How Mannheimia haemolytica defeats host defence through a kiss of death mechanismLaurent Zecchinon, Thomas Fett and Daniel Desmecht
Department of Pathology, Faculty of Veterinary Medicine, University of Liège, FMV Sart-Tilman B43, 4000 Liège, Belgium
(Received 22 June 2004; accepted 6 October 2004)
Abstract - Mannheimia haemolytica induced pneumonias are only observed in goats, sheep and cattle. The bacterium produces several virulence factors,whose principal ones are lipopolysaccharide and leukotoxin. The latter is cytotoxic only for ruminant leukocytes, a phenomenon that is correlated with its ability to bind and interact with the ruminant 2-integrin Lymphocyte Function-associated Antigen 1. This paper globally reviews all the information available on host-pathogen interactions underlying respiratory mannheimiosis (formerly pasteurellosis), from the stable and the Petri dish to the biochemical cascade of events triggered by the leukotoxin inside ruminant leukocytes. One conclusion can be made: the most widespread cattle respiratory disease with the most important impact on beef production worldwide, is probably due to a tiny ruminant-specific focal variation in the CD18- and/or CD11a-expressing genes.
Key words: Mannheimia haemolytica / leukotoxin / 2-integrin / ruminant
Corresponding author: Daniel Desmecht firstname.lastname@example.org
© INRA, EDP Sciences 2005