Léon Charles Albert Calmette ForMemRS was a French physician, bacteriologist and immunologist, and an important officer of the Pasteur Institute. He discovered the Bacillus Calmette-Guérin, an attenuated form of Mycobacterium bovis used in the BCG vaccine against tuberculosis. He also developed the first antivenom for snake venom, the Calmette's serum.

The Pasteur Institute is a French non-profit private foundation dedicated to the study of biology, micro-organisms, diseases, and vaccines. It is named after Louis Pasteur, who invented pasteurization and vaccines for anthrax and rabies. The institute was founded on 4 June 1887 and inaugurated on 14 November 1888.