Regulatory T cells (Tregs) specific for beta-galactosidase (βgal) were generated in the periphery and modulated a CD4 +
T cell mediated delayed-type hypersensitivity (DTH) response. (A) X-gal staining of retina and thymus from a βgal mouse and control B6 mouse thymus. Photoreceptor (PC) layer of βgal mouse retina indicated showing intense X-gal staining in the outer plexiform layer (top) and outer segments (bottom). Retinas were incubated for 2 h and thymus for 24 h with X-gal. (B) Inhibition of CD4+ T cell (BG2)-induced DTH to βgal in mice receiving βgal specific Tregs. Transferred mice received 5 x 105 Tregs intravenously (i.v.) from mice injected with bovine serum albumin (BSA) or βgal. Recipient mice were given βgal in the ear and then measured for ear swelling at the indicated times post-βgal injection. (C) Percent of pooled CD4+ T cells that are Tregs (GFP+) in control and antigen (Ag)-inoculated FG mice. (D) Enhancement of BG2-induced DTH following systemic depletion of Tregs. Mice were depleted by 250 ng DTx given intraperitoneally (i.p.) on days 0, 3, and 6, followed by βgal in the ear on day 7. Ear swelling was measured at indicated times post-βgal injection. (E) Analysis of Treg levels in the blood of control mice and FDG-BG2 mice given DTx i.p. at the time of βgal injection in the ear (day 7). Results are given as mean ± SD with P values determined by t test.