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Inhibitors of coaggregation between Actinomyces viscosus T14V and Streptococcus sanguis 34: beta-galactosides, related sugars, and anionic amphipathic compounds.

Coaggregation between Actinomyces viscosus T14V (T14V) and Streptococcus sanguis 34 (Ss34) depends upon specific reaction between lectin on T14V and carbohydrate on Ss34. Studies on coaggregation inhibition by sugars related to D-galactose, beta-galactosides, and amphipathic molecules revealed: (i) D-fucose, D-talose approximately equal to D-galactose, which was 0.2 potency of lactose. No other hexoses or pentoses inhibited at 0.1 M. (ii) Gal beta (1 leads to 3)GalNAc alpha OCH2C6H5 was the most potent beta-galactoside inhibitor; it had 20 times the potency of lactose. (iii) Anionic nonaromatic amphipathic compounds were good inhibitors; sodium deoxycholate (I) was equal to lactose; sodium dodecyl sulfate (II) had 15 times the potency of lactose; there was 90 to 100% irreversible inhibition when T14V was treated with 0.005 M (II). Treatment of Ss34 with II had no effect. (iv) Synergism of inhibition was observed between lactose and I or lactose and II, e.g., inhibition by 0.01 M lactose = 5%; inhibition by 0.01 M I = 9%; inhibition by 0.01 M lactose + 0.01 M I = 87%. (v) The irreversible inhibition by II was prevented when 0.25 M lactose or 0.25 M I was present during treatment of T14V with 0.005 M II. (vi) Synergism and prevention by lactose or by I of irreversible inhibition by II suggest that all three react at the same site on T14V lectin. We hypothesize that the T14V lectin combining site for Ss34 carbohydrate has specific affinity for beta-galactosides and for anionic nonaromatic amphipathic molecules. This site can be saturated by either kind of reagent to exclude the other reagent or to inhibit coaggregation.

Actinomyces↗

Antibodies against the Ag2 fimbriae of Actinomyces viscosus T14V inhibit lactose-sensitive bacterial adherence.

Monospecific antisera against the Ag1 and Ag2 fimbrial components of Actinomyces viscosus T14V were produced by immunizing rabbits with immune precipitates of each antigen harvested from crossed-immunoelectrophoresis plates. The Fab fragments prepared from these sera were used as specific reagents in immunoelectron microscopy to identify each fimbrial component on the bacterial surface and also were assayed for their abilities to prevent the coaggregation of A. viscosus T14V with Streptococcus sanguis 34, an interaction that is lactose sensitive. Each Fab preparation appeared to react with different fibrillar structures present on the actinomycete, and only the Ag2-specific Fabs blocked coaggregation. These results provide strong support for the presence of distinct types of fimbriae on A. viscosus T14V and indicate the exclusive involvement of Ag2 fimbriae in lactose-sensitive adherence.

Actinomyces↗

Cell-mediated cytotoxicity against rat fibroblasts induced by Actinomyces viscosus.

Cell-mediated cytotoxicity against syngeneic fetal rat fibroblasts that require in vitro exposure of effector cells to Actinomyces viscosus Ny1 fractions was investigated by measuring the uptake of radioactivity by fibroblasts during a 2-h pulse with [14C]aminoisobutyric acid after 1 to 3 days of coculture with splenic effector cells. By using splenocytes from inbred RIC-Sprague-Dawley rats as effector cells and syngeneic embryonic rat fibroblasts as target cells, strong cell-mediated cytotoxicity dependent on the in vitro exposure to an A. viscosus Ny1 fraction was observed, but only within a small range of effector-to-target cell ratios (3:1 to 10:1). Concanavalin A and lipopolysaccharide from Escherichia coli induced a comparable cytotoxicity, indicating that the effect might be connected with the mitogenic activity of the A. viscosus NY1 fraction. Splenocytes from rats immunized with A. viscosus Ny1 and from control rats induced similar levels of cytotoxicity in 72-h cytotoxicity assays. In shorter assays (24 h), however, splenocytes from immune animals induced low cytotoxicity, which was, however, significantly higher than that induced by splenocytes from control animals. We conclude that both antigen- and mitogen-dependent cell mediated effector mechanisms are operative in this system and that the two normally overlapping effects can be experimentally separated. This new system describes a fibroblast impairment in the presence of splenocytes and bacterial components and may provide a useful model for studying pathogenic mechanisms operative in periodontal disease.

Actinomyces↗

Effect of microbial interaction on the colonization rate of Actinomyces viscosus or Streptococcus mutans in the dental plaque of rats.

