Virologist, who discovered interferon. Born in Glasgow into a Russian-Jewish family, Isaacs read medicine at the University of Glasgow. He was a cousin of television documentary-maker Sir Jeremy Isaacs (b.1932). Taking up a career in research, Isaacs began to study the response of the body to different strains of the 'flu' virus in 1947. He joined the staff of the World Influenza Centre at the National Institute for Medical Research in London in 1951, rising to become its Director ten years later.
In 1957, with Swiss colleague Jean Lindemann, he discovered interferon, a naturally occurring antiviral protein produced by virus-infected cells. Interferon was later determined to have application in cancer treatment.