NEUROTROPIN INHIBITS ACCUMULATION OF EOSINOPHILS INDUCED BY ALLERGEN THROUGH THE SUPPRESSION OF SENSITIZED T-CELLS

A non-protein extract isolated from the inflamed dermis of rabbits ino culated with vaccinia virus (Neurotropin(R)) has been clinically used in Japan as an analgesic and anti-allergic drug. To clarify its anti-a llergic mechanism, the effect of Neurotropin on eosinophil accumulatio n induced by ragweed pollen extract or platelet-activating factor (PAF ) was examined in BALB/c mice. Neurotropin inhibited the T-cell-depend ent accumulation of eosinophils induced by allergen in a dose-dependen t manner when administered during sensitization. However, Neurotropin was unable to inhibit the T-cell-independent accumulation of eosinophi ls induced by PAF. A T-cell transfer experiment was performed to addre ss the inhibitory mechanism. A marked accumulation of eosinophils was observed when recipients were injected i.p. with allergen and Nylon wo ol column-passed splenic T-cells from the sensitized donor mice. Howev er, significant accumulation of eosinophils was not observed when sens itized donor mice were administered with Neurotropin but not saline. T aken together, these results suggest that Neurotropin inhibits the acc umulation of eosinophils induced by allergen via the suppression of se nsitized T-cell induction, or alternatively by interfering with T-cell function.