DOWN-REGULATION OF TH2 CELL-MEDIATED MURINE PERITONEAL EOSINOPHILIA BY ANTIALLERGIC AGENTS

Local eosinophilia has been linked to the pathogenesis of the inflamma tory aspect of allergic diseases. The present study found that co-inje ction of D10G4.1 (D10) cells, a murine Th2 clone, with conalbumin (CA) into the peritoneal cavity of AKR/J mice increased the number of peri toneal eosinophils. The accumulation of eosinophils reached a maximum level at 24 to 48 hr and was accompanied by a marked increase in the n umber of neutrophils and a minor increase in the number of mononuclear cells. D10-induced peritoneal eosinophilia was suppressed by administ ration of either anti-IL-4 and anti-IL-5 monoclonal antibodies in an a dditive manner or by cyclosporin A (CsA). Interestingly, suplatast tos ilate (IPD-1151T), known to be an antiallergic agent capable of suppre ssing IgE synthesis and chemical mediator release, but not disodium cr omoglycate, selectively suppressed eosinophil accumulation. Taken toge ther with the observation that CsA and IPD-1151T suppressed IL-4 and I L-5 production by CA-stimulated D10 cells in vitro, the present result s strongly suggest that agents capable of down-regulating Th2 cell cyt okine production may attenuate allergic inflammation by impairing the recruitment of eosinophils that is mediated by Th2 cells.