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 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 Latent Herpes Simplex Virus 1 Infection Does Not Induce Apoptosis in Human Trigeminal Ganglia

2015 ◽  
Vol 89 (10) ◽  
pp. 5747-5750 ◽  
Author(s):  
Susanne Himmelein ◽  
Anja Lindemann ◽  
Inga Sinicina ◽  
Michael Strupp ◽  
Thomas Brandt ◽  
...  
Keyword(s):  
T Cells ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Caspase 3 ◽  
Trigeminal Ganglia ◽  
Herpes Simplex Virus 1 ◽  
Reverse Transcription Quantitative Pcr ◽  
Latently Infected ◽  
Simplex Virus ◽  
Hsv 1

Herpes simplex virus 1 (HSV-1) can establish lifelong latency in human trigeminal ganglia. Latently infected ganglia contain CD8+T cells, which secrete granzyme B and are thus capable of inducing neuronal apoptosis. Using immunohistochemistry and single-cell reverse transcription-quantitative PCR (RT-qPCR), higher frequency and transcript levels of caspase-3 were found in HSV-1-negative compared to HSV-1-positive ganglia and neurons, respectively. No terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) assay-positive neurons were detected. The infiltrating T cells do not induce apoptosis in latently infected neurons.

scholarly journals Mutations Inactivating Herpes Simplex Virus 1 MicroRNA miR-H2 Do Not Detectably Increase ICP0 Gene Expression in Infected Cultured Cells or Mouse Trigeminal Ganglia

2016 ◽  
Vol 91 (2) ◽  
Author(s):  
Dongli Pan ◽  
Jean M. Pesola ◽  
Gang Li ◽  
Seamus McCarron ◽  
Donald M. Coen
Keyword(s):  
Gene Expression ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Trigeminal Ganglia ◽  
Herpes Simplex Virus 1 ◽  
Lytic Gene ◽  
Lytic Gene Expression ◽  
Latently Infected ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT Herpes simplex virus 1 (HSV-1) latency entails the repression of productive (“lytic”) gene expression. An attractive hypothesis to explain some of this repression involves inhibition of the expression of ICP0, a lytic gene activator, by a viral microRNA, miR-H2, which is completely complementary to ICP0 mRNA. To test this hypothesis, we engineered mutations that disrupt miR-H2 without affecting ICP0 in HSV-1. The mutant virus exhibited drastically reduced expression of miR-H2 but showed wild-type levels of infectious virus production and no increase in ICP0 expression in lytically infected cells, which is consistent with the weak expression of miR-H2 relative to the level of ICP0 mRNA in that setting. Following corneal inoculation of mice, the mutant was not significantly different from wild-type virus in terms of infectious virus production in the trigeminal ganglia during acute infection, mouse mortality, or the rate of reactivation from explanted latently infected ganglia. Critically, the mutant was indistinguishable from wild-type virus for the expression of ICP0 and other lytic genes in acutely and latently infected mouse trigeminal ganglia. The latter result may be related to miR-H2 being less effective in inhibiting ICP0 expression in transfection assays than a host microRNA, miR-138, which has previously been shown to inhibit lytic gene expression in infected ganglia by targeting ICP0 mRNA. Additionally, transfected miR-138 reduced lytic gene expression in infected cells more effectively than miR-H2. While this study provides little support for the hypothesis that miR-H2 promotes latency by inhibiting ICP0 expression, the possibility remains that miR-H2 might target other genes during latency. IMPORTANCE Herpes simplex virus 1 (HSV-1), which causes a variety of diseases, can establish lifelong latent infections from which virus can reactivate to cause recurrent disease. Latency is the most biologically interesting and clinically vexing feature of the virus. Ever since miR-H2's discovery as a viral microRNA bearing complete sequence complementarity to the mRNA for the important viral gene activator ICP0, inhibition of ICP0 expression by miR-H2 has been a major hypothesis to help explain the repression of lytic gene expression during latency. However, this hypothesis remained untested in latently infected animals. Using a miR-H2-deficient mutant virus, we found no evidence that miR-H2 represses the expression of ICP0 or other lytic genes in cells or mice infected with HSV-1. Although miR-H2 can repress ICP0 expression in transfection assays, such repression is weak. The results suggest that other mechanisms for miR-H2 activity and for the repression of lytic gene expression during latency deserve investigation.

