Human Submandibular-sublingual Saliva Research Articles

Murine monoclonal antibody which can distinguish cystatins SA1 and SA2

To develop a diagnostic trial enabling the selective examination for a target cystatin in human body fluids, we attempted to prepare monoclonal antibodies against human cystatin SA1 (originally cystatin SA) and its variant form (cystatin SA2). BALB/c mice were immunized with recombinant (r-) cystatins SA1 and SA2. Two monoclonal antibodies designated Cys3F11 and Cys2E5 were selected. By ELISA analyses, the Cys2E5 was shown to react with r-cystatin SA2 but also somewhat with r-cystatin SA1 (22% cross-reactivity) and with plasma cystatin C (18% cross-reactivity), indicating a high specificity for cystatin SA2. The Cys3F11 reacted not only with r-cystatin SA1 but also with r-cystatin SA2 (89% cross-reactivity) and plasma cystatin C (47% cross-reactivity). This finding was further emphasized by immunoblotting of human submandibular–sublingual saliva samples. ELISA additivity test suggests that the two monoclonal antibodies bind to distinct epitopes. In conclusion, we have succeeded in producing two antibodies that discriminate the structural differences between salivary cystatins S and SN, which share more than 90% identity in amino acid sequence with cystatin SA.

Active domains of salivary statherin on apatitic surfaces for binding to Fusobacterium nucleatum cells.

Fusobacterium nucleatum can bind to saliva-coated tooth surfaces. However, the nature of the domains of salivary protein that interact with F. nucleatum remains unclear. The ability of individual proteins in human submandibular-sublingual saliva (HSMSL) to bind F. nucleatum cells was examined by dot blot assay; statherin displayed the strongest binding activity. Statherin binding sites were determined based on binding of (125)I-labelled F. nucleatum to statherin-coated hydroxyapatite (sHAP) beads via inhibition assays using synthetic analogous peptide fragments of whole statherin. Analogous peptides corresponding to residues 19-26 and 32-39 of statherin inhibited binding by 77 % and 68 %, respectively. Synthetic peptides were also prepared by serial deletions of individual residues from N- and C-termini of the peptides GPYQPVPE (aa 19-26) and QPYQPQYQ (aa 32-39). The inhibitory effects of peptides YQPVPE (aa 21-26) and PYQPQYQ (aa 33-39) were very similar to those of GPYQPVPE and QPYQPQYQ, respectively. However, additional deletion of residues resulted in significant reduction of the inhibitory effect. Alanine-scan analysis of YQPVPE revealed that all tested peptides retained inhibitory activity; only YAPVPE exhibited significantly decreased inhibitory activity. These findings suggest that YQPVPE and PYQPQYQ may represent the minimal active segments of statherin for binding to F. nucleatum; moreover, Gln may be a key amino acid in the active segment.

Adsorption of Salivary Proteins on Titanium Implants

A major factor that contributes to the failure of a dental implant is peri-implantitis, which develops as a result of bacterial colonization onto the implant surface. Bacterial plaque formation to the intra-oral hard surface is dependent on surface roughness or pellicle adsorption. Early events in pellicle formation may affect plaque composition and pathogenesis. Recent studies showed that bacterial adherence to salivary coated biomaterials had unique characteristics mainly due to the different pellicle adsorption pattern onto diverse substratum. Titanium(Ti) implants present a different surface configuration from enamel and thus may alter plaque composition. Moreover, a surface modified Ti implant has variable surface characteristics according to the modification methods. The present study was designed to qualitatively characterize the pellicle adsorption pattern of the plasma sprayed Ti implant compared to enamel surface in vivo. Enamel slabs and plasma sprayed Ti implants were attached to the buccal surface of a vacuum-formed splint using dental floss silk. The splint was held in the volunteer’s mouth for 2 hours. The adsorbed pellicles were extracted from the substrates and lyophilized. Human whole saliva(HWS), human parotid saliva(HPS) and human submandibular-sublingual saliva(HSMSL) were also collected from the same subject. Salivary proteins components were analyzed by SDS-PAGE gel electrophoresis and Western blot analyses. SEM assessment was also conducted to identify the surface configuration changes. Results showed that the plasma sprayed Ti implant pellicle contains different salivary protein component from enamel surface and the protein component came primarily from HSMSL saliva, while amylase, sIgA and lactoferrin existed both in TiP and EP, the blotting intensity was different. A two hour adsorbed pellicle laid

