Poor effect of anti-CD3ε mAb administration on thymic epithelium in adult RAG2^R229Q mice. (A) Comparison between the M/C obtained in newborns and adults RAG2^R229Q mice 1 and 2 months after anti-CD3ε mAb treatment (statistical analysis was done between the 2 groups newborns versus adults); *P = .0286, **P = .0041. (B) H&E, CK5 and CK8, immunohistochemistry of thymi from PBS, and anti-CD3ε mAb treated mice (original magnification, ×20).