Recurrence of an allergic inflammation of air-pouch type in rats and possible participation of prostaglandin E2.

The recurrence of allergic inflammation, as examined by exudate accumulation, infiltration of polymorphonuclear leukocytes into the exudate, edema formation, vascular permeability and prostaglandin E2 levels in the exudate, was induced by injecting the antigen, azobenzene arsonate-conjugated acetyl bovine serum albumin, into the capsule of the proliferative granulation tissue which had been formed by the first-time antigenic challenge injection into an air pouch in the dorsum of the sensitized rat. The recurrence of the allergic inflammation 4 and 24 h after the antigenic challenge was inhibited dose-dependently by treatment with cyclooxygenase inhibitors, suggesting the possible participation of cyclooxygenase products, especially prostaglandin E2. The difference in the allergic inflammatory responses induced by the first-time antigenic challenge and the second-time antigenic challenge was discussed from the viewpoint of chemical mediators.