TY - JOUR
T1 - Superoxide production by stimulated neutrophils
T2 - Temperature effect
AU - Black, Christopher D.V.
AU - Cook, Ohn A.
AU - Russo, Angelo
AU - Samuni, Amram
PY - 1991
Y1 - 1991
N2 - Activation of neutrophils results in a one-electron reduction of oxygen to produce the superoxide anion and other oxygen-derived, microbicidal species. Evidence from many kinetic studies of oxygen-derived radicals generated by stimulated neutrophils in vitro shows that radical production is optimal at 37°C but only lasts several minutes and then rapidly subsides. These findings support the widely held perception that the neutrophil's "oxidative burst" is a transitory event that peaks within minutes of stimulation and ends shortly thereafter. However, while some studies have shown that under controlled conditions stimulated neutrophils can generate superoxide continuously for several hours, others have observed that the superoxide formation by neutrophils stimulated in buffer at 37°C does not persist. To reconcile the conflicting findings and to better understand neutrophil function, we have reinvestigated the effect of temperature on the kinetics of radical generation by PMA-stimulated cells. Electron paramagnetic resonance spectroscopy coupled with spin-trapping and SOD-inhibitable ferricytochrome c reduction were used to monitor superoxide production by neutrophils stimulated at either 25°C or 37°C in RPMI 1640 medium or in Hank's balanced salt solution. When oxygen was supplied continuously, neutrophils stimulated at 25°Cin buffer or in medium generated superoxide for several hours but at 37°C. particularly in HBSS, O2-formation strikingly and rapidly decreased. This cessation of superoxide generation was reversible by lowering the temperature back to 25°C. These data imply that in vivo neutrophils may be capable of generating oxy-radicals for prolonged periods. In part, our results may also explain the often observed termination of neutrophil-derived radical formation in vitro and help to dispel the perception that neutrophil-derived oxy-radical production is an ephemeral phenomenon.
AB - Activation of neutrophils results in a one-electron reduction of oxygen to produce the superoxide anion and other oxygen-derived, microbicidal species. Evidence from many kinetic studies of oxygen-derived radicals generated by stimulated neutrophils in vitro shows that radical production is optimal at 37°C but only lasts several minutes and then rapidly subsides. These findings support the widely held perception that the neutrophil's "oxidative burst" is a transitory event that peaks within minutes of stimulation and ends shortly thereafter. However, while some studies have shown that under controlled conditions stimulated neutrophils can generate superoxide continuously for several hours, others have observed that the superoxide formation by neutrophils stimulated in buffer at 37°C does not persist. To reconcile the conflicting findings and to better understand neutrophil function, we have reinvestigated the effect of temperature on the kinetics of radical generation by PMA-stimulated cells. Electron paramagnetic resonance spectroscopy coupled with spin-trapping and SOD-inhibitable ferricytochrome c reduction were used to monitor superoxide production by neutrophils stimulated at either 25°C or 37°C in RPMI 1640 medium or in Hank's balanced salt solution. When oxygen was supplied continuously, neutrophils stimulated at 25°Cin buffer or in medium generated superoxide for several hours but at 37°C. particularly in HBSS, O2-formation strikingly and rapidly decreased. This cessation of superoxide generation was reversible by lowering the temperature back to 25°C. These data imply that in vivo neutrophils may be capable of generating oxy-radicals for prolonged periods. In part, our results may also explain the often observed termination of neutrophil-derived radical formation in vitro and help to dispel the perception that neutrophil-derived oxy-radical production is an ephemeral phenomenon.
KW - Cytochromec
KW - Electron paramagnetic resonance
KW - Leukocytes
KW - Respiratory burst
UR - http://www.scopus.com/inward/record.url?scp=18244424981&partnerID=8YFLogxK
U2 - 10.3109/10715769109145764
DO - 10.3109/10715769109145764
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C2 - 1649095
AN - SCOPUS:18244424981
SN - 1071-5762
VL - 12
SP - 27
EP - 37
JO - Free Radical Research
JF - Free Radical Research
IS - 1
ER -