +0049-(0)-89-4140-7734 (M.C.B.)
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Bougard K, Maree HJ, Pietersen G, Meitz-Hopkins J, Bester R. First Report of Apple rubodvirus 2 Infecting Pear ( Pyrus communis) in South Africa. Plant Dis 2022; 106:1535. [PMID: 34649463 DOI: 10.1094/pdis-08-21-1631-pdn] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Affiliation(s)
- K Bougard
- Department of Genetics, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - H J Maree
- Department of Genetics, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
- Citrus Research International, P.O. Box 2201, Matieland, 7602, South Africa
| | - G Pietersen
- Department of Genetics, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - J Meitz-Hopkins
- Department of Plant Pathology, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - R Bester
- Department of Genetics, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
- Citrus Research International, P.O. Box 2201, Matieland, 7602, South Africa
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Bougard K, Maree HJ, Pietersen G, Meitz-Hopkins J, Bester R. First Report of Coguvirus eburi Infecting Pear ( Pyrus communis) in South Africa. Plant Dis 2022; 106:PDIS08211630PDN. [PMID: 34455805 DOI: 10.1094/pdis-08-21-1630-pdn] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Affiliation(s)
- K Bougard
- Department of Genetics, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - H J Maree
- Department of Genetics, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
- Citrus Research International, PO Box 2201, Matieland, 7602, South Africa
| | - G Pietersen
- Department of Genetics, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - J Meitz-Hopkins
- Department of Plant Pathology, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - R Bester
- Department of Genetics, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
- Citrus Research International, PO Box 2201, Matieland, 7602, South Africa
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Ko C, Su J, Festag J, Bester R, Kosinska AD, Protzer U. Intramolecular recombination enables the formation of hepatitis B virus (HBV) cccDNA in mice after HBV genome transfer using recombinant AAV vectors. Antiviral Res 2021; 194:105140. [PMID: 34284057 DOI: 10.1016/j.antiviral.2021.105140] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 07/09/2021] [Accepted: 07/12/2021] [Indexed: 01/11/2023]
Abstract
The mouse is not a natural host of hepatitis B virus (HBV) infection and - despite engraftment of hepatocytes with the HBV receptor - does not support formation of HBV covalently closed circular (ccc) DNA serving as a template for viral transcription and permitting persistent infection. In a recent study, cccDNA formation in mouse hepatocytes has been described following an HBV genome delivery by a recombinant, adeno-associated virus vector (rAAV) (Lucifora et al., 2017). The integrity of HBV cccDNA, its origin and functionality, however, remained open. In this study, we investigated the identity, origin, and functionality of cccDNA established in mice infected with rAAV carrying 1.3-fold overlength HBV genomes. We show that replication of HBV genotypes A, B, C and D can be initiated in mouse livers, and that cccDNA derived from all genotypes is detected. Restriction enzyme and exonuclease digestion as well as sequencing analysis of cccDNA amplicons revealed authentic HBV cccDNA without any detectable alteration compared to cccDNA established after HBV infection of human liver cells. Mouse livers transduced with a core protein-deficient HBV using rAAV still supported cccDNA formation demonstrating that the genesis of cccDNA was independent of HBV replication. When mice were infected with an rAAV-HBV1.3 carrying premature stop codons in the 5' but not in the 3' core protein open reading frame, the stop codon was partially replaced by the wild-type sequence. This strongly indicated that intramolecular recombination, based on >900 identical base pairs residing at the both ends of the HBV1.3 transgene was the origin of cccDNA formation. Accordingly, we observed a constant loss of cccDNA molecules from mouse livers over time, while HBeAg levels increased over the first two weeks after rAAV-HBV1.3 infection and remained constant thereafter, suggesting a minor contribution of the cccDNA molecules formed to viral transcription and protein expression. In summary, our results provide strong evidence that intramolecular recombination of an overlength, linear HBV genome, but not HBV genome recycling, enables cccDNA formation in rAAV-HBV mouse models.
