CD28 and inflammatory bowel disease: TGF-β has been described to be secreted by various Ts subpopulations: a) naturally occurring CD8+CD28− Ts that prevented colitis in an experimental IBD model, b) induced CD8+ T cells that were generated by myelin basic protein and protected animals from EAE, c) CD8+CD25+Foxp3+ that inhibited proliferation of responder T cells in vitro, and d) CD8+Foxp3+ that prevented lupus [34],[66],[67],[68],[69],[70],[71],[72].