Medawar, Sir Peter B(rian)

born Feb. 28, 1915, Rio de Janeiro, Braz.

died Oct. 2, 1987, London, Eng.

Brazilian-born British zoologist.

Educated at Oxford, he began transplant research in 1949. His finding (1953) that adult animals injected with foreign cells early in life accept skin grafts from the original donor or its twin lent support to Macfarlane Burnet's hypothesis that cells learn, during and just after birth, to distinguish "own" from "foreign." He found that nonidentical cattle twins accept skin grafts from each other, proving that antigens "leak" between the embryos' yolk sacs, and showed with mice that each cell contains genetic antigens important to immunity. His work deflected immunology from dealing with the fully developed immunity mechanism to attempting to alter the mechanism itself (e.g., suppression of transplant rejection). He and Burnet shared a 1960 Nobel Prize.

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