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Affiliation(s)
- Chunkyu Ko
- Institute of Virology, Technical University of Munich/Helmholtz Zentrum München, Munich, Germany; Infectious Diseases Therapeutic Research Center, Therapeutics & Biotechnology Division, Korea Research Institute of Chemical Technology, Daejeon, Republic of Korea
| | - Jinpeng Su
- Institute of Virology, Technical University of Munich/Helmholtz Zentrum München, Munich, Germany
| | - Julia Festag
- Institute of Virology, Technical University of Munich/Helmholtz Zentrum München, Munich, Germany
| | - Romina Bester
- Institute of Virology, Technical University of Munich/Helmholtz Zentrum München, Munich, Germany
| | - Anna D Kosinska
- Institute of Virology, Technical University of Munich/Helmholtz Zentrum München, Munich, Germany; German Center for Infection Research (DZIF), Munich partner site, Munich, Germany
| | - Ulrike Protzer
- Institute of Virology, Technical University of Munich/Helmholtz Zentrum München, Munich, Germany; German Center for Infection Research (DZIF), Munich partner site, Munich, Germany.
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8
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Stadler D, Kächele M, Jones AN, Hess J, Urban C, Schneider J, Xia Y, Oswald A, Nebioglu F, Bester R, Lasitschka F, Ringelhan M, Ko C, Chou W, Geerlof A, van de Klundert MA, Wettengel JM, Schirmacher P, Heikenwälder M, Schreiner S, Bartenschlager R, Pichlmair A, Sattler M, Unger K, Protzer U. Interferon-induced degradation of the persistent hepatitis B virus cccDNA form depends on ISG20. EMBO Rep 2021; 22:e49568. [PMID: 33969602 PMCID: PMC8183418 DOI: 10.15252/embr.201949568] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 03/18/2021] [Accepted: 03/23/2021] [Indexed: 12/16/2022] Open
Abstract
Hepatitis B virus (HBV) persists by depositing a covalently closed circular DNA (cccDNA) in the nucleus of infected cells that cannot be targeted by available antivirals. Interferons can diminish HBV cccDNA via APOBEC3-mediated deamination. Here, we show that overexpression of APOBEC3A alone is not sufficient to reduce HBV cccDNA that requires additional treatment of cells with interferon indicating involvement of an interferon-stimulated gene (ISG) in cccDNA degradation. Transcriptome analyses identify ISG20 as the only type I and II interferon-induced, nuclear protein with annotated nuclease activity. ISG20 localizes to nucleoli of interferon-stimulated hepatocytes and is enriched on deoxyuridine-containing single-stranded DNA that mimics transcriptionally active, APOBEC3A-deaminated HBV DNA. ISG20 expression is detected in human livers in acute, self-limiting but not in chronic hepatitis B. ISG20 depletion mitigates the interferon-induced loss of cccDNA, and co-expression with APOBEC3A is sufficient to diminish cccDNA. In conclusion, non-cytolytic HBV cccDNA decline requires the concerted action of a deaminase and a nuclease. Our findings highlight that ISGs may cooperate in their antiviral activity that may be explored for therapeutic targeting.
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9
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Mostert I, Bester R, Aldrich D, Visser M, Gazendam I, Cloete M, Maree HJ, Burger JT. Complete genome sequence of ornithogalum virus 3. Arch Virol 2021; 166:1213-1216. [PMID: 33502594 DOI: 10.1007/s00705-021-04965-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Accepted: 12/03/2020] [Indexed: 11/26/2022]
Abstract
Ornithogalum thyrsoides, a widely cultivated bulbous ornamental plant endemic to South Africa, has significant commercial value as a pot plant and for the production of cut flowers. However, infection by viruses threatens the success of commercial cultivation, as symptoms negatively affect the appearance of the plant and flowers. To date, four Ornithogalum-infecting viruses have been reported. Complete genome sequence data are available for three of these viruses, but the genome of the potyvirus ornithogalum virus 3 (OV3) has not been fully sequenced. In this study, the complete sequence of OV3 was determined by high-throughput sequencing (HTS) and validated by Sanger sequencing. Based on recognition of protease cleavage patterns and multiple sequence alignments with closely related viruses, the polyprotein of OV3 was predicted to be proteolytically cleaved to produce 10 mature peptides containing domains conserved in members of the genus Potyvirus. Phylogenetic analysis and species demarcation criteria confirm the previous classification of OV3 as a member of a separate species in this genus. This is the first report of a complete genome sequence of OV3.
