title: Critical role of corneal Langerhans cells in the CD4- but not CD8-mediated immunopathology in herpes simplex virus-1-infected mouse corneas.
abstract: Previous studies have revealed that the RE strain of HSV type 1 (HSV-1) induces a tissue-destructive inflammatory response in the mouse cornea that is mediated by CD4 T lymphocytes, whereas the KOS strain of HSV-1 preferentially activates CD8 T lymphocytes in the cornea. Langerhans cells (LC) normally reside only at the periphery of the cornea but can migrate centripetally after HSV-1 infection. We studied the relative contribution of LC to the corneal inflammation induced by the KOS and RE strains of HSV-1. Ten days after infection, the central one-third of RE HSV-1-infected corneas contained an average of 5.7 LC/high-power field compared with 0.6 LC/high-power field in KOS-infected corneas. We hypothesized that the increased density of LC in RE HSV-1-infected corneas at the time of T lymphocyte infiltration contributed to the preferential activation of CD4 T lymphocytes in these corneas. To test this hypothesis, we gave mice a low dose of UV-B corneal irradiation (150 mJ/cm2) 1 day before infection with HSV-1. UV-B irradiation effectively prevented the migration of LC into the central cornea when measured 10 or 21 days after corneal infection with either HSV-1 strain. UV-B corneal irradiation had no effect on the CTL response to HSV-1 Ag in the regional lymph nodes after corneal infection with KOS or RE HSV-1. The delayed-type hypersensitivity response induced by both strains of virus, when measured 8 and 14 days after corneal infection, was significantly reduced by UV-B irradiation. UV-B irradiation significantly reduced the incidence (p = 0.0023) and severity (p = 0.0008) of corneal stromal disease induced by RE HSV-1 but did not significantly affect the stromal disease induced by KOS HSV-1. To distinguish between the effect of UV-B treatment on the afferent and efferent arms of the Ir in mice, we administered UV-B treatment to one eye, followed 24 h later by RE HSV-1 infection of both eyes. These mice developed a normal delayed-type hypersensitivity response, and stromal inflammation developed normally in the untreated eye. However, stromal inflammation was significantly reduced in the treated eye. Our findings suggest that LC play a critical role in the activation of HSV-reactive CD4 T lymphocytes in the cornea. Moreover, the type of corneal inflammation induced by different strains of HSV-1 may reflect their differential capacity to induce LC migration into the central cornea.
authors.affiliation: Department of Ophthalmology and Visual Sciences, University of Illinois, Chicago 60612.
authors.forename: R L
authors.initials: RL
authors.lastname: Hendricks
authors.forename: M
authors.initials: M
authors.lastname: Janowicz
authors.forename: T M
authors.initials: TM
authors.lastname: Tumpey
mesh_terms: D000818:Animals; D015704:CD4 Antigens / Q000502:physiology*; D016827:CD8 Antigens / Q000502:physiology*; D003315:Cornea / Q000276:immunology* / Q000382:microbiology; D005260:Female; D016849:Keratitis, Herpetic / Q000209:etiology* / Q000276:immunology / Q000473:pathology; D007801:Langerhans Cells / Q000502:physiology*; D051379:Mice; D018139:Simplexvirus / Q000528:radiation effects; D013601:T-Lymphocytes / Q000502:physiology*; D014466:Ultraviolet Rays; D014779:Virus Replication / Q000528:radiation effects
chemical_list: D015704:CD4 Antigens; D016827:CD8 Antigens