scholarly journals Expression of Extremely Low Levels of Thymidine Kinase from an Acyclovir-Resistant Herpes Simplex Virus Mutant Supports Reactivation from Latently Infected Mouse Trigeminal Ganglia

2007 ◽  
Vol 81 (15) ◽  
pp. 8356-8360 ◽  
Author(s):  
Michael I. Besecker ◽  
Caroline L. Furness ◽  
Donald M. Coen ◽  
Anthony Griffiths
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Thymidine Kinase ◽  
Infected Mouse ◽  
Laboratory Strain ◽  
Trigeminal Ganglia ◽  
Wild Type ◽  
Latently Infected ◽  
Low Levels ◽  
Simplex Virus

ABSTRACT A single-cytosine-deletion in the herpes simplex virus gene encoding thymidine kinase (TK) was previously found in an acyclovir-resistant clinical isolate. A laboratory strain engineered to carry this mutation did not generate sufficient TK activity for detection by plaque autoradiography, which detected 0.25% wild-type activity. However, a drug sensitivity assay suggested that extremely low levels of TK are generated by this virus. The virus was estimated to express 0.09% of wild-type TK activity via a ribosomal frameshift 24 nucleotides upstream of the mutation. Remarkably, this appeared to be sufficient active TK to support a low level of reactivation from latently infected mouse trigeminal ganglia.

scholarly journals Low-Level Expression and Reversion both Contribute to Reactivation of Herpes Simplex Virus Drug-Resistant Mutants with Mutations on Homopolymeric Sequences in Thymidine Kinase

2006 ◽  
Vol 80 (13) ◽  
pp. 6568-6574 ◽  
Author(s):  
Anthony Griffiths ◽  
Malen A. Link ◽  
Caroline L. Furness ◽  
Donald M. Coen
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Thymidine Kinase ◽  
Trigeminal Ganglia ◽  
Virus Reactivation ◽  
Latently Infected ◽  
Low Levels ◽  
Simplex Virus ◽  
Translational Mechanisms ◽  
Virus Isolates

ABSTRACT Many acyclovir-resistant herpes simplex virus isolates from patients contain insertions or deletions in homopolymeric sequences in the thymidine kinase (TK) gene (tk). Viruses that have one (G8) or two (G9) base insertions in a run of seven G's (G string) synthesize low levels of active TK (TK-low phenotype), evidently via ribosomal frameshifting. These levels of TK can suffice to permit reactivation from latently infected mouse ganglia, but in a majority of ganglia, especially with the G9 virus, reactivation of virus that has reverted to the TK-positive phenotype predominates. To help address the relative contributions of translational mechanisms and reversion in reactivation, we generated viruses with a base either inserted or deleted just downstream of the G string. Both of these viruses had a TK-low phenotype similar to that of the G8 and G9 viruses but with less reversion. Both of these viruses reactivated from latently infected trigeminal ganglia, albeit inefficiently, and most viruses that reactivated had a uniformly TK-low phenotype. We also generated viruses that have one insertion in a run of six C's or one deletion in a run of five C's. These viruses lack measurable TK activity. However, they reactivated from latently infected ganglia, albeit inefficiently, with the reactivating viruses having reverted to the wild-type TK phenotype. Therefore, for G-string mutants, levels of active TK as low as 0.25% generated by translational mechanisms can suffice for reactivation, but reversion can also contribute. For viruses that lack TK activity due to mutations on other homopolymeric sequences, reactivation can occur via reversion.

scholarly journals Herpes Simplex Virus 1 Latency and the Kinetics of Reactivation Are Regulated by a Complex Network of Interactions between the Herpesvirus Entry Mediator, Its Ligands (gD, BTLA, LIGHT, and CD160), and the Latency-Associated Transcript

2018 ◽  
Vol 92 (24) ◽  
Author(s):  
Shaohui Wang ◽  
Alexander V. Ljubimov ◽  
Ling Jin ◽  
Klaus Pfeffer ◽  
Mitchell Kronenberg ◽  
...  
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Trigeminal Ganglia ◽  
Wild Type ◽  
Herpes Simplex Virus 1 ◽  
Latently Infected ◽  
Simplex Virus ◽  
Kinetics Of ◽  
Herpesvirus Entry Mediator ◽  
Hsv 1