The resident oral microflora of conventional Osborne-Mendel rats was challenged with Actinomyces viscosus or Streptococcus mutans strains. The adherence of the inoculated organism to the tooth surface and the subsequent growth were studied by means of viable counts determination. The initial growth rate of S. mutans in conventional rats was lower than in mono-associated gnotobiotic rats (doubling time, td = 5 h versus td = 1.1 h). The delayed start of growth and the low initial growth rate indicated that a competitive interaction between S. mutans and the resident microflora occurred. The initial growth rate of A. viscosus in conventional rats (td = 3.1 h) was approximately the same as that in gnotobiotic rats (td = 2.8 h). The start of growth of A. viscosus was only slightly delayed compared with the start in gnotobiotic rats. These results suggest a neutralistic relationship between A. viscosus and the resident microflora. A. viscosus reached a stationary level about 7 days after inoculation, whereas the S. mutans strains did not reach stationary levels until 2 weeks after inoculation.

Actinomyces↗

Role of macrophages in the lymphocyte response to Actinomyces viscosus.

Macrophage cooperation has been considered necessary for lymphocytes to express a variety of their differentiated functions. We attempted to characterize macrophage-lymphocyte cooperation in response to a known periodontal pathogen. Actinomyces viscosus T14V. Using adherent murine cells and subpopulations of splenocyte cultures, we assessed the effect of A. viscosus T14V fractions on lymphocyte proliferation. We determined that (i) various fractions of A. viscosus induced different proliferative responses; (ii) the physical state of the A. viscosus component determined the degree of dependence on adherent cells for proliferation; (iii) the proliferative response to supernatants of sonicated A. viscosus involved interaction among adherent cells and T and B cells; and (iv) the effects of adherent cells on the proliferative response were due to cell-to-cell interactions.

Actinomyces↗

Characterization of a galactose-specific lectin from Actinomyces viscosus by a model aggregation system.

A simple model system has been developed in which lectin-mediated aggregation of glycoprotein-coated beads can be monitored by following the decrease in light scattering at 650 nm. Aggregation has been characterized with the lectin of Actinomyces viscosus T14V. Its dependence on pH, temperature, and stirring rate was examined, and the number of bacterial cells in relation to the number of latex beads resulting in optimal aggregation was established. This system has the advantage of permitting the study of a single ligand of defined structure. The ligand density was determined with radiolabeled glycoproteins. Under the conditions of the assay, ligand leakage was less than 3%, and ligands were not displaced from the beads by various proteins, glycoproteins, or by other components present in the assay mixture. Latex beads coated with asialofetuin aggregate upon the addition of A. viscosus T14V cells. By contrast, when asialofetuin was first extensively treated with purified galactose oxidase, no aggregation occurred. Only after reduction with NaBH(4) was aggregation restored, demonstrating that galactose termini of asialofetuin are essential for the binding of A. viscosus lectin. An absolute requirement for calcium was also demonstrated. Various sugars inhibited aggregation in the following order, starting with the most effective: lactose, methyl-beta-D-galactopyranoside, galactose, N-acetylgalactosamine, methyl-alpha-D-galactopyranoside. Beads coated with fimbriae from A. viscosus coaggregated with neuraminidase-treated human erythrocytes and with Streptococcus sanguis cells. In each instance the aggregation was inhibited by lactose, indicating that the A. viscosus lectin is located in the fimbriae. Cells grown under different conditions differed in their effectiveness in aggregating glycoprotein-coated beads, suggesting differences in lectin density or accessibility. Two different experimental designs were used to establish the minimum ligand density for aggregation to occur. In one type of experiment, a threshold concentration was found for asialo alpha(1)-acid glycoprotein, but not for asialofetuin. With an alternate approach in which a different population of galactose residues was exposed, a threshold phenomenon was also demonstrated for asialofetuin. The importance of structural ligand features in the aggregation assay is discussed in view of these findings.

Actinomyces↗

Chemical characterization of extracellular polysaccharides produced by Actinomyces viscosus T14V and T14Av.

