Peter Brian Medawar Biography (1915-1987)


Peter Brian Medawar was a renowned biologist who made major contributions tothe study of immunology . Working extensively with skin grafts, he and his collaborators proved that one's immune system "learns" to distinguish between "self" and "non-self"--that is, such distinctions are not inherent. During hiscareer, Medawar also became a prolific author, penning books such as TheUniqueness of the Individual and Advice to a Young Scientist. Winner of the Nobel Prize in physiology or medicine in 1960, he was also knighted in 1965.

Medawar was born on February 28, 1915, in Rio de Janeiro, Brazil, to businessperson Nicholas Medawar and the former Edith Muriel Dowling. When he was a young boy, his family moved to England, which he thereafter called home. Medawar attended secondary school at Marlborough College, where he first became interested in biology. He once described his biology master at Marlborough as arough individual whose selection for the position was meant to discourage thestudents from taking up science. However, Medawar acknowledged his teacher'sdevotion to biology, while the educator, in turn, recognized the pupil's interest. The biology master encouraged Medawar to pursue the science under thetutelage of one of his former students, John Young, at Magdalen College. Medawar followed this advice and enrolled at Magdalen in 1932 as a zoology student. He found Young to be an excellent teacher.

Medawar earned his bachelor's degree from Magdalen in 1935, the same year heaccepted an appointment as Christopher Welch Scholar and Senior Demonstratorat Magdalen College. He followed Young's recommendation that he work with pathologist Howard Florey, who was undertaking a study of penicillin, work for which he would later become well-known. Medawar leaned toward experimental embryology and tissue cultures. While at Magdalen, he met zoology student Jean Shinglewood Taylor , who also joined Florey's lab. They married in 1937. In a1984 interview with New Scientist, she recalled her impressions of Medawar at Magdalen: "Nobody could forget him, because he was very tall, veryuntidy, obviously extremely clever, and very dominant." She spent less than ayear in Florey's lab. The couple had their first child in 1938. In all theyhad four children, sons Charles and Alexander, and daughters Caroline and Louise.

In 1938, Medawar, by examination, became a fellow of Magdalen College and received the Edward Chapman Research Prize. A year later, he received his master's from Oxford. When World War II broke out in Europe, the Medical Research Council asked Medawar to concentrate his research on tissue transplants, primarily skin grafts . While this took him away from his initial research studiesinto embryology, his work with the military would come to drive his future research and eventually lead to a Nobel Prize. During the war, Medawar developed a concentrated form of fibrinogen, a component of the blood. This substance acted as a glue to reattach severed nerves, and found a place in the treatment of skin grafts and in other operations. More importantly to Medawar's future research, however, were his studies at the Burns Unit of the Glasgow Royal Infirmary in Scotland. His task was to determine why patients rejected donor skin grafts. He observed that the rejection time for donor grafts was noticeably longer for initial grafts, compared to those grafts that were transplanted for a second time. Medawar noted the similarity between this reaction andthe body's reaction to an invading virus or bacteria. He formed the opinionthat the body's rejection of skin grafts was immunological in nature; the body built up an immunity to the first graft and then called on that already-built-up immunity to quickly reject a second graft.

Upon his return from the Burns Unit to Oxford, he began his studies of immunology in the laboratory. In 1944 he became a senior research fellow of St. John's College, Oxford, and university demonstrator in zoology and comparative anatomy. Although he qualified for and passed his examinations for a doctoratein philosophy while at Oxford, Medawar opted against accepting it because itwould cost more than he could afford. In his autobiography, Memoir of aThinking Radish, he wrote, "The degree served no useful purpose and cost, I learned, as much as it cost in those days to have an appendectomy. Havingjust had the latter as a matter of urgency, I thought that to have both would border on self-indulgence, so I remained a plain mister until I became a prof." He continued as researcher at Oxford University through 1947.

During that year Medawar accepted an appointment as Mason professor of zoology at the University of Birmingham. He brought with him one of his best graduate students at Oxford, Rupert Everett "Bill" Billingham. Another graduate student, Leslie Brent, soon joined them and the three began what was to become avery productive collaboration that spanned several years. Their research progressed through Medawar's appointment as dean of science, through his several-month-long trip to the Rockefeller Institute in New York in 1949--the same year he received the prestigious title of fellow from the Royal Society--and even a relocation to another college. In 1951 Medawar accepted a position as Jodrell Professor of Zoology and Comparative Anatomy at University College, London. Billingham and Brent followed him.

Their most important discovery had its experimental root in a promise Medawarmade at the International Congress of Genetics at Stockholm in 1948. He toldanother investigator, Hugh Donald , that he could formulate a foolproof method for distinguishing identical from fraternal twin calves. He and Billinghamfelt they could easily tell the twins apart by transplanting a skin graft from one twin to the other. They reasoned that a calf of an identical pair would accept a skin graft from its twin because the two originated from the sameegg, whereas a calf would reject a graft from its fraternal twin because theycame from two separate eggs. The results did not bear this out, however. Thecalves accepted skin grafts from their twins regardless of their status as identical or fraternal. Puzzled, they repeated the experiment, but received the same results.