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Affiliation(s)
- I Mostert
- Department of Genetics, Stellenbosch University, Stellenbosch, South Africa
| | - R Bester
- Department of Genetics, Stellenbosch University, Stellenbosch, South Africa
| | - D Aldrich
- Department of Genetics, Stellenbosch University, Stellenbosch, South Africa
| | - M Visser
- Department of Genetics, Stellenbosch University, Stellenbosch, South Africa
| | - I Gazendam
- Agricultural Research Council-Roodeplaat Vegetable and Ornamental Plants, Pretoria, South Africa
| | - M Cloete
- Agricultural Research Council-Roodeplaat Vegetable and Ornamental Plants, Pretoria, South Africa
| | - H J Maree
- Department of Genetics, Stellenbosch University, Stellenbosch, South Africa.
- Citrus Research International, Stellenbosch, South Africa.
| | - J T Burger
- Department of Genetics, Stellenbosch University, Stellenbosch, South Africa
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10
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von Olshausen G, Quasdorff M, Bester R, Arzberger S, Ko C, van de Klundert M, Zhang K, Odenthal M, Ringelhan M, Niessen CM, Protzer U. Hepatitis B virus promotes β-catenin-signalling and disassembly of adherens junctions in a Src kinase dependent fashion. Oncotarget 2018; 9:33947-33960. [PMID: 30338037 PMCID: PMC6188061 DOI: 10.18632/oncotarget.26103] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Accepted: 08/27/2018] [Indexed: 12/31/2022] Open
Abstract
Hepatitis B virus (HBV) infection is a prominent cause of hepatocellular carcinoma (HCC) but the underlying molecular mechanisms are complex and multiple pathways have been proposed such as the activation of the Wnt-/β-catenin-signalling and dysregulation of E-cadherin/β-catenin adherens junctions. This study aimed to identify mechanisms of how HBV infection and replication as well as HBV X protein (HBx) gene expression in the context of an HBV genome influence Wnt-/β-catenin-signalling and formation of adherens junctions and to which extent HBx contributes to this. Regulation of E-cadherin/β-catenin junctions and β-catenin-signalling as well as the role of HBx were investigated using constructs transiently or stably inducing replication of HBV+/-HBx in hepatoma cell lines. In addition, HCC and adjacent non-tumorous tissue samples from HBV-infected HCC patients and drug interference in HBV-infected cells were studied. Although HBV did not alter overall expression levels of E-cadherin or β-catenin, it diminished their cell surface localization resulting in nuclear translocation of β-catenin and activation of its target genes. In addition, HBV gene expression increased the amount of phosphorylated c-Src kinase. Treatment with Src kinase inhibitor Dasatinib reduced HBV replication, prevented adherens junction disassembly and reduced β-catenin-signalling, while Sorafenib only did so in cells with mutated β-catenin. Interestingly, none of the HBV induced alterations required HBx. Thus, HBV stimulated β-catenin-signalling and induced disassembly of adherens junctions independently of HBx through Src kinase activation. These pathways may contribute to hepatocellular carcinogenesis and seem to be more efficiently inhibited by Dasatinib than by Sorafenib.
