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

Local eosinophilia has been linked to the pathogenesis of the inflammatory aspect of allergic diseases. The present study found that co-injection of D10G4.1 (D10) cells, a murine Th2 clone, with conalbumin (CA) into the peritoneal cavity of AKR/J mice increased the number of peritoneal eosinophils. The accumulation of eosinophils reached a maximum level at 24 to 48 hr and was accompanied by a marked increase in the number of neutrophils and a minor increase in the number of mononuclear cells. D10-induced peritoneal eosinophilia was suppressed by administration of either anti-IL-4 and anti-IL-5 monoclonal antibodies in an additive manner or by cyclosporin A (CsA). Interestingly, suplatast tosilate (IPD-1151T), known to be an antiallergic agent capable of suppressing IgE synthesis and chemical mediator release, but not disodium cromoglycate, selectively suppressed eosinophil accumulation. Taken together with the observation that CsA and IPD-1151T suppressed IL-4 and IL-5 production by CA-stimulated D10 cells in vitro, the present results strongly suggest that agents capable of down-regulating Th2 cell cytokine production may attenuate allergic inflammation by impairing the recruitment of eosinophils that is mediated by Th2 cells.