Structure and immunological specificity of the Streptococcus mutans group b cell wall antigen

The impact of vitamin D on cancer: A mini review

In this review, we summarize the most recent advances in vitamin D cancer research to provide molecular clarity, as well as its translational trajectory across the cancer landscape. Vitamin D is well known for its role in regulating mineral homeostasis; however, vitamin D deficiency has also been linked to the development and progression of a number of cancer types. Recent epigenomic, transcriptomic, and proteomic studies have revealed novel vitamin D-mediated biological mechanisms that regulate cancer cell self-renewal, differentiation, proliferation, transformation, and death. Tumor microenvironmental studies have also revealed dynamic relationships between the immune system and vitamin D's anti-neoplastic properties. These findings help to explain the large number of population-based studies that show clinicopathological correlations between circulating vitamin D levels and risk of cancer development and death. The majority of evidence suggests that low circulating vitamin D levels are associated with an increased risk of cancers, whereas supplementation alone or in combination with other chemo/immunotherapeutic drugs may improve clinical outcomes even further. These promising results still necessitate further research and development into novel approaches that target vitamin D signaling and metabolic systems to improve cancer outcomes.

Immunochemical analysis and localisation of a cell wall antigen of Streptococcus rattus with a specific monoclonal antibody

A monoclonal antibody specific to a cell wall antigen of Streptococcus rattus (S. rattus) was prepared after cell fusion of mouse myeloma cells to the spleen cells of mice immunized with whole cells of strain FA1. The monoclonal antibody reacted with a crude and purified polysaccharide antigen of S. rattus in precipitin reactions as well as in a solid phase enzyme assay (EIA). It also reacted in the EIA with whole cells of S. rattus strains, but did not react with any other species of the mutans group or of other oral and streptococcal species. Moreover, among many haptenic sugars and their derivatives tested, D-galactosamine and D-glucosamine strongly inhibited the reaction in a competitive enzyme immunoassay using the purified antigen and whole cells, indicating that the type-specific antigenic determinant of the organism has a structure similar to the amino group of the sugar molecules. Furthermore, immunoelectron microscopy revealed that the antigen epitopes formed an irregular fibrous structure over the entire surface of individual cells.

In Lactococcus lactis subsp. cremoris SK110 protein, instead of lipoteichoic acid, reacts with the group-N-specific antiserum

The reaction between cell-surface components, isolated from two Lactococcus lactis subsp. cremoris strains, with their Group-specific antiserum were studied. No reaction between purified lipoteichoic acid and the antiserum was observed. Both strains, however, did belong to the lactococci (Group-N streptococci), as was demonstrated by the positive reaction between the antiserum and an acid- (Lancefield) or alkaline-extract. Experiments with proteolytic enzymes demonstrated the involvement of protein in the antigenic material in the latter reaction.

Structure of the type-specific polysaccharide antigen of Streptococcus rattus

The structure of the type-specific polysaccharide antigen of Streptococcus rattus was determined by methylation analysis, periodate oxidation, and by 2D-1H- and 13C-n.m.r.-spectroscopy. The polysaccharide was found to possess the trisaccharide repeating unit----3)-alpha-L-Rhap-(1----2)-[alpha-D-Galp-(1----3)]-alpha-L-+ ++Rhap- (1----.

Cross-reactive polysaccharide antigens (types a, d, and h) of the mutans group of streptococci: different molecular forms of the type as distinguishable by monoclonal antibodies

As compared to the previous precipitin inhibition tests differences were found in the reactivities of monoclonal antibodies (MAbs), a-4 and a-84 with Streptococcus cricetus (serotype a) in an enzyme immunoassay using whole cells, purified cell wall antigen and haptenic sugars coated onto microtitre wells. Investigation into the differences led to the finding that the purified antigen from S. cricetus cells consisted mainly of three forms with different molecular weights and sugar contents. MAb a-4 reacted with a high molecular weight form (AgI, molecular weight of 46,000) and low molecular weight forms (AgII and AgIII, molecular weights of 9,800 and 20,000, respectively) whereas MAb a-84 reacted only with the high-molecular form. Gas chromatographic analysis revealed that all antigens contained rhamnose, galactose and glucose but in different ratios of the sugars. Although the binding site of AgII/AgIII with MAb a-4 seemed to be slightly different from that of AgI with MAb a-84, the predominant immunodeterminant of the antigens was considered to be the same. On the basis of these results, the chemical structures of the antigenic determinants are suggested. The nature of the antigen-antibody reactions is discussed.

Type-specific antigen of Streptococcus rattus strains (KAY1 and FA1). I. Characterization

A serotype-specific antigen was extracted from Streptococcus rattus KAY1 strain isolated first in Japan from human dental plaque and purified on an ion exchange column to compare it chemically and immunologically with that of FA1 strain which had been examined extensively by previous workers. Antigens of both strains reacted in a double diffusion test specifically with anti-FA1 serum which had previously been demonstrated specific for the strains in the same test, agglutination reactions and/or radioimmunoassay using whole cells. After separation on a DEAE-Sephadex A-25 ion exchange column the antigen was found to be resistant to various enzymatic treatments with pronases, lipase and nucleases and produce a single precipitin band against absorbed anti-FA1 serum in immunoelectrophoresis. Chemical analysis of this antigen revealed that it composed of carbohydrate, protein and a few percentages of glycerol and phosphorus. Hapten inhibition tests between antigen and antibody showed that galactose as well as glucose were the most potent inhibitors, suggesting their involvement in the antigenic determinant. Involvement of the sugars was also supported by gas chromatographic analysis and abolishment of reactivity with antiserum after the treatment of antigens with NaIO4. Moreover, protein does not seem to be involved since after SDS-PAGE analysis an enzyme immunoassay gave a negative reaction with immunoblotted antigens.

