Ocular Surface Antigen Presenting Cells are Necessary for the Generation of Autoreactive T cells during Experimental Dry Eye

Abstract

Purpose: : Evaluate the contribution of ocular surface-derived antigen presenting cells (APCs) during the immunopathogenesis of experimental Dry Eye.

Methods: : Dry Eye was induced by exposing female C57BL/6 mice to desiccating stress (DS: subcutaneous scopolamine (0.5 mg/0.2ml) TID, humidity <40%, and sustained airflow). To determine the functional role of APCs during experimental Dry Eye, serial subconjunctival injections of liposome encapsulated clodronate were used to deplete ocular surface (OS) APCs. Following 5 days of DS, CD4+ T cells were isolated from Dry Eye mice treated with clodronate or PBS and adoptively transferred to T cell-deficient nude recipient mice, which were evaluated 3 days post-transfer.

Results: : Mice treated with clodronate displayed a significant (p<0.05) reduction in the number of CD11c+ cells within the conjunctiva (1.5±0.9) compared to control mice injected with PBS-loaded liposomes (4.2±0.9). Nude recipient mice receiving CD4+ T cells from clodronate-treated donor mice exposed to DS displayed a marked reduction OS inflammation compared to recipients of CD4+ T cells from controls. CD4+ T cells isolated from clodronate-treated mice displayed a reduced capacity to accumulate within the OS tissues of nude recipients (9.8±2.3) relative to controls (58.3±12.6), and muted inflammatory cell infiltration was associated with a marked reduction in the proinflammatory cytokine/chemokine response, indicated by reduced IL-1β, TNF-α, IL-2, IL-6, CCL5, CXCL10, IFN-γ and IL-17 levels within the tears of nude recipients. Attenuated inflammation correlated with preservation of OS tissues as Goblet cell counts were significantly (p<0.01) higher in the conjunctiva of recipients of CD4+ T cells from clodronate-treated donor mice (91.5±0.4) compared to controls (42.0±9.5).

Conclusions: : These data indicate that APCs are necessary for the generation of T cell-mediated chronic Dry Eye and support the paradigm that Dry Eye is a self-antigen driven autoimmune disease.

Keywords: cornea: basic science • inflammation • antigen presentation/processing