Characterization of the immunologic responses to human in vivo acquired enamel pellicle as a novel means to investigate its composition

Human acquired enamel pellicle is formedby proteins, peptides and other organicmolecules which selectively adsorb ontotooth surfaces. Pellicle exhibits severalfunctions such as the formation of a pro-tective interface between the tooth surfaceand the oral environment (22), acting as aselective permeability barrier that regu-lates mineralization/demineralization pro-cesses (24) and dictating the compositionof the microbial flora that form on the toothsurface (10). Studies on the composition ofpellicle are mandatory to understand themolecular principles that underlie thesefunctional processes.Since it is cumbersome to remove pel-licle from human teeth in vivo, only smallamounts can be harvested for analyticalinvestigations. Therefore, much work hasbeen done using in vitro models whichmimic the formation of the pellicle in vivo.These techniques use glandular salivarysecretions or whole saliva supernatantsin conjunction with hydroxyapatite pre-parations to study the protein interfacewhich is selectively adsorbed to the miner-al (2, 18). Considerable insights into se-lectivity and affinity characteristics ofvarious salivary proteins have been ob-tained. However, it has been recognizedthat in vitro pellicle does neither comple-tely mirror the electrophoretic patterns northe amino acid composition of in vivoformed pellicle (1, 7, 18, 38, 44). There-fore, information on the protein interfaceformed on tooth surfaces in the oral en-vironment can only beobtained by harvest-ing pellicle formed in vivo.Problems associated with the study ofin vivo pellicle are that a harvesting tech-nique requiring clinical skills is necessaryto selectively remove pellicle materialfrom tooth surfaces without contaminatingit with salivary secretions and bacteria.Recently, we developed a new pellicle