Proteins on different oral mucosal surfaces compared to saliva

Human saliva contains mucins and other proteins that maintain the integrity of the oral cavity. Unstimulated whole mouth saliva is the basal secretion from all glands and residual saliva remains on the mucosal surfaces after swallowing. Objective: To identify proteins in residual saliva from oral mucosal surfaces and compare with whole mouth saliva. Methods: Unstimulated whole mouth saliva (UWMS) was collected from healthy volunteers by drooling for 10 minutes. Residual saliva was collected from four oral mucosal surfaces; anterior hard palate (AHP), buccal (BUC), anterior tongue (AT) and labial (LL) using sterile Sialopaper strips applied for 10 seconds. Proteins were eluted from strips using an LDS buffer and electrophoresed on 4-12% Bis-Tris SDS-PAGE gels. Resolved proteins were stained with periodate Schiff's reagent (PAS) or Coomassie Brilliant Blue and identified by Western Blotting with specific antibodies or trypsin digested for LC-MSMS analysis. Results: Mucins and other salivary proteins were identified in whole mouth and mucosal surface salivas. A large number of components were identified as keratin or other epithelial cell derived proteins in mucosal surface salivas. The proportions of salivary proteins on buccal and tongue surfaces differed. Conclusion: Salivary proteins are present on oral surfaces and the composition can differ from whole mouth saliva and on different surfaces. Acknowledgements: This study is supported by GlaxoSmithKline.