Bacterial lipopolysaccharide enhances polymorphonuclear leukocyte function independent of changes in intracellular calcium.
Bacterial lipopolysaccharide (LPS) enhanced expression of C3bi receptors (CR3), phagocytosis of opsonized bacteria, and subsequent hydrogen peroxide (H2O2) production by human polymorphonuclear leukocytes (PMNs). The role of changes in intracellular calcium concentration ([Ca2+]i) in LPS-induced priming was examined by determining the effect of modulators of intracellular calcium on enhanced PMN function, determining the ability of calcium ionophores to reproduce the effects of LPS, and measuring PMN [Ca2+]i following addition of LPS. Inhibition of intracellular calcium-dependent processes with TMB-8 or quin-2 blocked all three measures of LPS-induced priming. LPS did not stimulate an increase in [Ca2+]i, and calcium ionophores failed to reproduce the effect of LPS. Maintenance of [Ca2+]i is necessary for LPS priming, but an increase in [Ca2+]i is not a component of the signal transduction pathway leading to PMN priming by LPS.
Klein
J B
JB
Department of Medicine, University of Louisville School of Medicine, Kentucky 40292.
Payne
V
V
Schepers
T M
TM
McLeish
K R
KR
D000634:Aminoquinolines / Q000494:pharmacology; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000502:physiology*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects; D005707:Gallic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D006801:Humans; D006861:Hydrogen Peroxide / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology*; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism; D010587:Phagocytosis / Q000187:drug effects; D011493:Protein Kinase C / Q000378:metabolism; D011951:Receptors, Complement / Q000096:biosynthesis; D017463:Receptors, Complement 3b; D015290:Second Messenger Systems / Q000187:drug effects*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014268:Trifluoperazine / Q000494:pharmacology
D000634:Aminoquinolines; D002121:Calcium Channel Blockers; D008070:Lipopolysaccharides; D011951:Receptors, Complement; D017463:Receptors, Complement 3b; D014268:Trifluoperazine; D000001:Calcimycin; D004533:Egtazic Acid; C006014:8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate; D005707:Gallic Acid; D006861:Hydrogen Peroxide; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate; C035739:Quin2; D002118:Calcium