Photo from the Nobel Foundation archive.
Sir Frank Macfarlane Burnet
Born: 3 September 1899, Traralgon, Australia
Died: 31 August 1985, Melbourne, Australia
Affiliation at the time of the award: Walter and Eliza Hall Institute for Medical Research, Melbourne, Australia
Prize motivation: "for discovery of acquired immunological tolerance."
Prize share: 1/2
Our immune system protects us against attacks by microorganisms and rejects foreign tissue. Part of our immunity has a hereditary basis, but part of it is acquired and is not present in the fetus. In 1949 Macfarlane Burnet theorized that the ability to distinguish between one's own and foreign tissue is not hereditary but is acquired during the fetus stage. The theory was substantiated when Peter Medawar succeeded in performing transplants of tissue between different mouse fetuses. The results had significance for organ transplants.