Enhancement of Chemotactic Factor - Stimulated Neutrophil

Leukotriene B4 (LTB4) is a potent primary stimulator of neutrophil chemotaxis, aggregation. and degranulation and induces superoxide production at higher concentrations. In order to determine whether LTB4 modulates neutrophil responses to oxidative stimuli, human neutrophils (PMNs) were incubated with LTB4 prior to stimulation with fMet-Leu-Phe (fMLP. 1 0 mol/L). opsonized zymosan (OZ. 250 tg/mL). or phorbol myristate acetate (PMA, 32 nmol/ 1). Superoxide (02) production by stimulated PMNs was assessed by the superoxide dismutase-inhibitable reduction of cytochrome c. LTB4 alone did not stimulate O production in concentrations below i07 mol/L and had no effect on the O assay. In the concentration range of 1012 to 108 mol/L, LTB4 did not alter 02 release induced by OZ or PMA. In contrast, LTB4-treated cells demonstrated enhanced 02 production following exposure to fMLP, and in the presence of 10 nmol/L LTB4. generated 180% ± 41%