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Xenotransplantation May 2022
Topics: Animals; Cytomegalovirus; Swine; Transplantation, Heterologous
PubMed: 35708717
DOI: 10.1111/xen.12769 -
Viruses Dec 2021There is a large unmet need for a prophylactic vaccine against human cytomegalovirus (HCMV) to combat the ubiquitous infection that is ongoing with this pathogen. A...
There is a large unmet need for a prophylactic vaccine against human cytomegalovirus (HCMV) to combat the ubiquitous infection that is ongoing with this pathogen. A vaccination against HCMV could protect immunocompromised patients and prevent birth defects caused by congenital HCMV infections. Moreover, cytomegalovirus (CMV) has a number of features that make it a very interesting vector platform for gene therapy. In both cases, preparation of a highly purified virus is a prerequisite for safe and effective application. Murine CMV (MCMV) is by far the most studied model for HCMV infections with regard to the principles that govern the immune surveillance of CMVs. Knowledge transfer from MCMV and mice to HCMV and humans could be facilitated by better understanding and characterization of the biological and biophysical properties of both viruses. We carried out a detailed investigation of HCMV and MCMV growth kinetics as well as stability under the influence of clarification and different storage conditions. Further, we investigated the possibilities to concentrate and purify both viruses by ultracentrifugation and ion-exchange chromatography. Defective enveloped particles were not separately analyzed; however, the behavior of exosomes was examined during all experiments. The effectiveness of procedures was monitored using CCID assay, Nanoparticle tracking analysis, ELISA for host cell proteins, and quantitative PCR for host cell DNA. MCMV generally proved to be more robust in handling. Despite its greater sensitivity, HCMV was efficiently (100% recovery) purified and concentrated by anion-exchange chromatography using QA monolithic support. The majority of the host genomic DNA as well as most of the host cell proteins were removed by this procedure.
Topics: Animals; Cell Line; Chromatography, Ion Exchange; Cryopreservation; Cytomegalovirus; Exosomes; Humans; Mice; Muromegalovirus; Ultracentrifugation; Virus Cultivation
PubMed: 34960750
DOI: 10.3390/v13122481 -
Microbiology and Immunology 1992
Review
Topics: Exanthema Subitum; Genome, Viral; Herpesviridae Infections; Herpesvirus 6, Human; Humans; Seroepidemiologic Studies; Skin Diseases, Infectious; Viral Envelope Proteins; Virion; Virus Replication
PubMed: 1326076
DOI: 10.1111/j.1348-0421.1992.tb02055.x -
MBio Dec 2021Cytomegaloviruses (CMVs) are among the largest pathogenic viruses in mammals. To enable replication of their long double-stranded DNA genomes, CMVs induce profound... (Review)
Review
Cytomegaloviruses (CMVs) are among the largest pathogenic viruses in mammals. To enable replication of their long double-stranded DNA genomes, CMVs induce profound changes in cell cycle regulation. A hallmark of CMV cell cycle control is the establishment of an unusual cell cycle arrest at the G/S transition, which is characterized by the coexistence of cell cycle stimulatory and inhibitory activities. While CMVs interfere with cellular DNA synthesis and cell division, they activate S-phase-specific gene expression and nucleotide metabolism. This is facilitated by a set of CMV gene products that target master regulators of G/S progression such as cyclin E and A kinases, Rb-E2F transcription factors, p53-p21 checkpoint proteins, the APC/C ubiquitin ligase, and the nucleotide hydrolase SAMHD1. While the major themes of cell cycle regulation are well conserved between human and murine CMVs (HCMV and MCMV), there are considerable differences at the level of viral cell cycle effectors and their mechanisms of action. Furthermore, both viruses have evolved unique mechanisms to sense the host cell cycle state and modulate the infection program accordingly. This review provides an overview of conserved and divergent features of G/S control by MCMV and HCMV.
Topics: Animals; Cell Cycle Checkpoints; Cytomegalovirus; Cytomegalovirus Infections; G1 Phase; Humans; Mice; Muromegalovirus; S Phase
PubMed: 34903047
DOI: 10.1128/mBio.02934-21 -
Viruses Aug 2021Human cytomegalovirus (HCMV) can cause serious diseases in immunocompromised patients. Current antiviral inhibitors all target the viral DNA polymerase. They have...
