scholarly journals The Latent Herpes Simplex Virus Type 1 Genome Copy Number in Individual Neurons Is Virus Strain Specific and Correlates with Reactivation

1998 ◽  
Vol 72 (7) ◽  
pp. 5343-5350 ◽  
Author(s):  
N. M. Sawtell ◽  
D. K. Poon ◽  
C. S. Tansky ◽  
R. L. Thompson
Keyword(s):  
Herpes Simplex ◽  
Viral Genome ◽  
Copy Number ◽  
Genetic Factors ◽  
Genome Copy ◽  
Latently Infected ◽  
Genome Copy Number ◽  
Simplex Virus

ABSTRACT The viral genetic elements that determine the in vivo reactivation efficiencies of fully replication competent wild-type herpes simplex virus (HSV) strains have not been identified. Among the common laboratory strains, KOS reactivates in vivo at a lower efficiency than either strain 17syn+ or strain McKrae. An important first step in understanding the molecular basis for this observation is to distinguish between viral genetic factors that regulate the establishment of latency from those that directly regulate reactivation. Reported here are experiments performed to determine whether the reduced reactivation of KOS was associated with a reduced ability to establish or maintain latent infections. For comparative purposes, latent infections were quantified by (i) quantitative PCR on DNA extracted from whole ganglia, (ii) the number of latency-associated transcript (LAT) promoter-positive neurons, using KOS and 17syn+ LAT promoter–β-galactosidase reporter mutants, and (iii) contextual analysis of DNA. Mice latently infected with 17syn+-based strains contained more HSV type 1 (HSV-1) DNA in their ganglia than those infected with KOS strains, but this difference was not statistically significant. The number of latently infected neurons also did not differ significantly between ganglia latently infected with either the low- or high-reactivator strains. In addition to the number of latent sites, the number of viral genome copies within the individual latently infected neurons has recently been demonstrated to be variable. Interestingly, neurons latently infected with KOS contained significantly fewer viral genome copies than those infected with either 17syn+ or McKrae. Thus, the HSV-1 genome copy number profile is viral strain specific and positively correlates with the ability to reactivate in vivo. This is the first demonstration that the number of HSV genome copies within individual latently infected neurons is regulated by viral genetic factors. These findings suggest that the latent genome copy number may be an important parameter for subsequent induced reactivation in vivo.

scholarly journals Replication of Herpes Simplex Virus Type 1 within Trigeminal Ganglia Is Required for High Frequency but Not High Viral Genome Copy Number Latency

2000 ◽  
Vol 74 (2) ◽  
pp. 965-974 ◽  
Author(s):  
Richard L. Thompson ◽  
N. M. Sawtell
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Herpes Simplex Virus Type ◽  
Viral Genome ◽  
Copy Number ◽  
Trigeminal Ganglia ◽  
Genome Copy ◽  
Genome Copy Number ◽  
Simplex Virus

ABSTRACT The replication properties of a thymidine kinase-negative (TK−) mutant of herpes simplex virus type 1 (HSV-1) were exploited to examine the relative contributions of replication at the body surface and within trigeminal ganglia (TG) on the establishment of latent infections. The replication of a TK− mutant, 17/tBTK−, was reduced by ∼12-fold on the mouse cornea compared to the rescued isolate 17/tBRTK+, and no replication of 17/tBTK− in the TG of these mice was detected. About 1.8% of the TG neurons of mice infected with 17/tBTK− harbored the latent viral genome compared to 23% of those infected with 17/tBRTK+. In addition, the latent sites established by the TK− mutant contained fewer copies of the HSV-1 genome (average, 2.3/neuron versus 28/neuron). On the snout, sustained robust replication of 17tBTK− in the absence of significant replication within the TG resulted in a modest increase in the number of latent sites. Importantly, these latently infected neurons displayed a wild-type latent-genome copy number profile, with some neurons containing hundreds of copies of the TK− mutant genome. As expected, the replication of the TK− mutant appeared to be blocked prior to DNA replication in most ganglionic neurons in that (i) virus replication was severely restricted in ganglia, (ii) the number of neurons expressing HSV proteins was reduced 30-fold compared to the rescued isolate, (iii) cell-to-cell spread of virus was not detected within ganglia, and (iv) the proportion of infected neurons expressing late proteins was reduced by 89% compared to the rescued strain. These results demonstrate that the viral TK gene is required for the efficient establishment of latency. This requirement appears to be primarily for efficient replication within the ganglion, which leads to a sixfold increase in the number of latent sites established. Further, latent sites with high genome copy number can be established in the absence of significant virus genome replication in neurons. This suggests that neurons can be infected by many HSV virions and still enter the latent state.

