Fig. 1 Limited role of lymph nodes and spleen in allograft rejection. a, Lymph nodes are not essential for the rejection of skin allografts. Full-thickness tail skin was transplanted from 5–8-wk-old BALB/c mice to the dorsal flank area of 5–8-wk-old C57BL/6 or B6-Lta–/–recipients. Rejection was defined as graft necrosis more than 80%. Time course of rejection of allogeneic (BALB/c) skin grafts is near identical in Lta–/–(; n= 5) and wild-type (; n= 5) mice. Similar results were also obtained when donor abdominal skin was used. b, Lymph nodes and spleen are not essential for the rejection of cardiac allografts. Cardiac allograft transplant was performed using BALB/c donors and C57BL/6 (; n= 7), splenectomized B6-Lta–/–(; n= 5) or splenectomized B6Ltbr–/–(; n= 4) recipients. Allograft survival was assessed by palpation. Rejection was defined as cessation of heart beat. Splenectomized B6-Lta–/–and B6-Ltbr–/–recipients show delayed, but fully competent rejection.