EFFECT OF TYB-2285 ON HISTAMINE-RELEASE FROM HUMAN BASOPHILS IN THE PRESENCE ABSENCE OF IL-3

1. The present study was carried out to investigate the effect of TYB-2285 (3,5-bis(acetoxyacetyl-amino)-4-chlorobenzonitrile) on histamine release from human basophils upon stimulation with anti-IgE in the presence/absence of recombinant interleukine 3 (rIL-3). 2. Histamine release was enhanced by the pretreatment of basophils with rIL-3 (0.3-10 U/ml) in 18 out of 22 subjects. 3. Histamine release in the presence of rIL-3 was inhibited by TYB-2285 and disodium cromoglycate (DSCG) in a dose-dependent manner (1-100 muM). 4. Histamine release in the absence of rIL-3 was not inhibited by TYB 2285 or DSCG at concentrations less than 1 mM. 5. From these results, it is suggested that TYB-2285 and DSCG might regulate allergic inflammation by the suppression of mediator release enhanced by IL-3.