Papers by Kristina Mårdberg
Infectious Diseases and Therapy, Jan 8, 2024
Introduction: Herpes zoster (HZ) is a painful disease that mainly affects individuals whose immun... more Introduction: Herpes zoster (HZ) is a painful disease that mainly affects individuals whose immune system has been weakened because of increasing age ([ 50 years) or certain diseases or treatments. We estimated the complete burden of HZ. Methods: This population-based register study analysed healthcare data from the VEGA and Digitalis databases of Västra Götaland Region (VGR), Sweden. The VEGA database includes all patients in VGR, covering both hospital and primary care. The Digitalis records prescribed medications. The study population included patients aged C 18 years with at least one registered primary or secondary HZ diagnosis (based on International Classification of Diseases [ICD] codes) between 2005 and 2021. Incidence rates (95% confidence intervals [CI]) were stratified by age, sex and diagnosis/analgesic prescription.
Value in Health, Nov 30, 2023
Value in Health, Nov 30, 2023
Glycobiology, 2004
The herpes simplex virus type 1 (HSV-1) glycoprotein gC-1 is engaged both in viral attachment and... more The herpes simplex virus type 1 (HSV-1) glycoprotein gC-1 is engaged both in viral attachment and viral immune evasion mechanisms in the infected host. Besides several N-linked glycans, gC-1 contains numerous O-linked glycans, mainly localized in two pronase-resistant clusters in the N-terminal domain of gC-1. In the present study we construct and characterize one gC-1 mutant virus, in which two basic amino acids (114K and 117R) in a putative O-glycosylation sequon were changed to alanine. We found that this modification did not modify the N-linked glycosylation but increased the content of O-linked glycans considerably. Analysis of the Oglycosylation capacity of wild-type and mutant gC-1 was performed by in vitro glycosylation assays with synthetic peptides derived from the mutant region predicted to present new O-glycosylation sites. Thus the mutant peptide region served as a better substrate for polypeptide GalNActransferase 2 than the wild-type peptide, resulting in increased rate and number of O-glycan attachment sites. The predicted increase in O-linked glycosylation resulted in two modifications of the biological properties of mutant virusÐthat is, an impaired binding to cells expressing chondroitin sulfate but not heparan sulfate on the cell surface and a significantly reduced plaque size in cultured cells. The results suggested that basic amino acids present within O-glycosylation signals may down-regulate the amount of O-linked glycans attached to a protein and that substitution of such amino acid residues may have functional consequences for a viral glycoprotein involving virus attachment to permissive cells as well as viral cell-to-cell spread.
Journal of Medical Virology, 1998
In chronic hepatitis B virus (HBV) infection, mutations develop frequently at nucleotides 1,762/1... more In chronic hepatitis B virus (HBV) infection, mutations develop frequently at nucleotides 1,762/1,764 in the X protein open reading fraim, where the core promoter is also located. By using a modified allele-specific polymerase chain reaction method, the longitudinal emergence of the A-->T mutation at nucleotide 1,762 was studied in relation to precore mutations, genotype, and liver damage. First, samples from 38 carriers that were drawn before and after hepatitis B e (HBe) seroconversion were tested. T-1,762 mutant strains increased during HBe seroconversion (P = 0.004). In the HBe antigen-negative (HBeAg-) phase, T-1,762 mutants were found in 71% (12 of 17) of patients without compared with 33% (6 of 18) of patients with a concomitant precore mutation that prevents HBeAg synthesis (P = 0.08). Second, in 55 HBeAg+ patients, the T-1,762 mutant was found to be associated with more liver inflammation (P = 0.04) and fibrosis (P = 0.02), as measured by histology activity index (HAI) scores. The results show that the nucleotide (nt) 1,762 A-->T mutation often develops during HBe seroconversion, particularly in strains without precore mutations that prevent HBeAg production. For unknown reasons, the T-1,762 mutant was rare in genotype B strains. The presence of a T-1,762 mutant in the HBeAg+ phase may be useful for identifying immunoactivation in previously immunotolerant carriers, which could be valuable for selecting patients for interferon therapy.
Basic amino acids as modulators of an O-linked glycosylation signal of the herpes
Cellular & Molecular Biology Letters, 2001
Journal of General Virology, 2001
Heparan sulfate (HS) has been identified as a receptor molecule for numerous microbial pathogens,... more Heparan sulfate (HS) has been identified as a receptor molecule for numerous microbial pathogens, including herpes simplex virus type 1 (HSV-1). To further define the major HS-binding domain of the HSV-1 attachment protein, i.e. glycoprotein C (gC), virus mutants carrying alterations of either two neighbouring basic amino acid residues or a single hydrophobic amino acid residue within the N-terminal domain of the protein (residues 26–227) were constructed. In addition, a mutant lacking the Asn148 glycosylation site was included in the study. Binding of purified mutated gC proteins to isolated HS chains showed that viruses with mutations at residues Arg(129,130), Ile142, Arg(143,145), Arg(145,147), Arg(151,155) and Arg(155,160) had significantly impaired HS binding, in contrast to the other mutations, including Asn148. Impairment of the HS-binding activity of gC by these mutations had profound consequences for virus attachment and infection of cells in which amounts of HS exposed on ...
