Mannheimia haemolytica leukotoxin-induced increase in leukotriene B4 production by bovine neutrophils is mediated by a sustained and excessive increase in intracellular calcium concentration.

TitleMannheimia haemolytica leukotoxin-induced increase in leukotriene B4 production by bovine neutrophils is mediated by a sustained and excessive increase in intracellular calcium concentration.
Publication TypeJournal Article
Year of Publication2003
AuthorsCudd L, Clarke CR, Clinkenbeard K
JournalFEMS microbiology letters
Volume224
Issue1
Pagination85-90
Date Published2003 Jul 15
ISSN0378-1097
KeywordsAnimals, Calcimycin, Calcium, Calcium Signaling, Carcinogens, Cattle, Exotoxins, Ionophores, Leukotriene B4, Mannheimia haemolytica, Neutrophils, Pasteurellosis, Pneumonic, Tetradecanoylphorbol Acetate
Abstract

Isolated bovine neutrophils were used to study the relationship between the duration and magnitude of the Mannheimia haemolytica leukotoxin-induced increase in intracellular calcium concentration and leukotriene B4 synthesis. In contrast to recombinant human C5a, which caused a transient, small increase in intracellular calcium concentration and no effects on leukotriene B4 synthesis, exposure of neutrophils to leukotoxin resulted in a rapid, sustained, large increase in intracellular calcium concentration, followed by leukotriene B4 synthesis. This leukotoxin-induced response was similar to those produced by the calcium ionophore, A23187, and phorbol myristate acetate, which also caused significant leukotriene B4 production. Manipulation of the duration and magnitude of leukotoxin- and A23187-induced intracellular calcium concentration increase confirmed that a high and sustained intracellular calcium concentration was necessary to stimulate production of leukotriene B4, which is believed to play an important role in the pathogenesis of pulmonary M. haemolytica infection.

Alternate JournalFEMS Microbiol. Lett.