scholarly journals Herpes Simplex Virus 1 Replication, Ocular Disease, and Reactivations from Latency Are Restricted Unilaterally after Inoculation of Virus into the Lip

2019 ◽  
Vol 93 (24) ◽  
Author(s):  
Nolwenn Poccardi ◽  
Antoine Rousseau ◽  
Oscar Haigh ◽  
Julie Takissian ◽  
Thierry Naas ◽  
...  
Keyword(s):  
Gene Expression ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Ocular Disease ◽  
Viral Reactivation ◽  
Trigeminal Ganglia ◽  
Herpes Simplex Virus 1 ◽  
Simplex Virus ◽  
Kinetics Of ◽  
Hsv 1

ABSTRACT Ocular herpes simplex keratitis (HSK) is a consequence of viral reactivations from trigeminal ganglia (TG) and occurs almost exclusively in the same eye in humans. In our murine oro-ocular (OO) model, herpes simplex virus 1 (HSV-1) inoculation in one side of the lip propagates virus to infect the ipsilateral TG. Replication here allows infection of the brainstem and infection of the contralateral TG. Interestingly, HSK was observed in our OO model only from the eye ipsilateral to the site of lip infection. Thus, unilateral restriction of HSV-1 may be due to differential kinetics of virus arrival in the ipsilateral versus contralateral TG. We inoculated mice with HSV-1 reporter viruses and then superinfected them to monitor changes in acute- and latent-phase gene expression in TG after superinfection compared to the control (single inoculation). Delaying superinfection by 4 days after initial right lip inoculation elicited failed superinfecting-virus gene expression and eliminated clinical signs of disease. Initial inoculation with thymidine kinase-deficient HSV-1 (TKdel) completely abolished reactivation of wild-type (WT) superinfecting virus from TG during the latent stage. In light of these seemingly failed infections, viral genome was detected in both TG. Our data demonstrate that inoculation of HSV-1 in the lip propagates virus to both TG, but with delay in reaching the TG contralateral to the side of lip infection. This delay is responsible for restricting viral replication to the ipsilateral TG, which abrogates ocular disease and viral reactivations from the contralateral side. These observations may help to understand why HSK is observed unilaterally in humans, and they provide insight into vaccine strategies to protect against HSK. IMPORTANCE Herpetic keratitis (HK) is the leading cause of blindness by an infectious agent in the developed world. This disease can occur after reactivation of herpes simplex virus 1 in the trigeminal ganglia, leading to dissemination of virus to, and infection of, the cornea. A clinical paradox is evidenced by the bilateral presence of latent viral genomes in both trigeminal ganglia, while for any given patient the disease is unilateral with recurrences in a single eye. Our study links the kinetics of early infection to unilateral disease phenomenon and demonstrates protection against viral reactivation when kinetics are exploited. Our results have direct implications in the understanding of human disease pathogenesis and immunotherapeutic strategies for the treatment of HK and viral reactivations.

scholarly journals Herpes Simplex Virus 1 UL34 Protein Regulates the Global Architecture of the Endoplasmic Reticulum in Infected Cells

