Scottish virologist who, with Swiss colleague
Jean Lindenmann, in 1957 discovered interferon, a naturally occurring
antiviral substance produced by cells infected with viruses. The full
implications of this discovery are still being investigated.
Isaacs was born in 1921 and educated in Glasgow.
From 1951 he worked at the World Influenza Centre, London, becoming
its director in 1961.
Isaacs began in 1947 studying different strains of the influenza virus
and the body's response to them. Working with Lindenmann, he eventually
found that when a virus invades a cell, the cell produces interferon,
which then induces uninfected cells to make a protein that prevents
the virus from multiplying. Almost any cell in the body can make interferon,
which seems to act as the first line of defense against viral pathogens,
because it is produced very quickly (interferon production starts within
hours of infection whereas antibody production takes several days) and
is thought to trigger other defense mechanisms.