Failure to detect superoxide in human neutrophils stimulated with latex particles

Human neutrophils stimulated with either latex particles or opsonized zymosan exhibited equivalent rates of net oxygen consumption as well as hydrogen peroxide release. The quantity of superoxide (O2-) detected in latex-stimulated neutrophils was less than 2% of that seen with opsonized zymosan stimulation, and only several-fold greater than that of resting cells. The failure to detect O2- in the latex-stimulated neutrophils was due neither to latex acting as a O2- scavenger nor to its interference with the O2- -forming system of the neutrophil. An intracellular site of O2- generation could not be demonstrated. NADPH oxidase activity in cells exposed to latex particles was only 10% of that seen in cells comparably activated with opsonized zymosan. Latex particles have the unusual property of stimulating the respiratory burst of the human neutrophil without the extracellular release of O2-. The potential physiologic importance of this finding is discussed.