Two eosinophil granule proteins, eosinophil peroxidase and major basic protein, inhibit mucin release from hamster tracheal surface epithelial cells in primary culture.

Abstract

Effects of eosinophil proteins on airway goblet cell mucin release were investigated using primary hamster tracheal surface epithelial (HTSE) cell cultures. HTSE cells were metabolically labeled using 3H-glucosamine and chased in the presence of varying concentrations of eosinophil proteins. The amount of 3H-mucin in the spent media was measured by Sepharose CL-4B gel-filtration column chromatography. Possible cytotoxicity by the eosinophil proteins was assessed by measurements of both lactic dehydrogenase and mucin release during as well as after the treatment period. (1) Neither eosinophil cationic protein nor eosinophil-derived neurotoxin affected mucin release at concentrations up to 10(-6) M; (2) both major basic protein (MBP) and eosinophil peroxidase (EPO) inhibited mucin release in a dose-dependent fashion, and the inhibitory effect by these proteins appeared to be reversible; (3) neither MBP nor EPO caused any apparent cytotoxicity at concentrations up to 10(-6) M. Eosinophil proteins such as MBP and EPO inhibit mucin release from primary HTSE cells without causing any apparent cytotoxicity.