Burnet and Medawar | Biography

Working half a world apart, these two men made a highly significant contribution to immunology. Although Burnet developed the theoretical foundation of immunology, Medawar succeeded in proving it.

Born in Traralgon, a country town in Victoria, Australia, MacFarlane Burnet attended Geelong College, Victoria, and earned his medical degree from Melbourne University in 1923. He received his Ph.D. from the University of London in 1927. Burnet was associated with Melbourne Hospital for his entire career and also directed the University of Melbourne's Walter and Eliza Hall Institute for Medical Research. He conducted research on immunology throughout his career, even after retirement, and wrote scientific books for the general public.

On his return to Australia from England in 1928, Burnet investigated the deaths of twelve children following diphtheria vaccination. He found that the vaccine had been contaminated by staphylococcus bacteria. This focused Burnet's interest on the ways in which the body defends itself against infection. He began to study animal viruses and contributed to the basic understanding of bacteriophages (bacteria that attack viruses). In 1932, Burnet developed a laboratory technique for cultivating viruses; they could not grow outside living cells, and mammal cells were difficult to maintain in lab containers. Burnet's method of growing viruses in chick embryos became standard for the next twenty years.

Burnet noted that the chick embryos were unable to resist virus infection and produced no antibodies against viruses. This led Burnet to speculate that animals do not produce antibodies to substances they encounter very early in life, assuming such substances to be present at birth. That, Burnet thought, would explain how the body is able to distinguish between "self" cells and "antiself," or foreign, cells. Burnet attempted to prove his theory by inducing immunological tolerance in chick embryos with injections of antigens, but his efforts failed.

His idea, however, was picked up by P. B. Medawar at Oxford University. Medawar was born in Rio de Janeiro, Brazil, in 1915 to British parents, but his father was a native of Lebanon. At the age of four, Medawar moved with his family to England. He studied zoology at Oxford, graduating in 1939. From 1938 to 1947, he was a Fellow at Magdalen and St. John's Colleges, Oxford. In 1947, he became professor of zoology, first at Birmingham University and then at University College, London. He completed his career as director of the National Institute for Medical Research. Besides his research activities, Medawar became well-known for his books about the philosophy of science. During World War II, Medawar worked in a burns unit and became involved with the problem of skin-graft rejection. Patients with severe burns could not accept grafts from donors. Medawar used the fact that a second graft from the same donor was rejected more rapidly than the first to prove that rejection of transplants was an immune reaction against antigens on the foreign tissue. Medawar's continued work in this field established transplantation immunobiology as an important area of specialized study.

When Burnet suggested that immunological tolerance could be induced by exposing embryos to antigens, Medawar decided to test the theory. He inoculated mouse embryos with tissue cells from mice of a different strain. The embryos did not reject the foreign tissue, and when the embryos matured, they accepted skin grafts from those other strains of mice as well. By 1953, Medawar had proven Burnet's theory of acquired immunological tolerance, which had important implications for tissue transplantation. The two men received the Nobel Prize for physiology or medicine in 1960 in recognition of their discovery.

Burnet married Edith Linda Druce in 1928; the pair had one son and two daughters. Burnet died in 1985. Medawar married Jean Shinglewood Taylor, with whom he had two sons and two daughters. Medawar died in 1987.