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Affiliation(s)
- Gesa von Olshausen
- Department of Internal Medicine I, University Hospital rechts der Isar, Technical University of Munich, Munich, Germany
| | - Maria Quasdorff
- Molecular Infectiology, Institute for Medical Micro biology, Immunology and Hygiene, University Hospital Cologne, Cologne, Germany.,Department of Gastroenterology and Hepatology, University Hospital Cologne, Cologne, Germany
| | - Romina Bester
- Institute of Virology, Technical University of Munich/Helmholtz Zentrum München, Munich, Germany
| | - Silke Arzberger
- Molecular Infectiology, Institute for Medical Micro biology, Immunology and Hygiene, University Hospital Cologne, Cologne, Germany.,Institute of Virology, Technical University of Munich/Helmholtz Zentrum München, Munich, Germany
| | - Chunkyu Ko
- Institute of Virology, Technical University of Munich/Helmholtz Zentrum München, Munich, Germany
| | - Maarten van de Klundert
- Institute of Virology, Technical University of Munich/Helmholtz Zentrum München, Munich, Germany
| | - Ke Zhang
- Institute of Virology, Technical University of Munich/Helmholtz Zentrum München, Munich, Germany
| | - Margarete Odenthal
- Institute of Pathology, University Hospital Cologne, Cologne, Germany.,Center for Molecular Medicine (CMMC), University of Cologne, Cologne, Germany
| | - Marc Ringelhan
- Institute of Virology, Technical University of Munich/Helmholtz Zentrum München, Munich, Germany.,Department of Internal Medicine II, University Hospital rechts der Isar, Technical University of Munich, Munich, Germany
| | - Carien M Niessen
- Center for Molecular Medicine (CMMC), University of Cologne, Cologne, Germany.,Department of Dermatology, University Hospital of Cologne, Cologne, Germany.,Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Ulrike Protzer
- Institute of Virology, Technical University of Munich/Helmholtz Zentrum München, Munich, Germany.,German Center for Infection Research (DZIF), Munich Partner Site, Munich, Germany
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11
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Fehlinger A, Wolf H, Hossinger A, Duernberger Y, Pleschka C, Riemschoss K, Liu S, Bester R, Paulsen L, Priola SA, Groschup MH, Schätzl HM, Vorberg IM. Prion strains depend on different endocytic routes for productive infection. Sci Rep 2017; 7:6923. [PMID: 28761068 PMCID: PMC5537368 DOI: 10.1038/s41598-017-07260-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Accepted: 06/27/2017] [Indexed: 01/08/2023] Open
Abstract
Prions are unconventional agents composed of misfolded prion protein that cause fatal neurodegenerative diseases in mammals. Prion strains induce specific neuropathological changes in selected brain areas. The mechanism of strain-specific cell tropism is unknown. We hypothesised that prion strains rely on different endocytic routes to invade and replicate within their target cells. Using prion permissive cells, we determined how impairment of endocytosis affects productive infection by prion strains 22L and RML. We demonstrate that early and late stages of prion infection are differentially sensitive to perturbation of clathrin- and caveolin-mediated endocytosis. Manipulation of canonical endocytic pathways only slightly influenced prion uptake. However, blocking the same routes had drastic strain-specific consequences on the establishment of infection. Our data argue that prion strains use different endocytic pathways for infection and suggest that cell type-dependent differences in prion uptake could contribute to host cell tropism.
