British immunologist who shared with Macfarlane Burnet the 1960 Nobel Prize for Physiology or Medicine for his work on acquired immunological tolerance and the development of the immune system in embryos and young animals. He was knighted in 1965, became a CH in 1972, and was appointed to the OM in 1981.
Born in Brazil, the son of a Lebanese businessman, Medawar was educated in England and obtained a zoology degree from Magdalen College, Oxford. After lecturing and researching at Oxford he became professor of zoology first at Birmingham University (1947–51) and then at University College, London (1951–62). He was director of the National Institute for Medical Research (1962–71) and subsequently head of the Transplantation Biology Section of the Clinical Research Centre.
Medawar's interest in immunology arose from his research after World War II into the problems of skin grafting for burns. In 1949 Burnet suggested that during embryonic life and the early postnatal period cells gradually acquire the ability to distinguish their own tissues from foreign material, and Medawar found evidence to support this idea when he discovered that fraternal cattle twins accept skin grafts from each other. This indicated that antigens ‘leak’ from the yolk sac of each embryo to that of the other, giving them immunity to each other's tissues before their own system is fully developed. In a series of experiments on mice, Medawar found evidence that each cell contains genetically determined markers (antigens) important to the immunity process. An individual injected with a donor's cells while still an embryo will later accept tissues from all parts of the donor's body and from its twin. Medawar's work changed the basis of immunological research from attempting to treat the fully developed immune system to altering the mechanism itself. It has been invaluable in research to find methods of preventing the rejection of transplanted organs. In addition to his own research, Medawar was much admired for his essays on the philosophy of science, especially for his Reith lectures The Future of Man (1960) and his book The Art of the Soluble (1967).
Subjects: Science and Mathematics — Contemporary History (Post 1945).