Biosyntheses of galactosyl lipids and polysaccharide in Streptococcus mutans

The syntheses of galactosylphospholipids and a galactose-containing polymer were observed when radio-labeled UDP-galactose was incubated with the membrane enzymes prepared from a strain of Streptococcus mutans, FA-1. The lipids were resolved into two components, lipids-1 and -2, by thin-layer and DEAE-cellulose column chromatographies. In the latter chromatography, lipid-1 was eluted by 0.0075 M and lipid-2 by 0.18 M ammonium acetate. The syntheses of lipids-1 and -2 were strongly inhibited by UDP and UMP, respectively. Both lipids-1 and -2 were degraded by mild acid, but were stable to mild alkaline hydrolysis. These results, together with their mobilities on thin-layer chromatography, suggest that lipid-1 is a galactosylphosphorylundecaprenol, and lipid-2 is a galactosylpyrophosphorylundecaprenol. When UDP-galactose was incubated with radiolabeled undecaprenol and ATP in the presence of membrane enzymes, lipids with thin-layer chromatographic mobilities of lipid-1 and lipid-2 were observed. The phosphate-to-galactose ratios in lipid-1 and lipid-2 were determined to be 1:1 and 2:1, respectively. These results indicated that lipid-1 and lipid-2 formed are galactosylmonophosphorylundecaprenol and galactosylpyrophosphorylundecaprenol, respectively. The polymer formed was eluted from the DEAE-cellulose column with a low concentration of salts (less than 0.1 M), suggesting that it is probably a polysaccharide, but not a lipoteichoic acid or teichoic acid-type polymer. In order to identify the sugars present in the polymer synthesized, the polymer purified by Sephadex G-50 and DEAE-cellulose column chromatographies was subjected to acid hydrolysis followed by NaB3H4 reduction and paper chromatographic analysis. [3H]Galactitol and a small amount of [3H]galactosaminitol were detected. This result suggests that the polymer is a nascent polysaccharide containing mainly galactose and a small amount of galactosamine, which probably derived from N-acetylgalactosamine during acid hydrolysis of the polymer.

Serological typing of reference strains and clinical isolates of Streptococcus mutans by agglutination reactions and/or radioimmunoassay

Rabbit antisera were prepared against eight different serotypes of Streptococcus mutans. After absorption with heterologous serotype strains the antisera were able to distinguish 21 reference strains of different serotypes of S. mutans by simple agglutination reactions and radioimmunoassay, both using intact whole cells. The reference serotypes a, b, d and g were differentiated by specific agglutination using the corresponding monospecific antiserum. Strains of serotypes c, e, f and h were discriminated by differential agglutination using anti-c, anti-e, anti-f or anti-h serum respectively, but the antisera cross-reacted slightly with other serotype strains. Using these antisera a total of 261 clinical isolates of S. mutans from human dental plaques were serotyped by agglutination reactions, in addition to which radioimmunoassay and the classical immunodiffusion tests in agar were also used in some cases. The results were quite consistent in the three methods. The predominant strain was of serotype c (187), followed by serotype f (28), g (10), d (5), e (4) and b (1). 26 strains were untypable and there were no serotype a or h strains.

Isolation and characterization of an extracellular glucosyltransferase synthesizing insoluble glucan from Streptococcus mutans serotype c

A glucosyltransferase which synthesized insoluble glucan in polyacrylamide gel was isolated from the culture supernatant of Streptococcus mutans Ingbritt (serotype c) by ultrafiltration, ethanol fractionation, isoelectric focusing, and preparative gel electrophoresis. The enzyme preparation was electrophoretically homogeneous and immunologically distinct from the highly branched 1,6-alpha-D-glucan synthase and fructosyltransferase from the same strain and glucosyltransferases from serotypes a and g. The molecular weight was 99,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and the isoelectric point was 8.5. The enzyme had the optimum pH of 6.0 and Km value for sucrose of 9.4 mM. Besides the insoluble glucan with 96% 1,3-alpha linkage, this enzyme synthesized a considerable amount of diffusible glucan with 84% 1,6-alpha linkage, separately. This enzyme may be the one released from the enzyme aggregates by extracellular proteases, because the addition of extraneous trypsin to the crude enzyme preparation increased the amount of the enzyme species.

Natural antibodies in man to Streptococcus mutans: specificity and quantification

Antibodies to whole cells of Streptococcus mutans were examined in 108 subjects by a solid-phase radioimmunoassay and quantified by reference to isotype-specific affinity-purified antibodies. Serum antibodies of each isotype were present in all subjects examined. The mean concentration of serum antibodies to S. mutans was calculated as about 84 micrograms/ml of IgG (range 33-140 micrograms/ml), 26 micrograms/ml of IgA (range 12-43 micrograms/ml) and 9 micrograms/ml of IgM (range 4-15 micrograms/ml). The mean antibody values accounted for about 0.7, 1 and 0.8% of the total IgG, IgA, and IgM, respectively. Overall the antibody binding to whole cells of S. mutans accounted for about 0.8% of the total immunoglobulin. Inhibition experiments using a variety of purified cell wall antigens revealed that the binding of antibodies to whole cells could be inhibited by about 30% with a purified protein antigen (SA I/II) and with glucosyltransferase (GTF), by 25% with c polysaccharide and by 16% with lipoteichoic acid. The protein antigens GTF and SA I/II appear to be major immunogenic cell wall antigens, but natural antibodies in man that bind to S. mutans whole cells have been induced by several antigens, some of which are specific to S. mutans and some of which are shared with other Gram-positive bacteria.

Detection of antigens in enzymic lysates of cell wall from Streptococcus mutans strains

Lysis of cell wall preparations from strains representing serotypes a - g of Streptococcus mutans has provided a convenient and efficient means of obtaining the typing antigens in a soluble undegraded form, and has demonstrated that, in each case, the antigen is a cell wall component in the strict sense of a component joined covalently to peptidoglycan. This influences the choice of extraction procedures.

Trimethylsilyl-sugar profiles of Streptococcus milleri and Streptococcus mitis

Seventy strains of 'viridans-group' streptococci were analysed gas chromatographically after preparation of trimethylsilyl ethers of their cellular sugars. The resulting profiles were evaluated as a possible aid to taxonomy. Glycerol, glucose, galactose, N-acetyl-glucosamine and N-acetylmuramic acid were found in all strains, in varying amounts. Rhamnose was the major neutral sugar in most strains, other than representatives of Streptococcus mitis, which invariably had ribose and usually anhydroribitol but no rhamnose. One strain of Strep. mitis possessed arabitol. Some strains of Strep. mitis and 'Strep. milleri' were alone in containing N-acetylgalactosamine. A combination of N-acetylgalactosamine and rhamnose in the absence of ribose was diagnostic for strains of 'Strep. milleri'.

