Distribution of cell surface saccharides on pancreatic cells. II. Lectin-labeling patterns on mature guinea pig and rat pancreatic cells.

Abstract

The surface saccharide composition of collagenase-dispersed pancreatic cells from adult guinea pig and rat glands was examined by using 8 lectins and their ferritin conjugates: Concanavalin A (ConA); lens culinaris (LCL); Lotus tetragonolobus (LTL); Riciinus communis agglutinins I and II (RCA I, RCA II); Soybean agglutinin (SBA); Ulex europaeus lectin (UEL) and wheat germ agglutinin (WGA). Binding studies of iodinated lectins and lectin-ferritin conjugates revealed one population of saturable, high-affinity receptor sites on the total cell population (approximately 95% acinar cells). EM revealed differences in lectin-ferritin binding to the plasmalemma of acinar, centroacinar and endocrine cells. Whereas acinar cells bound heavily all lectin conjugates, endocrine and centroacinar cells were densely labeled only by ConA, LCL, WGA and RCA I, and possessed few receptors for LTL, UEL and SBA. Endocrine and centroacinar cells were differentiated from each other by using RCA II, which binds to centroacinar cells but not to endocrine cells. Some RCA II receptors appeared to be glycolipids because they were extracted by ethanol and chloroform-methanol in contrast to WGA receptors which resisted solvent treatment but were partly removed by papain digestion. RCA I receptors were affected by neither treatment. The apparent absence of receptors for SBA on endocrine and centroacinar cells, and for RCA II on endocrine cells, was reversed by neuraminidase digestion, which suggested masking of lectin receptors by sialic acid. The absence of LTL and UEL receptors on endocrine and centroacinar cells were not reversed by neuraminidase. The differential lectin-binding patterns observed on acinar, centroacinar and endocrine cells from the adult pancreas apparently reflect surface-carbohydrate-developmental programs expressed during morphogenesis and cytodifferentiation of the gland.