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Affiliation(s)
- Andrea Fehlinger
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Sigmund-Freud-Strasse 27, 53127, Bonn, Germany
| | - Hanna Wolf
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Sigmund-Freud-Strasse 27, 53127, Bonn, Germany
| | - André Hossinger
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Sigmund-Freud-Strasse 27, 53127, Bonn, Germany
| | - Yvonne Duernberger
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Sigmund-Freud-Strasse 27, 53127, Bonn, Germany
| | - Catharina Pleschka
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Sigmund-Freud-Strasse 27, 53127, Bonn, Germany
| | - Katrin Riemschoss
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Sigmund-Freud-Strasse 27, 53127, Bonn, Germany
| | - Shu Liu
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Sigmund-Freud-Strasse 27, 53127, Bonn, Germany
| | - Romina Bester
- Institut für Virologie, Technische Universität München, Trogerstr. 30, 81675, München, Germany
| | - Lydia Paulsen
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Sigmund-Freud-Strasse 27, 53127, Bonn, Germany
| | - Suzette A Priola
- Laboratory of Persistent Viral Diseases, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, 903 South 4th Street, Hamilton, MT, 59840, USA
| | - Martin H Groschup
- Friedrich-Loeffler-Institut, Institute of Novel and Emerging Infectious Diseases, 17493, Greifswald-Insel Riems, Germany
| | - Hermann M Schätzl
- Dept. of Comparative Biology & Experimental Medicine, University of Calgary, Calgary, AB T2N 4Z6, Canada
| | - Ina M Vorberg
- Deutsches Zentrum für Neurodegenerative Erkrankungen e.V., Sigmund-Freud-Strasse 27, 53127, Bonn, Germany. .,Department of Neurology, Rheinische Friedrich-Wilhelms-Universität, 53127, Bonn, Germany.
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12
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Bester R, Pepler PT, Burger JT, Maree HJ. Relative quantitation goes viral: An RT-qPCR assay for a grapevine virus. J Virol Methods 2014; 210:67-75. [PMID: 25286180 DOI: 10.1016/j.jviromet.2014.09.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Revised: 09/16/2014] [Accepted: 09/24/2014] [Indexed: 10/24/2022]
Abstract
Accurate detection and quantitation of viruses can be beneficial to plant-virus interaction studies. In this study, three SYBR green real-time RT-PCR assays were developed to quantitate grapevine leafroll-associated virus 3 (GLRaV-3) in infected vines. Three genomic regions (ORF1a, coat protein and 3'UTR) were targeted to quantitate GLRaV-3 relative to three stably expressed reference genes (actin, GAPDH and α-tubulin). These assays were able to detect all known variant groups of GLRaV-3, including the divergent group VI, with equal efficiency. No link could be established between the concentration ratios of the different genomic regions and subgenomic RNA (sgRNA) expression. However, a significant lower virus concentration ratio for plants infected with variant group VI compared to variant group II was observed for the ORF1a, coat protein and the 3'UTR. Significant higher accumulation of the virus in the growth tip was also detected for both variant groups. The quantitation of viral genomic regions under different conditions can contribute to elucidating disease aetiology and enhance knowledge about virus ecology.
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Affiliation(s)
- R Bester
- Department of Genetics, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa
| | - P T Pepler
- Department of Genetics, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa
| | - J T Burger
- Department of Genetics, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa
| | - H J Maree
- Department of Genetics, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa; ARC Infruitec-Nietvoorbij (The Fruit, Vine and Wine Institute of the Agricultural Research Council), Private Bag X5026, Stellenbosch 7599, South Africa.
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13
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Hafner-Bratkovic I, Bester R, Pristovsek P, Gaedtke L, Veranic P, Gaspersic J, Mancek-Keber M, Avbelj M, Polymenidou M, Julius C, Aguzzi A, Vorberg I, Jerala R. Globular domain of the prion protein needs to be unlocked by domain swapping to support prion protein conversion. J Biol Chem 2011; 286:12149-56. [PMID: 21324909 DOI: 10.1074/jbc.m110.213926] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Prion diseases are fatal transmissible neurodegenerative diseases affecting many mammalian species. The normal prion protein (PrP) converts into a pathological aggregated form, PrPSc, which is enriched in the β-sheet structure. Although the high resolution structure of the normal PrP was determined, the structure of the converted form of PrP remains inaccessible to high resolution techniques. To map the PrP conversion process we introduced disulfide bridges into different positions within the globular domain of PrP, tethering selected secondary structure elements. The majority of tethered PrP mutants exhibited increased thermodynamic stability, nevertheless, they converted efficiently. Only the disulfides that tether subdomain B1-H1-B2 to subdomain H2-H3 prevented PrP conversion in vitro and in prion-infected cell cultures. Reduction of disulfides recovered the ability of these mutants to convert, demonstrating that the separation of subdomains is an essential step in conversion. Formation of disulfide-linked proteinase K-resistant dimers in fibrils composed of a pair of single cysteine mutants supports the model based on domain-swapped dimers as the building blocks of prion fibrils. In contrast to previously proposed structural models of PrPSc suggesting conversion of large secondary structural segments, we provide evidence for the conservation of secondary structural elements of the globular domain upon PrP conversion. Previous studies already showed that dimerization is the rate-limiting step in PrP conversion. We show that separation and swapping of subdomains of the globular domain is necessary for conversion. Therefore, we propose that the domain-swapped dimer of PrP precedes amyloid formation and represents a potential target for therapeutic intervention.