Human cytomegalovirus (HCMV) can cause serious diseases in immunocompromised patients. Current antiviral inhibitors all target the viral DNA polymerase. They have adverse effects, and prolonged treatment can select for drug resistance mutations. Thus, new drugs targeting other stages of replication are an urgent need. The terminase complex (pUL56-pUL89-pUL51) is highly specific, has no counterpart in the human organism, and thus represents a target of choice for new antivirals development. This complex is required for DNA processing and packaging. pUL52 was shown to be essential for the cleavage of concatemeric HCMV DNA and crucial for viral replication, but its functional domains are not yet identified. Polymorphism analysis was performed by sequencing from 61 HCMV naive strains and from 14 HCMV strains from patients treated with letermovir. Using sequence alignment and homology modeling, we identified conserved regions and potential functional motifs within the pUL52 sequence. Recombinant viruses were generated with specific serine or alanine substitutions in these putative patterns. Within conserved regions, we identified residues essential for viral replication probably involved in CXXC-like or zinc finger motifs. These results suggest that they are essential for pUL52 structure/function. Thus, these patterns represent potential targets for the development of new antivirals.
Topics: Acetates; Amino Acid Motifs; Antiviral Agents; Conserved Sequence; Cytomegalovirus; Cytomegalovirus Infections; Endodeoxyribonucleases; Humans; Quinazolines; Viral Proteins; Virus Replication
PubMed: 34452502
DOI: 10.3390/v13081638 -
Viruses Sep 2021An evolutionary arms race occurs between viruses and hosts. Hosts have developed an array of antiviral mechanisms aimed at inhibiting replication and spread of viruses,... (Review)
Review
An evolutionary arms race occurs between viruses and hosts. Hosts have developed an array of antiviral mechanisms aimed at inhibiting replication and spread of viruses, reducing their fitness, and ultimately minimising pathogenic effects. In turn, viruses have evolved sophisticated counter-measures that mediate evasion of host defence mechanisms. A key aspect of host defences is the ability to differentiate between self and non-self. Previous studies have demonstrated significant suppression of CpG and UpA dinucleotide frequencies in the coding regions of RNA and small DNA viruses. Artificially increasing these dinucleotide frequencies results in a substantial attenuation of virus replication, suggesting dinucleotide bias could facilitate recognition of non-self RNA. The interferon-inducible gene, zinc finger antiviral protein (ZAP) is the host factor responsible for sensing CpG dinucleotides in viral RNA and restricting RNA viruses through direct binding and degradation of the target RNA. Herpesviruses are large DNA viruses that comprise three subfamilies, alpha, beta and gamma, which display divergent CpG dinucleotide patterns within their genomes. ZAP has recently been shown to act as a host restriction factor against human cytomegalovirus (HCMV), a beta-herpesvirus, which in turn evades ZAP detection by suppressing CpG levels in the major immediate-early transcript IE1, one of the first genes expressed by the virus. While suppression of CpG dinucleotides allows evasion of ZAP targeting, synonymous changes in nucleotide composition that cause genome biases, such as low GC content, can cause inefficient gene expression, especially in unspliced transcripts. To maintain compact genomes, the majority of herpesvirus transcripts are unspliced. Here we discuss how the conflicting pressures of ZAP evasion, the need to maintain compact genomes through the use of unspliced transcripts and maintaining efficient gene expression may have shaped the evolution of herpesvirus genomes, leading to characteristic CpG dinucleotide patterns.
Topics: Alphaherpesvirinae; Animals; Betaherpesvirinae; Dinucleoside Phosphates; Evolution, Molecular; Gammaherpesvirinae; Gene Expression; Genome, Viral; Herpesviridae; Host-Pathogen Interactions; Humans; Interferons; RNA Splicing; RNA, Viral; RNA-Binding Proteins; Signal Transduction; Viral Proteins
PubMed: 34578438
DOI: 10.3390/v13091857 -
Frontiers in Cellular and Infection... 2020Mounting experimental evidence hints to an import role for natural killer (NK) cells in adaptive immune responses to pathogens. NK cells with adaptive features are... (Review)
Review
Mounting experimental evidence hints to an import role for natural killer (NK) cells in adaptive immune responses to pathogens. NK cells with adaptive features are heterogeneous and belong to different subsets according to their phenotype as well as the nature of their adaptive recall reactions. Three types of adaptive NK cell responses have been described: (i) NK cells with long-lived memory of multiple different haptens and viral antigens were described in murine liver tissue with a possible human counterpart; (ii) infection of human and mouse cytomegalovirus is associated with an expansion of NKG2C and Ly49H NK cells, respectively, that selectively recognize CMV-encoded peptides thereby facilitating recall responses; (iii) cytokine-stimulated NK cells respond to different stimuli with enhanced production of IFN-γ after re-stimulation. These exciting findings not only support the idea of NK cells with adaptive features, but define a novel field of harnessing memory NK cell subsets for therapeutic strategies.
