Purchase this article with an account.
Ana Chucair-Elliott, Christopher Conrady, Min Zheng, Daniel Carr; Corneal Pathology Profile in the Absence of a Functional Type I Interferon Pathway Following HSV-1 Infection. Invest. Ophthalmol. Vis. Sci. 2013;54(15):2534.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Type I interferon (IFN) production elicited by HSV-1-driven IFI16/p204 sensor activation in corneal epithelial cells is critical for viral surveillance. How type I IFN pathways regulate tissue pathology in the cornea is unknown. Previously, we reported mice that lack the type I IFN alpha 1 chain (CD118-/-) were highly susceptible to ocular HSV-1 infection. Here, we hypothesize an aberrant immune cell infiltrate and the loss of viral containment in the cornea contribute to significant corneal pathology in the CD118-/- mice mainly by immune-mediated events.
C57BL/6 wild type (WT) and CD118-/- mice were infected with 1,000 plaque forming units of HSV-1 (McKrae strain). At times post infection (pi), the mice were euthanized, and the corneas were collected and processed for inflammatory cell influx by flow cytometry, viral titers by plaque assay, leukocyte and HSV-1 antigen expression by immunohistochemistry and confocal microscopy, and MMP9 levels by ELISA. We compared corneal pathology including corneal thickness, opacity, and fluorescein staining by histological techniques and slit lamp imaging.
CD118-/- infected corneas had higher viral loads than WT mice, but harbored fewer NK cells, macrophages, and inflammatory monocytes but elevated neutrophils compared to WT mice by day 5 pi. Ly6G+ neutrophils within the stroma of CD118-/- mice co-stained with HSV-1 antigen but this was not evident in WT mice. However, adoptive transfer of neutrophils from the cornea of WT or CD118-/- mice into naive CD118-/- mice resulted in 50 and 100% mortality respectively of the recipients. Along with elevated viral titers, CD118-/- mice exhibited almost complete loss of corneal epithelial cell layers despite overall thickening of the cornea. The pathology was consistent with slit lamp images that showed a dramatic increase in the areas of epithelial lesions, corneal opacity, and loss of iris details coinciding with a significant increase in MMP9 levels in the CD118-/- mice.
The loss of a functional type I IFN pathway pre-disposes the cornea to substantial pathology following HSV-1 infection associated with larger viral loads and a significant increase in neutrophil influx and MMP9 expression. Infiltrating neutrophils from WT and CD118-/- mice endocytose virus that is not destroyed and may serve as an additional source for virus to replicate and disseminate.
This PDF is available to Subscribers Only