Abstract
The enzyme collagenase was used to disperse human lung into its component cells. The resulting cell suspensions containedcirca 8% mast cells and were used for studies of mediator release without further purification. They exhibited a low (circa 7%) spontaneous release of histamine. They could be sensitized passively and released histamine upon challenge with anti-human IgE. They responded to concanavalin A but not to dextran. Phosphatidyl serine did not potentiate the release induced by these agents. The calcium ionophores, A23187 and ionomycin, both elicited histamine release. The cells were refractory to the action of the basic releasers 48/80 and peptide 401 (MCD-peptide). These results indicate marked differences between human pulmonary mast cells and the more widely used rat peritoneal mast cells.