Topics: Animals; Antigens, Viral; Cytomegalovirus; Killer Cells, Natural; Mice; Muromegalovirus; Phenotype
PubMed: 32477964
DOI: 10.3389/fcimb.2020.00208 -
Mediators of Inflammation 2012The interaction between human cytomegalovirus (HCMV) and its host is a complex process that begins with viral attachment and entry into host cells, culminating in the... (Review)
Review
The interaction between human cytomegalovirus (HCMV) and its host is a complex process that begins with viral attachment and entry into host cells, culminating in the development of a specific adaptive response that clears the acute infection but fails to eradicate HCMV. We review the viral and cellular partners that mediate early host responses to HCMV with regard to the interaction between structural components of virions (viral glycoproteins) and cellular receptors (attachment/entry receptors, toll-like receptors, and other nucleic acid sensors) or intrinsic factors (PML, hDaxx, Sp100, viperin, interferon inducible protein 16), the reactions of innate immune cells (antigen presenting cells and natural killer cells), the numerous mechanisms of viral immunoevasion, and the potential exploitation of events that are associated with early phases of virus-host interplay as a therapeutic strategy.
Topics: Animals; Cytomegalovirus; Cytomegalovirus Infections; Host-Pathogen Interactions; Humans; Virion
PubMed: 22701276
DOI: 10.1155/2012/607276 -
Virology Journal Jan 2012Human cytomegalovirus (HCMV), a member of the Betaherpesvirinae sub-family of Herpesviridae family, is a widespread pathogen that infects a majority of the world's... (Review)
Review
Human cytomegalovirus (HCMV), a member of the Betaherpesvirinae sub-family of Herpesviridae family, is a widespread pathogen that infects a majority of the world's population by early adulthood. In individuals whose immune systems are immature or weakened, HCMV is a significant pathogen causing morbidity and mortality. There is no effective vaccine and only limited antiviral treatments against HCMV infection to date. A possible target for novel antiviral treatments is the HCMV proteins that localize to the tegument of the virion, since they play important roles in all stages of the viral life cycle, including, viral entry, gene expression, immune evasion, assembly, and egress. The most likely tegument protein candidates are pp65 (immune evasion), pp71 (gene expression), and pp150 and pp28 (assembly and egress). Although the subcellular localization of these proteins has been identified during HCMV infections in vitro, their localization patterns have not been determined when each protein is expressed individually in living cells. Thus, the objective of this review is elucidate the HCMV tegument as well as present current research findings concerning the subcellular localization of the tegument proteins pp65, pp71, pp150, and pp28 as fusions to one of several fluorescent proteins.
Topics: Cytomegalovirus; Gene Expression Regulation, Viral; Humans; Immune Evasion; Viral Structural Proteins; Virulence Factors; Virus Assembly; Virus Release
PubMed: 22251420
DOI: 10.1186/1743-422X-9-22 -
Virology Journal Jun 2022Certain clinical manifestations of coronavirus disease (COVID-19) mimic those associated with human herpesvirus (HHV) infection. In this study, we estimated the...
BACKGROUND
Certain clinical manifestations of coronavirus disease (COVID-19) mimic those associated with human herpesvirus (HHV) infection. In this study, we estimated the prevalence of herpesvirus in patients with COVID-19 and determined if coinfection is associated with poorer outcomes and neurological symptoms.
METHODS
We analyzed samples of 53 patients diagnosed with COVID-19. The samples were evaluated for the presence of alphaherpesviruses, betaherpesviruses, and gammaherpesviruses, and the viral loads were quantified using quantitative polymerase chain reaction (qPCR) method.
RESULTS
Among the patients, in 79.2% had detection at least one type of herpesvirus. HHV-6 (47.2%), cytomegalovirus (43.3%), and HHV-7 (39.6%) showed the highest detection rates. Patients with a high severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) load were more likely to show herpes simplex virus 1 detection (p = 0.037). Among patients coinfected with SARS-CoV-2 and HHVs, 26.4% showed central nervous system-associated neurological symptoms and herpetic manifestations. A statistically significant association was observed between neurological changes and HHV-6 detection (p = 0.034).
CONCLUSIONS
The findings showed a high prevalence of herpesvirus in patients with COVID-19. Furthermore, even though SARS-CoV-2 and HHV coinfection was not associated with poorer outcomes, the findings demonstrated the association between neurological symptoms and HHV-6 detection.
Topics: COVID-19; Cytomegalovirus; Herpesviridae; Herpesviridae Infections; Herpesvirus 6, Human; Herpesvirus 7, Human; Humans; SARS-CoV-2
PubMed: 35676707
DOI: 10.1186/s12985-022-01828-9