Functional comparison of different histamine-containing IgE-receptor positive cells.

The present study was performed to investigate the histamine-releasing activity of non-immunological stimuli on cultured mast cell lines in comparison to isolated skin mast cells and basophils as human therapeutic target cells. The ionophore A23187 induced a dose dependent histamine release from all cell populations (enzymatically isolated human skin mast cells, human peripheral basophils and rat basophilic leukemia cells, RBL-1 and RBL-2H3). The lectin concanavalin A and the tripeptide formyl-methionyl-leucyl-phenylalanine activated only basophils, while the neural mediator substance P and compound 48/80 were active only in experiments with skin mast cells. Activators of protein kinase C (different phorbol esters and the non-phorbol mezerein) induced direct histamine release only from basophils. The data provide further evidence for heterogeneity of mast cells and indicate different signal transduction mechanisms following non-immunological activation.