Purification of large quantities of human salivary cystatins S, SA and SN: their interactions with the model cysteine protease papain in a non-inhibitory mode.

Our aim was to purify large quantities of human salivary cystatins S, SA and SN in order to determine whether these salivary cystatins have a stable interaction with cysteine proteases at a second binding site, other than the protease active site. This property may affect their availability to act as cysteine protease inhibitors within the oral environment. Salivary cystatins S, SA and SN were purified from human submandibular sublingual saliva to homo- geneity by column chromatography. Formation of stable complexes between the model cysteine protease papain in the absence of reductant was assessed by SDS-PAGE and probing Western blots with antibody to human salivary cystatin SN. Proteolytic activity of the complex was determined in the gel after electrophoresis. Only cystatin SN (14.3 kD) was found to form a stable complex with papain (22 kD) that could be separated by SDS-PAGE producing a Coomassie stained band at (37 kD). After western transfer this same band (37 kD) cross-reacted with antibody to SN. In the presence of E64, an active site inhibitor of cysteine proteases, the same complex was formed, suggesting that SN is able to bind to papain at a site other than the active site. Activity staining of the gel confirmed that this complex (-E64) retained proteolytic activity. Such complex formation between cystatin SN and cysteine proteases in a non-inhibitory mode may reduce its availability to act as an effective cysteine protease inhibitor in the oral environment.

Co-aggregation of micelle-like globules from human submandibular/sublingual and parotid saliva

Salivary micelle-like globules (SMGs) closely related to the casein micelles in milk have been observed in human whole saliva (HWS) and in human parotid saliva (HPS). Isolation of the SMGs from HWS, by acidification to the iso-electric point, has been observed to result in markedly larger amounts of SMGs than for HPS. The hypotheses to be tested in the present study were that SMGs also exist in human submandibular/sublingual saliva (HSMSL) and that the SMGs, as present in the pure salivary secretions, are precursors of the whole saliva SMGs in the oral cavity. Stimulated HPS and HSMSL saliva were collected from five subjects and examined by TEM, zeta potential determinations, photon correlation spectroscopy (PCS) and bacterial agglutination studies. Mixing HSMSL saliva and HPS in the ratio 1:3 and analysis by TEM and PCS examined possible co-aggregation of SMGs from different sources. TEM studies of HSMSL saliva showed occasional SMG-like particles and many large particulate aggregates, while PCS analyses indicated structures varying in diameter from 100 to 600 nm (mean 340 nm). The zeta potential of HSMSL at physiological pH varied among subjects from −13 to −20 mV (mean −17 mV). HSMSL saliva and SMGs isolated from HSMSL saliva were able to agglutinate streptococcal strains. TEM studies of the saliva mixture showed many SMGs and a few large aggregates consisting of SMG-like structures with diameters in the range of 20–80 nm. PCS analyses indicated structures in the saliva mixture from 400 to 2000 nm in diameter (mean 1030 nm). The results of this study show that SMGs are also found in HSMSL and suggest that the SMGs in HWS are likely to be the result of a co-aggregation of SMGs from the pure salivary secretions.

Functional aspects of the human salivary cystatins in the oral environment.

