Induction of normal human eosinophil migration in vitro by substance P.

To investigate the role of tachykinins in allergic inflammation, the effect of substance P (SP) on normal human eosinophil migration was examined in Boyden chamber type assays. SP stimulated eosinophil migration in vitro with an EC50 of about 1-10 pM and maximal effects were seen at 100 pM. A carboxy-terminal fragment of SP possessed appreciable activity whereas an amino-terminal fragment was inactive. Data represented in this paper and previous studies suggest that eosinophils are attracted by SP and activated to enhanced mediator release and cytotoxic activity.