Selective antibacterial properties of lysozyme for oral microorganisms

The antibacterial properties of lysozyme were investigated with oral microorganisms representing the seven serotypes (a through g) of Streptococcus mutans, Veillonella alcalescens, and the virulent (V) and avirulent (AV) strains of Actinomyces viscosus T14. Growth of bacteria in defined medium was monitored spectrophotometrically after the addition of various amounts (25 mug to 5 mg/ml) of enzyme. No growth inhibition of V. alcalescens was observed. Inhibition of A. viscosus T14(V) and A. viscosus T14(AV) occurred with 160 mug of lysozyme per ml. Of the S. mutans cultures tested, the serotype a and b strains were inhibited with as little as 25 mug of enzyme per ml, whereas e and f strains were most resistant to the bacteriostatic activity of lysozyme. The presence of dl-threonine or sucrose in growth medium did not significantly affect the results. A lysoplate assay was developed to rapidly survey the bacterial cultures for their susceptibility to the lytic ability of the enzyme. Lysis, as a measure of a zone of clearing in agarose plates, occurred for all microorganisms in the presence of lysozyme after the subsequent addition of NaCl or detergent. The bactericidal activity of lysozyme was determined on S. mutans BHT and S. mutans LM-7 by the pour plate technique. Preincubation of S. mutans LM-7 with as much as 1 mg of enzyme for 90 min did not affect viability or growth, whereas preincubation of S. mutans BHT with 1 mg of lysozyme resulted in no recoverable colony-forming units. An antigen containing extract of S. mutans LM-7 blocked the growth inhibitory property of lysozyme. Human lysozyme was a more effective antibacterial factor than hen egg white lysozyme. Total growth inhibition of S. mutans BHT was effected with 40 mug of human enzyme, and as little as 10 mug of human enzyme inhibited growth for greater than 20 h. The data presented indicate that different mechanisms may be responsible for the bacteriostatic, lytic, and bactericidal properties of the enzyme and that lysozyme is a selective but effective antibacterial factor for oral microorganisms.

Biology, immunology, and cariogenicity of Streptococcus mutans

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Association of protein with the cell wall of Streptococcus mutans

Cell walls from Streptococcus mutans were prepared by conventional technique and subjected to a series of extraction procedures involving classical protein solvents. The extracted walls contained several non-peptidoglycan amino acids and were also amenable to radiolabeling with [125I]sodium iodide and chloramine T. The cell walls could be chemically modified with tetranitromethane and diazo-1H-tetrazole, suggesting the presence of tyrosine or histidine or both. Flourescence spectra of the walls revealed the presence of either tyrosine or tryptophan. Several proteases, including pronase, trypsin, subtilisin, and proteinase K, removed some of the label from the walls. In contrast, treatment of the walls with salts or denaturants did not result in the solubilization of label. When the walls were solubilized with mutanolysin and subjected to chromatography, three peaks of radioactivity with apparent molecular weights of 73,000, 39,000, and 9,600 were observed. Wall digests subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed a single band of radioactivity corresponding to an apparent molecular weight of 79,000. Isoelectric focusing of labeled wall digest gave rise to two major bands of radioactivity with isoelectric points of approximately 2.4 and 5.6. The results suggest that the cell wall of S. mutans contains tightly and possibley covalently bound polypeptide molecules. We propose that the cell wall polypeptides of S. mutans serve as factors in the attachment of the bacteria to smooth surfaces.

Chemical composition of Streptococcus mutans cell walls and their susceptibility to Flavobacterium L-11 enzyme

The susceptibility to a cell wall lytic L-11 enzyme from Flavobacterium sp. and the quantitative and/or qualitative composition of the cell walls of some strains of cariogenic Streptococcus mutans and a non-cariogenic strain of Streptococcus mitis were determined. The purified cell walls of S. mutans strains HS-1 (serotype a), BHT (b), NCTC10449 (c), C67-1 (c), C67-25 (c), OMZ 176 (d), MT703 (e), MT557 (f), OMZ65 (g), and AHT (g), and S. mitis CHT contained glutamic acid, alanine, and lysine as well as muramic acid and glucosamine as a peptidoglycan component. Besides these amino acids, significant amounts of threonine were detected in strains HS-1, OMZ65, and AHT cell walls, and considerable amounts of aspartic acid and/or threonine as well as several other amino acids in OMZ176, OMZ65, and CHT cell walls. Rhamnose was a common special component of the cell walls of S. mutans strains BHT, NCTC10449, MT703, B2 (e), MT557, and AHT, and S. mitis CHT. An additional sugar component, glucose, was detected in the cell walls of all of these strains except BHT, and galactose was found in BHT, AHT, and CHT cell walls. Galactosamine was present in S. mitis CHT cell walls. Varying amounts of phosphorus were detected in the cell walls of all the strains examined. The cell walls of all these streptococcal strains except MT703, 6715, and AHT were susceptible to the lytic action of the L-11 enzyme to various extents. No consistent relationship was observed between the amino acid and sugar composition of these cell walls and their susceptibility to the L-11 enzyme. The chemical composition of these cell walls is discussed in terms of the serological classification of S. mutans.

Serotype-dependent inhibition of glucan synthesis and cell adherence of Streptococcus mutans by antibody against glucosyltransferase of serotype e S. mutans

A crude glucosyltransferase (GTase) preparation was obtained from the culture supernatant of Streptococcus mutans strain MT703 (serotype e) by 50% ammonium sulphate precipitation. Antiserum specific against the GTase was prepared by immunizing rabbits intramuscularly with the GTase in Freund incomplete adjuvant, followed by GTase without adjuvant intravenously. Gamma globulin fractions of the antiserum and normal serum were partially purified by 1/3 saturated ammonium sulphate precipitation. The antibody strongly inhibited the GTase activity (greater than 90%) of type c, e and f S. mutans, whereas the GTase of type a, d and g was not affected by the antibody. The GTase from type b S. mutans was slightly inhibited. The adherence of viable cells of type c, e, and f S. mutans to a glass surface due to synthesis of glucan by the cell-associated GTase was also significantly inhibited by the antibody to the enzyme. These results suggest that type c, e, and f and types a, d, and g S. mutans can be separated into two major groups in terms of the immunological relationship of GTase.