The aim of this study was to investigate the cysteine protease inhibitory properties of the human salivary cystatins S, SA and SN in order to identify potential in vivo target cysteine proteases which may include those involved in periodontal tissue destruction. In addition, the potential role of the salivary cystatins with respect to the tooth mineral balance and pellicle formation was also investigated. Salivary cystatins S major, S minor, SA, SAT (a truncated form of SA) and SN were purified from human submandibular sublingual saliva. Sensitive fluorometric assays were used to test the inhibitory action of each purified form of salivary cystatin against a variety of cysteine proteases and to determine whether pH affected their inhibitory activity towards the well-characterized cysteine protease papain. Their potential role in the mineral balance of the tooth was assessed by the measurement of calcium binding and the rate of binding to carbonated apatite (CAP). Salivary cystatin SN was found to inhibit the human lysosomal cathepsins B, H and L and salivary cystatin SA was found to inhibit human lysosomal cathepsin L in vitro. These proteases are involved in periodontal tissue destruction and these data suggest that salivary cystatins SA and SN are involved in the control of the proteolytic events in vivo. Salivary cystatin S was not an inhibitor of the cysteine proteases tested suggesting that its primary role is not as a cysteine protease inhibitor. However, S was able to bind more calcium and bind more rapidly to CAP than SA or SN, suggesting that its primary role in the oral environment is likely to be the involvement with the mineral balance of the tooth.

Binding of the pili of Pseudomonas aeruginosa to a low-molecular-weight mucin and neutral cystatin of human submandibular-sublingual saliva.

In previous experiments, we have shown that [125I]pili of Pseudomonas aeruginosa exhibited specific binding to a low-molecular-weight mucin (MG2) of human submandibular-sublingual saliva (HSMSL; Reddy MS, Levine MJ, Paranchych W. Crit Rev Oral Biol Med 4:315-323, 1993). In the present study, I have utilized unlabeled pili and immunostaining to identify the receptor molecules in HSMSL. In addition to MG2, pili also bound to neutral cystatin (CsnSN). Binding of unlabeled pili to MG2 and CsnSN could be abolished by treatment of HSMSL with trypsin to hydrolyze the peptide moieties or N-acetylation to neutralize the positive charges of the lysine residues. Reductive methylation of HSMSL, which modifies the lysine residues to methyl lysines while retaining the positive charges, did not affect the binding of pili to either MG2 or CsnSN. Further, pili also exhibited binding to a recombinant MG2 peptide (aa 1-86). Collectively, the data suggested that a protein-to-protein interaction via electrostatic forces mediates the binding of the pili to MG2 and CsnSN. Iodination of pili, which modifies tyrosine-24 and/or -27 residues to O-iodotyrosine(s), abolished its binding to CsnSN but not to MG2. These results suggested that the conformation of pili also plays a role in interaction with CsnSN. Conformational change(s) of pili induced by iodination also made it susceptible to hydrolysis with trypsin.