2017 ◽  
Vol 91 (12) ◽  
Author(s):  
Fumio Maeda ◽  
Jun Arii ◽  
Yoshitaka Hirohata ◽  
Yuhei Maruzuru ◽  
Naoto Koyanagi ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Null Mutation ◽  
Wild Type ◽  
Herpes Simplex Virus 1 ◽  
Nuclear Egress ◽  
Infected Cells ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT Upon herpes simplex virus 1 (HSV-1) infection, the CD98 heavy chain (CD98hc) is redistributed around the nuclear membrane (NM), where it promotes viral de-envelopment during the nuclear egress of nucleocapsids. In this study, we attempted to identify the factor(s) involved in CD98hc accumulation and demonstrated the following: (i) the null mutation of HSV-1 UL34 caused specific dispersion throughout the cytoplasm of CD98hc and the HSV-1 de-envelopment regulators, glycoproteins B and H (gB and gH); (ii) as observed with CD98hc, gB, and gH, wild-type HSV-1 infection caused redistribution of the endoplasmic reticulum (ER) markers calnexin and ERp57 around the NM, whereas the UL34-null mutation caused cytoplasmic dispersion of these markers; (iii) the ER markers colocalized efficiently with CD98hc, gB, and gH in the presence and absence of UL34 in HSV-1-infected cells; (iv) at the ultrastructural level, wild-type HSV-1 infection caused ER compression around the NM, whereas the UL34-null mutation caused cytoplasmic dispersion of the ER; and (v) the UL34-null mutation significantly decreased the colocalization efficiency of lamin protein markers of the NM with CD98hc and gB. Collectively, these results indicate that HSV-1 infection causes redistribution of the ER around the NM, with resulting accumulation of ER-associated CD98hc, gB, and gH around the NM and that UL34 is required for ER redistribution, as well as for efficient recruitment to the NM of the ER-associated de-envelopment factors. Our study suggests that HSV-1 induces remodeling of the global ER architecture for recruitment of regulators mediating viral nuclear egress to the NM. IMPORTANCE The ER is an important cellular organelle that exists as a complex network extending throughout the cytoplasm. Although viruses often remodel the ER to facilitate viral replication, information on the effects of herpesvirus infections on ER morphological integrity is limited. Here, we showed that HSV-1 infection led to compression of the global ER architecture around the NM, resulting in accumulation of ER-associated regulators associated with nuclear egress of HSV-1 nucleocapsids. We also identified HSV-1 UL34 as a viral factor that mediated ER remodeling. Furthermore, we demonstrated that UL34 was required for efficient targeting of these regulators to the NM. To our knowledge, this is the first report showing that a herpesvirus remodels ER global architecture. Our study also provides insight into the mechanism by which the regulators for HSV-1 nuclear egress are recruited to the NM, where this viral event occurs.

scholarly journals Dok-1 and Dok-2 Are Required To Maintain Herpes Simplex Virus 1-Specific CD8+ T Cells in a Murine Model of Ocular Infection

2017 ◽  
Vol 91 (15) ◽  
Author(s):  
Soumia Lahmidi ◽  
Mitra Yousefi ◽  
Slimane Dridi ◽  
Pascale Duplay ◽  
Angela Pearson
Keyword(s):  
T Cells ◽  
Herpes Simplex ◽  
Acute Infection ◽  
T Cell Response ◽  
Ocular Infection ◽  
Trigeminal Ganglia ◽  
Herpes Simplex Virus 1 ◽  
Latently Infected ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT Dok-1 and Dok-2 negatively regulate responses downstream of several immune receptors in lymphoid and myeloid cells. Recent evidence showed that Dok proteins are essential in the formation of memory CD8+ T cells to an exogenous epitope expressed by vaccinia virus; however, the importance of Dok-1 and Dok-2 in the control of viral infection is unknown. Here, we investigated the role of Dok proteins in modulating the immune response against herpes simplex virus 1 (HSV-1) in a mouse model of ocular infection. During acute infection, viral titers in the eye were similar in wild-type (WT) and Dok-1 and Dok-2 double-knockout (DKO) mice, and the percentages of infiltrating leukocytes were similar in DKO and WT corneas and trigeminal ganglia (TG). DKO mice exhibited a diminished CD8+ T cell response to the immunodominant HSV-1 glycoprotein B (gB) epitope in the spleen and draining lymph nodes compared to WT mice during acute infection. Remarkably, gB-specific CD8+ T cells almost completely disappeared in the spleens of DKO mice during latency, and the reduction of CD8+ effector memory T (Tem) cells was more severe than that of CD8+ central memory T (Tcm) cells. The percentage of gB-specific CD8+ T cells in TG during latency was also dramatically reduced in DKO mice; however, they were phenotypically similar to those from WT mice. In ex vivo assays, reactivation was detected earlier in TG cultures from infected DKO versus WT mice. Thus, Dok-1 and Dok-2 promote survival of gB-specific CD8+ T cells in TG latently infected with HSV-1. IMPORTANCE HSV-1 establishes lifelong latency in sensory neurons of trigeminal ganglia (TG). In humans, HSV-1 is able to sporadically reactivate from latently infected neurons and establish a lytic infection at a site to which the neurons project. Most herpetic disease in humans is due to reactivation of HSV-1 from latency rather than to primary acute infection. CD8+ T cells are thought to play an important role in controlling recurrent infections. In this study, we examined the involvement of Dok-1 and Dok-2 signaling proteins in the control of HSV-1 infection. We provide evidence that Dok proteins are required to maintain a CD8+ T cell response against HSV-1 during latency—especially CD8+ Tem cells—and that they negatively affect HSV-1 reactivation from latency. Elucidating Dok-mediated mechanisms involved in the control of HSV-1 reactivation from latency might contribute to the development of therapeutic strategies to prevent recurrent HSV-1-induced pathology.

