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Studies of adenovirus-induced eye disease in the rabbit model
M D Trousdale1, R Nóbrega, R L Wood
1Doheny Eye Institute, Los Angeles, CA 90033, USA.
Purpose:
To achieve a better understanding of the pathogenic processes associated with human adenovirus (Ad)-induced ocular disease.
Methods:
Growth curves of Ad5 and Ad14 were performed in cell cultures derived from rabbit and human corneal epithelium (CE) and corneal keratocytes (CK). For in vivo studies, rabbit eyes were inoculated intrastromally and topically with 10(6) plaque-forming units per eye of Ad5 and ultraviolet light-inactivated (UV-1) Ad5 or Ad14, and the clinical features of the eyes were evaluated by biomicroscopic slit lamp examinations. Duration and quantitation of virus in tear samples were monitored. Humoral response was evaluated by enzyme-linked immunosorbent assay and serum neutralization titrations. Histopathologic and immunocytochemical staining of frozen corneal tissues was performed to determine the expression of major histocompatibility complex (MHC) class I and II and the presence of CD4+ and CD8+ T lymphocytes and CD18+ cells after the immunopathologic response elicited by virus inoculation.
Results:
Both Ad5 and Ad14 replicated in all human cell cultures studied. In cells of rabbit origin, Ad5 replicated in cultured CE and CK cells, whereas Ad14 replication appeared restricted. Virus titers in ocular samples from Ad5-inoculated eyes peaked on postinoculation days 3 through 4, with approximately a 100-fold increase in infectious virus in comparison to initial titers. The duration of Ad5 shedding was 8.9 +/- 2.4 days. Ad5, Ad5 UV-I, and Ad14 induced seroconversion and subepithelial opacities. CD4+ and CD8+ T lymphocytes and CD18+ cells were present in these intrastromal immune cell infiltrates. Expression of MHC class I and II was observed in keratocytes and immune cells; MHC class I also was expressed on CE cells in inflamed areas.
Conclusions:
Ad5 is capable of replicating in both CE and CK cells of the rabbit eye. The presence of Ad antigens within the corneal stroma originating from infectious virus (Ad5), UV-inactivated virus (Ad5), or nonreplicating infectious virus (Ad14) can elicit indistinguishable immunopathologic responses in the stroma composed of CD4+, CD8+, and CD18+ cells.
Insights
Human adenovirus (Ad) infection causes ocular disease. Both Ad5 and Ad14 replicate in human corneal cells, but Ad5 replicates in rabbit corneal cells, leading to immune responses in the stroma.
Area of Science:
- Ophthalmology
- Virology
- Immunology
Background:
- Human adenovirus (Ad) infections can cause significant ocular disease.
- Understanding the pathogenesis of Ad-induced ocular conditions is crucial for developing effective treatments.
Purpose of the Study:
- To elucidate the pathogenic mechanisms of human adenovirus-induced ocular disease.
- To compare the replication and immunopathogenic potential of Ad5 and Ad14 in ocular tissues.
Main Methods:
- Adenovirus serotypes 5 (Ad5) and 14 (Ad14) growth curves were assessed in human and rabbit corneal epithelial (CE) and keratocyte (CK) cell cultures.
- Rabbit eyes were inoculated with Ad5, UV-inactivated Ad5, or Ad14, and clinical features, viral shedding in tears, and humoral responses were evaluated.
- Corneal tissues were analyzed for immune cell infiltration (CD4+, CD8+, CD18+) and major histocompatibility complex (MHC) expression.
Main Results:
- Both Ad5 and Ad14 replicated in human CE and CK cells. Ad5 replicated in rabbit CE and CK cells, while Ad14 replication was restricted in rabbit cells.
- Inoculation with Ad5, UV-inactivated Ad5, or Ad14 induced seroconversion and subepithelial opacities in rabbit eyes.
- Intrastromal immune infiltrates containing CD4+, CD8+, and CD18+ cells were observed, with MHC class I and II expression on corneal cells and infiltrating immune cells.
Conclusions:
- Ad5 replicates effectively in both corneal epithelial and keratocyte cells of the rabbit eye.
- The presence of adenovirus antigens, regardless of infectivity or inactivation status, can trigger similar immunopathologic responses in the corneal stroma.
- These findings highlight the role of the host immune response in adenovirus-mediated ocular pathology.