Drug-induced tolerance for skin allografts across the H-2 barrier in adult mice.

Mice treated with methylhydrazine derivatives for 3 to 4 weeks before the transplantation showed markedly prolonged survival times for allogeneic skin grafts differing at the H-2 histocompatibility locus. Presumably permanent tolerance was induced in about 20 to 30 percent of the mice when the drug treatment was combined with a single injection of additional donor antigen. The tolerance persists without further drug treatment and is specific for donor tissue.