title: SIgA binding to mucosal surfaces is mediated by mucin-mucin interactions.
abstract: The oral mucosal pellicle is a layer of absorbed salivary proteins, including secretory IgA (SIgA), bound onto the surface of oral epithelial cells and is a useful model for all mucosal surfaces. The mechanism by which SIgA concentrates on mucosal surfaces is examined here using a tissue culture model with real saliva. Salivary mucins may initiate the formation of the mucosal pellicle through interactions with membrane-bound mucins on cells. Further protein interactions with mucins may then trigger binding of other pellicle proteins. HT29 colon cell lines, which when treated with methotrexate (HT29-MTX) produce a gel-forming mucin, were used to determine the importance of these mucin-mucin interactions. Binding of SIgA to cells was then compared using whole mouth saliva, parotid (mucin-free) saliva and a source of purified SIgA. Greatest SIgA binding occurred when WMS was incubated with HT29-MTX expressing mucus. Since salivary MUC5B was only able to bind to cells which produced mucus and purified SIgA showed little binding to the same cells we conclude that most SIgA binding to mucosal cells occurs because SIgA forms complexes with salivary mucins which then bind to cells expressing membrane-bound mucins. This work highlights the importance of mucin interactions in the development of the mucosal pellicle.
authors: Salivary Research Unit, King's College London Dental Institute, London, United Kingdom.
authors: Hannah L
authors: HL
authors: Gibbins
authors: Salivary Research Unit, King's College London Dental Institute, London, United Kingdom.
authors: Gordon B
authors: GB
authors: Proctor
authors: Australian Research Council Centre of Excellence in Plant Cell Walls, School of Chemical Engineering, The University of Queensland, Queensland, Australia.
authors: Gleb E
authors: GE
authors: Yakubov
authors: Unilever R&D Discover, Colworth Science Park, Sharnbrook, United Kingdom.
authors: Stephen
authors: S
authors: Wilson
authors: Salivary Research Unit, King's College London Dental Institute, London, United Kingdom.
authors: Guy H
authors: GH
authors: Carpenter
mesh_terms: D044622:Dental Pellicle / Q000378:metabolism*; D019073:HT29 Cells; D006801:Humans; D007071:Immunoglobulin A, Secretory / Q000378:metabolism*; D008727:Methotrexate / Q000494:pharmacology; D055271:Mucin 5AC; D055257:Mucin-5B; D009077:Mucins / Q000378:metabolism*; D012463:Saliva / Q000378:metabolism
chemical_list: D007071:Immunoglobulin A, Secretory; C524678:MUC5AC protein, human; C524578:MUC5B protein, human; D055271:Mucin 5AC; D055257:Mucin-5B; D009077:Mucins; D008727:Methotrexate