ABSTRACTRecently, we reported that the herpesvirus entry mediator (HVEM; also called TNFRSF14 or CD270) is upregulated by the latency-associated transcript (LAT) of herpes simplex virus 1 (HSV-1) and that the absence of HVEM affects latency reactivation but not primary infection in ocularly infected mice. gD has been shown to bind to HVEM. LIGHT (TNFSF14), CD160, and BTLA (B- and T-lymphocyte attenuator) also interact with HVEM and can interfere with HSV gD binding. It was not known if LIGHT, CD160, or BTLA affected the level of latency reactivation in the trigeminal ganglia (TG) of latently infected mice. To address this issue, we ocularly infected LIGHT−/−, CD160−/−, and BTLA−/−mice with LAT(+) and LAT(−) viruses, using similarly infected wild-type (WT) and HVEM−/−mice as controls. The amount of latency, as determined by the levels of gB DNA in the TG of the LIGHT−/−, CD160−/−, and BTLA−/−mice infected with either LAT(+) or LAT(−) viruses, was lower than that in WT mice infected with LAT(+) virus and was similar in WT mice infected with LAT(−) virus. The levels of LAT RNA in HVEM−/−, LIGHT−/−, CD160−/−, and BTLA−/−mice infected with LAT(+) virus were similar and were lower than the levels of LAT RNA in WT mice. However, LIGHT−/−, CD160−/−, and BTLA−/−mice, independent of the presence of LAT, had levels of reactivation similar to those of WT mice infected with LAT(+) virus. Faster reactivation correlated with the upregulation of HVEM transcript. The LIGHT−/−, CD160−/−, and BTLA−/−mice had higher levels of HVEM expression, and this, along with the absence of BTLA, LIGHT, or CD160, may contribute to faster reactivation, while the absence of each molecule, independent of LAT, may have contributed to lower latency. This study suggests that, in the absence of competition with gD for binding to HVEM, LAT RNA is important for WT levels of latency but not for WT levels of reactivation.IMPORTANCEThe effects of BTLA, LIGHT, and CD160 on latency reactivation are not known. We show here that in BTLA, LIGHT, or CD160 null mice, latency is reduced; however, HVEM expression is upregulated compared to that of WT mice, and this upregulation is associated with higher reactivation that is independent of LAT but dependent on gD expression. Thus, one of the mechanisms by which BTLA, LIGHT, and CD160 null mice enhance reactivation appears to be the increased expression of HVEM in the presence of gD. Thus, our results suggest that blockade of HVEM-LIGHT-BTLA-CD160 contributes to reduced HSV-1 latency and reactivation.

scholarly journals Competition and complementation between thymidine kinase-negative and wild-type herpes simplex virus during co-infection of mouse trigeminal ganglia

2006 ◽  
Vol 87 (12) ◽  
pp. 3495-3502 ◽  
Author(s):  
Shih-Heng Chen ◽  
Yu-Wen Lin ◽  
Anthony Griffiths ◽  
Wen-Yen Huang ◽  
Shun-Hua Chen
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Thymidine Kinase ◽  
Antiviral Drug ◽  
Wild Type Virus ◽  
Trigeminal Ganglia ◽  
Wild Type ◽  
Viral Genomes ◽  
Simplex Virus

Laboratory strains of herpes simplex virus lacking thymidine kinase (TK) cannot replicate acutely to detectable levels in mouse trigeminal ganglia and do not reactivate from latency. However, many pathogenic clinical isolates that are resistant to the antiviral drug acyclovir are heterogeneous populations of TK-negative (TK−) and TK-positive (TK+) viruses. To recapitulate this in vivo, mice were infected with mixtures of wild-type virus and a recombinant TK− mutant in various ratios. Following co-infection, the replication, number of latent viral genomes and reactivation efficiency of TK+ virus in trigeminal ganglia were reduced in a manner related to the amount of TK− virus in the inoculum. TK+ virus did not always complement the acute replication or increase the number of latent viral genomes of TK− mutant in mouse ganglia. Even so, TK+ virus could still confer the pathogenic phenotype to a TK− mutant, somehow providing sufficient TK activity in trans to permit a TK− mutant to reactivate from latently infected ganglia.

scholarly journals CD8+T Cells Play a Bystander Role in Mice Latently Infected with Herpes Simplex Virus 1

