Lectin receptors of amyloid in corneas with lattice dystrophy

N. Panjwani, M. Rodrigues, K. Free, J. H. Krachmer, D. Albert and J. Baum

We analyzed lectin binding patterns of amyloid glycoconjugates in patients with lattice dystrophy of the cornea. Results of paraffin and frozen sections differed in some instances. With paraffin sections, three lectins--wheat germ agglutinin (WGA), Ricinus communis agglutinin I (RCA-I), and concanavalin A (Con A)--stained the abnormal deposits. In frozen sections, the abnormal deposits were stained by five lectins--WGA, RCA-I, Con A, peanut agglutinin (PNA), and soybean agglutinin (SBA). In paraffin sections, PNA and SBA did not stain amyloid deposits. In both paraffin and frozen sections, some lectin-positive deposits corresponded to the Congo red-positive material, whereas others were present surrounding and encroaching on the Congo red-reactive material. This study demonstrates that WGA-, RCA-I-, Con A-, PNA-, and SBA-positive abnormal deposits are present in corneas with lattice dystrophy. Since lectins bind to specific sugar residues, we conclude that the abnormal deposits consist, at least in part, of glycoconjugates and that these glycoconjugates contain oligosaccharides with N-acetylglucosamine/sialic acid, mannose/glucose and terminal beta-galactose residues and chains with terminal beta-galactose-N-acetylgalactosamine disaccharides.