Importance of IL-7–expressing stromal cells for LN regeneration. Inguinal LNs of IL-7–CrexR26-iDTR and IL-7–CrexR26-EYFP mice were transplanted under the kidney capsule of C57BL/6 mice. Between weeks 4 and 8 after transplantation, recipients were treated with DT (20 ng/g body weight) twice weekly. (A) LN remnants of IL-7–CrexR26-iDTR LNs. None of the 14 transplanted LNs had regenerated. (B) Fully regenerated IL-7–CrexR26-EYFP LNs from the contralateral kidney. Eleven of 14 transplanted LNs had regenerated.