Prostaglandin-generating factor of anaphylaxis. Identification and isolation.

Abstract

Anaphylaxis of human lung in vitro is accompanied by prostaglandin (PG) formation. To search for factors capable of generating PG, supernatants prepared by reversed anaphylaxis of human lung tissue were added to guinea pig lung and PG formation examined. The PG-generating activity fractionated between Mr = 500 and 5000 by ultramembrane filtration and was designated prostaglandin-generating factor of anaphylaxis or PGF-A. Partially purified PGF-A was soluble in 80% ethanol and insoluble in chloroform or ethyl acetate. Paper chromatography of anti-IgE-treated human lung preparations revealed a ninhydrin-positive spot at RF 0.27 to 0.41 with PG-generating activity. When subjected to gel filtration on Sephadex G-50 or G-25, PGF-A demonstrated peak PG-generating capacity at Mr = 1200 to 1800. Peak fractions were pooled and chromatographed on CM52 cellulose with PGF-A activity eluting at 0.16 to 0.3 M NH4COOH. The pooled peak of PGF-A activity from Sephadex G-25 filtration and CM52 chromatography eluted as a single peak at 0.024 M NH4HCO3 on DE52. Application of the peak off DE52 to a paper chromatogram revealed a single ninhydrin-positive spot with an RF 0.27 to 0.41 with the capacity to generate PGs. Amino acid analysis of three purifications revealed the following: Glu/Asp/Gly/Ser/Thr (6:3:2:1:1). Based on these analyses, a Mr = 1450 was calculated for the PGF-A. Therefore, PGF-A represents a novel mediator of lung anaphylaxis which may be partly responsible for PG generation accompanying allergic reactions.