Binding of glucosyltransferase and glucan synthesis by Streptococcus mutans and other bacteria

Lyophilized and heat-treated cells from the seven serotypes of Streptococcus mutans were examined for their ability to bind added insoluble-product glucosyl-transferase (GTase) and to synthesize cell-associated glucan from [(14)C]sucrose. Lyophilized cells of serotypes a and g did not synthesize any more additional glucan than did the controls after exposure to GTase. These cells, however, synthesized four- to eightfold-greater quantities of glucan than did the cells of the remaining serotypes. Lyophilized cells of serotypes b, c, d, e, and f synthesized two- to threefold-greater quantities of glucan after exposure to GTase than did the controls without added enzyme. Lyophilized cells of serotypes a and g synthesized 6- to 10-fold-greater quantities of glucan than did heat-treated cells of the same strain after binding of GTase. Lyophilized cells of the remaining serotypes synthesized only 1.6- to 3.3-fold-greater quantities of glucan than did the heat-treated cells. These results demonstrate that heat treatment to inactivate cell-associated GTase does not create additional GTase binding sites in S. mutans and that serotypes a and g are considerably more active in cell-associated glucan synthesis than cells of the other five serotypes. Ten species of gram-positive and gram-negative bacteria from five genera which do not produce in vitro plaque synthesized 10- to 100-fold-less glucan than did the S. mutans strains after exposure to GTase. Of these species, S. sanguis, Actinomyces viscosus, and A. naeslundii synthesized the largest quantities of glucan. Three mutant strains of S. mutans which possess a reduced ability for in vitro adherence but do agglutinate with glucan or dextran synthesized only one-third as much glucan after binding of GTase as the control. These results are discussed in relation to in vitro and in vivo plaque development and the agglutination of S. mutans. The results support earlier findings which indicate that the presence of bacterial species other than S. mutans in smooth-surface dental plaque is due in part to contact of the cells with glucan in the developing plaque and not to the binding of cell-free GTase and the in situ synthesis of glucan. The results obtained with these representative strains of the seven serotypes of S. mutans may not apply to the same extent to other strains within the serotypes.

Antigens of Streptococcus mutans: isolation of a serotype-specific and a cross-reactive antigen from walls of strain V-100 (serotype e)

Two cell wall-associated polysaccharide antigens were extracted from purified cell walls of Streptococcus mutans serotype e strain V-100. One of these purified antigens (I) is specific for serotype e, whereas the other (II) has antigenic determinants reactive with both heterologous anti-serotype c serum (GS-5) and the homologous (e) serum. When crude formamide extracts of V-100 cell walls were loaded onto a Cellex-D column and eluted with a linear gradient of ammonium carbonate (0.02 to 0.40 M), the two products mentioned above could be recovered. The purified, antigenically reactive products (I and II) were each composed only of rhamnose and glucose in approximately a 2:1 molar ratio. Immunoelectrophoresis of the crude formamide extract, peak I, and peak II showed the purified fractions to have opposite mobilities and the crude extract to have a mobility that encompassed both purified peaks when reacted with homologous antiserum (V-100). When these three fractions were immunoelectrophoresed and reacted with heterologous anti-serotype c serum (GS-5), only the anodic portion of the crude V-100 formamide extract and purified peak II formed precipitates. Ouchterlony analysis with homologous antiserum produced precipitin patterns between the crude formamide extract and both purified peaks, indicating complete identity. However, only crude extracts of V-100 and the purified peak II material reacted with heterologous (c) antiserum; peak I did not cross-react in these Ouchterlony assays. Hapten inhibition studies revealed that a beta-glucosyl moiety is the immunodeterminant for serotype e and is present on each purified fraction. The basis of the cross-reaction between anti-c sera and the purified antigen II of e is discussed.

Binding of lectins to Streptococcus mutans cells and type-specific polysaccharides, and effect on adherence

The lectin concanavalin A (Con A) agglutinated the cells of 13 of 15 strains of the seven serotypes of Streptococcus mutans in an 18-h incubation period. Strains of types a, d, f, and g agglutinated within 2 h. Strains of a, d, and f were also agglutinated in 2 h by the castor bean lectin RCA. S. sanguis, S. salivarius, S. bovis, Actinomyces viscosus, A. naeslundii, and Lactobacillus plantarum were agglutinated within 2 h. The S. mutans type f polysaccharide was precipitated by Con A. The a, b, c, d, and e polysaccharides were not precipitated. Glucan from d and e strains of S. mutans and dextran T2000 were also precipitated by Con A. D-glucose inhibited the agglutination of type f cells by Con A and the agglutination of type d cells by D-galactose. The quantity of [acetyl-3H]Con A bound was not proportional to the degree of agglutination. Cells grown in sucrose medium bound more Con A than those grown in glucose medium. After treatment with dextranase, the sucrose-grown cells bound two- to fourfold more Con A. The binding of Con A to the type-specific polysaccharide or to teichoic acid could not be determined by the use of specific antibody due to the binding of Con A to the antibody globulin on the cell surface. Con A bound to S. mutans cells did not inhibit the activity of cell-bound glucosyltransferase, glucan synthesis, and in vitro adherence. Bound Con A also did not inhibit the ability of heat-treated cells to bind glucosyltransferase, synthesize glucan, and produce in vitro adherence.

