Sir Peter Medawar, D.Sc.

Peter Medawar

 Brief Bio

Peter Brian Medawar was born on February 28, 1915, in Rio de Janeiro. His father was a businessman of Lebanese descent who was a naturalized British subject, and his mother was English. Immediately after the conclusion of the First World War in 1918, the family moved to England where Medawar spent his childhood. After attending boarding school at Marlborough College, Medawar studied zoology at Magdalen College, Oxford, completing his undergraduate studies with first-class honours in 1935. He stayed at Magdalen as a Christopher Welch Scholar and a senior demonstrator. He developed an interest in biological research with medical applications while working under Howard Florey at the School of Pathology at Oxford. He was named a fellow at Magdalen in 1938 and remained at Oxford until 1947 when he accepted an appointment as Mason Professor of Zoology at the University of Birmingham. From 1951 to 1962, he served as Jodrell Professor of Zoology and Comparative Anatomy at University College London. He became the Director of the National Institute for Medical Research (NIMR), Mill Hill, in 1962 and thrived in the position, reserving two days each week for research in the laboratory while managing his administrative duties.

While delivering the President's Address to the British Association for the Advancement of Science in 1969, Medawar suffered a debilitating stroke; it was the first of several. Although the stroke left him partially paralyzed on the left side of his body, he continued his research and writing with the help of his wife Jean and his colleagues in the laboratory. Concerns about his health forced him to step down as head of the NIMR in 1971, at which time he was named the head of the Transplantation Biology Section of the Clinical Research Centre, Harrow, a position he held until 1986.

In late September 1987, Medawar suffered a severe stroke that rendered him comatose. He died eight days later, on October 2, at the Royal Free Hospital in London. Medawar was 72 at the time of his death.

 Nobel Prize in Physiology or Medicine

1960 Nobel Prize in Physiology or Medicine with Sir Macfarlane Burnet (AAI '61) “for discovery of acquired immunological tolerance.”

 AAI Service History

Joined: 1973

 Nobel Prize in Science

Peter Medawar was awarded the 1960 Nobel Prize in Physiology or Medicine jointly with Sir Macfarlane Burnet (AAI '61) for their "discovery of acquired immunological tolerance." Medawar provided experimental evidence that confirmed Burnet's theory of immunological tolerance, which hypothesized that the concept of "self" was defined by the immune system during embryogenesis.

Medawar's interest in immunological tolerance grew directly out of his research in skin grafts begun during the Second World War. When a plane crashed near his Oxford home during the Battle of Britain, the doctors treating the severely burned pilot sought Medawar's advice, hoping that his studies in cell development might provide some critical insight. Medawar believed skin grafts were the best possible treatment, but he also knew that they almost always failed. Unable to help the pilot, Medawar became fixated on the problem of treating burn victims and traveled to Glasgow to further investigate the matter for the Medical Research Council with the surgeon Thomas Gibson. Experimenting with autografts from a patient's own body and homografts (now called allografts) from donors, Medawar and Gibson found that, although both autografts and homografts initially healed successfully, homografts were rejected within two weeks. When a second homograft from the same donor was attempted, the graft was rejected much more quickly. Medawar suggested that the latent period following the initial graft and the heightened resistance to subsequent grafts were characteristic of an immune response. Continuing his study of skin grafts on rabbits in his laboratory at the University of Oxford, Medawar was further convinced that his initial suspicion was correct: the homograft reaction was in fact immunological.

It was while conducting further investigations of homograft reactions in the early 1950s that Medawar encountered Burnet's theory of immunological tolerance. At the time, Medawar was investigating the use of skin grafts as tests to determine whether cattle twins were monozygotic or dizygotic. His understanding of the homograft reaction had led him to believe that only monozygotic twins would accept grafts from one another, so he was surprised to discover that grafts between some sets of known dizygotic twins remained healthy and intact after several weeks. Seeking an explanation, he ran across Burnet's theory that the immune system was not fully developed until after birth and that self and "non-self" were defined during embryogenesis, a theory that Burnet had based on Ray D. Owen's (AAI '55) discovery of "chimerism" in dizygotic cattle twins.

With his colleagues Rupert Billingham (AAI '59) and Leslie Brent at University College London, Medawar tested Burnet's theory by inoculating fetuses of one mouse strain with cells from a second. Once the mice reached adulthood, Medawar performed skin homografts from the original donor strain. The grafts were accepted, but grafts from a third, unrelated mouse strain were rejected, indicating that self was defined during embryonic development as Burnet had hypothesized. This was a fundamental discovery in immunology that, although not directly translatable to medicine, provided the foundation for the field of transplant immunology and renewed hopes that successful organ transplants might one day be possible.

Medawar continued to study transplant immunology throughout his career. He was particularly interested in the nature of the histocompatibility antigens of mice. The limited biochemical techniques available at the time, however, prevented his investigations in this area from being as fruitful as his earlier experiments had been. He had far more success in demonstrating the immunosuppressive properties of and reviving interest in antilymphocyte serum. During his final years in the laboratory, Medawar turned his attention to cancer research, focusing primarily on immunopotentiation as a means of stopping tumor growth.

Medawar also established himself as a remarkably articulate and witty science writer. From the late 1950s until the end of his life, he wrote or co-wrote over one dozen books on science and the philosophy of science aimed at a popular audience, including The Uniqueness of the Individual (1957), The Future of Man (1957 [originally delivered as the BBC Reith Lectures]), The Hope of Progress (1972), The Limits of Progress (1984), and his autobiography, Memoir of a Thinking Radish (1986).

Medawar was the "foremost biologist of his generation," according to the British immunologist N. Avrion Mitchison (AAI '76). His work on immunological tolerance "performed the immensely important service of making transplantation scientifically respectable and gave the clinicians a well-defined goal to attain. Moreover, antigen-specific suppression of the immune response by something akin to acquired tolerance remains an aim of research in transplantation and auto-immunity." But Medawar was remembered by his friends and colleagues for more than just his scientific accomplishments. Göran Möller (AAI '84) declared that Medawar "represented the very best of the British University tradition: a critical but pleasant personality, an imaginative and honest mind."

 Awards and Honors

  • Fellow, Royal Society, 1949
  • Commander, Order of the British Empire, 1958
  • Royal Medal, Royal Society (UK), 1959
  • Foreign member, American Academy of Arts and Sciences, 1959
  • Nobel Prize in Physiology or Medicine, 1960
  • Foreign member, American Philosophical Society, 1961
  • Knighted, 1965
  • Foreign member, National Academy of Sciences, 1965
  • Copley Medal, Royal Society (UK), 1969
  • Companion of Honour, 1972
  • Order of Merit, 1981

 Institutional/Biographical Links

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