André Michel Lwoff was a pioneering French microbiologist born on May 8, 1902, in Ainay-le-Château to Russian-Polish parents. He joined the prestigious Institut Pasteur in Paris at the remarkably young age of 19, where he would spend the majority of his research career. After obtaining his M.D. in 1927 and Ph.D. in biology in 1932, he pursued postdoctoral research at renowned institutions including the Kaiser Wilhelm Institute in Heidelberg and the Molteno Institute in Cambridge with support from the Rockefeller Foundation. Lwoff was appointed Head of the Department of Microbiological Physiology at the Institut Pasteur in 1938, and later served as Professor of Microbiology at the Sorbonne from 1959 to 1968. During World War II, his laboratory at the Pasteur Institute served as a center for the French Resistance, demonstrating his commitment to both science and democracy.
Lwoff's most groundbreaking contribution was his elucidation of the mechanism of lysogeny, demonstrating that bacterial viruses (bacteriophages) can exist in a noninfective form called prophage that is passed on through bacterial cell division. In 1950, together with Louis Siminovitch and Niels Kjeldgaard, he discovered that ultraviolet radiation could induce the prophage to enter its infective form, causing bacterial lysis and releasing new bacteriophages. His work established the fundamental understanding that what he termed 'temperate bacteriophages' follow one of two pathways when infecting bacteria, either immediately destroying the host cell or integrating their genetic material into the bacterial genome. Lwoff also made significant discoveries regarding vitamins, showing they function as both growth factors for microbes and as coenzymes essential for cellular metabolism, contributions that earned him the Nobel Prize in Physiology or Medicine in 1965.
Lwoff's work fundamentally transformed the field of microbiology and established critical concepts that underpin our understanding of viral infection mechanisms and genetic regulation. His discovery of the prophage mechanism provided the conceptual framework for understanding how viruses can lie dormant within host cells before becoming active, a principle that extends to many viral infections including those affecting humans. Awarded the Nobel Prize in 1965 alongside François Jacob and Jacques Monod, Lwoff's research was recognized as pivotal in elucidating 'genetic control of enzyme and virus synthesis.' Beyond his scientific achievements, Lwoff was honored with the Medal of the Resistance for his work in the French underground during World War II and was made an officer of the Legion of Honour, reflecting his profound commitment to both scientific advancement and humanitarian values. His legacy endures as a cornerstone of molecular biology, with his concepts continuing to inform contemporary research in virology, genetics, and infectious disease.