多層築盛による市販光重合型硬質レジンの色調再現性に関する研究

The purpose of this study was to examine the role of protein of human submandibular-sublingual saliva in the retention and stability of dentures. This study was performed by analyzing how changes in protein affect viscosity.Submandibular-sublingual saliva samples obtained from 15 subjects, each with a healthy oral cavity and good general condition, were studied. A Kuette type rotary viscometer Low-Shear 30 (Contraves) was used to determine viscosity. The analysis of salivary proteins was achieved by combining microscale twodimensional SDS-PAGE with silver staining.In high viscosity saliva, 44 protein spots were detected. These spots appeared in the range of pI 3.8-10.0 and estimated molecular weight of 15, 000-1, 000, 000. In low viscosity saliva, approximately 30 protein spots were detected. These spots appeared in the range of pI 3.8-10.0 and estimated molecular weight of 15, 000-1, 000, 000.There was a significant correlation between the concentration of high molecular weight proteins with an estimated weight of more than 700, 000 and viscosity (r=071, p<0.01). High molecular weight proteins (with an estimated weight of more than 700, 000) were characterized into five groups to the isoelectric point. The two groups (more than pI 7.0 and pI 4.1-5.1) showed significant correlations with high viscosity of human submandibular-sublingual saliva (r=0.73 and p<001 for both groups).To standardize the reproducibility of the color of composite resin, the color range and tendency of photopolymerized composite resin were investigated. The color of single and multiple layer A 1 and A 3.5 were compared and analyzed using the L*a*b* color system. The results were as follows:1. The color range of the single layer photopolymerized composite resin was Opaque: L*=73.78 to 84.50, a*=0.47 to 4.01, and b*=11.96 to 19.59; Dentine: L*=50.47 to 63.95, a*=-3.75 to -1.68, and b*=-2.65 to 6.92; and Enamel: L*=38.02 to 42.33, a*=-1.67 to -0.51, and b*=-14.56 to -12.49.2. The color of triple-layer resin measured by L* and a* decreased when the thickness of dentine was increased from 0.4 mm to 1.0 mm and that of enamel was increased from 0.1 mm to 0.3 mm. However, the color of A 3.5 measured by a* was high when the thickness of enamel was between 0.1 and 0.2 mm. Hab° fluctuated within the YR and Y range in A 1 and within the YR range in A 3.5.3. The thickness of resin that is required for color expression in triple-layer photopolymerized composite resin was more than 0.6 mm of dentine and more than 0.2 mm enamel in A 1, and more than 0.6 mm of dentine and more than 0.1 mm of enamel in A 3.5.

義歯床の維持に関与する唾液蛋白質 二次元ポリアクリルアミドゲル電気泳動法によるヒト顎舌下腺唾液の分析

The purpose of this study was to examine the role of protein of human submandibular-sublingual saliva in the retention and stability of dentures. This study was performed by analyzing how changes in protein affect viscosity.Submandibular-sublingual saliva samples obtained from 15 subjects, each with a healthy oral cavity and good general condition, were studied. A Kuette type rotary viscometer Low-Shear 30 (Contraves) was used to determine viscosity. The analysis of salivary proteins was achieved by combining microscale twodimensional SDS-PAGE with silver staining.In high viscosity saliva, 44 protein spots were detected. These spots appeared in the range of pI 3.8-10.0 and estimated molecular weight of 15, 000-1, 000, 000. In low viscosity saliva, approximately 30 protein spots were detected. These spots appeared in the range of pI 3.8-10.0 and estimated molecular weight of 15, 000-1, 000, 000.There was a significant correlation between the concentration of high molecular weight proteins with an estimated weight of more than 700, 000 and viscosity (r=071, p<0.01). High molecular weight proteins (with an estimated weight of more than 700, 000) were characterized into five groups to the isoelectric point. The two groups (more than pI 7.0 and pI 4.1-5.1) showed significant correlations with high viscosity of human submandibular-sublingual saliva (r=0.73 and p<001 for both groups).

Surface-modified poly(methyl methacrylate) enhances adsorption and retains anticandidal activities of salivary histatin 5.

Denture-induced stomatitis is a common intraoral disease which is associated with high levels of Candida albicans adhesion to a denture surface. The aim of this study was to produce a surface-modified denture resin, which is usually manufactured from poly(methyl methacrylate) (PMMA), carrying an immobilized anticandidal protein. PMMA was modified by surface polymerization of methyl methacrylic acid to enhance adsorption of a potent candidacidal salivary protein, histatin 5. The modified PMMA showed higher surface adsorption and desorption of histatin 5 than the unmodified material. Because histatin 5 destabilizes C. albicans cell membranes and allows efflux of intracellular molecules, candidacidal activity was monitored by dye release from fungal cells. Adsorbed histatin 5 did not release dye from the yeast cells; however, dye was detected as histatin was desorbed from the surface. In an adhesion assay, modified PMMA decreased human submandibular-sublingual saliva (HSMSL) mediated adherence of yeast cells to the polymer. Precoating histatin 5 onto unmodified PMMA also abolished HSMSL-mediated adhesion. These experiments show that dental acrylic may be surface modified and loaded with histatin 5 as a means of controlled release of histatin 5 to an affected area. This surface modification may additionally reduce adhesion of C. albicans cells to the saliva-coated material.