Selective adsorption of heterophile polyglycerophosphate antigen from antigen extracts of Streptococcus mutans and other gram-positive bacteria

Hot saline extracts of Streptococcus mutans have been shown to contain antigenic substances which occasionally react nonspecifically with some antisera against whole cells of various serological groups and types of streptococci. Chromatography of the extract of S. mutans strain MT703 (serotype e) on a diethylaminoethyl-Sephadex A-25 column gave two principal antigens. One antigen was eluted without adsorption to the resin and was identified as the serotype-specific polysaccharide. The other antigen, which contained a large quantity of phosphorus, was absorbed to and released from the resin by gradient elution. It was reactive against the antisera specific for polyglycerophosphate (PGP) from group A Streptococcus pyogenes and/or S. mutans strain Ingbritt (type c). The PGP antigen was further purified by gel filtration with Sephadex G-75. Two peaks, PGP-1, and PGP-2, were obtained. Each possessed the same antigenic specificity to anti-PGP serum as shown by immunodiffusion. Chemical analyses revealed that the molar ratio of phosphorus to glycerol in both was about 1:1, although the protein content between the two was significantly different. PGP antigen was found to be widely distributed in hot saline extracts from various gram-positive bacteria, with a few exceptions. However, all gram-negative bacteria examined were free of PGP. The PGP in the hot saline extracts of various gram-positive bacteria possessed an essentially identical antigenic specificity. The addition of diethylaminoethyl-Sephadex A-25 resin to hot saline extracts successfully removed the cross-reacting PGP antigen. After adsorption of the extract from S. mutans, the supernatant contained only type-specific polysaccharide antigen, except type b, in which both type b-specific polysaccharide and PGP antigens were absorbed with the resin. This simple procedure should be useful for the removal of the PGP-type teichoic acid from antigen extracts of bacteria that contain uncharged polysaccharides.

Chemical and immunological properties of the type f polysaccharide antigen of Streptococcus mutans

The type-specific cell wall polysaccharide antigen was extracted, purified, and characterized from type f Streptococcus mutans strain OMZ175 and MT557. The antigen was extracted from lyophilized cells with 5% trichloroacetic acid at 85 C for 15 min or saline at 120 C for 30 min. The trichloroacetic acid antigen was chromatographically separated into three antigenic fractions on a diethylaminoethyl-Sephadex A-25 column. Antigen 1 (Ag1P), which was specific for type f antiserum, was further purified by passing through carboxymethyl-Sephadex C-25 and Sephadex G-200 columns. It was a polysaccharide composed of 49% rhamnose and 47% glucose. No reaction was obtained with anti-polyglycerophosphate (PGP) serum. Antigen 2 was reactive with both type f and PGP antisera and contained significant amounts of protein and phosphorus. Antigen 3 was reactive only with PGP antiserum and had no type specificity. The polysaccharide antigen gave a single precipitin band against type-specific antiserum on immunodiffusion and immunoelectrophoresis. The presence of alpha-1,6-glucosidic linkages was indicated by a 90% inhibition of the precipitin reaction by isomaltose and alpha-methyl-D-glucopyranoside, adsorption to and release from a concanavalin A-Sepharose column, and reaction with an S. mutans (type e) glucan antiserum. This antiserum was used to show that the type f polysaccharide antigen did not contain free glucan. An analysis of the antigen released from the antigen-glucan antiserum complex showed the presence of rhamnose and glucose. This released antigen also reacted with an f antiserum, which did not react with commercial dextran. The results show that the type f polysaccharide antigen is the first of those S. mutans type-specific polysaccharides identified to be immunologically related to an S. mutans glucan.

Purification and immunochemical characterization of type e polysaccharide antigen of Streptococcus mutans

The type-specific antigen of Streptococcus mutans strain MT703, serotype e, has been chromatographically purified and characterized. Two chromatographic fractions were obtained from saline extracts which reacted with both anti-MT703 whole-cell serum and Lancefield group E serum. The major fraction (eI) was identified as a polysaccharide composed of 37% glucose, 56% rhamnose, 5% protein, and 0.3% phosphorus, whereas the minor fraction (eII) contained 66% protein in addition to 10% glucose and 17% rhamnose. The immunological specificity of these antigens was found to be the same by immunodiffusion in agar gel. Another fraction with a negative charge (eIII) reacted with polyglycerophosphate antisera from Streptococcus mutans and Streptococcus pyogenes. For comparison, the MT703 antigen in a hot trichloroacetic acid extract (eA) and the group E antigen from a saline extract of cells of strain K129 (EI) were similarly purified by anionic ion-exchange chromatography. Although the ratio of glucose and rhamnose in eA was 1:0.9 and in eI and eII approximately 1:1.5, reactions of identity were obtained in gel diffusion against specific anti-e serum. This difference in ratio is probably a result of the extraction procedures. Both the type e and group E antisera were reactive with both eI and EI antigens. The adsorption of group E antiserum with MT703 cells removed all E antibody, whereas type e-specific antibody remained after adsorption with K129 cells. These results suggest that eI antigen possesses both e and E specificities, whereas EI possesses E only. These findings were supported by the quantitative precipitin test and immunodiffusion and/or immunoelectrophoretic patterns in agar gel. Methyl-beta-D-glucopyranoside markedly inhibited the precipitin reaction in both type e and group E sera. However, a significantly stronger inhibition by cellobiose of type e serum than of group E serum indicates that a beta-linked glucose-glucose dimer is the predominant antigenic determinant of the e specificity. The presence of both e and E specificities on a single polysaccharide molecule was demonstrated by the use of purified e antigen released from a specific e-anti-e complex. This antigen reacted with a group E-specific serum as well as a type e-specific serum. An examination of five S. mutans type e strains showed the presence of group E specificity also, whereas the I, II, and IV serotypes of group E streptococci only possessed the group E specificity.

Variations in surface polymers of Streptococcus mutans

The cell wall composition of strains of S mutans with respect to sugars and proteins appears to be correlated to the serological grouping although groups c and E are rather similar. There also appear to be similarities in the structure of the polysaccharide formed by the glycosyltransferases from organisms of serological groups b and d. However, the activity of these enzymes appears to be variable in these groups. The most noteworthy difference found was that between the three Ingbritt strains. All three strains gave identical results with regard to their cell wall composition, and presumably this would mean that they were identical serologically. However, Ingbritt LH differed considerably from both the others in the types of polysaccharide formed by their glycosyltransferases from sucrose. Ingbritt B was a reisolate from monkeys, whereas Ingbritt LH was maintained in laboratory culture, and this may explain the difference. Clearly, more work will be required to explain this difference and as c strains are commonly isolated from plaque, it would seem desirable to clear up this point.

