The phagocyte chemiluminescence paradox: luminol can act as an inhibitor of neutrophil NADPH-oxidase activity

Abstract

The chemiluminescence system amplified by luminol or isoluminol is a sensitive and widely used method for determination of respiratory burst products generated by the NADPH‐oxidase in phagocytes. The present study shows that luminol, but not isoluminol, can inhibit the release of oxygen metabolites generated by human neutrophil NADPH‐oxidase. The difference in structure between luminol and isoluminol (rendering luminol more lipophilic than isoluminol, and thereby membrane‐permeable), is suggested to determine indirectly whether or not the molecule is inhibitory. Luminol was shown to have an increased inhibitory effect after preincubation of neutrophils on a surface of aggregated IgG, suggesting that the cells can be transferred from a ‘luminol‐insensitive’ to a ‘luminol‐sensitive’ state. Since luminol had no inhibitory effect in a cell‐free NADPH‐oxidase system, it is likely that it interferes with the signal transduction pathway, leading to assembly and/or activation of the oxidase. As a consequence of the present results, showing that luminol but not isoluminol can inhibit NADPH‐oxidase activity, we suggest that isoluminol is used in future studies of superoxide anion release from phagocytes. Copyright © 1999 John Wiley & Sons, Ltd.

fMLP-induced respiratory burst and the intracellular Ca2+ signal are not interrelated in neutrophils

“…2, Curve A). In accordance with data in the literature [20], when PMNLs were kept in a reaction mixture containing luminol for 10 min before stimulation , they exhibited a reduced .62 § 20/% ROI production upon fMLP stimulation. Therefore, the points of Curve A in Fig.…”

Lipid peroxidation caused by oxygen radicals from Fusobacterium‐stimulated neutrophils as a possible model for the emergence of periodontitis

“…For LPO the observation period of 4 h was chosen as we previously, with similar experimental conditions, have found a continuous LPO during 4 h (Wu et al , 1999). As to the oxidative metabolism we dared not extend the observation period beyond 1 h as we have found that not all neutrophils in a population survive several hours in NBT (unpublished data) and as luminol might act as an inhibitor of neutrophil NADPH‐oxidase activity (Fäldt et al , 1999).…”

Simultaneous use of electrochemistry and chemiluminescence to detect reactive oxygen species produced by human neutrophils

“…Together these findings lead to the following. First, since there was no significant effect of LumH 2 itself on neutrophils in our studies, on inhibition of O 2 À release (Faldt et al, 1999) or on LumH 2 -induced CL (Allred et al, 1980), in the absence of extracellular HRP the LumH 2 -dependent CL signal corresponds to a first approximation to intracellular production of ROS. Therefore, the difference between the two curves presented in Fig.…”