The interactions of human neutrophils with the constituents of an experimental dental biofilm.

Despite the antibacterial properties of neutrophils, their ability to prevent colonization of the dental biofilm by pathogenic bacteria is limited. The present study examined the ability of human neutrophils to attach to an experimental dental biofilm and tested their antibacterial functions following adhesion. Neutrophil adhesion was greatest to hydroxyapatite (HA) in the absence of biofilm. Among the biofilms, glucosyltransferase or fructosyltransferase adsorbed onto saliva-coated HA showed the highest adhesion of cells. The adhesion of neutrophils was directly related to their initial concentration in the solution and to the duration of incubation. Plasma was found to reduce neutrophil attachment significantly, while stimulation of the cells had no effect. Stimulation of attached neutrophils induced superoxide secretion with levels significantly lower than that secreted by suspended cells. The presence of neutrophils on the biofilm reduced the number and the viability of Streptococcus mutans attached to the beads. The present findings suggest that neutrophils are able to attach to dental biofilms and that the attached neutrophils retained their antibacterial activity.

Amino acid composition of experimental salivary pellicles.

The amino acid compositions of pellicles formed in vitro from submandibular, parotid, and mixed saliva were determined and compared. Samples of the total pellicles as well as the relatively acid-soluble supernates and acid-insoluble sediments were collected and analyzed. In each instance striking differences in composition between the pellicle and the saliva from which it was formed indicate that pellicle formation is a highly selective process. The similarity in composition of the total and fractionated submandibular-parotid pellicle samples indicated a representative dissolution of the total mixed pellicle in the collection acid, rather than a preferential dissolution of part of the total pellicle. In the case of the pellicles formed from the isolated submandibular and parotid salivas, the supernate and the total pellicle were quite similar in composition, but differed somewhat from the sediment. Those results indicate that most of the salivary pellicle is soluble in the dilute acid used to collect the pellicle, and that a portion of the total submandibular or parotid salivary pellicle dissolves preferentially. The compositions of the total parotid pellicle and the parotid supernate and sediment were remarkable similar to the counterparts formed from submandibular saliva alone, suggesting similar origins and mechanisms of formation.

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 formed by molecules selectively adsorbed onto tooth surfaces. The present work describes the use of monoclonal antibody (mAb) technology as a novel approach to identify micro amounts of components present in pellicle. MAbs were obtained with reactivities against statherin, histatin, mucous glycoprotein 1(MGI), albumin, amylase and human immunoglobulins (Igs), indicating that these are pellicle components, which was further confirmed by immunoblotting. No mAbs against proline-rich proteins (PRPs), lysozyme, mucous glycoprotein 2 (MG2), carbonic anhydrase, lactoferrin or peroxidase were obtained, suggesting that these components are absent, present in low amounts, or exhibit low antigenicity. Further characterization of the binding epitopes of some of th e obtained anti-MGO, anti-statherin and anti-histatin mAbs were carried out and the biological relevance is discussed. The results open up the possibility that immunization with human pellicle and mAbs production can be employed to identify hitherto unknown constituents of pellicle.