New, peripherally generated beta-galactosidase (βgal)-specific regulatory T cells (Tregs) inhibit delayed-type hypersensitivity (DTH). (A) Ear swelling assay showing that retinal βgal is required to generate βgal-specific Tregs that can modulate the DTH response to βgal. Mice were analyzed 80 days post-transfer of 5 x 104 CD4+GFP− cells from FG-BG2 mice. (B) Ear swelling assay showing that the presence of the retina is not necessary for maintaining βgal-specific Tregs. Mice were enucleated and compared to non-enucleated mice 4 months post-enucleation. Ear swelling measured at indicated time post-βgal injection. Results are given as mean ± SD with P values determined by t test.