Simultaneous assay for oxidative metabolism and adhesion of human neutrophils: evidence for correlations and dissociations of the two responses

Abstract

An assay method for the simultaneous evaluation of the oxidative metabolism and adherence of human neutrophils is described, together with certain specific applications. Incubations were performed in serum-coated microtiter plates, where oxidative metabolism was measured as O2- release and, after washing out the nonadherent cells, the adhesion was measured as activity of acid phosphatase. Three agonists tested in this system--opsonized zymosan, concanavalin A, and N-formyl-methionyl-leucyl-phenylalanine--induced both activation of O2- release and cell adhesion, but the two functions had time course and dose dependence patterns that varied depending on the stimulant. Particularly with concanavalin A, O2- release and adhesion response were markedly dissociated; this lectin at low doses increased neutrophil adherence without triggering any O2- production, whereas at high doses it increased both O2- production and adherence. Anti-integrin monoclonal antibodies did not affect adhesion induced by low-dose concanavalin A but inhibited the adhesion induced by the other tested agonists. Adhesion and O2- production were also found to be differentially affected by the NADPH oxidase inhibitor diphenylene iodonium, the sulfhydryl reagent N-ethylmaleimide and the A2 agonist adenosine, indicating that these neutrophil responses have various transductional pathways that also depend on the type of stimulus.