Physiological and pathobiological significance of ocular glycoproteins. I. Studies using fluorescein labelled glycine max.

Abstract

SUMMARY Cell surface carbohydrates play an important role in several biological, immunological, and neoplastic phenomena including development, growth regulation, cellular locomotion, receptor activation, and tumour metastasis. Fluorescein labelled lectins which bind to specific carbohydrate residues in glycoproteins and glycolipids are being increasingly used as chemical probes to study cell components. Several different preparations of ocular tissues from human, rabbit, and rat were examined for the distribution of N-acetyl-D-galactosamine (D-gal NAc) by means of fluorescein-labelled lectin from soybean (glycine max). A very strong fluorescence was observed in the corneal epithelium; Descemet's membrane and corneal endothelium were also strongly fluorescent. The conjunctival epithelium similarly showed a strong reaction, as did the goblet cells. The iris epithelium and the dilator pupillae were only weakly fluorescent, but the ciliary body showed strong fluorescence, as did the blood vessels. As compared with lens fibres the lens epithelium was strongly fluorescent. The outer retina, that is, the photoreceptors, the pigment epithelium, and Bruch's membrane, showed a very strong reactivity. The optic nerve showed moderate fluorescence, but reaction with extraocular muscles was variable. The skin of the upper and lower eyelids, hair follicles, and blood vessels showed strong lectin binding. Sections of retinoblastoma and malignant melanoma showed no reaction. The physiological and pathological significance of these findings is discussed.

Delay in Migration of the Corneal Epithelium after Incorporation of [3H]-Mannose in Organ Cultures

“…Carbohydrate moieties on the surface of corneal epithelial cells influence migration during wound healing (1)(2)(3)(4). The expression of cell surface glycosylation of non-migrating and migrating corneal epithelia has been studied with lectin-binding profiles (5,6). Using fluorescein-labeled lectin, soybean agglutinin that binds to N-acetyl-D-galactosamine, Ahmed and Rahi (5) found very strong fluorescence in preparations of normal corneal epithelia.…”

“…The expression of cell surface glycosylation of non-migrating and migrating corneal epithelia has been studied with lectin-binding profiles (5,6). Using fluorescein-labeled lectin, soybean agglutinin that binds to N-acetyl-D-galactosamine, Ahmed and Rahi (5) found very strong fluorescence in preparations of normal corneal epithelia. Blockage of the N-acetyl-galactosamine delays corneal epithelial migration.…”