Immunization with skin isografts taken from tolerant mice.

Skin isografts from mice that were immunologically tolerant to allogeneic tissue had the ability to immunize isogeneic recipients against subsequent skin allografts. The immunizing isografts showed no gross signs of rejection themselves and appeared to be only the vehicles for transplantation antigen. It seems likely that allogeneic leukocytes derived from the spleen and bone marrow cells used to confer tolerance were contained in the skin of the tolerant mice and were transferred by the skin isografts in sufficient numbers to stimulate transplantation immunity.