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Abstract

Lipopolysaccharide (LPS) pretreatment "primes" neutrophils to release increased amounts of superoxide anion (O2-) when stimulated. We investigated the molecular basis of this enhanced activity. Comparison of kinetic parameters of the respiratory burst NADPH oxidase in unstimulated LPS-primed and control neutrophils disclosed a similar Km for NADPH and no difference was seen in the content of cytochrome b. Pertussis toxin, which inhibits some G proteins, did not prevent priming. Change in membrane potential (delta psi) was five-fold greater in LPS-primed cells and paralleled the increased O2- release. Cytofluorographic analysis indicated that the increased change in delta psi was due to the creation of a new population of active cells. Changes in the concentration of intracellular free Ca2+ ([Ca2+]i) are believed to antecede changes in delta psi. There was a consistent increment (67 +/- 8%, n = 12) in resting [Ca2+]i in cells preincubated with LPS compared with control. When stimulated, the peak [Ca2+]i was significantly higher in LPS-primed cells. Ca2+-dependent protein kinase C activity was unaltered in resting and FMLP-stimulated neutrophils preexposed to LPS. Addition to cells of the intracellular Ca2+ chelator MAPTAM before preincubation with LPS blocked the changes in [Ca2+]i and the enhanced respiratory burst that characterize LPS priming. The increased resting [Ca2+]i in LPS-primed cells may enhance stimulus-induced cellular activity by modifying a Ca2+-dependent step in signal transduction.

Authors

J R Forehand, M J Pabst, W A Phillips, R B Johnston Jr

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Total citations by year

Year: 2012 2011 2010 2009 2008 2007 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990 1989 Total
Citations: 1 5 2 1 4 2 5 5 6 2 3 5 11 7 3 9 12 9 7 10 3 4 116
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Citations to this article in year 1989 (4)

Title and authors Publication Year
The neutrophil
C Haslett, JS Savill, L Meagher
Current Opinion in Immunology 1989
Polymorphonuclear leukocyte adherence induces actin polymerization by a transduction pathway which differs from that used by chemoattractants
FS Southwick, GA Dabiri, M Paschetto, SH Zigmond
The Journal of Cell Biology 1989
Activation of neutrophils by recombinant interleukin 6
L Borish, R Rosenbaum, L Albury, S Clark
Cellular Immunology 1989
Leukocyte membrane adhesion proteins LFA-1, CR3 and p150,95: A review of functional and regulatory aspects
TW Kuypers, D Ross
Research in Immunology 1989

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