Effect of drugs on the increase in cell numbers in the peritoneal cavity of the actively sensitised mouse after intraperitoneal challenge with antigen.

The injection of antigen into the peritoneal cavity of actively sensitised mice produced an increase in the number of neutrophils in peritoneal washings collected 4 h later but after 1 day the numbers had returned to control levels. The increase in numbers of mononuclear cells and eosinophils in the peritoneal washings peaked at 2 days and persisted for at least 5 days. Dosing the mice with phenidone, a dual inhibitor of the cyclo-oxygenase and lipoxygenase pathways of arachidonic acid metabolism, potentiated the neutrophil infiltration at 4 h but had no significant effect upon the subsequent mononuclear cell and eosinophil infiltration. In contrast, treatment with the corticosteroid, dexamethasone, reduced the infiltration by all three types of cells, providing further evidence that the corticosteroids can inhibit immune-induced cellular infiltrations by mechanisms other than the inhibition of arachidonic acid metabolism. Isoprenaline, given to the mice before antigen challenge, had no effect on the subsequent neutrophil infiltration, but repeated doses did inhibit the mononuclear cell and eosinophil infiltration measured 4 days later. Aminophylline, disodium cromoglycate and cyproheptadine had no effect upon the cellular changes.