Baruj Benacerraf is a Venezuelan-born immunologist whose major contribution to modern immunology was the discovery of the immune-response gene (Ir) , which triggers the body's war on disease. For his work linking Ir genes to the major histocompatibility complex or supergene, which controls the nature and vigor of the body's immune response, Benacerraf was awarded the 1980 Nobel Prize in physiology or medicine, which he shared with two other immunologists.

Benacerraf was born on October 29, 1920, in Caracas, Venezuela, to Henriette Lasry and Abraham Benacerraf. His father was a Sephardic Jew who had emigrated from North Africa to Venezuela, working his way to wealth and prominence as a financier and textile importer. When Benacerraf was five, the family moved to France where Benacerraf attended the Lycée Janson and received a classic French education in pre-World War II Paris. In 1938, fearing the outbreak of war in Europe, the family returned...