scholarly journals Oral Inoculation of Chickens with a Candidate Fowl Adenovirus 9 Vector

2013 ◽  
Vol 20 (8) ◽  
pp. 1189-1196 ◽  
Author(s):  
Li Deng ◽  
Shayan Sharif ◽  
Éva Nagy
Keyword(s):  
Gene Expression ◽  
Antibody Response ◽  
Virus Replication ◽  
Viral Genome ◽  
Copy Number ◽  
Cytokine Gene Expression ◽  
Genome Copy ◽  
Virus Shedding ◽  
Genome Copy Number

ABSTRACTFowl adenoviruses (FAdVs) are a potential alternative to human adenovirus-based vaccine vectors. Our previous studies demonstrated that a 2.4-kb region at the left end of the FAdV-9 genome is nonessential for virus replication and is suitable for the insertion or replacement of transgenes. Ourin vivostudy showed that the virus FAdV-9Δ4, lacking six open reading frames (ORFs) at the left end of its genome, replicates less efficiently than wild-type FAdV-9 (wtFAdV-9) in chickens that were infected intramuscularly. However, the fecal-oral route is the natural route of FAdV infection, and the oral administration of a vaccine confers some advantages compared to administration through other routes, especially when developing an adenovirus as a vaccine vector. Therefore, we sought to investigate the effects of FAdV-9 in orally inoculated chickens. In the present study, we orally inoculated specific-pathogen-free (SPF) chickens with FAdV-9 and FAdV-9Δ4 and assessed virus shedding, antibody response, and viral genome copy number and cytokine gene expression in tissues. Our data showed that FAdV-9Δ4 replicated less efficiently than did wtFAdV-9, as evidenced by reduced virus shedding in feces, lower viral genome copy number in tissues, and lower antibody response, which are consistent with the results of the intramuscular route of immunization. Furthermore, we found that both wtFAdV-9 and FAdV-9Δ4 upregulated the mRNA expression of alpha interferon (IFN-α), IFN-γ, and interleukin-12 (IL-12). In addition, there was a trend toward downregulation of IL-10 gene expression caused by both viruses. These findings indicate that one or more of the six deleted ORFs contribute to modulating the host response against virus infection as well as virus replicationin vivo.

scholarly journals The Probability of In Vivo Reactivation of Herpes Simplex Virus Type 1 Increases with the Number of Latently Infected Neurons in the Ganglia

1998 ◽  
Vol 72 (8) ◽  
pp. 6888-6892 ◽  
Author(s):  
N. M. Sawtell
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Pearson Correlation ◽  
Virus Reactivation ◽  
Wild Type ◽  
Latently Infected ◽  
Simplex Virus ◽  
The Relationship

ABSTRACT The purpose of this study was to define the relationship between herpes simplex virus (HSV) latency and in vivo ganglionic reactivation. Groups of mice with numbers of latently infected neurons ranging from 1.9 to 24% were generated by varying the input titer of wild-type HSV type 1 strain 17syn+. Reactivation of the virus in mice from each group was induced by hyperthermic stress. The number of animals that exhibited virus reactivation was positively correlated with the number of latently infected neurons in the ganglia over the entire range examined (r = 0.9852, P< 0.0001 [Pearson correlation]).