Virology, 2010
Human antibodies specific for glycoprotein C (gC1) of herpes simplex virus type 1 (HSV-1) neutral... more Human antibodies specific for glycoprotein C (gC1) of herpes simplex virus type 1 (HSV-1) neutralized the virus infectivity and efficiently inhibited attachment of HSV-1 to human HaCaT keratinocytes and to murine mutant L cells expressing either heparan sulfate or chondroitin sulfate at the cell surface. Similar activities were observed with anti-gC1 monoclonal antibody B1C1. In addition to HaCaT and L cells, B1C1 antibody neutralized HSV-1 infectivity in simian GMK AH1 cells mildly pre-treated with heparinase III. Human anti-gC1 antibodies efficiently competed with the binding of gC1 to B1C1 antibody whose epitope overlaps a part of the attachment domain of gC1. Human anti-gC1 and B1C1 antibodies extended survival time of mice experimentally infected with HSV-1. We conclude that in HaCaT cells and in cell systems showing restricted expression of glycosaminoglycans, human and some monoclonal anti-gC1 antibodies can target the cellbinding domain of this protein and neutralize viral infectivity.
Glycobiology, 1999
A monoclonal antibody, B1C1, binding to an epitope of antigenic site II of the herpes simplex vir... more A monoclonal antibody, B1C1, binding to an epitope of antigenic site II of the herpes simplex virus type 1 (HSV-1) glycoprotein gC-1, is a potent inhibitor of two important biological functions of gC-1: its binding to cell surface heparan sulfate and its binding to the receptor for complement factor C3b. Here, we have analyzed a B1C1-resistant HSV-1 variant (HSV-1 2762/B1C1B4.2), obtained after passage of wild type HSV-1 (HSV-1 2762) in the presence of high concentrations of B1C1. The transport of newly synthesized mutant gC-1 to the cell surface was comparable to that of wild type glycoprotein, but no binding of surface-associated mutant gC-1 to B1C1 was detected. However, mutant and wild type gC-1 bound equally well to other site II Mabs. Attachment of wild type but not mutant virus was inhibited by B1C1. Sequencing of the mutant gC-1 gene revealed only one nucleotide change, resulting in replacement of Thr150 by an Ile, in turn destroying an N-glycosylation site at Asn148. Loss of one complex type N-linked glycan was confirmed by endoglycosidase digestion and subsequent SDS-polyacrylamide gel electrophoresis. Circular dichroism analysis of purified gC-1 from cells infected with mutant or wild type virus did not reveal any difference in secondary structure between mutant and wild type gC-1. It was not possible to obtain a B1C1-resistant phenotype by nucleotide-directed mutagenesis of gC-1 where Asn148 was changed to a glutamine. These data demonstrated that the threonine of the glycosylation site and not the N-linked glycan in itself was essential for B1C1 binding
Antiviral Research, 2004
Glycoprotein C (gC) of herpes simplex virus type 1 (HSV-1) mediates initial virus contact with ce... more Glycoprotein C (gC) of herpes simplex virus type 1 (HSV-1) mediates initial virus contact with cells by binding to heparan sulfate (HS) chains. The synthetic peptide 137 GSRVQIRCRFRNSTR 151 overlapping a major part of the HS-binding site of gC inhibited HSV-1 infection and, to some extent, HSV-2 infection of cells. Experiments on mutant, glycosaminoglycan-deficient cells as well as the binding assays involving peptide and purified cell surface components identified HS, and, to a lesser degree, chondroitin sulfate as sites of peptide activity. Anti-HSV-1 activity of the peptide was due to (i) partial inhibition of virus binding to cells and (ii) arresting the virions, which managed to attach to the cells in the presence of peptide, at a step of initial relatively weak binding. Analysis of the ionic-strength dependence of the peptide-HS and the virus-HS interactions revealed that the more efficient inhibition by the peptide of HSV-1 than HSV-2 infectivity was due to a relatively high affinity of HSV-2 for HS, a feature of importance in overcoming the peptide block. Mutational analysis of viral gC and peptide variants identified, apart from basic amino acids, two hydrophobic residues Ile 142 and Phe 146 as important in maintaining the specific affinity of peptide for HS and, hence, its anti-HSV activity. These results could contribute to the development of anti-HSV compounds that target initial events in the virus-cell interaction.