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Affiliation(s)
- Iva Hafner-Bratkovic
- Department of Biotechnology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia
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14
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Le Roux FH, Bouic PJD, Bester R. The effect of choral music on emotions, immune parameters and lung function during physiotherapy treatment of pneumonia and bronchitis. South African Journal of Physiotherapy 2007. [DOI: 10.4102/sajp.v63i2.131] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Introduction: Music, processed by the brain, has a strong impacton the emotions and health. The Magnificat in D major of JS Bach communicates not only a positive emotion of happiness but also motivational behaviour. Infectious lung conditions are often associated with negative emotions which develop due to physiological changes. The hormonal action of the hypothalamuspituitary-adrenal axes (HPA) could be negatively affected by emotions of anger and depression. This will result in a disturbance of the mind-body inter-action. Music therefore can exert a powerful influence on therapeutic benefits by changing the psychological status and the immune endocrine functions. The purpose of this study was to determine the effect of music, during respiratory physiotherapy treatment on a) theemotional status, b) neuroendocrine responses, c) immune functions and d) lung functions of subjects with infected lung conditions.Method and Materials: Forty subjects attending physiotherapy treatment was selected according to set criteria and randomly assigned to an experimental and control group. The parameters (Profile Of Mood State [POMS]; CD4:CD8 cell ratios; Cortisol; the Cortisol: DHEA ratio; PF; FEV1; FVC and FEV1/FVC %) were measured on day 1before the treatment and on day 3 after the treatment. Data were analysed with Statistica (Statsoft) using the RepeatedANOVA tests. Results: Results indicated that the intervention of music had a positive effect on the immunological parameter (CD4+:CD8+ cell ratios) and on the cortisol and cortisol:DHEA ratio levels. At the same time the psychological status as measured by Profile of Mood States (POMS scale) improved with a significant improvement in the lung functions.Conclusion: The research provided sufficient scientific evidence that music affects both the biomedical and psycho-somatic aspects of infectious lung conditions.
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Abstract
Illegal dumping of contaminated medical waste occurs commonly in South Africa. There is little information on the management and outcome of the children exposed to and injured by medical waste. On 15 September 1999, 54 children where involved in a mass exposure incident. 44 presented the same evening and 10 following day. Used needles and syringes were discarded on their soccer field. Children gave one another injections and played darts with the discarded needles. Parents were counselled and blood was drawn for HIV and Hepatitis B virus (HBV) serology. All were given HBV vaccination (HBVV). Stat doses of zidovudine (ZDV) and lamivudine (LMV) were given to all with visible wounds or history of percutaneous injury. Younger children were given prophylaxis as we considered their histories unreliable. Further visits were conducted at the community clinic for patient convenience. Children were reviewed at weeks 1 and 3 for drug adherence and side effects. At week 4, the second HBVV was given. At 3 months and 6 months HIV and HBV serology were repeated. 18/44 (40 per cent) had entry wounds. 44/54 (81 per cent) were given antiretroviral treatment (ART). Initial screening for HIV was negative in all, 6 had antibodies to HBV surface antigen, and 2 were HBV surface antigen positive. At week 1 all patients on ART were seen but at week 3 only 30 (55 per cent) attended. 41 (75 per cent) attended at 4 weeks, 8 non-attendees being located by primary healthcare workers. At 3 months, none of the 35 (64 per cent) children had seroconverted for either virus. 44 (81 per cent) attended at 6 months and all serology was negative. All were also Hepatitis C negative. The exposure incident sensitized the community to HIV. Follow up of patients after mass exposure is difficult and time-consuming. Adherence to ART was poor and should be carefully monitored. ZDV was probably adequate for this incident. In a non-mobile community a 3 month visit unnecessary.
