The presence of VZV primarily in the adventitia early in infection and in the media and intima later supports the notion that after reactivation from ganglia, VZV spreads transaxonally to the arterial adventitia followed by transmural spread of virus. Disruption of the internal elastic lamina, progressive intimal thickening with cells expressing α-SMA and SM-MHC, and decreased smooth muscle cells in the media are characteristic features of VZV vasculopathy. Stroke in VZV vasculopathy may result from changes in arterial caliber and contractility produced in part by abnormal accumulation of smooth muscle cells and myofibroblasts in thickened neointima and disruption of the media.

Varicella zoster virus (VZV) establishes latency in neurons of human peripheral ganglia where the virus genome is most likely maintained as a circular episome bound to histones. There is considerable variability among individuals in the number of latent VZV DNA copies. The VZV DNA burden does not appear to exceed that of herpes simplex type 1 (HSV-1). Expression of VZV genes during latency is highly restricted and is regulated epigenetically. Of the VZV open reading frames (ORFs) that have been analyzed for transcription during latency using cDNA sequencing, only ORFs 21, 29, 62, 63, and 66 have been detected. VZV ORF 63 is the most frequently and abundantly transcribed VZV gene detected in human ganglia during latency, suggesting a critical role for this gene in maintaining the latent state and perhaps the early stages of virus reactivation The inconsistent detection and low abundance of other VZV transcripts suggest that these genes play secondary roles in latency or possibly reflect a subpopulation of neurons undergoing VZV reactivation. New technologies, such as GeXPS multiplex PCR, have the sensitivity to detect multiple low abundance transcripts and thus provide a means to elucidate the entire VZV transcriptome during latency.

Varicella zoster virus (VZV) latency is characterized by limited virus gene expression and the absence of virus DNA replication. Investigations of VZV latency and reactivation have been hindered by the lack of an in vitro model of virus latency. Since VZV is an exclusively human pathogen, we used naturally infected human trigeminal ganglia (TG) obtained at autopsy to study virus latency. Herein, we report optimization of medium to maintain TG integrity as determined by histology and immunohisto-chemistry. Using the optimized culture medium, we also found that both herpes simplex virus-1 (HSV-1) and VZV DNA replicated in TG explants after 5 days in culture. The increase in HSV-1 DNA was fourfold greater than the increase in VZV DNA. Overall, we present a model for alphaherpesvirus latency in human neurons in which the key molecular events leading to virus reactivation can be studied.

Varicella-zoster virus (VZV) is a ubiquitous, highly cell-associated, and exclusively human neurotropic alphaherpesvirus. VZV infection is initiated by membrane fusion, an event dependent in part on VZV glycoproteins gH and gL. Consistent with its location on the virus envelope, the gH/gL complex is a target of neutralizing antibodies produced after virus infection. One week after immunizing a 59-year-old VZV-seropositive man with Zostavax, we sorted his circulating blood plasma blasts and amplified expressed immunoglobulin variable domain sequences by single-cell PCR. Sequence analysis identified two plasma blast clones, one of which was used to construct a recombinant monoclonal antibody (rec-RC IgG). V aricella-zoster virus (VZV), the etiologic agent of varicella (chickenpox) and zoster (shingles), is an exclusively human pathogen and a member of the Herpesviridae family of enveloped DNA viruses. Herpesviruses cause both lytic and latent infections. Lytic infection requires membrane fusion, an event governed by a core complex consisting of conserved glycoproteins gB, gH, and gL. Along with membrane fusion, VZV gH and gL are also involved in virus egress and are essential for virus replication (1-4). In addition to mediating virus entry, VZV glycoproteins can traffic from infected cells to uninfected cells (5). VZV glycoproteins induce strong humoral immune responses both in naturally infected individuals and in varicella or zoster vaccine recipients (6-10). While VZV gE is the most immunogenic and predominant glycoprotein in VZV-infected cell membranes, antibodies to VZV gH are the major neutralizing antibodies (11-16). It is likely that neutralizing activity by the gH/gL complex effectively prevents cell-to-cell virus spread (5,(17)(18)(19)(20).Analysis of VZV attachment and membrane fusion requires highly specific neutralizing antibodies. Hybridoma cell lines and phage display libraries produce human anti-VZV gE and gH monoclonal antibodies (MAbs) that neutralize virus infection (21-24). Monoclonal antibodies that recognize the VZV gH/gL protein complex hold promise in therapies involving passive transfer of neutralizing VZV antibodies (15,16,25,26). Here we present a new method for constructing a recombinant human monoclonal anti-VZV antibody and show that this antibody detects a conformational epitope on the gH/gL complex and neutralizes virus. MATERIALS AND METHODS Cells and virus.Human lung fibroblast (HFL) and human embryonic kidney (HEK-EBNA 293) cells (American Type Culture Collection, Manassas, VA) were cultured in Dulbecco's modified Eagle's medium supplemented with 4 mM L-glutamine (DMEM; Sigma-Aldrich, St. Louis, MO) and 10% fetal bovine serum (FBS) (Atlanta Biologicals, Lawrenceville, GA). VZV was propagated by cocultivating infected cells with uninfected cells as described previously (27). Infected HFL cultures were harvested at the height of virus-induced cytopathic effect, usually at 3 days postinfection (dpi).Construction of recombinant antibody. Blood was collected 7 days after immunization...

Varicella zoster virus (VZV) is highly cell-associated. At least 68 VZV open reading frames (ORFs) are transcribed in varying amounts that increase as infection progresses. Using reverse transcriptase PCR, quantification of total and newly synthesized mRNA showed that ongoing VZV DNA replication is required for continued accumulation of VZV ORF 63, 9, and 40 transcripts. Analysis of stability of 4-thiouridine-labeled transcripts of nine VZV ORFs revealed a similar half-life for all VZV ORFs tested. Thus, difference in mRNA synthesis, and not mRNA decay, is the major factor contributing to the difference in the relative abundance of VZV transcripts in infected cells.