CD4 and colitis: Intravenous injection of exosomes released by intestinal epithelial cells from untreated mice to DSS-treated mice reduces the severity of experimental colitis by decreasing the number of CD4+ T lymphocytes and by activating Treg cells and immunosuppressive dendritic cells, while the inhibition of exosome production in vivo increases the severity of DSS-induced colitis [101].