The human isolates Actinomyces viscosus T14V and T14Av produced extracellular polysaccharides in the absence of sucrose. In contrast to strain T14V, strain T14Av produced abundant viscous slime polysaccharide in the culture supernatant fluids when grown in a chemically defined medium containing glucose. After resolution of the T14Av polysaccharides into seven fractions, it was demonstrated that two of these exhibited viscous properties and lacked methylpentose and muramic acid. The major slime polysaccharide purified by gel filtration and ion-exchange column chromatography contained 39% (moles percent carbohydrate) galactose, 37% N-acetylglucosamine, 19% glucose, and 5% mannose. Only trace amounts of protein and phosphorus were detected in this preparation. On the other hand, strain T14V produced negligible slime polysaccharide under the same culture conditions. The major extracellular polysaccharide fraction from this strain contained methylpentoses, hexoses, hexosamines, muramic acid, protein, and phosphorus, suggesting that this fraction might be derived from the cell wall.

Actinomyces↗

Influence of physicochemical parameters on adsorption of Actinomyces viscosus to hydroxyapatite surfaces.

Adsorption of Actinomyces viscosus strains T14V and T14AV to saliva-treated and untreated hydroxyapatite (HA) under various environmental conditions was studied. Strain T14V adsorption to saliva-treated HA was not influenced by pH, whereas strain T14AV adsorbed in higher numbers under acidic conditions. The addition of cations inhibited adsorption of strains T14V and T14AV to saliva-treated HA. Strain T14V possessed a greater affinity for hydrophobic gels than did strain T14AV, but incorporation of non-ionic detergents, which inhibit hydrophobic interactions, did not influence adsorption of strain T14V to saliva-treated HA. Adsorption of strain T14V to saliva-treated HA increased in the presence of an anionic detergent; however, strain T14AV adsorption was not affected. Strain T14V adsorption decreased in the presence of a cationic detergent, whereas strain T14AV adsorption increased. Collectively, these data suggest that electrostatic interactions, but not hydrophobic interactions, are of major importance in the adsorption of strain T14V to saliva-treated HA.

Actinomyces↗

Specific absence of type 2 fimbriae on a coaggregation-defective mutant of Actinomyces viscosus T14V.

The coaggregation-defective (COG-) mutant Actinomyces viscosus T14V(PK455), which is unable to participate in lactose-sensitive adherence, and its COG+ parent were compared to structurally define the mutational loss of cell-associated lectin activity. Immunoelectrophoretic comparisons of crude extracts or isolated fimbriae from both strains demonstrated type 2 fimbriae (previously designated Ag2) in preparations obtained from the parent but none in those obtained from the mutant. This result was verified by the immunoelectron-microscopic identification of type 1 (previously designated Ag1 or VAl) and type 2 fimbriae on the parent organism but only type 1 fimbriae on the mutant. A comparison of the amounts of extractable fimbriae of each type and the capacity of the cells to bind 14C-labeled monoclonal antibodies specific for each fimbrial component showed that the mutational loss of type 2 fimbriae had no significant quantitative effect on fimbriation of the COG- mutant with type 1 structures. Cells of A. viscosus T14AV, a mutant with various adherence defects that include the COG- phenotype, displayed fimbriae of both types, but in greatly reduced amounts. Thus, the properties of mutant strain T14V(PK455) associated the lectin activity with type 2 fimbriae, whereas those of strain T14AV provided little insight into the mechanism of lactose-sensitive adherence. In addition, the precise nature of the cell surface modification displayed by strain T14V(PK455) provides clear evidence for the existence of distinct and independent fimbriae on A. viscosus T14V.

Actinomyces↗

Coaggregation of human oral Cytophaga species and Actinomyces israelii.

A total of 19 strains of oral Cytophaga sp. obtained from subgingival plaque deposits were tested for their ability to coaggregate with strains of Actinomyces israelii, A. viscosus, A. naeslundii, Streptococcus sanguis, S. mutans, S. salivarius, and S. mitis. Coaggregation was observed only with A. israelii. Based on their coaggregation patterns with eight A. israelii strains, the Cytophaga strains were distributed among three distinct groups: those that coaggregated with A. israelii PK16 but not with A. israelii W1011 (ATCC 29322), those that coaggregated with A. israelii ATCC 29322 but not with A. israelii PK16, and those that coaggregated with none of the eight A. israelii strains. In each of the coaggregations, prior heat treatment (85 degrees C, 30 min) of the Cytophaga cells prevented coaggregation, whereas identical treatment of the A. israelii cells had no effect. The ability of A. israelii PK16 to form adherent plaque on a tooth surface previously coated with Cytophaga plaque was tested with one of the coaggregating Cytophaga strains. White patches of A. israelii plaque were found covering both the amber-colored Cytophaga plaque on the cementum surface as well as the enamel surface to which Cytophaga strains do not adhere. Electron micrographs of thin-sectioned mixed-plaque material revealed both cell types in close proximity. In addition, electron micrographs of negatively stained coaggregated cells showed interbacterial adherence between surface fimbrae on A. israelii and outer membrane blebs on the gram-negative Cytophaga sp. The kinetics of binding of A. israelii to spheroidal hydroxyapatite and to root powder were indicative of a high-affinity binding system with comparatively large numbers of available binding sites on both substrata. These results indicate the highly specific nature of Cytophaga sp.--A. israelii recognition. The contribution of such recognition toward the mechanisms that are responsible for the indigenous nature of these oral bacteria is discussed.

