A rapid stimulation of phosphatidylinositol metabolism in rabbit leukocytes by pseudomonal leukocidin.

The time course experiments of 32Pi-labelling and breakdown of phospholipids in rabbit leukocytes exposed to leukocidin from Pseudomonas aeruginosa suggested that the initial action of this toxin was to stimulate phosphatidic acid production, presumably by causing a rapid metabolic change of phosphatidylinositol (PI response) correlating with phosphatidylinositol-specific phospholipase C and 1,2-diacylglycerol kinase. It appears that a rapid formation of phosphatidic acid and degradation of polyphosphoinositides in leukocytes treated with the toxin might be related a Ca2+-movement from extra- and intracellular spaces, resulting in the activation of Ca2+-dependent enzymes involved in the leukocidic process.