Abstract
Purpose :
Reactivation of varicella-zoster virus (VZV) can result in herpes zoster ophthalmicus (HZO). Up to half of HZO patients develop uveitis, which is characterized by inflammation dominated by lymphocytes (especially CD4+ T cells) and can lead to blindness. Limitations associated with studying ocular fluid from patients have hindered a better understanding of VZV uveitis. The purpose of our study was to establish VZV infection of human retinal pigmented epithelial (RPE) cell line ARPE-19 as an in vitro model of VZV uveitis.
Methods :
ARPE-19 cells were infected at a multiplicity of infection of 0.01 or 0.05 for increasing times with cell-associated VZV. Samples were prepared for immunoblotting and microscopy to monitor infection kinetics. Supernatants were collected from uninfected and VZV-infected ARPE-19 cells to evaluate the kinetics of mediators using MesoScale 10-PLEX human proinflammatory cytokine and chemokine panels. Transwell assays containing supernatants were used to quantify migration of CD4+ T cells from PBMCs of healthy volunteers.
Results :
We confirmed that ARPE-19 cells were infected by VZV and supported viral replication. The multiplex assays indicated that MCP-1 and IL-8 were the most abundantly detected chemokines (ng/mL) in VZV-infected supernatants, which were 2- to 3-fold higher than those in uninfected supernatants. Other mediators, such as IL-6 and IP-10, were also increased in VZV-infected supernatants but to a lesser extent (pg/mL). Cytokines such as IFN-γ and MIP-1β were minimally detected in VZV-infected supernatants. The majority of detected mediators are known lymphocyte chemoattractants, especially CD4+ T cells. Accordingly, we observed an increased migration of CD4+ T cells towards VZV-infected supernatants.
Conclusions :
VZV-infected ARPE-19 cells secreted high levels of MCP-1 and IL-8, which agrees with reports using ocular fluid from uveitis patients, suggesting that these chemokines are produced by VZV-infected RPE in vivo. In contrast, other cytokines found at high levels in ocular fluid, such as IL-6 and IFN-γ, were detected at low levels in our studies, indicating that other cell types contribute to their production in vivo. The observation that CD4+ T cell migration increased towards VZV-infected supernatants corroborates clinical findings. Thus, our data demonstrate that VZV infection of ARPE-19 cells serves as a useful model to study VZV uveitis.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.