scholarly journals Spontaneous Reactivation of Herpes Simplex Virus Type 1 in Latently Infected Murine Sensory Ganglia

2007 ◽  
Vol 81 (20) ◽  
pp. 11069-11074 ◽  
Author(s):  
Todd P. Margolis ◽  
Fred L. Elfman ◽  
David Leib ◽  
Nazzy Pakpour ◽  
Kathleen Apakupakul ◽  
...  

ABSTRACT Careful studies of mouse trigeminal ganglia (TG) latently infected with herpes simplex virus type 1 (HSV-1) indicate the presence of productive cycle viral gene products and persistent immune response, suggesting ongoing spontaneous viral reactivation in these tissues. In the present study we set out to determine whether infectious virus is present in murine TG latently infected with HSV-1 (KOS). At 37 days after ocular inoculation we found a small amount of infectious virus in ca. 6% of latently infected murine TG. Furthermore, the amount of infectious virus that we detected (PFU per viral antigen-positive neuron) was similar to that detected in acutely infected ganglia. We conclude that spontaneous reactivation of infectious HSV-1 occurs in the mouse TG and is likely the principle cause of viral protein expression in these tissues. We next examined the role of latency-associated transcript (LAT) in spontaneous ganglionic reactivation by examining ganglia latently infected with KOS dlLAT1.8, a LAT deletion virus. Through the use of immunocytochemistry we found that KOS dlLAT1.8 had a rate of spontaneous ganglionic reactivation very similar to that of HSV-1 (KOS). Studying spontaneous ganglionic reactivation of HSV in the mouse TG allows a direct study of viral reactivation from latently infected neurons without the potential confounders and complicating downstream events that accompany the study of viral reactivation by explantation or peripheral viral shedding. Since most cases of human viral shedding and reactivation are not associated with a known trigger, spontaneous ganglionic reactivation of HSV-1 may be a better model of human disease than existing models.

2000 ◽  
Vol 191 (9) ◽  
pp. 1459-1466 ◽  
Author(s):  
Ting Liu ◽  
Kamal M. Khanna ◽  
XiaoPing Chen ◽  
David J. Fink ◽  
Robert L. Hendricks

Recurrent herpes simplex virus type 1 (HSV-1) disease usually results from reactivation of latent virus in sensory neurons and transmission to peripheral sites. Therefore, defining the mechanisms that maintain HSV-1 in a latent state in sensory neurons may provide new approaches to reducing susceptibility to recurrent herpetic disease. After primary HSV-1 corneal infection, CD8+ T cells infiltrate the trigeminal ganglia (TGs) of mice, and are retained in latently infected ganglia. Here we demonstrate that CD8+ T cells that are present in the TGs at the time of excision can maintain HSV-1 in a latent state in sensory neurons in ex vivo TG cultures. Latently infected neurons expressed viral genome and some expressed HSV-1 immediate early and early proteins, but did not produce HSV-1 late proteins or infectious virions. Addition of anti-CD8α monoclonal antibody 5 d after culture initiation induced HSV-1 reactivation, as demonstrated by production of viral late proteins and infectious virions. Thus, CD8+ T cells can prevent HSV-1 reactivation without destroying the infected neurons. We propose that when the intrinsic capacity of neurons to inhibit HSV-1 reactivation from latency is compromised, production of HSV-1 immediate early and early proteins might activate CD8+ T cells aborting virion production.


2008 ◽  
Vol 83 (5) ◽  
pp. 2246-2254 ◽  
Author(s):  
Kevin R. Mott ◽  
Catherine J. Bresee ◽  
Sariah J. Allen ◽  
Lbachir BenMohamed ◽  
Steven L. Wechsler ◽  
...  

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.


1999 ◽  
Vol 73 (2) ◽  
pp. 920-929 ◽  
Author(s):  
Guey-Chuen Perng ◽  
Susan M. Slanina ◽  
Ada Yukht ◽  
Barbara S. Drolet ◽  
William Keleher ◽  
...  

ABSTRACT The herpes simplex virus type 1 (HSV-1) latency-associated transcript (LAT) gene is essential for efficient spontaneous reactivation of HSV-1 from latency. We previously reported that insertion of the LAT promoter and just the first 1.5 kb of the 8.3-kb LAT gene into an ectopic location in the virus restored wild-type spontaneous reactivation to a LAT null mutant. This mutant, LAT3.3A (previously designated LAT1.5a), thus showed that the expression of just the first 1.5 kb of LAT is sufficient for wild-type spontaneous reactivation. We also showed that in the context of the entire LAT gene, deletion of LAT nucleotides 76 to 447 (LAT mutantdLAT371) had no effect on spontaneous reactivation or virulence. We report here on a LAT mutant designated LAT2.9A. This mutant is similar to LAT3.3A, except that the ectopic LAT insert contains the same 371-nucleotide deletion found in dLAT371. We found that LAT2.9A had a significantly reduced rate of spontaneous reactivation compared to marker-rescued and wild-type viruses. This was unexpected, since the combined results of dLAT371 and LAT3.3A predicted that spontaneous reactivation of LAT2.9A would be wild type. We also found that LAT2.9A was more virulent than wild-type or marker-rescued viruses after ocular infection of rabbits. This was unexpected, since LAT null mutants and LAT3.3A have wild-type virulence. These results suggest for the first time (i) that regions past the first 1.5 kb of LAT can compensate for deletions in the first 1.5kb of LAT and may therefore play a role in LAT dependent spontaneous reactivation and (ii) that regions of LAT affect viral virulence.


