| ObjectiveRecurrent herpetic stromal keratitis (HSK) is a potentially blinding, immune - mediated disease. To better understand the immunopathology of HSK mediated by CD4+ T cells, we established the BALB/c mouse model of recurrent HSK, which maximize fidelity to human disease; With this system, we studied the relative contributions of Th1 and Th2 cells to the pathogenesis of HSK; In BALB/c mouse model of primary HSK, we examined the role of CD28/CTLA -4:B7 in the activation of naive CD/ T cells during the development of HSK.MethodsIn the first part, BALB/c mice were infected with 1+ 106 PFU HSV - 1 Mckrae strain by cornea! scarification and established latent infection of virus in the trigeminal ganglia. Six weeks later, the eyes of latently infected mice were exposed to 170mJ/cm2 UV - B light. The eyes of mice were swabbed to detect recurrent virus shedding from the cornea by culture of swab material on VERO cells, and were examined for corneal pathology. The pattern of cytokine expression was detected by RT - PCR in the mouse model of recurrent HSK. In the second part, murine rIL -10 was inoculated intracorneally 6 h before and again on days 0, + 2, + 4, + 7, +10, +14 relative to the time of ultraviolet - B (UV-B) irradiation to test whether IL - 10 suppress the development of HSK. In the third part, CD28, CTLA -4, B7 - 1 and B7 -2 molecules were examined in BALB/c mouse model of primary model. Meanwhile, BALB/c mice infected with HSV -1 Mckrae strain by corneal scarification were injected intrap-eritoneally with murine CTLA - 4Ig given on days 0, + 2, +4 postinfection. The inhibitions of CTLA -4Ig on CD/ T and CD/ T cells were evaluated by flowcytometry.ResultsFollowing infection of the cornea with HSV -1 McKrae strain in BALB/c mice, virus shedding from the cornea was detected within the first 5 days and was not recovered after 6 days. Mice were examined by slit lamp biomicroscopy after infection. Epithelial damage was observed by day 1 postinfection in some mice. Superficial epithelial keratitis such as characteristical dendrites was displayed by day 3 in all mice. By day 7, eyes were judged to be normal by slit lamp biomicroscopy. By week 7 postinfection, infectious virus was recovered from all of the trigeminal ganglia and from none of the ocular surfaces of these animals. After 30 latently infected mice were exposed to 170mJ/cm UV-B radiation, 55 of the 70 mice (78.6% ) shed infectious virus at the ocular surface by the 2-6th day postirradiation. the recurrent mice developed stromal opacities and neovascularization. Histopathological section of cornea displays that cornea! stroma were swollen and contained a heavy inflammatory cells infiltrate consisting primarily of neutrophils and lymphocytes, and cornea! neovascularization. Thus the recurrent HSK clinically and histologically parallels the human condition.Using the murine models of recurrent HSK, IFN -r,IL - 12 p40,IL - 10 and IL - 4 mRNA were simultaneously expressed before and during recurrent HSK. Semi-quantitative RT-PCR evaluation of cytokine mRNA revealed highest IFN - rexpression before and during clinical disease with a decline thereafter. IL -4 levels peaked and declined before day 14, IL -10 peaked on days 7 or 14 and paralleled IFN- r at lower levels. Large amounts of IL-12 p40 mRNA were detected over the course of recurrent disease.In the second part, in the IL -10 - treated animals, corneal stromal opaci-fication were reduced, and extensive cellular infiltrates were prevented in cornea. Examination of the proinflammatory cytokine levels in the cornea 10 days after reactivation revealed that the presence of IL -1 a and IL-6 were lower than that found in the controls. The IL -10 did not suppress the viral reacti-vation rate after UV - B irradiation and viral clearance from the eye, nor was DTK.The third part: Our studies detected the expression of CD28,CTLA -4 and B7 - 1 mRNA in murine peripheral blood during the development of HSK in BALB/c mouse model of primary model. B7-2 mRNA was not expressed...
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