They found their error when they became aware of work done by Dr. Frank Macfarlane Burnet of the University of Melbourne, and Ray D. Owen of the California Institute of Technology. Owen found that blood transfuses between twin calves, both fraternal and identical. Burnet believed that an individual's immunological framework developed before birth, and felt Owen's finding demonstrated this by showing that the immune system tolerates those tissues that are made known to it before a certain age. In other words, the body does not recognize donated tissue as alien if it has had some exposure to it at an early age.Burnet predicted that this immunological tolerance for non-native tissue could be reproduced in a lab. Medawar, Billingham, and Brent set out to test Burnet's hypothesis.

The three-scientist team worked closely together, inoculating embryos from mice of one strain with tissue cells from donor mice of another strain. When the mice had matured, the trio grafted skin from the donor mice to the inoculated mice. Normally, mice reject skin grafts from other mice, but the inoculated mice in their experiment accepted the donor skin grafts. They did not develop an immunological reaction. The prenatal encounter had given the inoculatedmice an acquired immunological tolerance . They had proven Burnet's hypothesis. They published their findings in a 1953 article in Nature. Although their research had no applications to transplants among humans, it showedthat transplants were possible. The scientific world previously held no hopefor successful transplants. In Memoir of a Thinking Radish, Medawarexplained: "Thus the ultimate importance of the discovery of tolerance turned out to be not practical, but moral. It put new heart into the many biologists and surgeons who were working to make it possible to graft, for example, kidneys from one person to another."

In the years following publication of the research, Medawar accepted severalhonors, including the Royal Medal from the Royal Society in 1959. A year later he and Burnet accepted the Nobel Prize for Physiology or Medicine for theirdiscovery of acquired immunological tolerance: Burnet developed the theory and Medawar proved it. Medawar shared the prize money with Billingham and Brent.

Medawar's scientific concerns extended beyond immunology, even during the years of his work toward acquired immunological tolerance. While at Birmingham,he and Billingham also investigated pigment spread, a phenomenon seen in someguinea pigs and cattle where the dark spots spread into the light areas of the skin. "Thus if a dark skin graft were transplanted into the middle of a pale area of skin it would soon come to be surrounded by a progressively widening ring of dark skin," Medawar asserted in his autobiography. The team conducted a variety of experiments, hoping to show that the dark pigment cells weresomehow "infecting" the pale pigment cells. The tests never panned out. "Itwas a weary and disheartening business representing a loss of about two years' work, at the end of which I had to admit that the hypothesis on which I hadbeen working was mistaken."

Medawar also delved into animal behavior at Birmingham. He edited a book on the subject by noted scientist Nikolaas Tinbergen, who ultimately netted a Nobel Prize in 1973. Medawar felt Tinbergen's work was important enough that he went beyond his literary assistance, and wrote to a granting agency toassure that Tinbergen's work was funded. In 1957, Medawar also became a bookauthor with his first offering, The Uniqueness of the Individual, which was actually a collection of essays. In 1959, his second book, The Future of Man, was issued, containing a compilation of a series of broadcasts he read for British Broadcasting Corporation (BBC) radio. The series examined the impacts of evolution on man.

Medawar remained at University College until 1962 when he took the post of director of the National Institute for Medical Research in London, where he continued his study of transplants and immunology. While there, he continued writing with mainly philosophical themes. The Art of the Soluble, published in 1967, is an assembly of essays, while his 1969 book, Induction and Intuition in Scientific Thought, is a sequence of lectures examining the thought processes of scientists. In 1969 Medawar, then president of the British Association for the Advancement of Science, experienced the first of aseries of strokes while speaking at the group's annual meeting. As soon as possible, he returned to work, sometimes relying on research assistants to conduct the laboratory bench work. He finally retired from his position as director of the National Institute for Medical Research in 1971. In spite of his physical limitations, he went ahead with scientific research in his lab at theclinical research center of the Medical Research Council. There he began studying cancer. In the 1984 interview with New Scientist, he said, "I believe that vaccination is possible against a wide range of cancers, in principle. This is now our principal line of research."

Through the 1970s and 1980s, Medawar produced several other books--some withhis wife as co-author--in addition to his many essays on growth, aging, immunity, and cellular transformations. In one of his most well-known books, Advice to a Young Scientist, he states that scientists are not geniuses,but people who have the combined characters of common sense and curiosity. Hewrites, "Like any other human being, a young scientist growing up will probably say to himself at the end of each decade, 'Ah well, that's it then. It has all been great fun, but nothing now remains except to play out time with dignity and composure and hope that some of my work will last a bit longer thanI do.'" Medawar died on October 2, 1987, at the age of seventy-two.

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