Differential binding to glycotopes among the layers of three mammalian retinal neurons by man-containing N-linked glycan, T(alpha) (Galbeta1-3GalNAcalpha1-), Tn (GalNAcalpha1-Ser/Thr) and I (beta)/II (beta) (Galbeta1-3/4GlcNAcbeta-) reactive lectins.

Carbohydrate structures between retinal neurons and retinal pigment epithelium (RPE) play an important role in maintaining the integrity of retinal adhesion to underlying RPE, and in retinal detachment pathogenesis. Since relevant knowledge is still in the primary stage, glycotopes on the adult retina of mongrel canines (dog), micropigs and Sprague-Dawley rats were examined by lectino-histochemistry, using a panel of 16 different lectins. Paraffin sections of eyes were stained with biotinylated lectins, and visualized by streptavidin-peroxidase and diaminobenzidine staining. Mapping the affinity profiles, it is concluded that: (i) all sections of the retina reacted well with Morniga M, suggesting that N-linked glycans are present in all layers of the retina; (ii) no detectable human blood group ABH active glycotopes were found among retinal layers; (iii) outer and inner segments contained glycoconjugates rich in ligands reacting with T (alpha) (Galbeta1-3GalNAcalpha1-Ser/Thr) and Tn (GalNAcalpha1-Ser/Thr) specific lectins; (iv) cone cells of retina specifically bound peanut agglutinin (PNA), which recognizes T (alpha) residues and could be used as a specific marker for these photoreceptors; (v) the retinas of rat, dog and pig, had a similar binding profile but with different intensity; (vi) each retinal layer had its own binding characteristic. This information may provide useful background knowledge for normal retinal physiology and miscellaneous retinal diseases, including retinal detachment (RD) and age-related macular degeneration (ARMD).