Diethylaminoethyl-cellulose-bacterial cell immunoadsorbent columns: preparation of serotype-specific globulin and immunofluorescent conjugates for Streptococcus mutans serotypes a and d

Diethylaminoethyl (DEAE)-cellulose was used as a support material for preparing bacterial cell columns. Pretreatment of the bacterial cells with formalin was essential in obtaining satisfactory adherence of the cells to DEAE-cellulose. Cross-reacting antibodies were removed from antibody preparations against strains of Streptococcus mutans serotypes a and d by adsorption on appropriate bacterial cell columns. S. mutans serotype d was further divided into two subtypes on the basis of immunofluorescent staining with conjugates of immunospecifically adsorbed immunoglobulin G. The DEAE-cellulose-bacterial cell columns were regenerated after use by desorbing the cross-reacting antibodies with low-pH buffer and were used repeatedly over and 18-month period with no detectable loss in effectiveness.

Some serological cross-reactions between Streptococcus mutans, S sanguis, and other dental plaque streptococci

From the preliminary observations described in this report, the following conclusions may be drawn. When attempting to produce diagnostic antiserums specific for S mutans, S mitior, or S sanguis, care must be taken to eliminate cross-reactions as a result of antibodies against extracellular glucans or dextrans. Other antigenic components, associated with the cell wall, may be common to different species. One soluble protein or polypeptide antigen normally present in S sanguis and S mitior may also be demonstrated in certain strains of S mutans. Antiserums prepared against S sanguis, S mitior, or S mutans should be carefully checked for interspecies cross-reactions before being used for identification purposes.

Streptococcus mutans serotypes: some aspects of their identification, distribution, antigenic shifts, and relationship to caries

For an immunologic point of view, several facts are worth consideration. S mutans can be separated into at least seven serotypes. Five of the types are based on antigens that may be specific for S mutans. One type, e, is related to the Lancefield group E streptocci, and one type, f, may lack an antigen that shows serological specificity. Analyses of plaque samples from individuals with a high caries activity have, in most instances, shown the presence of c, d, and possibly the g types. This does not necessarily mean that they are per se more cariogenic than the other types, but if all the serotypes cannot be combatted simultaneously, the c, d, and g types are an obvious first choice. S mutans strains do have antigens other than those used for serological identification, and it is not known which antigens can evoke antibodies with the highest protective capacity in humans. The phenomenon of antigenic shifts may make it possible for the bacteria to elude antibodies. However, the number of possible changes may be restricted. If certain antigens are of importance for the cariogenicity of S mutans, a change in their structure might result in a less cariogenic flora.

Adherence of serotype e Streptococcus mutans and the inhibitory effect of Lancefield group E and S mutans type e antiserum

S mutans strain MT703 from an active carious lesion in the tooth of a child had type e specificity and showed a cross-reaction with the Lancefield group E cell wall streptococcal polysaccharide antigen. Heat-killed cells MT703 adhered to a glass surface in the presence of CGT MT703 and sucrose. Pretreatment of the cells with anti-MT703 whole cell serums inhibited adherecne. The removal of glycerol teichoic acid antibody and group E antibody from the MT703 serum did not result in a loss of inhibitory activity. Antiserum with or without adsorption significantly inhibited glucan synthesis by CGT from sucrose. Antibodies specific for the polyglycerol phosphate of teichoic acid did not inhibit adherence. Anti-group E serum and serums specific for other types of S mutans, did not show adherence inhibitory activity except for an occasional type c specific antiserum. Antibody specific for the type e antigen produced significant inhibition of the binding of CGT to the MT703 cell wall, and adherence of these cells did not occur. Antibody to CGT inhibited glucan synthesis. Treatment of the cells with dextranase, dextran antibody, or trypsin caused a significant reduction in adherence. The results suggest that the type antigen and dextran on the surface of the S mutans type e cell are functional in adherence, and that these polymers are associated with cell wall protein.

Formation of cross-reacting antibodies against cellular and extracellular lipoteichoic acid of Streptococcus mutans BHT

Antisera prepared against strains of Streptococcus mutans, particularly strain BHT, contain antibodies to the membrane lipoteichoic acid component that will cross-react with lipoteichoic acids from three species of lactobacilli. A more detailed study of the antibodies to strain BHT confirmed that the antibodies are specific for the polyglycerol phosphate component common to the lipoteichoic acids. Sera with a higher hemagglutinating titer could be obtained by injecting disrupted organisms. The partially purified lipoteichoic acid isolated from the culture fluid of S. mutans BHT was also immunogenic antibodies; antibodies were also formed against another unidentified component in this extracellular fraction.

Chemical composition of Streptococcus mutans type c antigen: comparison to type a, b, and d antigens

Studies of the serotype a, b, and d antigens of S mutans were extended to include the serotype c antigen. Type c antigen was extracted from cells of strain Ingbritt and purified by repeated column chromatography. Two type c antigens fractions were separated by chromatography on DEAE-Sephadex and were designated I and II. On agar gel diffusion, the major components of antigens I and II were serologically identical with the major component of the crude Ingbritt extract. Rhamnose and glucose were present in a 2.4:1 ratio and comprised 98 and 93% of the purified antigens, respectively. The compositions of the c antigens were directly related to the carbohydrate content of the serotype c cell wall. In contrast, purified a, b-II, and d antigens, which are also cell wall polysaccharides contain only trace amounts of rhamnose, a major wall carbohydrate. Studies which used comparative immunoelectrophoresis demonstrated that the purified a, b-I, and d antigens were serologically identical to the antigen preparations that have been used for the immunological classification of these serotypes.

