Sialyl Lewis X, Lewis X, and N-acetyllactosamine expression on normal and glaucomatous eyes

Purpose. Sialyl Lewis X (sLe(X)), Lewis X (Le(X)), and N-acetyllactosamine are carbohydrate chains of neolactoglycoconjugates which are expressed by specific cell types and are important in the functioning of cells within an organism. This study attempts to determine the expression of these glycoconjugates on the conjunctiva, cornea, and trabecular meshwork (TM) of both normal and glaucomatous eyes. Methods. Frozen anterior segment sections of both normal and glaucomatous human cadaver eyes, as well as rabbit eyes, were stained with a panel of monoclonal antibodies (mAbs) to neolactoglycoconjugates using an Avidin Biotin Peroxidase Complex/Alkaline Phosphatase staining method. Results. SLe(X) characteristically stained both human conjunctival and corneal epithelia in normal (n = 5) and glaucomatous (n = 5) sections. SLe(X) stained corneal and conjunctival epithelia of glaucomatous eyes much more intensely than normal eyes. Rabbit cornea sections stained for sLe(X), Le(X), and N-acetyllactosamine. However, human cornea only consistently stained with sLe(X). Normal and glaucomatous human TM sections did not stain for sLe(X), Le(X), or N-acetyllactosamine. Conclusion. The expression of glycoconjugates with sLe(X) side chains appears to be upregulated in the conjunctival and corneal epithelia of glaucomatous eyes. Distinct species specific differences were noted in Le(X) and N-acetyllactosamine staining patterns in rabbit and human corneal epithelia.