Lipopolysaccharide priming of human neutrophils for an enhanced respiratory burst. Role of intracellular free calcium

  • Forehand J
  • Pabst M
  • Phillips W
 et al. 
  • 14


    Mendeley users who have this article in their library.
  • 166


    Citations of this article.


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.

Get free article suggestions today

Mendeley saves you time finding and organizing research

Sign up here
Already have an account ?Sign in

Find this document

Get full text


  • J. R. Forehand

  • M. J. Pabst

  • W. A. Phillips

  • R. B. Johnston

Cite this document

Choose a citation style from the tabs below

Save time finding and organizing research with Mendeley

Sign up for free