Experimental
melanin-
protein-induced
uveitis (EMIU), which is also known as experimental autoimmune
anterior uveitis, was first described in 1993 by Broekhuyse et al. This experimental
uveitis may be induced in certain inbred and outbred rat strains by immunization with bovine ocular
melanin. The
inflammation shares clinical features with human acute
anterior uveitis. The duration of the first episode is approximately 1 month. Spontaneous recovery to a near normal clinical state is the rule, but multiple recurrences are common.
Slit-lamp biomicroscopic examination reveals a florid anterior-chamber reaction, with formation of a retro-
iridal empyema,
fibrin clots and posterior synechiae. At a microscopic level, leukocytic infiltration is first observed in the anterior uvea. Although this tissue remains the site of maximum
inflammation throughout an attack, in severe cases, limbitis, vitritis and
choroiditis are also observed. Abrogation of EMIU occurs
after treatment with anti-CD4 antibody, indicating that the
uveitis is controlled by CD4-positive T cells. Several research groups have used EMIU to investigate various aspects of the pathogenesis of acute anterior uveal
inflammation, including the participation of different leukocyte subsets, the expression of
cell adhesion molecules,
cytokines,
chemokines and
nitric oxide, the role of
complement and the impact of apoptosis. In addition, EMIU has also been used to evaluate various
biologic interventions with potential implications for the treatment of human disease.