New research reveals that gut microbes produce a molecule that mimics a retinal protein and may activate retina-specific T cells that trigger autoimmune uveitis, a major cause of blindness (Horai R et al. Immunity. 2015;43:343-353).
Since the blood-retinal barrier prevents unactivated T cells from entering the eye and sequesters retinal proteins that could present target antigens, it has remained unclear how and where retina-specific T cells become primed to cause autoimmune uveitis. When researchers led by National Institutes of Health investigators examined immune cells in different tissues of mice genetically engineered to develop spontaneous uveitis, they discovered activated T cells in the gut preceding the onset of uveitis.
Hampton T. Gut Microbes May Trigger Autoimmune Eye Disease. JAMA. 2015;314(13):1331. doi:10.1001/jama.2015.12349