Abstract
Purpose: :
Dendritic cells (DC) are fundamentally important in antigen presentation, but have been difficult to study for phenotype and function in retina. Because retinal CD11c cells change rapidly in response to minor injury such as a needle stick into the cornea, a partial optic nerve crush was tested as a method to manipulate changes in retinal CD11c cells in terms of numbers, morphology, origin, and function.
Methods: :
A partial optic nerve crush (ONC) was done to one eye of CD11c DTR-Tg mice to study DC properties in retina. At specified times post-crush, retinas were harvested, lightly fixed, and stained with antibodies. Whole retina was flat-mounted and analyzed by fluorescence microscopy. Retina blood vessels were stained with isolectin B4 and retina nerve fibers with β3-tubulin to examine CD11c cell distribution and association with blood vessels and nerve fibers. Adoptive transfer of T cells was done to test susceptibility to experimental autoimmune uveoretinitis (EAU).
Results: :
Doing a partial ONC in one eye led to the large increase of CD11c cells in the retina in both eyes simultaneously. Up-regulation of CD11c cells in retina was rapid and stable for about 35 days before the numbers started to decrease to naïve levels. Eyes receiving sham surgery were used as controls. In crushed and opposite eyes, CD11c cells occurred in an amoeboid and ramified phenotype. Amoeboid CD11c cells were mainly found associated with nerve fibers whereas ramified CD11c cells were associated with blood vessels. Naïve eyes contained ramified CD11c cells associated with blood vessels and nerve fibers. Eyes receiving the ONC were more susceptible to EAU induced by adoptive transfer of T cells.
Conclusions: :
Our studies show that retina is a highly dynamic environment in which CD11c cell numbers change rapidly in response to a partial optic nerve crush. The recruited cells support the pathogenic response of autoreactive T cells.
Keywords: antigen presentation/processing • immunohistochemistry • microglia