GENERATION AND PARTIAL CHARACTERIZATION OF AN EOSINOPHIL CHEMOTACTIC CYTOKINE PRODUCED BY SENSITIZED EQUINE MONONUCLEAR-CELLS STIMULATED WITH STRONGYLUS-VULGARIS ANTIGEN

Supernatants generated by stimulation of peripheral blood mononuclear cells (PBMC) from Strongylus vulgaris sensitized or immunized ponies w ere assayed in vitro for eosinophil chemotactic activity (ECA) using t he filter system in blind well chambers. The supernatants from these c ultures were chemotactic for eosinophils, but not for neutrophils. Sup ernates from cultures of unsensitized PBMC stimulated with S. vulgaris antigen were not chemotactic for eosinophils. ECA was first detected in culture supernatants after 1.5 h of incubation and was dependent on both antigen and PBMC concentrations, but independent of serum concen trations. Both female and male S. vulgaris worm antigens stimulated EC A production from sensitized PBMC. ECA was not induced by in vitro sti mulation of sensitized S. vulgaris PBMC by female Strongylus edentatus worm antigen. Partial characterization of the eosinophil chemotactic cytokine showed it to be nondialyzable, greater than 8000 molecular we ight (MW), and sensitive to heating (56 and 95-degrees-C), trypsin, an d sodium metaperiodate treatments, suggesting that the cytokine is a p rotein containing some essential carbohydrate moieties. The cytokine d escribed in this paper could partially contribute to the in vivo blood and tissue eosinophilia in experimental S. vulgaris infection.