Active enhancement of heart transplants in the inbred rat with donor strain blood.

Prolongation of survival time of heart transplants in inbred rats following intravenous injection of donor strain blood according to various time-dose schedules is described. The immunological status of long-term survivors shows detectable antidonor antibodies, normal graft-versus-host reactions and rejection of skin grafts in the usual time. Lymphocytotoxic activity is well related to the survival time of the heart in those rats which respond to the treatment.