Actinomyces↗

A factor from Actinomyces viscosus T14V that specifically aggregates Streptococcus sanguis H1.

A highly specific aggregation factor for Streptococcus sanguis H1 (AFH1) was obtained by lysozyme treatment of Actinomyces viscosus T14V. At 1 micrograms/ml, AFH1 aggregated a suspension of S. sanguis H1, with which A. viscosus T14V coaggregates by a mechanism not inhibited by lactose: even at much higher levels AFH1 caused little or no aggregation of streptococci from other coaggregation groups (J. O. Cisar et al., Infect. Immun. 24:742-752, 1979). The most active fraction of AFH1 obtained by gel chromatography (near the void volume of Bio-Gel A1.5 m) reacted as a single antigen with anti-A. viscosus T14V serum and was unrelated to the fimbrial antigens of A. viscosus T14V. Smaller molecular fractions, at high levels, inhibited aggregation of S. sanguis H1 by high-molecular-weight AFH1 as well as coaggregation of S. sanguis H1 with A. viscosus T14V. The AFH1 fraction with high aggregating activity was composed of approximately 53% cell wall components (alanine, glutamine, lysine, N-acetylglucosamine, and N-acetylmuramic acid). 40% polysaccharide (N-acetylgalactosamine, rhamnose, and 6-deoxytalose), and 7% protein; teichoic acid was not detected. The fraction which inhibited aggregation and coaggregation contained much less of the cell wall constituents and more of the polysaccharide than the fraction with potent aggregating activity. Aggregation was completely prevented either by treating AFH1 with 0.01 M periodate at 25 degrees C for 4 h or by treating S. sanguis H1 with heat or pronase. A role for electrostatic forces in the aggregation was indicated by: (i) NaCl inhibition of aggregation, and (ii) a great decrease in aggregation potency as a result of chemical modification of either cationic or anionic groups of AFH1. On the other hand, NaCl reversed the aggregation only very weakly. The overall data suggest that a carbohydrate-protein interaction may be dominant in the aggregation of S. sanguis H1 by AFH1 and in the coaggregation of S. sanguis H1 with A. viscosus T14V.

Acetylgalactosamine↗

Identification and preliminary characterization of a major heat-stable surface antigen of Actinomyces israelii by two-dimensional (crossed) immunoelectrophoresis.

We have identified, employing two-dimensional (crossed) immunoelectrophoresis, a major heat-stable surface antigen in Actinomyces israelii with an electrophoretic mobility of 0.86 compared to bovine albumin. The surface component was protease sensitive and non-dialyzable and was found in relatively large amounts in two serotype 2 strains of A. israelii (WVU 307 and ATCC 23860). Serotype 1 strains either lacked antigen 0.86 (ATCC 12103 and CDC X522) or contained small quantities of a cross-reacting antigen which was not identical to antigen 0.86 (CDC W855). Thus, antigen 0.86 may be useful in the serotaxonomy of A. israelii. Our data also suggest the possibility that a greater degree of antigenic heterogeneity exists within the species than can be accommodated within the two currently recognized serotypes.

Actinomyces↗

Carbohydrate metabolism by Actinomyces viscosus growing in continuous culture.

