Leukotriene B4 generation by human neutrophils following IgG-dependent stimulation.

It has previously been shown that human neutrophils generate substantial quantities of LTB₄ when stimulated with the calcium ionophore, A23187, or with unopsonised zymosan. We now report that normal human neutrophils produced substantial quantities of LTB₄ (measured by radioimmunoassay and validated by RP-HPLC) when incubated with large non-phagocytosable IgG-coated beads (Sepharose 4B). LTB₄ was identified in both the extra and intracellular compartments. The production of LTD. was dependent upon the number of IgG-coated particles and the concentration of IgG bound to the beads. Release was maximal after a 15-30 min incubation time and was enhanced by prior activation of the neutrophils with the synthetic bacterial product f-met-leu-phe. Comparable LTB₄ production was also observed when neutrophils were incubated with antigen (Aspergillus fumigatus)-coated beads sensitized with purified IgG obtained from the sera of patients with allergic bronchopulmonary aspergillosis. These results suggest a further mechanism by which neutrophils may be activated to produce inflammatory mediators in the tissues. [ABSTRACT FROM AUTHOR]