France

Pascale Cossart

2013 Balzan Prize for Infectious Diseases: Basic and Clinical Aspects

For her seminal discoveries on the molecular biology of pathogenic bacteria and their interaction with host cells. Her research has provided very significant insights into the mechanisms underlying infectious diseases and how they might be combatted.

Pascale Cossart was born in 1948 and is a French citizen. She is a professor at the Pasteur Institute and head of the “Unité des Interactions Bactéries-Cellules”.
Pascale Cossart is recognized as a pioneer in a discipline that emerged 25 years ago that combines molecular and cell biology approaches and was termed by her “cellular microbiology”. Her key contributions are the identification of a variety of bacterial virulence factors and strategies, the elucidation of sophisticated mechanisms allowing bacteria to enter, survive and spread in cells and tissues. She has elegantly demonstrated how a bacterium targets and crosses host body barriers. She has also discovered new mechanisms that allow bacteria to down-regulate the innate immune response of the host.
Pascale Cossart’s research has led to Listeria becoming both one of the best-studied microorganisms and a model system in infection biology. Her discoveries in relation to this organism have revealed mechanisms shared by many other bacteria and helped solve a number of important problems in cell biology. She and her group were the first to describe how Listeria escape destruction by intracellular host defences, for example by preventing their capture in vacuoles through the production of a potent pore-forming toxin. She has also shown the presence in the pathogen of an enzyme that neutralises bile salts allowing the bacteria to persist in the intestinal tract, and of other proteins which help Listeria evade innate immune defences.
A number of new insights into the pathophysiology of infectious processes have been obtained by Cossart’s group. She has shown that Listeria and other bacteria induce rearrangements in the actin cytoskeleton and the cell membrane of the host cell to permit bacterial invasion. These studies have inspired many other investigations into bacterial signalling and intracellular manipulations that facilitate microbial uptake by the host organism.
The new techniques and the creative approaches taken by Pascale Cossart have allowed the multiple ways and mechanisms used by pathogens for efficient infection to be unravelled. Her work has illuminated the ways pathogens exploit and subvert host cell function – and ultimately will facilitate the development of new therapeutic strategies.