Use of herpes simplex virus type 1 for transgene expression within the nervous system*

1999 ◽  
Vol 96 (6) ◽  
pp. 533-541 ◽  
Author(s):  
Robin H. LACHMANN ◽  
Stacey EFSTATHIOU
Keyword(s):  
Gene Therapy ◽  
Nervous System ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Virus Type ◽  
Herpes Simplex Virus Type ◽  
Viral Genome ◽  
Latently Infected ◽  
Simplex Virus

Gene therapy might provide a useful treatment for a number of neurological diseases and a great deal of effort is going into the development of vector systems which will allow the delivery of potentially therapeutic genes to terminally differentiated neurons within the intact mammalian brain. The ability of herpes simplex virus type 1 (HSV-1) to establish a lifelong latent infection within neurons has led to interest in its use as a neuronal gene delivery vector. During HSV latency no viral proteins are produced and transcription from the latent viral genome is limited to a family of nuclear RNAs, the latency-associated transcripts, whose function is not well understood. Obtaining prolonged expression of a transgene in latently infected neurons has proven difficult due to transcriptional silencing of exogenous promoters introduced into the latent viral genome. For this reason there is a great deal of interest in utilizing the HSV latency-associated promoter to drive the expression of therapeutic genes in latently infected neurons of both the peripheral and central nervous systems. In this review we describe a strategy which allows the latency-associated promoter to drive long-term reporter gene expression in the mammalian nervous system. These observations open up the possibility of using similar HSV-based vectors to express therapeutic transgenes within the brain and investigate the potential of gene therapy in a range of neurological disorders.

scholarly journals Herpes Simplex Virus Type 1 Evades the Effects of Antibody and Complement In Vivo

2002 ◽  
Vol 76 (18) ◽  
pp. 9232-9241 ◽  
Author(s):  
John M. Lubinski ◽  
Ming Jiang ◽  
Lauren Hook ◽  
Yueh Chang ◽  
Chad Sarver ◽  
...  
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Virus Type ◽  
Immune Evasion ◽  
Herpes Simplex Virus Type ◽  
Complement Components ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT Herpes simplex virus type 1 (HSV-1) encodes a complement-interacting glycoprotein, gC, and an immunoglobulin G (IgG) Fc binding glycoprotein, gE, that mediate immune evasion by affecting multiple aspects of innate and acquired immunity, including interfering with complement components C1q, C3, C5, and properdin and blocking antibody-dependent cellular cytotoxicity. Previous studies evaluated the individual contributions of gC and gE to immune evasion. Experiments in a murine model that examines the combined effects of gC and gE immune evasion on pathogenesis are now reported. Virulence of wild-type HSV-1 is compared with mutant viruses defective in gC-mediated C3 binding, gE-mediated IgG Fc binding, or both immune evasion activities. Eliminating both activities greatly increased susceptibility of HSV-1 to antibody and complement neutralization in vitro and markedly reduced virulence in vivo as measured by disease scores, virus titers, and mortality. Studies with C3 knockout mice indicated that other activities attributed to these glycoproteins, such as gC-mediated virus attachment to heparan sulfate or gE-mediated cell-to-cell spread, do not account for the reduced virulence of mutant viruses. The results support the importance of gC and gE immune evasion in vivo and suggest potential new targets for prevention and treatment of HSV disease.

Phosphorylation of herpes simplex virus type 1 Us11 protein is independent of viral genome expression

1995 ◽  
Vol 16 (1) ◽  
pp. 1317-1322 ◽  
Author(s):  
Denis Simonin ◽  
Jean-Jacques Diaz ◽  
Karine Kindbeiter ◽  
Patrick Pernas ◽  
Jean-Jacques Madjar
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Virus Type ◽  
Herpes Simplex Virus Type ◽  
Viral Genome ◽  
Genome Expression ◽  
Simplex Virus ◽  
Us11 Protein
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