Identification of salivary proteins inhibiting herpes simplex virus 1 replication

Salivary proteins play an important role in the maintenance of the oral ecology. Previous studies have indicated that human submandibular-sublingual and parotid salivas can selectively suppress the in vitro infectivity of herpes simplex virus 1. The purpose of this study was to identify the salivary components in human submandibular-sublingual saliva that modulate in vitro infectivity. Assessment of the interaction of viral particles with salivary components was accomplished using an in vitro solid-phase assay. These experiments revealed that herpes simplex virus particles selectively interact with the members of the salivary proline-rich protein and cystatin families. Subsequent yield reduction assays demonstrated the ability of proline-rich proteins and salivary cystatins to inhibit the viral replication, with basic proline-rich peptides being more effective. Subsequent assays suggest that basic proline-rich peptides reduced the virus titer by interfering with penetration and/or cellular processing of virus within the target cell. Collectively, these results further suggest that salivary proteins have an important role in the host defense mechanism against recurrent herpesvirus infection.

Genetic polymorphisms of the CST2 locus coding for cystatin SA

A new genetic polymorphism of cystatin SA has been identified in human submandibular-sublingual saliva by means of basic gel electrophoresis and immunoblotting with anti-cystatin S. Two proteins, SA1 and SA2, are given by two alleles of CST2, viz., CST2*1 and CST*2. Inheritance is controlled by two codominant alleles at an autosomal locus. This hypothesis is supported by studies of 16 families 32 children. Gene frequencies for CST2*1 and CST2*2 are 0.935 and 0.065, respectively (n = 341). Eighteen amino acids determined among 20 N-terminal residues of cystatin SA2 are identical with the sequence encoded by CST2. Three forms of cystatin S (mono-phosphorylated cystatin S, di-phosphorylated cystatin S, and non-phosphorylated cystatin S) are present in the 341 saliva samples tested.

Human submandibular-sublingual saliva promotes adhesion of Candida albicans to polymethylmethacrylate.

The purpose of this study was to identify components of saliva that interact with Candida albicans in solution and that may modulate adhesion to dental acrylic (polymethylmethacrylate [PMMA]) surfaces. Saliva-derived pellicles extracted from C. albicans blastoconidia and hyphal-form cells mixed with fresh human submandibular-sublingual saliva (HSMSL) contained predominantly high- and low-molecular-weight mucins (MG1 and MG2, respectively). In contrast, few components from fresh human parotid saliva were adsorbed to yeast cells. Coating PMMA beads with HSMSL significantly enhanced (10-fold) adhesion of both growth forms of C. albicans compared with human parotid saliva (2-fold), suggesting a role for mucins in adhesion. HSMSL-enhanced adhesion was completely abolished by preadsorbing HSMSL with either blastoconidia or hyphal-form cells prior to coating PMMA. However, coating PMMA with purified salivary mucins or the addition of mucin to preadsorbed saliva did not enhance or restore adhesion to levels found with fresh HSMSL. Adhesion assays employing guanidine-treated fresh HSMSL showed a complete lack of Candida binding, suggesting that subjecting HSMSL to dissociating conditions may alter a property of salivary mucins crucial for C. albicans adhesion. Protease and glycosidase treatment of yeast cells significantly reduced adhesion to HSMSL-coated PMMA. In addition, preincubation of C. albicans with mannose and galactose inhibited adhesion to HSMSL-coated PMMA. These results suggest that mucins may play a role in C. albicans adhesion to saliva-coated PMMA and that a glycoprotein on the yeast surface may be involved in these events.

Low-molecular-mass human salivary mucin, MG2: structure and binding of Pseudomonas aeruginosa.

