Abstract
The effects of ketotifen on the chemiluminescence (CL) and chemotaxis of human neutrophils were studied in vitro. Stimulation of neutrophils by concanavalin A (Con A), calcium ionophore A 23187 (CI), zymosan treated serum, and formyl-methionyl-leucyl-phenylalanine (FMLP) were strongly suppressed in contrast with by zymosan, which was only slightly inhibited in CL assay: the inhibitory effect of ketotifen was dose dependent. The addition of ketotifen even after stimulations of CI or FMLP also inhibited CL response. The neutrophils which were activated by incubation with FMLP (10-7M) or ZAS at 37°C for 60 min emitted much greater light in CI, con A, or zymosan-induced CL assays than those without the pretreatment with chemotactic factors. Such enhanced CL of treated cells was also markedly suppressed by ketotifen. On the other hand, ketotifen did not show any inhibitory effect on the direct movement of neutrophils by FMLP (10-7M) at the concentrations which inhibited CL responses. Thesse unique pharmacological activities of ketotifen are encourageing for its potential clinical usage as an antiinflammatory agent in some disorders associated with neutrophils as well as for its experimental usefulness for the analysis of various functions of neutrophils.