scholarly journals Herpes Simplex Virus 1 DNA Polymerase RNase H Activity Acts in a 3′-to-5′ Direction and Is Dependent on the 3′-to-5′ Exonuclease Active Site

2017 ◽  
Vol 92 (5) ◽  
Author(s):  
Jessica L. Lawler ◽  
Purba Mukherjee ◽  
Donald M. Coen
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Dna Polymerase ◽  
Polymerase Activity ◽  
Rnase H ◽  
Exonuclease Activity ◽  
Wild Type ◽  
Herpes Simplex Virus 1 ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACTThe catalytic subunit (Pol) of herpes simplex virus 1 (HSV-1) DNA polymerase has been extensively studied both as a model for other family B DNA polymerases and for its differences from these enzymes as an antiviral target. Among the activities of HSV-1 Pol is an intrinsic RNase H activity that cleaves RNA from RNA-DNA hybrids. There has long been a controversy regarding whether this activity is due to the 3′-to-5′ exonuclease of Pol or whether it is a separate activity, possibly acting on 5′ RNA termini. To investigate this issue, we compared wild-type HSV-1 Pol and a 3′-to-5′ exonuclease-deficient mutant, D368A Pol, for DNA polymerase activity, 3′-to-5′ exonuclease activity, and RNase H activityin vitro. Additionally, we assessed the RNase H activity using differentially end-labeled templates with 5′ or 3′ RNA termini. The mutant enzyme was at most modestly impaired for DNA polymerase activity but was drastically impaired for 3′-to-5′ exonuclease activity, with no activity detected even at high enzyme-to-DNA substrate ratios. Importantly, the mutant showed no detectable ability to excise RNA with either a 3′ or 5′ terminus, while the wild-type HSV-1 Pol was able to cleave RNA from the annealed RNA-DNA hairpin template, but only detectably with a 3′ RNA terminus in a 3′-to-5′ direction and at a rate lower than that of the exonuclease activity. These results suggest that HSV-1 Pol does not have an RNase H separable from its 3′-to-5′ exonuclease activity and that this activity prefers DNA degradation over degradation of RNA from RNA-DNA hybrids.IMPORTANCEHerpes simplex virus 1 (HSV-1) is a member of theHerpesviridaefamily of DNA viruses, several of which cause morbidity and mortality in humans. Although the HSV-1 DNA polymerase has been studied for decades and is a crucial target for antivirals against HSV-1 infection, several of its functions remain to be elucidated. A hypothesis suggesting the existence of a 5′-to-3′ RNase H activity intrinsic to this enzyme that could remove RNA primers from Okazaki fragments has been particularly controversial. In this study, we were unable to identify RNase H activity of HSV-1 DNA polymerase on RNA-DNA hybrids with 5′ RNA termini. We detected RNase H activity on hybrids with 3′ termini, but this was due to the 3′-to-5′ exonuclease. Thus, HSV-1 is unlikely to use this method to remove RNA primers during DNA replication but may use pathways similar to those used in eukaryotic Okazaki fragment maturation.

