We like to view ourselves as special snowflakes, as one-of-a-kind as our fingerprints. In a way, we are: The surfaces of our cells teem with a unique array of antigens that identify us and prevent our own immune systems, under normal circumstances, from attacking those cells. Ascertaining the genetic basis of this major histocompatibility complex, or MHC, earned Baruj Benacerraf the 1980 Nobel Prize in physiology or medicine and advanced our understanding of immune response and autoimmune diseases (such as multiple sclerosis) by leaps and bounds. He shared the award with George D. Snell, who uncovered the initial evidence for the MHC in the 1940s in mice, and Jean Dausset, the first to find a human compatibility antigen [sources: Benacerraf; Encyclopaedia Britannica; Nobel Prize].
Benacerraf was born in Caracas, Venezuela, but lived in Paris as a youth and spent most of his life and career in America. There he became a naturalized citizen in 1943 after serving in a U.S. Army wartime medical training program that drafted him out of medical school. His father hailed from Spanish Morocco, but he was greatly influenced by his French-Algerian mother's culture. Benacerraf later recalled how the mixture of his heritage and upbringing created difficulties for him both in America and when he later temporarily moved to Paris [sources: Benacerraf; Encyclopaedia Britannica; Nobel Prize].