2016 ◽  
Vol 90 (10) ◽  
pp. 5059-5067 ◽  
Author(s):  
Kevin R. Mott ◽  
David Gate ◽  
Harry H. Matundan ◽  
Yasamin N. Ghiasi ◽  
Terrence Town ◽  
...  
Keyword(s):  
T Cells ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Trigeminal Ganglia ◽  
Wild Type ◽  
Herpes Simplex Virus 1 ◽  
Link Type ◽  
Latently Infected ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACTBased on an explant reactivation model, it has been proposed that CD8+T cells maintain latency in trigeminal ganglia (TG) of mice latently infected with herpes simplex virus 1 (HSV-1) [T. Liu, K. M. Khanna, X. Chen, D. J. Fink, and R. L. Hendricks, J Exp Med 191:1459–1466, 2000, doi:10.1084/jem.191.9.1459; K. M. Khanna, R. H. Bonneau, P. R. Kinchington, and R. L. Hendricks, Immunity 18:593-603, 2003, doi:10.1016/S1074-7613(03)00112-2]. In those studies, BALB/c mice were ocularly infected with an avirulent HSV-1 strain (RE) after corneal scarification. However, in our studies, we typically infect mice with a virulent HSV-1 strain (McKrae) that does not require corneal scarification. Using a combination of knockout mice, adoptive transfers, and depletion studies, we recently found that CD8α+dendritic cells (DCs) contribute to HSV-1 latency and reactivation in TG of ocularly infected mice (K. R. Mott, S. J. Allen, M. Zandian, B. Konda, B. G. Sharifi, C. Jones, S. L. Wechsler, T. Town, and H. Ghiasi, PLoS One 9:e93444, 2014, doi:10.1371/journal.pone.0093444). This suggested that CD8+T cells might not be the major regulators of HSV-1 latency in the mouse TG. To investigate this iconoclastic possibility, we used a blocking CD8 antibody and CD8+T cells in reactivated TG explants from mice latently infected with (i) the avirulent HSV-1 strain RE following corneal scarification or (ii) the virulent HSV-1 strain McKrae without corneal scarification. Independently of the strain or approach, our results show that CD8α+DCs, not CD8+T cells, drive latency and reactivation. In addition, adoptive transfer of CD8+T cells from wild-type (wt) mice to CD8α−/−mice did not restore latency to the level for wt mice or wt virus. In the presence of latency-associated transcript (LAT(+); wt virus), CD8+T cells seem to play a bystander role in the TG. These bystander T cells highly express PD-1, most likely due to the presence of CD8α+DCs. Collectively, these results support the notion that CD8+T cells do not play a major role in maintaining HSV-1 latency and reactivation.SIGNIFICANCEThis study addresses a fundamentally important and widely debated issue in the field of HSV latency—reactivation. In this article, we directly compare the effects of anti-CD8 antibody, CD8+T cells, LAT, and CD8α+DCs in blocking explant reactivation in TG of mice latently infected with avirulent or virulent HSV-1. Our data suggest that CD8+T cells are not responsible for an increase or maintenance of latency in ocularly infected mice. However, they seem to play a bystander role that correlates with the presence of LAT, higher subclinical reactivation levels, and higher PD-1 expression levels.

scholarly journals Failure of Thymidine Kinase-Negative Herpes Simplex Virus To Reactivate from Latency following Efficient Establishment

2004 ◽  
Vol 78 (1) ◽  
pp. 520-523 ◽  
Author(s):  
Shih-Heng Chen ◽  
Angela Pearson ◽  
Donald M. Coen ◽  
Shun-Hua Chen
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Thymidine Kinase ◽  
Wild Type Virus ◽  
Trigeminal Ganglia ◽  
Type Virus ◽  
Wild Type ◽  
Viral Loads ◽  
Simplex Virus

ABSTRACT Thymidine kinase-negative mutants of herpes simplex virus did not reactivate from latency in mouse trigeminal ganglia, even when their latent viral loads were comparable to those that permitted reactivation by wild-type virus. Thus, reduced establishment of latency does not suffice to account for the failure to reactivate.

scholarly journals The Polyserine Tract of Herpes Simplex Virus ICP4 Is Required for Normal Viral Gene Expression and Growth in Murine Trigeminal Ganglia

1998 ◽  
Vol 72 (9) ◽  
pp. 7115-7124 ◽  
Author(s):  
Patricia A. Bates ◽  
Neal A. DeLuca
Keyword(s):  
Gene Expression ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Productive Infection ◽  
Wild Type Virus ◽  
Trigeminal Ganglia ◽  
Type Virus ◽  
Wild Type ◽  
Low Levels ◽  
Simplex Virus

ABSTRACT ICP4 of herpes simplex virus (HSV) is essential for productive infection due to its central role in the regulation of HSV transcription. This study identified a region of ICP4 that is not required for viral growth in culture or at the periphery of experimentally inoculated mice but is critical for productive growth in the trigeminal ganglia. This region of ICP4 encompasses amino acids 184 to 198 and contains 13 nearly contiguous serine residues that are highly conserved among the alphaherpesviruses. A mutant in which this region is deleted (ΔSER) was able to grow on the corneas of mice and be transported back to the trigeminal ganglia. ΔSER did not grow in the trigeminal ganglia but did express low levels of several immediate-early (ICP4 and ICP27) and early (thymidine kinase [tk] and UL42) genes. It expressed very low levels of the late gC gene and did not appear to replicate DNA. This pattern of gene expression was similar to that observed for a tk mutant,dlsptk. Both ΔSER and dlsptk expressed higher levels of the latency-associated transcript (LAT) per genome earlier in infected ganglia than did the wild-type virus, KOS. However, infected ganglia from all three viruses accumulated the same level of LAT per genome at 30 days postinfection (during latency). The data suggest that the polyserine tract of ICP4 provides an activity that is required for lytic infection in ganglia to progress to viral DNA synthesis and full lytic gene expression. In the absence of this activity, higher levels of LAT per genome accumulate earlier in infection than with wild-type virus.

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