Activation of phospholipid metabolism during mediator release from stimulated rat mast cells
Kennerly, D.A.; Sullivan, T.J.; Parker, C.W.
Journal of Immunology 122(1): 152-159
1979
ISSN/ISBN: 0022-1767 PMID: 762413 Document Number: 139706
Phospholipid metabolism was studied during mediator release from highly purified rat mast cells. The incorporation of 32PO4 into individual phospholipids was determined after isolation of phospholipid classes by 2-dimensional TLC. Various stimulators of histamine release (anti-Ig) increased 32PO4 incorporation into phosphatidic acid (PA), phosphatidylinositol (PI) and phosphatidylcholine (PC) 4- to 10-fold within 15 min. No change in 32PO4 incorporation into phosphatidylserine (PS), phosphatidylethanolamine or sphingomyelin was detected. Anti-IgE Ab caused significantly increased labeling of PA within 8 s and of PI and PC within 30 s. The concentrations of anti-IgE and Con A causing threshold, half maximal and maximal phospholipid labeling were slightly less than those required for comparable changes in histamine release. Phospholipid labeling and mediator release in response to anti-IgE or Con A were enhanced 3- to 4-fold by PS. The addition of 50 mM .alpha.-methylmannoside to mast cells 10 min after challenge with Con A rapidly halted ongoing mediator release and PA labeling. Marked and selective changes in phospholipid metabolism may occur before and during mediator release from mast cells ad that these reactions may be an intrinsic part of the biochemical mechanisms that control mediator release.