A human oral strain of Actinomyces viscosus, GN431/75, was grown anaerobically in a defined medium in continuous culture with a glucose limitation at dilution rates (D) between 0.025 and 0.2 h-1 and with a nitrogen limitation at D = 0.005 and 0.1 h-1. With 5 mg of glucose per ml, the culture was limited for carbon at D = 0.025 and 0.05 h-1, but became nitrogen limited (asparagine) at D = 0.1 and 0.2 h-1. The molar growth yield (Yglucose) decreased from 50.0 to 40.9 g of cells per mol of glucose as the dilution rate was increased from 0.025 to 0.2 h-1, reflecting the limitation of asparagine. With high glucose and low amino acid concentrations (nitrogen limited), the cell yields at D = 0.05 and 0.1 h-1 were 37 to 33% lower than in the glucose-limited culture. The major products of metabolism were succinic and lactic acids with lesser amounts of acetic and formic acids and ethanol. The rate of glucose fermentation by resting cells removed from the glucose-limited culture and assayed in a pH stat increased with the dilution rate and was always higher than that for the fermentation of sucrose (60%) and fructose (40%). Activity for the glucose-P-enolpyruvate phosphotransferase system was observed in whole homogenates, with the highest activity evident at D = 0.1 h-1 with the glucose-limited culture. The observed activity was significantly lower than the rate of glucose metabolism at each dilution rate, suggesting that glucose-P-enolpyruvate phosphotransferase system was underestimated or that an additional transport system exists in the organism. The glucose-limited culture showed considerable ability to synthesize glycogen during the transition from carbon to nitrogen limitation, when 35% of the cell mass was present at this polymer. The organism was shown to possess the glycogen synthetic enzymes ADP glucose synthase and ADP glucose transferase, as well as the degradative enzyme maltodextrin phosphorylase. Washed cells of A. viscosus GN431/75 were shown to be relatively insensitive to the inhibiting actions of NaF in pH-fall and constant-pH experiments at all dilution rates. At pH 7.0, 25 mM NaF was required to completely inhibit glycolysis by glucose-limited cells at D = 0.05 h-1, whereas a concentration of only 11 mM NaF was required with cells of Streptococcus mutans grown and incubated under identical conditions. An interesting feature of the growth of A. viscosus GN431/75 in the chemostat was the shift from individual nonadherent cells at the low dilution rates to the appearance at D = 0.2 h-1 of large cell aggregates forming tenacious adherent films reminiscent of its characteristics in the oral cavity.

Actinomyces↗

Evidence for the participation of N-acetylated amino sugars in the coaggregation between Cytophaga species strain DR2001 and Actinomyces israelii PK16.

Coaggregation between Cytophaga sp. strain DR2001 and Actinomyces israelii PK16 was partially inhibited by certain N-acetylated amino sugars (N-acetylneuraminic acid, N-acetylgalactosamine, and N-acetylglucosamine) and was completely inhibited by the trisaccharide neuraminin-lactose. The monosaccharides exerted their effect at concentrations between 30 to 100 mM, whereas the trisaccharide was an effective inhibitor at significantly lower concentrations. Outer membrane preparations caused A. israelii PK16 cells to aggregate; however, vesicles released from the cell envelope during growth failed to do so. Adherence studies with a non-coaggregating mutant of the cytophaga suggest that the spheroidal hydroxyapatite attachment sites and coaggregation receptors are separate entities.

Acetylgalactosamine↗

Effect of local and parenteral immunization on implantation of Actinomyces viscosus T6 in rats.

Groups of rats immunized in the vicinity of the major salivary glands or immunized intraperitoneally with Actinomyces viscosus T6 and their sham-immunized controls were infected with the homologous bacterium. Significantly higher levels of salivary and serum antibody were induced by intraperitoneal than by salivary gland immunization. There were also significant inverse correlations between the levels of salivary and serum antibody and the levels of implantation of A. viscosus T6. The level of implantation of A. viscosus T6 was significantly lower in the immunized animals than in the controls. However, antibody had limited capacity to inhibit the establishment of this bacterium.

Actinomyces↗

Factors affecting binding of galacto ligands to Actinomyces viscosus lectin.

The specificity requirements for the binding of Actinomyces viscosus T14V were examined by testing simple sugars, oligopeptides, and glycoproteins as inhibitors of the aggregation of glycoprotein-coated latex beads and washed A. viscosus cells. Lactose was the most inhibitory simple sugar; D-fucose and D-galactose were equally inhibitory, methyl-alpha-D-fucoside was slightly less inhibitory, and L-fucose and raffinose were not inhibitory. The concentration of galactose residues required for 50% inhibition of aggregation was 15 times higher in the form of lactose than in the form of asialoglycoprotein, suggesting an enhancement of lectin binding when galactose residues are clustered. However, when the inhibitory power of bi-, tri-, and tetraantennary asialooligopeptides of alpha 1-acid glycoprotein was compared with that of equivalent concentrations of galactose in the form of lactose, the biantennary form was slightly less effective than lactose, the triantennary form was approximately as effective as lactose, and the tetraantennary form was slightly more effective than lactose. Steric interference may prevent this type of clustering from enhancing lectin binding. The O-linked asialooligopeptides of asialofetuin were 10 times more inhibitory than an equivalent concentration of galactose in the form of N-linked asialooligopeptides. Thus, galactose beta-1----3 linked to N-acetylgalactosamine exhibits greater specificity for the A. viscosus lectin than does galactose beta-1----4 linked to N-acetylglucosamine. These results, taken together with previously reported data, are consistent with a lectin of low affinity, binding enhanced by multivalency, and specificity for beta-linked galactose.

