title: Distinct localization of MUC5B glycoforms in the human salivary glands.
abstract: Salivary mucins, encoded by the MUC5B gene, make up a heterogeneous family of molecules, which are secreted by several glands, including the submandibular, sublingual, and palatine glands. Previous studies have shown that heterogeneity in the salivary mucin population is related to its multiglandular origin. In the present study we address the question to what extent the mucin (MUC5B) population from a single human salivary gland is made up of different glycoforms. Using monoclonal antibodies to defined protein and sulfated carbohydrate epitopes specific to MUC5B, we conduct an immunohistochemical study of different salivary gland types, including submandibular, sublingual, and labial glands. In all tissues studied we found a mosaic expression pattern of sulfo-Lewis a antigen, recognized by mAb F2, which in salivary glands is exclusively present on MUC5B. On the other hand, mucous acini were uniformly labeled by mAb EU-MUC5Bb, evoked against a peptide-stretch of the tandem repeat region of MUC5B. Double staining with both antibodies confirmed the presence of MUC5B-positive/sulfo-Lewis a-positive cells, as well as MUC5B-positive/sulfo-Lewis a-negative cells within one glandular unit. These results indicate that one and the same salivary gland synthesizes different MUC5B glycoforms.
authors.affiliation: Department of Dental Basic Sciences, Section of Oral Biochemistry, Academic Centre for Dentistry Amsterdam (acta), Vrije Universiteit, Van Der Boechorststraat 7, 1081 Bt Amsterdam, The Netherlands. eci.veerman.obc.acta@med.vu.nl
authors.forename: E C I
authors.initials: EC
authors.lastname: Veerman
authors.forename: P A M
authors.initials: PA
authors.lastname: van den Keijbus
authors.forename: K
authors.initials: K
authors.lastname: Nazmi
authors.forename: W
authors.initials: W
authors.lastname: Vos
authors.forename: J E
authors.initials: JE
authors.lastname: van der Wal
authors.forename: E
authors.initials: E
authors.lastname: Bloemena
authors.forename: J G M
authors.initials: JG
authors.lastname: Bolscher
authors.forename: A V Nieuw
authors.initials: AV
authors.lastname: Amerongen
mesh_terms: D000911:Antibodies, Monoclonal; D015153:Blotting, Western; D006801:Humans; D007150:Immunohistochemistry; D055257:Mucin-5B; D009077:Mucins / Q000032:analysis* / Q000235:genetics; D009092:Mucous Membrane / Q000737:chemistry / Q000378:metabolism*; D020033:Protein Isoforms / Q000032:analysis; D012463:Saliva / Q000737:chemistry / Q000378:metabolism; D012469:Salivary Glands / Q000737:chemistry / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; C524578:MUC5B protein, human; D055257:Mucin-5B; D009077:Mucins; D020033:Protein Isoforms