CD4 and colitis: We noted that the percentages of CD3e+CD4+CD25+Foxp3+ cells in the spleens of mice with DSS-induced colitis that were treated with M2b macrophage exosomes were significantly increased (12.7 ± 0.7%; P < 0.05), compared with those in the spleens of PBS-treated mice with DSS-induced colitis (9.3 ± 1%) (Figure 5, Table 5).