Autoreactive T cells must normally be held in check by the suppressive environment produced by microglia and dendritic cells in the eye. These cells produce large amounts of TGF beta and other suppressive cytokines, including IL-10, to prevent damage to the eye by reducing inflammation and causing T cells to differentiate to inducible T reg cells. Innate immune stimulation by bacteria and cellular stress is normally suppressed by myeloid suppression while inducible Treg cells prevent activation and clonal expansion of the autoreactive Th1 and Th17 cells that possess potential to cause damage to the eye.