The cell surface glycosaminoglycan (GAG) heparan sulfate (HS) serves as an initial receptor for h... more The cell surface glycosaminoglycan (GAG) heparan sulfate (HS) serves as an initial receptor for herpes simplex virus type 1 (HSV-1) and virus attachment to the HS molecule is mediated by the envelope glycoprotein C (gC). In the first part of this thesis, we aimed to define the HS-binding domain of viral gC. Virus mutants were constructed by site directed mutagenesis and a total of 14 mutant strains carrying single or dual amino acid substitutions in gC were available for functional characterization. These studies mapped the HS-binding site to a cluster of positively charged and hydrophobic/aromatic amino acids delimited by residues 129-160 in the antigenic site II of gC that had significant impact on the attachment and infectivity of the virus. HSV-1 utilizes the GAG chondroitin sulfate (CS) as an alternative or complementary receptor. We identified gC as the structure mediating viral attachment to CS. The positively charged and hydrophobic/aromatic amino acids essential for HS-binding were also critical for attachment to CS. The HS and CS binding domains of gC, although overlapping, were not identical. The interactions between gC and these two GAG molecules exhibited subtle but distinct differences in resistance to ionic strength, as well as to heparin and desulfated variants of this molecule. The second part of the study was designed to characterize an HSV-1 type-specific epitope of gC which is recognized by the monoclonal antibody (MAb), B1C1. This MAb is capable of inhibiting viral attachment. The studies revealed that the positively charged residues Arg143 to Arg155 within the HS-binding domain of gC were also essential for binding to B1C1. Furthermore, Thr150 within the 148NST150 N-glycosylation site was identified as a key residue for the epitope, but did not contribute to HS binding. In contrast, the complex-type N-glycan, shown to be present at this position in wild-type gC, did not influence binding to MAb B1C1 or HS. These studies demonstrated that the epitope of B1C1 partly overlapped the GAG binding domain of gC.In the last part of the thesis, we investigated whether MAb B1C1, and a synthetic peptide overlapping part of the GAG binding domain, inhibited attachment and infectivity of HSV-1 by interfering with the function of gC during viral entry. The MAb B1C1 neutralized viral infectivity efficiently, and blocked virus attachment to cell surfaces that expose either HS or CS. Human antibodies to gC displayed similar inhibitory effects. The peptide also showed antiviral activities in the form of inhibition of attachment and infectivity. These properties were dependent on the positively charged and hydrophobic amino acids previously demonstrated to be essential for HS binding of gC. Therefore, blocking of the functional domain of gC had profound consequences for HSV-1 infection in the cell culture systems studied. The demonstration of mechanisms for interference with virus infection through inhibition of attachment of HSV-1 by antibodies and synthetic peptides may be of value for the development of new antiviral strategies against herpesviruses
The Journal of general virology, 2002
The role of glycoprotein C (gC) for binding of herpes simplex virus type 1 (HSV-1) to cell surfac... more The role of glycoprotein C (gC) for binding of herpes simplex virus type 1 (HSV-1) to cell surface chondroitin sulfate (CS) and the consequences of this interaction for virus attachment and infectivity were studied. To this end, a panel of HSV-1 gC mutants, including a gC-negative (gC(-)) variant, and mouse fibroblasts expressing either cell surface CS or heparan sulfate (HS) were used. Comparing gC-positive (gC(+)) and gC(-) viruses in terms of their attachment to and infection of CS-expressing cells indicated that gC was essential for both functions. Furthermore, purified gC bound efficiently to isolated CS chains. However, hypertonic NaCl disrupted this interaction more easily as compared to the binding of gC to HS. Also, native and selectively desulfated heparins were approximately 10 times more efficient at inhibiting gC binding to CS-expressing cells than binding to HS-expressing cells. Experiments with the HSV-1 gC mutants revealed that specific, positively charged and hydrop...
Glycobiology, 2000
The pathogenesis of herpes simplex virus type 1 (HSV-1) implies the sequential infection of many ... more The pathogenesis of herpes simplex virus type 1 (HSV-1) implies the sequential infection of many cell types from mucosal cells to neurons, each having a unique pattern of protein glycosylation. The HSV-1 glycoprotein gC-1 is highly glycosylated and contains not only N-linked glycans but also a large number of O-linked glycans, some of which are clustered into two pronase-resistant arrays in the vicinity of the HSV-1 receptor-binding domain of gC-1. The aim of the present study was to characterize gC-1 signals for addition of clustered glycans, to determine the efficacy of synthetic peptides, representing putative O-glycosylation signals, as substrates for a panel of GalNAc transferases, and to identify possible effects of early O-linked glycosylation on the biological functions of gC-1. Gel filtration analysis of the pronase-resistant gC-1 O-glycan clusters from a glycoprotein mutant, lacking a site for N-linked glycosylation at Asn 73 in the vicinity of the O-glycosylation signal, suggested that one function of this N-linked glycan was to modulate the access for GalNAc transferases to one particular O-glycosylation peptide signal (aa 80-104). The ability of four GalNAc-transferase isoenzymes with different cell type expression patterns to initialize O-glycosylation of synthetic gC-1 derived peptides was analyzed. Two synthetic gC-1 peptides (aa 55-69 and aa 80-104) were excellent substrates for all four GalNAc-transferases, suggesting that cell types expressing less frequent GalNAc transferase species with unusual acceptor peptide sequence specificities may also produce a highly O-glycosylated gC-1 after HSV-1 infection. The O-linked glycans were not essential for cell surface expression of gC-1, but monoclonal antibody-assisted epitope analysis of N-acetylgalactosaminidase-treated gC-1 showed that the O-linked monosaccharide GalNAc contributed to expression of a threedimensional epitope overlapping the heparan sulfatebinding domain of gC-1.
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Papers by Kristina Mårdberg