HISTOCHEMICAL-STUDY OF THE EPITHELIA OF NASAL POLYPS BY BIOTINYLATED LECTINS AND NEOGLYCOPROTEIN - A COMPARISON WITH THE NORMAL HUMAN RESPIRATORY EPITHELIUM

Formalin-fixed, paraffin-embedded sections from human nasal polyps and the normal respiratory epithelium were glycohistochemically investiga ted. Three biotinylated lectins were used : peanut (Arachis hypogaea) agglutinin (PNA) which, binds to terminal galactose (beta 1-3)N-acetyl galactosamine residues that can be unmasked by a neuraminidase digesti on; wheat germ (Triticum vulgare) agglutinin (WGA), which binds to N-a cetylglucosamine and N-acetylneuraminic acids; and gorse seed (Ulex eu ropaeus) agglutinin (UEA-I), which binds to L-fucose. In addition, the presence of accessible galactose (beta 1-3)N-acetylgalactosamine (T-a ntigen) glycan receptors (endolectins) was also assessed. The avidin-b iotin-peroxidase complex (ABC) and diaminobenzidine (DAB) were used as chromogen. The ciliated cells of the normal respiratory epithelium an d those of the pseudostratified epithelium of nasal polyps possess sim ilar glycohistochemical characteristics suggesting no major alteration s an the level of lectin-reactive carbohydrate epitopes as indicators of cellular glycosylation. Notably, this parameter can respond sensiti vely to changes in cell differentiation or activation. The basal and m ucus-secreting cells in the two epithelia display different reactivity patterns emphasizing the presence of dissimilar sugar residues. Simil arly, the dysplasia reflecting squamous epithelium of nasal polyps sho ws a distinct staining behaviour, indicative for disparate glycoconjug ate display. Thus, quantitative differences in the lectin-selective st aining of various cell types are detectable. The expression of T-antig en-bearing neoglycoprotein binding is weak and similar in both the nor mal epithelium and the pseudostratified epithelium lining nasal polyps . Only the most superficial cells of the squamous epithelium disclose a moderate labelling with this probe. These results indicate that furt her studies in this field are warranted, employing neoglycoproteins an d also endolectins from human tissues to correlate glycobiological pro perties of the epithelium of the conducting airways and its diseased f orms with functional features.