Preparation of antiserums for use in the fluorescent antibody identification of certain plaque bacteria

The interaction of many factors involved in FA antiserum production determines the quality of each antiserum or conjugate prepared. Performance and physicochemical characteristics of 58 FA antiserums to S mutans currently in use suggested that many of these conjugates could have been improved by using the methods and evaluation procedures described in this symposium. Deficiencies in the conjugates included low titers, incomplete fractionation, inadequately labeled antibody, fluorochromed albumin, free fluorescein and cross-reactions. Titers ranged from 1:1 up to 1:4,000. Titers for S mutans serotype c conjugates were uniformly low. S mutans serotype c conjugates were prepared from antiserums produced using a modified immunization schedule. The schedule used both viable and killed whole cells and gave FA titers as high as 1:1,000 (adjusted to 10 mg protein/ml). Procedures presented in this paper and the report by Pittman and co-workers27 should permit direct FA serum titers of up to 1:1,000 for each of the recognized serotypes of S mutans. The availability of highly specific antiserums with adequate titers will advance the use of the FA technique to identify microorganisms directly in specimens, such as dental plaque.29,30 This technique could be used to study such phenomena as the transmission of microorganisms from person to person and the establishment of the oral flora. It could also be used in epidemiological studies and perhaps to monitor the effect of a therapeutic agent on microbial composition of dental plaque.

Antigens of Streptococcus mutans: characterization of a polysaccharide antigen from walls of strain GS-5

A cell wall-associated polysaccharide antigen was isolated from Streptococcus mutans GS-5 and appeared to determine serotype c specificity. Ouchterlony double-diffusion analysis of crude formamide extracts derived from purified cell walls of two serotype c strains (GS-5 and JC-2) showed complete identify when reacted with anti-GS-5 sera. Immunoelectrophoresis of this extract demonstrated the typical mobility for this serotype as described by others. Column chromatography on BioGel P-100 of the crude formamide extracts derived from GS-5 walls resulted in a single antigenic peak being resolved. This material, when loaded onto a diethylaminoethylcellulose column and eluted with a linear gradient of ammonium carbonate (0.0 to 0.2 M), was resolved further into two serologically reactive peaks (I and II). Only two consituents, rhamnose and glucose, were detected in the purified column fractions. Peak 1 had a rhamnoseto-glucose molar ratio of 0.9:1.0, and peak II, the major resolvable fraction, had a molar ratio of 1.7:1.0, The peak II ratio was very similar to that found in the formamide extract residue pellet (1.6:1.0)9 Ouchterlony analysis of the crude formamide extract and the purified fractions revealed only partial identify between peaks I and II but complete identify between peak II and the crude extract. Likewise, immunoelectrophoresis showed no differences in mobility of peak II and the crude extract, whereas peak I moved towards the cathode. Possible structural relationships between the two antigenic fractions are discussed below. Hapten inhibition studies suggested that an alpha-glucosyl group is at the immunodeterminant site of the antigen.

Serological purification of polysaccharide antigens from Streptococcus mutans serotypes a and d: characterization of multiple antigenic determinants

The polysaccharide antigen preparations from serotype a and serotype d strains of Streptococcus mutans contained both a serotype-specific antigenic determinant and a common a-d antigenic determinant, as demonstrated by agar gel diffusion studies and a quantitative cross-precipitin assay. The chromatographically purified antigens were isolated by a method which depended on their serological specificity to determine if these two antigenic determinants were located on the same molecule. The a and d polysaccharides were recovered from specific antigen-antibody complexes and characterized with respect to their immunological specificity and chemical composition. Agar gel diffusion tests demonstrated that, in both the a and d preparations, the serotype-specific antigenic determinant and the common a-d antigenic determinant were present in one molecule.

Glucosamine-labelled envelope proteins of Escherichia coli K-12. I. Electrophoretic studies and partial fractionation of phenol-soluble proteins

Hydrophobic envelope proteins were extracted by phenol from a glucosamine- and leucine-requiring mutant of Escherichia coli K-12 (E-110). Three protein fractions labelled with D-[1-14C]glucosamine and L-[4,5-3H]leucine were obtained by electrophoretic separation. Envelopes were isolated from cells labelled with D-[1-14C]glucosamine--HCL and acid hydrolyzed. At least 68% of the radioactivity was recovered as glucosamine and glucose with no random distribution of label. Fingerprinting of pronase digests of glucosamine-labelled proteins showed four radioactive spots associated with peptides. The glycoproteins were pronase- and trypsin-sensitive and had apparent molecular weights of 11 000 (fast mobility), 35 000 (intermediate mobility) and 62 000 (slow mobility) as estimated by sodium dodecyl sulfate-polyacrylamide disc electrophoresis. The two heavier fractions were labelled with meso-diamino[1,7-14C2]pimelic acid, while orth[32P]phosphate was not incorporated into any fraction. The glucosamine radioactivity of the fast fraction underwent rapid changes upon a chase with non-radioactive glucosamine. Using a Sephadex LH-20 column, the radioactive proteins were separated from the phenol and subsequently fractionated on a DEAE-cellulose column. The DEAE-cellulose fractions were distinct from each other in the number and composition of protein bands, when analyzed by sodium dodecyl sulfate-polyacrylamide disc electrophoresis. Radioactive bands with intermediate and fast electrophoretic mobilities were found in separate DEAE-cellulose fractions.

Characterization of group N streptococcus lipoteichoic acid

Lipoteichoic acid was extracted from the group N organism Streptococcus lactis ATCC 9936 with hot aqueous phenol and purified by gel chromatography followed by affinity chromatography using Ricinus communis lectin as the specific absorbent. The teichoic acid moiety of the lipoteichoic acid was calculated to contain 16 to 17 glycerol phosphate units, approximately half of which were substituted with alpha-D-galactosyl residues; the glycolipid moiety contained O-alpha-D-glucosyl-1 yields 2-O-alpha-D-glucosyl-1 yields 1-glycerol. The finding of 2-O-alpha-D-galactosyl glycerol in the lipid fraction of hydrofluoric acid hydrolysates suggests that fatty acids also occur as substituents on the main chain of the lipoteichoic acid. The reactivity of the lipoteichoic acid with R. communis lectin was studied by the quantitative precipitin method and compared with the reactivity of Lactobacillus fermenti lipoteichoic acid, which has a lower degree of alpha-D-galactosyl substitution. Group N antiserum reacted strongly with the S. lactis lipoteichoic acid and cross-reacted with L. fermenti lipoteichoic acid. From inhibition studies it is concluded that the antibodies are specific for alpha-D-galactosyl substituents. In addition to lipoteichoic acid, a fraction was obtained by gel chromatography which contained galactose and reacted with group N antiserum but could be distinguished from the lipoteichoic acid by immunoelectrophoresis.

