Pro-inflammatory response of alveolar macrophages induced by sulphite: studies with lucigenin-dependent chemiluminescence.

Alveolar macrophages (AM) were studied for their capability to release mediators involved in modulation of neutrophil (PMN) functions. Initial responses were induced by sulphite. Supernatants obtained from canine, human and rat AM pre-treated with sulphite in concentrations of 0.1-2 mmol/L enhanced the respiratory burst of canine, human and rat PMN, measured by lucigenin-dependent chemiluminescence (CL). This PMN-stimulating activity exhibited platelet-activating factor (PAF)-like properties, as indicated by desensitization of the PAF receptor, inhibition with PAF antagonists WEB 2086 and CV 3988, and the kinetic CL response like PAF after chloroform extraction of supernatants inhibitable by PAF antagonist CV 3988. These results indicate that AM are triggered by sulphite to release mediators that activate the respiratory burst of PMN, primarily via the PAF receptor.