Low-molecular-mass human salivary mucin, MG2, was isolated from human submandibular-sublingual saliva (HSMSL) employing citraconylation, gel filtration, and ion-exchange chromatography. Following proteolysis with trypsin, two glycopeptides were purified. The higher molecular weight glycopeptide was highly glycosylated with O-linked units. The lower molecular weight glycopeptide was less glycosylated and contained most of the N-linked units. Interaction between components of HSMSL and pili of Pseudomonas aeruginosa was examined by an overlay binding assay. Pili were found to bind to MG2. Preliminary studies indicated that the binding may involve a protein to protein interaction.

Modulation of intergeneric adhesion of oral bacteria by human saliva.

Porphyromonas gingivalis adheres in vitro to biofilms containing Streptococcus and Actinomyces species. On initial entry to the mouth, this interbacterial adhesion may enable P. gingivalis to colonize dental plaque and to avoid clearance by saliva flow. Saliva may also interfere directly with P. gingivalis colonization of dental plaque; a 43-kDa glycoprotein in human submandibular-sublingual saliva binds to P. gingivalis surfaces and diminishes interbacterial adhesion activity. To avoid fouling of its surface by host components, P. gingivalis produces surface-localized proteases that can degrade adsorbed proteins and may serve to unmask bacterial adhesins. Successful management of P. gingivalis colonization might be achieved in the future by devising artificial methods to block its surface adhesins or to prevent bacterial proteolysis of native salivary molecules that have protective functions.

Inhibition of Porphyromonas gingivalis adhesion to Streptococcus gordonii by human submandibular-sublingual saliva.

Porphyromonas gingivalis W50 adheres in vitro to biofilms of Streptococcus gordonii G9B. This phenomenon is believed to facilitate the initial colonization of the oral cavity by P. gingivalis and to contribute to the maturation of dental plaque. In this report, we describe the modulating effects of human submandibular-sublingual saliva (HSMSL) on this in vitro model of intergeneric bacterial adhesion (coaggregation). HSMSL inhibited P. gingivalis adhesion to S. gordonii by 50% at a concentration of 57 micrograms of protein per ml. Maximum inhibitory activity was associated with a 43-kDa protein obtained by sequential Sephadex G200 gel filtration and CM52 ion-exchange chromatography of HSMSL. Pools of other column fractions of HSMSL showed no effect or were slightly stimulatory for bacterial adhesion. The binding of radioiodinated column fractions containing the 43-kDa protein by P. gingivalis was accompanied by their rapid enzymatic degradation. Treating P. gingivalis at 60 degrees C for 30 min or with protease inhibitors (phenylmethylsulfonyl fluoride and sodium iodoacetate) reduced adherence to streptococcal biofilms. These treatments did not prevent P. gingivalis from binding soluble HSMSL saliva components, although subsequent proteolysis was nearly eliminated. These observations indicate that surface-associated proteases of P. gingivalis, either independently or in concert with adjacent surface adhesins, interact with surfaces of oral streptococci to facilitate interbacterial adhesion. The adhesion-blocking properties of HSMSL, particularly the 43-kDa protein, may represent an important host defense mechanism in the oral cavity.

Large-scale purification and characterization of the major phosphoproteins and mucins of human submandibular-sublingual saliva

The major components of human submandibular-sublingual saliva (HSMSL) are mucins, amylases, cystatins, proline-rich proteins and statherin. Structure-function studies of these molecules have been hampered by the small amounts of purified materials that can be isolated from human secretions. The present study describes an integrated purification protocol for the large-scale preparation of many of these molecules. To dissociate partially heterotypic complexes among salivary molecules, HSMSL was initially fractionated into four pools by gel filtration with 6 M-guanidine hydrochloride. Subsequent fractionation of these four pools by gel-filtration and ion-exchange chromatography resulted in the purification of high- and low-Mr mucins, neutral and acidic cystatins, acidic and basic proline-rich proteins and statherin. Many variants or isoforms of these salivary molecules have been identified and biochemically characterized. Biochemical studies indicated that the low-Mr mucin exists as two isoforms which vary in their sialic acid to fucose ratios. Three isoforms of acidic cystatin S were characterized which differ in their phosphate content. Two isoforms of a basic proline-rich peptide were identified; the smaller peptide was a truncated form missing the first seven amino acids.