2008 ◽  
Vol 83 (5) ◽  
pp. 2237-2245 ◽  
Author(s):  
Brian S. Sheridan ◽  
Thomas L. Cherpes ◽  
Julie Urban ◽  
Pawel Kalinski ◽  
Robert L. Hendricks

ABSTRACT In C57BL/6 (B6) mice, most herpes simplex virus (HSV)-specific CD8 T cells recognize a strongly immunodominant epitope on glycoprotein B (gB498) and can inhibit HSV type 1 (HSV-1) reactivation from latency in trigeminal ganglia (TG). However, half of the CD8 T cells retained in latently infected TG of B6 mice are not gB498 specific and have been largely ignored. The following observations from our current study indicate that these gB498-nonspecific CD8 T cells are HSV specific and may contribute to the control of HSV-1 latency. First, following corneal infection, OVA257-specific OT-1 CD8 T cells do not infiltrate the infected TG unless mice are simultaneously immunized with OVA257 peptide, and then they are not retained. Second, 30% of CD8 T cells in acutely infected TG that produce gamma interferon in response to HSV-1 stimulation directly ex vivo are gB498 nonspecific, and these cells maintain an activation phenotype during viral latency. Finally, gB498-nonspecific CD8 T cells are expanded in ex vivo cultures of latently infected TG and inhibit HSV-1 reactivation from latency in the absence of gB498-specific CD8 T cells. We conclude that many of the CD8 T cells that infiltrate and are retained in infected TG are HSV specific and potentially contribute to maintenance of HSV-1 latency. Identification of the viral proteins recognized by these cells will contribute to a better understanding of the dynamics of HSV-1 latency.


2003 ◽  
Vol 77 (11) ◽  
pp. 6556-6561 ◽  
Author(s):  
Ling Jin ◽  
Weiping Peng ◽  
Guey-Chuen Perng ◽  
David J. Brick ◽  
Anthony B. Nesburn ◽  
...  

ABSTRACT The herpes simplex virus type 1 (HSV-1) latency-associated transcript (LAT) gene is essential for the high spontaneous and induced reactivation phenotype of HSV-1 in the rabbit ocular model and for the high induced reactivation phenotype in the mouse ocular model. Recently we showed that LAT has an antiapoptosis function, and we hypothesized that LAT's ability to inhibit apoptosis played an important role in LAT's ability to enhance the reactivation phenotype. Expression of just the first 1.5 kb of the 8.3-kb LAT gene is sufficient for both inhibition of apoptosis in an in vitro transient-transfection assay and the high spontaneous reactivation phenotype in vivo. Here we show the results of more complex mapping studies in which inhibition of apoptosis and the enhanced spontaneous reactivation phenotype also appear to be linked. The HSV-1 mutant virus dLAT371 has a high spontaneous reactivation phenotype in rabbits, suggesting that the LAT region deleted in this mutant (LAT nucleotides 76 to 447) is not required for this phenotype. The LAT3.3A viral mutant (which expresses LAT nucleotides 1 to 1499) also has a high spontaneous reactivation phenotype, suggesting that the region of LAT not expressed by this mutant (LAT nucleotide 1500 to the end of LAT) is also not required for this phenotype. Surprisingly, LAT2.9A, which is a combination of dLAT371 and LAT3.3A (i.e., it expresses LAT nucleotides 1 to 76 and 447 to 1499), has a low spontaneous reactivation phenotype indistinguishable from that of LAT null mutants. We report here that consistent with the low spontaneous reactivation phenotype of LAT2.9A, a plasmid expressing the identical LAT RNA did not inhibit caspase 9-induced apoptosis. In contrast, plasmids containing the same deletion but able to transcribe up to or past LAT nucleotide 2850 (rather than just up to LAT nucleotide 1499) inhibited caspase 9-induced apoptosis, consistent with the high spontaneous reactivation phenotype of dLAT371. Thus, LAT2.9A may have a low spontaneous reactivation phenotype because the LAT RNA that is made cannot block apoptosis, and dLAT371 apparently has a high spontaneous reactivation phenotype because the LAT RNA made has significant antiapoptosis activity. Furthermore, LAT appeared to have at least two regions capable of interfering with caspase 9-induced apoptosis. One region partially overlaps LAT nucleotides 76 to 447. The second region is partially (or completely) downstream of LAT nucleotide 1499.


2000 ◽  
Vol 74 (4) ◽  
pp. 1885-1891 ◽  
Author(s):  
Guey-Chuen Perng ◽  
Susan M. Slanina ◽  
Ada Yukht ◽  
Homayon Ghiasi ◽  
Anthony B. Nesburn ◽  
...  