Actinomyces↗

Lactate dehydrogenase from Streptococcus mutans: purification, characterization, and crossed antigenicity with lactate dehydrogenases from Lactobacillus casei, Actinomyces viscosus, and Streptococcus sanguis.

A cytoplasmic fructose-1,6-diphosphate-dependent lactate dehydrogenase (LDH; EC 1.1.1.27) from Streptococcus mutans OMZ175 was purified to homogeneity as judged by sodium dodecyl sulfate-gel electrophoresis. The purification consisted of ammonium sulfate precipitation of the cytoplasmic fraction, DEAE-Sephacel and Blue-Sepharose CL.6B chromatography, and Sephacryl S200 gel permeation. The catalytic activity of the purified enzyme required the presence of fructose-1,6-diphosphate with a broad optimum between pH 5 and 6.2. The concentration of fructose-1,6-diphosphate required for half-maximal velocity was around 0.02 mM and was affected by the pyruvate concentration. The enzyme seemed to have at least two binding sites for the activator which interact in a cooperative manner. Increasing concentrations of fructose-1,6-diphosphate up to 2 mM enhanced the relative affinity of the enzyme for pyruvate and modified the pyruvate saturation curve from sigmoidal to hyperbolic. The enzyme activity showed also a sigmoidal response to NADH, exhibiting two binding sites for the cofactor with a Hill coefficient of about 1.9. The molecular weight of the native enzyme was 150,000 as determined by gel permeation on Sephacryl S200. Monomers (38,000 daltons) and dimers (85,000 daltons) were observed by sodium dodecyl sulfate-gel electrophoresis; the latter form was dissociated after reduction with 2-mercaptoethanol, and the enzyme could be considered a tetramer. Antibodies obtained against the purified S. mutans OMZ175 LDH cross-reacted with the sodium dodecyl sulfate-dissociated forms of LDHs from different S. mutans serotypes, Streptococcus sanguis OMZ9, Lactobacillus casei ATCC 4646, and Actinomyces viscosus NY 1. A competitive enzyme-linked immunosorbent assay allowed us to detect a very close relationship between the native states of L-LDHs from S. mutans serotypes and S. sanguis. Cross-reactions were also observed with the LDHs from A. viscosus and L. casei, the latter being the least related. A very weak immunological relationship was obtained between the L-LDH from S. mutans OMZ175 and the D-LDH from Lactobacillus leichmannii, whereas no cross-reaction could be detected with mammal LDHs.

Actinomyces↗

Fimbria-specific antibodies in serum and saliva of mice immunized with Actinomyces viscosus T14V fimbriae.

Fimbria-specific antibody responses were compared in mice immunized with purified fimbrial adhesins in the region of the submandibular gland (i.e., local site) or at a remote site in the back. One hundred micrograms of fimbriae isolated from Actinomyces viscosus T14V was used as the vaccine. Four subcutaneous injections of the vaccine in the local site induced greater amounts of fimbria-specific immunoglobulin G (IgG) in serum and saliva than three injections. However, there was no difference in the response of fimbria-specific IgA in serum and saliva. Fimbria-specific IgG in serum and saliva were first detected 21 days after the primary immunization at both the local or remote sites. Fimbria-specific IgA in serum was first detected 28 days after the primary immunization at both the local or remote sites. However, fimbria-specific IgA in saliva occurred only in mice immunized with the fimbrial vaccine at the local site and was first detected 14 days after the primary immunization. Both serum and saliva from mice immunized 4 times with the fimbrial vaccine in the local site inhibited in vitro adsorption of strain T14V cells to hydroxyapatite beads pretreated with normal mouse saliva, whereas adsorption of strain T14V cells suspended in serum and saliva from sham-immunized animals was not inhibited. Collectively, these data suggest that mice immunized locally in the submandibular gland region with a vaccine composed of purified fimbrial adhesins provide a potential model for evaluating the efficacy of fimbria-specific antibodies in saliva to inhibit strain T14V colonization of tooth surfaces.

Actinomyces↗