Localization of lectin binding sites in human, cat, and rabbit corneas

Paraffin sections of human, cat, and rabbit corneas were stained with nine lectins, using an avidin-biotin-complex procedure to study glycoconjugates of the epithelium, keratocytes, and stromal matrix. Wheat germ agglutinin (WGA) stained plasma membranes of all epithelial cell layers of cat and human and superficial and wing cells of rabbit. Plasma membranes of superficial and wing cells of cat epithelium also stained with peanut agglutinin (PNA) and Ricinus communis agglutinin I (RCA-I). Human and cat keratocytes stained with WGA and RCA-I. Stromal matrices of all three species were stained with concanavalin A and lentil agglutinin. In neuraminidase-treated sections, the entire epithelium and keratocytes of all three species stained with PNA. Corneal sections from the three species did not stain with Bandeiraea simplicifolia I, Bandeiraea simplicifolia II, Ulex europeus I, and Soybean agglutinin. These data suggest the presence of oligosaccharides with: N-acetylglucosamine/sialic acid residues in cell membranes of corneal epithelium of all species studied and in the keratocytes of human and cat; terminal beta-galactose residues in cat and human keratocytes, beta-galactose-galactosamine chains in cat epithelial cell membranes; and sialic acid-beta-galactose-galactosamine chains in epithelial cell membranes and keratocytes of all three species.