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Affiliation(s)
- N de Waal
- Department of Paediatrics and Child Health and Medical Virology, Tygerberg Children's Hospital, Tygerberg, South Africa
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16
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Du Plessis KR, Botha A, Joubert L, Bester R, Conradie WJ, Wolfaardt GM. Response of the microbial community to copper oxychloride in acidic sandy loam soil. J Appl Microbiol 2005; 98:901-9. [PMID: 15752337 DOI: 10.1111/j.1365-2672.2004.02537.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
AIMS Determining the response of different microbial parameters to copper oxychloride in acidic sandy loam soil samples using cultivation-dependent and direct microscopic techniques. METHODS AND RESULTS Culturable microbial populations were monitored for 245 days in a series of soil microcosms spiked with different copper oxychloride concentrations. Microbial populations responded differently to additional Cu. Protistan numbers and soil metabolic potential decreased. Experiments with more soil samples revealed that metabolic potential was not significantly affected by < or =100 mg kg(-1) additional Cu. However, a negative impact on protista was noted in soil containing only 15 mg kg(-1) EDTA-extractable Cu. The negative impact on protistan numbers was less severe in soils with a higher phosphorous and zinc content. CONCLUSIONS Bacterial populations responded differently, and protista were most sensitive to elevated Cu levels. Protistan numbers in soil from uncultivated land were higher and seemed to be more sensitive to additional Cu than the numbers of these organisms in soil originating from cultivated land. SIGNIFICANCE AND IMPACT OF THE STUDY Protistan sensitivity to small increases in Cu levels demonstrates the vulnerability of the soil ecosystem to Cu perturbations, especially when the importance of protista as link in the flow of energy between trophic levels is considered.
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Affiliation(s)
- K R Du Plessis
- Department of Microbiology, University of Stellenbosch, Matieland, Stellenbosch, 7602 South Africa
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17
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Abstract
We prospectively studied South African children with cancer for viral isolates during episodes of febrile neutropaenia. Viruses were found in seven (31.8 per cent) and bacteria in five (22.7 per cent) of 22 episodes. The most common isolate was the herpes simplex virus and the most common source was from nasopharyngeal aspirates. There was no dual detection of viral and bacterial isolates. This study emphasizes the important contribution of viruses to febrile neutropaenia.
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Affiliation(s)
- R Uys
- Department of Paediatrics and Child Health, University of Stellenbosch, Tygerberg, South Africa
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18
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Abstract
In this study, the mechanism of ischaemia-induced increased sarcolemmal permeability, as manifested by release of intracellular enzymes, was investigated. The role of changes in the sarcolemmal phospholipid bilayer in this process was evaluated by experimental modulation of the phospholipid fatty acid composition. The isolated perfused rat heart subjected to low-flow hypoxia, was used as a model of global ischaemia. Glucose as well as saturated (palmitate) and unsaturated (linoleate) long-chain fatty acids were used as substrates. Hearts perfused with palmitate or linoleate (1.5 mM, fatty acid/albumin ratio, 3.4) showed a significantly higher rate of lactate dehydrogenase release in both control and ischaemic conditions than hearts perfused with glucose (10 mM). Lactate dehydrogenase release in the fatty acid-perfused hearts was associated with a significant increase in the percentage unsaturation of the sarcolemmal phospholipid fatty acids. Glucose-perfused hearts, on the other hand, showed only minor changes in the sarcolemmal phospholipid fatty acid composition. Attempts to correlate enzyme release directly with an increase in the percentage unsaturation of phospholipid fatty acids failed, since enzyme release was also stimulated in control fatty-acid-perfused hearts which (when compared with glucose) contained a higher percentage saturated phospholipid fatty acids. The results suggest that myocardial ischaemia, apart from changes in the sarcolemmal phospholipid fatty acid composition, also induces several other changes in sarcolemmal composition (e.g., cholesterol loss) which may affect is permeability for macromolecules.