ABSTRACT The latency-associated transcript (LAT) gene the only herpes simplex virus type 1 (HSV-1) gene abundantly transcribed during neuronal latency, is essential for efficient in vivo reactivation. Whether LAT increases reactivation by a direct effect on the reactivation process or whether it does so by increasing the establishment of latency, thereby making more latently infected neurons available for reactivation, is unclear. In mice, LAT-negative mutants appear to establish latency in fewer neurons than does wild-type HSV-1. However, this has not been confirmed in the rabbit, and the role of LAT in the establishment of latency remains controversial. To pursue this question, we inserted the gene for the enhanced green fluorescent protein (EGFP) under control of the LAT promoter in a LAT-negative virus (ΔLAT-EGFP) and in a LAT-positive virus (LAT-EGFP). Sixty days after ocular infection, trigeminal ganglia (TG) were removed from the latently infected rabbits, sectioned, and examined by fluorescence microscopy. EGFP was detected in significantly more LAT-EGFP-infected neurons than ΔLAT-EGFP-infected neurons (4.9% versus 2%, P < 0.0001). The percentages of EGFP-positive neurons per TG ranged from 0 to 4.6 for ΔLAT-EGFP and from 2.5 to 11.1 for LAT-EGFP (P = 0.003). Thus, LAT appeared to increase neuronal latency in rabbit TG by an average of two- to threefold. These results suggest that LAT enhances the establishment of latency in rabbits and that this may be one of the mechanisms by which LAT enhances spontaneous reactivation. These results do not rule out additional LAT functions that may be involved in maintenance of latency and/or reactivation from latency.


2002 ◽  
Vol 83 (12) ◽  
pp. 2933-2942 ◽  
Author(s):  
Guey-Chuen Perng ◽  
Kevin R. Mott ◽  
Nelson Osorio ◽  
Ada Yukht ◽  
Susan Salina ◽  
...  

Herpes simplex virus type 1 (HSV-1) strain McKrae is neurovirulent in rabbits infected by the ocular route, causing fatal encephalitis in approximately 50% of the animals, and has a high-level spontaneous reactivation phenotype, with 10% of rabbit eyes containing reactivated virus at any given time. In contrast, HSV-1 strain KOS is completely avirulent (no rabbits die) and has a completely negative spontaneous reactivation phenotype. Mutations of the ICP34.5 gene can reduce the neurovirulence of HSV-1 strains McKrae and 17syn+ by up to 100000-fold. ICP34.5 mutants also have reduced spontaneous reactivation phenotypes. To determine whether differences in the ICP34.5 gene might be involved in the reduced neurovirulence and spontaneous reactivation phenotypes of KOS compared with McKrae, we constructed chimeric viruses containing the KOS ICP34.5 gene in place of the McKrae ICP34.5 gene. Rabbits ocularly infected with the chimeric viruses had a high spontaneous reactivation phenotype indistinguishable from McKrae. In contrast, neurovirulence of the chimeric viruses was decreased compared with McKrae. Thus, one or more ‘defects’ in the KOS ICP34.5 gene appeared to be at least partially responsible for the reduced neurovirulence of KOS compared with McKrae. However, there appeared to be no ‘defect′ in the KOS ICP34.5 function required for efficient spontaneous reactivation.


2001 ◽  
Vol 75 (21) ◽  
pp. 10401-10408 ◽  
Author(s):  
Naomi S. Taus ◽  
William J. Mitchell

ABSTRACT Herpes simplex virus type 1 (HSV-1) establishes a latent infection in neurons of sensory ganglia, including those of the trigeminal ganglia. Latent viral infection has been hypothesized to be regulated by restriction of viral immediate-early gene expression in neurons. Numerous in situ hybridization studies in mice and in humans have shown that transcription from the HSV-1 genome in latently infected neurons is limited to the latency-associated transcripts. In other studies, immediate-early gene (ICP4) transcripts have been detected by reverse transcription-PCR (RT-PCR) in homogenates of latently infected trigeminal ganglia of mice. We used reporter transgenic mice containing the HSV-1(F) ICP4 promoter fused to the coding sequence of the β-galactosidase gene to determine whether neurons in latently infected trigeminal ganglia activated the ICP4 promoter. Mice were inoculated via the corneal route with HSV-1(F). At 5, 11, 23, and 37 days postinfection (dpi), trigeminal ganglia were examined for β-galactosidase-positive cells. The numbers of β-galactosidase-positive neurons and nonneuronal cells were similar at 5 dpi. The number of positive neurons decreased at 11 dpi and returned to the level of mock-inoculated transgenic controls at 23 and 37 dpi. The number of positive nonneuronal cells increased at 11 and 23 dpi and remained elevated at 37 dpi. Viral proteins were detected in neurons and nonneuronal cells in acutely infected ganglia, but were not detected in latently infected ganglia. Colabeling experiments confirmed that the transgenic ICP4 promoter was activated in Schwann cells during latent infection. These findings suggest that the cells that express the HSV-1 ICP4 gene in latently infected ganglia are not neurons.


Sign in / Sign up

Export Citation Format

Share Document