Experimental autoimmune uveoretinitis initiated by non-phagocytic destruction of inner segments of photoreceptor cells

Abstract

[Background] Experimental autoimmune uveoretinitis (EAU) is a cell-mediated disease that is induced in animals sensitive to several retinal antigens. The recruitment of leukocytes is crucial for ocular inflammation in EAU, whereas the target cells and the effector cells have not yet been clearly characterized. [Methods] EAU was induced in B10RIII mice by immunization with human IRBP peptide 161-180 in emulsion with CFA supplemented with M. tuberculosis. Disease severity was assessed clinically by fundoscopic examination. We treated retinas from normal or EAU mice with proteases and prepared retinal monodispersed cells from normal mice as a candidate of target cells and those from EAU mice as a candidate of effector cells. The cytotoxic activity was defined by ⁵¹Cr or LDH release assay. The candidates of target cells were also explored either by opsin RT-PCR experiments or by comparing electron microscopic features of cells from retina of untreated mice with those from retina of EAU mice. [Results] Retinal damage during EAU was initiated by non-phagocytic destruction of inner segments of photoreceptor cells, followed by the phagocytic activity of macrophage against outer segments of photoreceptor cells and fragments of retinal pigmented epithelial cells. [Conclusion] EAU was initiated by non-phagocytic destruction of inner segments of photoreceptor cells. [J Physiol Sci. 2008;58 Suppl:S215]