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Affiliation(s)
- R Bester
- Department of Medical Physiology and Biochemistry, University of Stellenbosch Medical School, Tygerberg (Republic of South Africa)
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Swart P, Swart AC, Meyer PC, Bester R, van der Merwe KJ. A novel method for the preparation of substrate-free cytochrome P-450(11) beta. Prep Biochem 1985; 15:281-90. [PMID: 2422643 DOI: 10.1080/00327488508062446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A new method for the removal of the stabilizing substrate, deoxycorticosterone, from adrenal cytochrome P-450(11) beta, has been developed. Dextran coated charcoal is used for the adsorption of the steroid and the adsorbed steroid is separated from the cytochrome P-450-preparation by low speed centrifugation. The substrate-free enzyme, obtained in this manner, has all the characteristic spectral properties of low-spin cytochrome P-450(11) beta and may be converted to the high-spin form by the addition of deoxycorticosterone. The dextran coated charcoal method has the following advantages over the previously used method of substrate removal. It does not require the addition of the cofactors for cytochrome P-450-dependant hydroxylation of deoxycorticosterone, small amounts of enzyme may be prepared in a short time and the enzyme preparation is not diluted to any great extent during the process.
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20
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Plit M, Lipman J, Roos CP, Clausen L, Decker GA, Josselsohn E, Katz T, Bester R. The principles, structure and function of the J.G. Strijdom Hospital pre-operative assessment clinic. S AFR J SURG 1984; 22:203-9. [PMID: 6495076] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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21
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Retief AE, Bernstein R, Grace HJ, Nelson MM, Jansen S, Benjamin M, Bester R. A 3-year cytogenetic survey of 9 661 patients in South Africa. S Afr Med J 1983; 63:48-53. [PMID: 6849163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
During the period 1 January 1977 - 31 December 1979, 9 661 patients underwent cytogenetic investigation at seven participating laboratories in South Africa. The chromosome data were coded using a standard protocol and the results tabulated, being listed according to the clinical signs which led to referral for investigation. Cytogenetic investigation was most commonly requested for prenatal studies, and 22% of the group's effort was directed towards this. One in 27 amniotic cell specimens was reported to have shown anomalous chromosomes, trisomy 21 being the most frequent abnormality. The majority of postnatal investigations were requested because congenital abnormalities suggested an underlying chromosomal defect. In 42,3% of 2 420 patients a chromosome defect was confirmed. Results of chromosome studies are tabulated by indication for referral and the findings summarized. This collaborative study gives an indication of the nature and frequency of chromosome disorders in South Africa.
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22
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Beech J, Dubielzig R, Bester R. Portal vein anomaly and hepatic encephalopathy in a horse. J Am Vet Med Assoc 1977; 170:164-6. [PMID: 833038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Periodic episodes of diffuse central nervous system disease occurred in a yearling Thoroughbred gelding that had a history of frequent respiratory tract disease and stunted growth. Hepatic encephalopathy was diagnosed on the basis of history, clinical signs, prolonged bromsulphalein clearance, and increased blood ammonia content. Because of the poor prognosis and recurrent clinical signs the horse was euthanatized. Necropsy revealed an arteriovenous anomaly and thrombosis of the portal vein. Histologically, there was diffuse primary astrocytosis of the brain.
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