scholarly journals Optimized Viral Dose and Transient Immunosuppression Enable Herpes Simplex Virus ICP0-Null Mutants To Establish Wild-Type Levels of Latency In Vivo

2000 ◽  
Vol 74 (13) ◽  
pp. 5957-5967 ◽  
Author(s):  
William P. Halford ◽  
Priscilla A. Schaffer
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Inoculum Size ◽  
Wild Type ◽  
Latently Infected ◽  
Viral Dose ◽  
Simplex Virus ◽  
Null Mutants ◽  
Hsv 1

ABSTRACT The reduced efficiency with which herpes simplex virus type 1 (HSV-1) mutants establish latent infections in vivo has been a fundamental obstacle in efforts to determine the roles of individual viral genes in HSV-1 reactivation. For example, in the absence of the “nonessential” viral immediate-early protein, ICP0, HSV-1 is severely impaired in its ability to (i) replicate at the site of inoculation and (ii) establish latency in neurons of the peripheral nervous system. The mouse ocular model of HSV latency was used in the present study to determine if the conditions of infection can be manipulated such that replication-impaired, ICP0-null mutants establish wild-type levels of latency, as measured by viral genome loads in latently infected trigeminal ganglia (TG). To this end, the effects of inoculum size and transient immunosuppression on the levels of acute replication in mouse eyes and of viral DNA in latently infected TG were examined. Following inoculation of mice with 2 × 103, 2 × 104, 2 × 105, or 2 × 106 PFU/eye, wild-type virus replicated in mouse eyes and established latency in TG with similar efficiencies at all four doses. In contrast, increasing the inoculum size of the ICP0-null mutants n212 and 7134 from 2 × 105 to 2 × 106PFU/eye significantly decreased the levels of infectious virus detected in the tear films of mice from days 4 to 9 postinfection. In an attempt to establish the biological basis for this finding, the effect of viral dose on the induction of the host proinflammatory response was examined. Quantitative reverse transcription-PCR demonstrated that increasing the inoculum of 7134 from 2 × 104 to 2 × 106 PFU/eye significantly increased the expression of proinflammatory (interleukin 6), cell adhesion (intercellular adhesion molecule 1), and phagocyte-associated (CD11b) genes in mouse eyes 24 h postinfection. Furthermore, transient immunosuppression of mice with cyclophosphamide, but not cyclosporin A, significantly enhanced both the levels of acute n212 and 7134 replication in the eye and the levels of mutant viral genomes present in latently infected TG in a dose-dependent manner. Thus, the results of this study demonstrate that acute replication in the eye and the number of ICP0-null mutant genomes in latently infected TG can be increased to wild-type levels for both n212 and 7134 by (i) optimization of inoculum size and (ii) transient immunosuppression with cyclophosphamide.

scholarly journals Phosphorylation of Herpes Simplex Virus 1 dUTPase Upregulated Viral dUTPase Activity To Compensate for Low Cellular dUTPase Activity for Efficient Viral Replication

2014 ◽  
Vol 88 (14) ◽  
pp. 7776-7785 ◽  
Author(s):  
Akihisa Kato ◽  
Yoshitaka Hirohata ◽  
Jun Arii ◽  
Yasushi Kawaguchi
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Viral Replication ◽  
Enzymatic Activity ◽  
Wild Type ◽  
Herpes Simplex Virus 1 ◽  
Wild Type Level ◽  
Simplex Virus ◽  
Efficient Viral Replication ◽  
Hsv 1