Interaction of a salivary mucin-secretory immunoglobulin A complex with mucosal pathogens

This study examined the interaction of a human salivary low-molecular-weight mucin (MG2) with Staphylococcus aureus and Pseudomonas aeruginosa by using both solution-phase and solid-phase assays. In solution phase, MG2 in human submandibular-sublingual saliva (HSMSL) bound to the bacterial surface; however, the highly purified mucin isoforms (MG2a and MG2b) did not. Mucin binding appeared to be dependent on heterotypic complexing between MG2 and secretory immunoglobulin A (IgA), although other salivary molecules may also be involved. In contrast, in a solid-phase assay in which HSMSL, MG2-containing fractions with secretory IgA, and purified MG2 were immobilized onto a solid surface, there was minimal adherence of S. aureus. The collective results suggest that mucin binding to S. aureus and P. aeruginosa may be predicated on the formation of an MG2-secretory IgA complex. Such interactions may facilitate microbial clearance from the oral cavity and play an important role in preventing colonization of the oral cavity and the respiratory tract by potential pathogens.

Purification and characterization of subunits of a high molecular weight human salivary mucin

A high molecular-weight mucin was purified from human submandibular-sublingual saliva. The purity of the mucin preparation was demonstrated by the absence of other salivary proteins, by antibody reactivity and by gel electrophoresis. After reduction with mercaptoethanol a putative link component with approximate M r 150,000 and a glycoprotein component of higher M r could be detected by gel electrophoresis. These subunits were subsequently purified and they showed distinct differences in their amino acid compositions, demonstrating that the mucin consisted of two different subunits. The link had a number of similarities with the link component of intestinal mucin and a parotid agglutinin and has previosuly been shown to cross-react with antiserum to link component from intestinal mucin. Salivary and intestinal mucins may therefore have similar subunit structure.

A human salivary protein which promotes adhesion of Streptococcus mutans serotype c strains to hydroxyapatite.

The aim of this study was to investigate the nature of one of the factors in human submandibular-sublingual (SMSL) saliva which promotes the adhesion of Streptococcus mutans serotype c strains to hydroxyapatite (HA) surfaces. Gel filtration chromatography of SMSL saliva on Trisacryl GF2000 gave a void volume peak which contained the major fraction of adhesion-promoting activity for S. mutans JBP to HA. Maximum adhesion-promoting activity, however, eluted slightly later than the maximum 220-nm absorbance of the void volume peak. Gel filtration of the void volume material after treatment with sodium dodecyl sulfate (SDS) gave an early-eluting larger peak followed by a smaller peak with which the adhesion-promoting activity was associated. SDS-polyacrylamide gel electrophoresis (SDS-PAGE) showed the presence of relatively slowly migrating material associated with the larger inactive peak, presumably mucin, and a faster-migrating band(s) associated with the smaller active peak. SDS-PAGE indicated molecular weights in the range of 300,000 to 350,000 by extrapolation from size standards. Comparison of SMSL from five individuals showed the presence of single bands or double bands associated with adhesion-promoting activity, indicating genetic polymorphism. The active material did not resemble either secretory immunoglobulin A, based on SDS-PAGE and immunoassay, or fibronectin, based on SDS-PAGE, and also differed in molecular weight from salivary mucins and salivary constituents previously reported to promote aggregation of certain oral bacteria, but a relationship to these materials cannot be excluded. This adhesion-promoting material may play a significant role in the initial colonization of tooth surfaces by S. mutans strains.