Delaying the Expression of Herpes Simplex Virus Type 1 Glycoprotein B (gB) to a True Late Gene Alters Neurovirulence and Inhibits the gB-CD8+ T-Cell Response in the Trigeminal Ganglion

Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213, USA.
Journal of Virology (Impact Factor: 4.44). 09/2010; 84(17):8811-20. DOI: 10.1128/JVI.00496-10
Source: PubMed

ABSTRACT Following herpes simplex virus type 1 (HSV-1) ocular infection of C57BL/6 mice, activated CD8(+) T cells specific for an immunodominant epitope on HSV-1 glycoprotein B (gB-CD8 cells) establish a stable memory population in HSV-1 latently infected trigeminal ganglia (TG), whereas non-HSV-specific CD8(+) T cells are lost over time. The retention and activation of gB-CD8 cells appear to be influenced by persistent viral antigenic exposure within the latently infected TG. We hypothesized that the low-level expression of gB from its native promoter before viral DNA synthesis is critical for the retention and activation of gB-CD8 cells in the TG during HSV-1 latency and for their ability to block HSV-1 reactivation from latency. To test this, we created a recombinant HSV-1 in which gB is expressed only after viral DNA synthesis from the true late gC promoter (gCp-gB). Despite minor growth differences compared to its rescuant in infected corneas, gCp-gB was significantly growth impaired in the TG and produced a reduced latent genome load. The gCp-gB- and rescuant-infected mice mounted similar gB-CD8 effector responses, but the size and activation phenotypes of the memory gB-CD8 cells were diminished in gCp-gB latently infected TG, suggesting that the stimulation of gB-CD8 cells requires gB expression before viral DNA synthesis. Surprisingly, late gB expression did not compromise the capacity of gB-CD8 cells to inhibit HSV-1 reactivation from latency in ex vivo TG cultures, suggesting that gB-CD8 cells can block HSV-1 reactivation at a very late stage in the viral life cycle. These data have implications for designing better immunogens for vaccines to prevent HSV-1 reactivation.

Download full-text


Available from: Katherine Anne Davoli, Sep 29, 2015
112 Reads
  • Source
    • "During latency, the LAT intron is the predominant transcript that is made from the viral genome (Wagner et al. 1988). There is evidence, however, of low-level lytic gene expression despite the presence of repressive chromatin modifications (Ramachandran et al. 2010). It has been suggested that, in neuronal cultures, low-level gene expression is required for the production of VP16, a γ gene. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Herpes simplex virus type 1 (HSV-1) is capable of causing a latent infection in sensory neurons that lasts for the lifetime of the host. The primary infection is resolved following the induction of the innate immune response that controls replication of the virus until the adaptive immune response can clear the active infection. HSV-1-specific CD8(+) T cells survey the ganglionic regions containing latently infected neurons and participate in preventing reactivation of HSV from latency. The long-term residence and migration dynamics of the T cells in the trigeminal ganglia appear to distinguish them from the traditional memory T cell subsets. Recently described tissue resident memory (TRM) T cells establish residence and survive for long periods in peripheral tissue compartments following antigen exposure. This review focuses on the immune system response to HSV-1 infection. Particular emphasis is placed on the evidence pointing to the HSV-1-specific CD8(+) T cells in the trigeminal belonging to the TRM class of memory T cells and the role of TRM cells in virus infection, pathogenesis, latency, and disease.
    Journal of NeuroVirology 08/2013; 19(4). DOI:10.1007/s13365-013-0189-3 · 2.60 Impact Factor
  • Source
    • "gB is a leaky-late gene and, the fact that the reactivating neuron was recognized by a gB-specific CD8 + T cell indicates that IE and early genes are likely to be expressed prior to a CD8 + T cell-mediated block in reactivation . These data indicate that, not only are neurons able to survive high viral genome inputs, they can also survive extensive viral gene expression (Kramer et al., 1998; Ramachandran et al., 2010). This is in agreement with studies using primary neuronal cultures where upon infection with replication defective mutants, transient IE promoter activity was detected in the majority of the neurons in culture prior to the establishment of latent infection (Arthur et al., 2001). "
    [Show abstract] [Hide abstract]
    ABSTRACT: Herpes simplex virus type 1 is a neurotropic herpesvirus that establishes latency within sensory neurones. Following primary infection, the virus replicates productively within mucosal epithelial cells and enters sensory neurones via nerve termini. The virus is then transported to neuronal cell bodies where latency can be established. Periodically, the virus can reactivate to resume its normal lytic cycle gene expression programme and result in the generation of new virus progeny that are transported axonally back to the periphery. The ability to establish lifelong latency within the host and to periodically reactivate to facilitate dissemination is central to the survival strategy of this virus. Although incompletely understood, this review will focus on the mechanisms involved in the regulation of latency that centre on the functions of the virus-encoded latency-associated transcripts (LATs), epigenetic regulation of the latent virus genome and the molecular events that precipitate reactivation. This review considers current knowledge and hypotheses relating to the mechanisms involved in the establishment, maintenance and reactivation herpes simplex virus latency.
    FEMS microbiology reviews 12/2011; 36(3):684-705. DOI:10.1111/j.1574-6976.2011.00320.x · 13.24 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The protein kinase found in the short region of alphaherpesviruses, termed US3 in herpes simplex virus type 1 (HSV-1) and pseudorabies virus (PRV) and ORF66 in varicella-zoster virus (VZV), affects several viral and host cell processes, and its specific targets remain an area of active investigation. Reports suggesting that HSV-1 US3 substrates overlap with those of cellular protein kinase A (PKA) prompted the use of an antibody specific for phosphorylated PKA substrates to identify US3/ORF66 targets. HSV-1, VZV, and PRV induced very different substrate profiles that were US3/ORF66 kinase dependent. The predominant VZV-phosphorylated 125-kDa species was identified as matrin 3, one of the major nuclear matrix proteins. Matrin 3 was also phosphorylated by HSV-1 and PRV in a US3 kinase-dependent manner and by VZV ORF66 kinase at a novel residue (KRRRT150EE). Since VZV-directed T150 phosphorylation was not blocked by PKA inhibitors and was not induced by PKA activation, and since PKA predominantly targeted matrin 3 S188, it was concluded that phosphorylation by VZV was PKA independent. However, purified VZV ORF66 kinase did not phosphorylate matrin 3 in vitro, suggesting that additional cellular factors were required. In VZV-infected cells in the absence of the ORF66 kinase, matrin 3 displayed intranuclear changes, while matrin 3 showed a pronounced cytoplasmic distribution in late-stage cells infected with US3-negative HSV-1 or PRV. This work identifies phosphorylation of the nuclear matrix protein matrin 3 as a new conserved target of this kinase group.
    Journal of Virology 10/2010; 85(1):568-81. DOI:10.1128/JVI.01611-10 · 4.44 Impact Factor
Show more