ABSTRACTWe recently reported that herpes simplex virus 1 (HSV-1) protein kinase Us3 phosphorylated viral dUTPase (vdUTPase) at serine 187 (Ser-187) to upregulate its enzymatic activity, which promoted HSV-1 replication in human neuroblastoma SK-N-SH cells but not in human carcinoma HEp-2 cells. In the present study, we showed that endogenous cellular dUTPase activity in SK-N-SH cells was significantly lower than that in HEp-2 cells and that overexpression of cellular dUTPase in SK-N-SH cells increased the replication of an HSV-1 mutant with an alanine substitution for Ser-187 (S187A) in vdUTPase to the wild-type level. In addition, we showed that knockdown of cellular dUTPase in HEp-2 cells significantly reduced replication of the mutant vdUTPase (S187A) virus but not that of wild-type HSV-1. Furthermore, the replacement of Ser-187 in vdUTPase with aspartic acid, which mimics constitutive phosphorylation, and overexpression of cellular dUTPase restored viral replication to the wild-type level in cellular dUTPase knockdown HEp-2 cells. These results indicated that sufficient dUTPase activity was required for efficient HSV-1 replication and supported the hypothesis that Us3 phosphorylation of vdUTPase Ser-187 upregulated vdUTPase activity in host cells with low cellular dUTPase activity to produce efficient viral replication.virus.IMPORTANCEIt has long been assumed that dUTPase activity is important for replication of viruses encoding a dUTPase and that the viral dUTPase (vdUTPase) activity was needed if host cell dUTPase activity was not sufficient for efficient viral replication. In the present study, we showed that the S187A mutation in HSV-1 vdUTPase, which impaired its enzymatic activity, reduced viral replication in SK-N-SH cells, which have low endogenous cellular dUTPase activity, and that overexpression of cellular dUTPase restored viral replication to the wild-type level. We also showed that knockdown of cellular dUTPase in HEp-2 cells, which have higher dUTPase activity than do SK-N-SH cells, reduced replication of HSV-1 with the vdUTPase mutation but had no effect on wild-type virus replication. This is the first report, to our knowledge, directly showing that dUTPase activity is critical for efficient viral replication and that vdUTPase compensates for low host cell dUTPase activity to produce efficient viral replication.

scholarly journals Level of Herpes Simplex Virus Type 1 Latency Correlates with Severity of Corneal Scarring and Exhaustion of CD8+ T Cells in Trigeminal Ganglia of Latently Infected Mice

2008 ◽  
Vol 83 (5) ◽  
pp. 2246-2254 ◽  
Author(s):  
Kevin R. Mott ◽  
Catherine J. Bresee ◽  
Sariah J. Allen ◽  
Lbachir BenMohamed ◽  
Steven L. Wechsler ◽  
...  
Keyword(s):  
T Cells ◽  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Infected Individual ◽  
Trigeminal Ganglia ◽  
Corneal Scarring ◽  
Latently Infected ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT A hallmark of infection with herpes simplex virus type 1 (HSV-1) is the establishment of latency in ganglia of the infected individual. During the life of the latently infected individual, the virus can occasionally reactivate, travel back to the eye, and cause recurrent disease. Indeed, a major cause of corneal scarring (CS) is the scarring induced by HSV-1 following reactivation from latency. In this study, we evaluated the relationship between the amount of CS and the level of the HSV-1 latency-associated transcript (LAT) in trigeminal ganglia (TG) of latently infected mice. Our results suggested that the amount of CS was not related to the amount of virus replication following primary ocular HSV-1 infection, since replication in the eyes was similar in mice that did not develop CS, mice that developed CS in just one eye, and mice that developed CS in both eyes. In contrast, mice with no CS had significantly less LAT, and thus presumably less latency, in their TG than mice that had CS in both eyes. Higher CS also correlated with higher levels of mRNAs for PD-1, CD4, CD8, F4/80, interleukin-4, gamma interferon, granzyme A, and granzyme B in both cornea and TG. These results suggest that (i) the immunopathology induced by HSV-1 infection does not correlate with primary virus replication in the eye; (ii) increased CS appears to correlate with increased latency in the TG, although the possible cause-and-effect relationship is not known; and (iii) increased latency in mouse TG correlates with higher levels of PD-1 mRNA, suggesting exhaustion of CD8+ T cells.

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