Release of substance P by granuloma eosinophils in response to secretagogues in murine schistosomiasis mansoni.

In murine schistosomiasis, granulomas form around parasite ova which lodge in the liver and intestines. The granulomas contain eosinophils which produce substance P. In order to demonstrate substance P release by individual granuloma eosinophils and mechanisms regulating this release, a reverse hemolytic plaque assay was developed. Release of substance P was demonstrated by plaque formation around granuloma eosinophils only when a specific substance P antiserum was used. Few cells released substance P in the basal state. However, eosinophils produced plaques in the presence of calcium ionophore A23187 or histamine. Plaque size and number were dependent upon secretagogue concentration. It is thus concluded that granuloma eosinophils can release substance P in response to both pharmacological and physiological agents.