Preparation and chemical composition of the cell walls of Streptococcus mutans

Purified cell walls from Streptococcus mutans strain BHT were prepared without the use of proteolytic enzymes in order to retain all cell wall constituents for chemical analysis. Of four methods employed, the Ribi cell fractionator produced disrupted cell suspensions which could be most thoroughly purified on sucrose gradients. Results of chemical analyses on purified cell walls prepared in this 8.9% glycerol teichoic acid, 33.6% non-peptidoglycan polysaccharide, and 49.9% peptidoglycan.

Isolation and immunochemical characterization of the group-specific antigen of Streptococcus mutants 6715

The group d antigen of Streptococcus mutans 6515 was isolated from a buffer (pH 7.3)-boiled extract of whole cells and analyzed immunochemically. Rabbits immunized in three different fashions with whole S. mutans 6715 each responded to the same antigenic cell surface component. This presumptive major antigen was found in culture supernatant, sonically treated supernatant, acid and buffer extracts of whole cells, and trichloroacetic acid extract of cell membranes. A crude preparation of this antigen could completely inhibit antibody-mediated cell (S. mutans 6715) agglutination in a spectrophotometric analysis. The antigen was purified from buffer-boiled extracts by gel filtration on columns of Sepharose 4B. The antigen did not migrate to the anode on electrophoresis nor did it contain appreciable quantities of phosphorus, glycerol, or ribitol. This suggested that the d antigenicity did not reside in a teichoic acid. The d antigen contained galactose and glucose as the sole saccharides, in a ratio of 5.9:1.0. Protein (9.5%) appeared to be a portion of the antigen, although Pronase-digested antigen retained the same electrophoretic mobility and could precipitate virtually all (98.6%) purified antibody directed to the intact antigen. The data obtained from hapten innvolved. Glucose also contributed to the immunodominant region. Antibody directed to the d antigen may be of importance in the inhibition of adherence phenomena manifested by S. mutans organisms of the d group.

Glycerolphosphate-containing cell wall polysaccharides from Streptococcus sanguis

Six glycerolphosphate-containing tetraheteroglycans, a, b-1, b-2, b-3, b-4, and b-5, have been purified from the formamide extracts of Streptococcus sanguis by alcohol and acetone precipitations, Sephadex G-75, and diethylaminoethyl-cellulose column chromatography. The polysaccharides were judged as at least 95% pure by analytical disc gel electrophoresis and immune double diffusion against rabbit antiserum. They were shown to be cell wall polysaccharides, since they formed a single band of identity in immune double diffusion with partially purified polysaccharide extracted from a purified cell wall preparation of S. sanguis. The polysaccharides were composed of l-rhamnose, d-glucose, and N-acetyl d-glucosamine in a similar molar ratio, but varied in their glycerol and phosphate contents. They exhibited four different mobilities in polyacrylamide disc gel electrophoresis at pH 8.9. When they were treated with formamide at 170 C for 20 min, the faster moving polysaccharide(s) yielded polysaccharides with mobilities corresponding to the other slower moving polysaccharides. These results indicate that the polysaccharides originated from the same cell wall polysaccharide and were produced as a result of breakage in the phosphodiester bonds during the formamide extraction procedure. A preliminary structural study shows that the terminal reducing sugar is l-rhamnose and that the glycerol moiety is probably linked to the polysaccharide through a phosphodiester bond.

Mechanism of the Adherence of Streptococcus mutans to Smooth Surfaces III. Purification and Properties of the Enzyme Complex Responsible for Adherence

Enzymes which possess the ability to cause the adherence of Streptococcus mutans cells to a smooth glass surface were purified 1,100 times by chromatography on agarose gel followed by hydroxylapatite gel. During the purification procedures, the enzymes from strain HS6 (group a ) were examined for the synthesis of water-soluble and water-insoluble polysaccharide and the ability to produce adherence. The enzyme preparations producing adherence of the S. mutans cells in the presence of sucrose possessed a molecular size of about 400,000 to 2,000,000 and were composed of approximately equivalent amounts of dextran and levan sucrases and 5 to 30% polysaccharide. The most highly purified preparation contained a negligible amount of contaminating protein as judged by polyacrylamide gel electrophoresis, immunoelectrophoresis, and gel diffusion. In these three tests, the location of the enzyme responsible for the synthesis of insoluble polymer was detected by embedding or covering the enzyme-containing gel with a layer of sucrose-containing agarose gel and observing the formation of insoluble polymer. During purification the ability of all fractions to produce adherence was parallel with the enzyme activity responsible for the synthesis of insoluble polysaccharide from sucrose. About two-thirds of the sucrase enzyme complex in the S. mutans culture fluid synthesized water-soluble polymer. This complex, obtained by filtration through agarose gel, was smaller in molecular size, lower in sugar content, and did not produce adherence, in contrast to the enzyme complex which possessed adherence activity. The inhibition of the enzyme complex synthesizing soluble polymer required more anti-synthetase serum than that required to inhibit the synthesis of water-insoluble polymer. It is not known whether the lack of adherence activity in this enzyme was due to its smaller size and lower sugar content or the absence of unknown factors which are essential for its activity. The carbohydrate in these enzyme preparations, composed of glucose, may represent a primer molecule and/or a remnant of the polymer synthesized by the enzyme. The enzyme activity was not inhibited by anti-dextran globulin.

Purification and characterization of Streptococcus mutans group d cell wall polysaccharide antigen

The Streptococcus mutans group d antigen of strain B13 has been purified and characterized with respect to chemical composition and immunochemical properties. The antigen was extracted from lyophilized cells or cell walls by using 5% trichloroacetic acid at 5 C for 16 h. The antigen could also be extracted with water or 0.01 N HCl at 100 C for 20 min. The antigen was purified by ion-exchange and gel chromatography and was found to contain 96% carbohydrate, 1.6% protein, and 0.3% phosphorus. Characterization by gas chromatography indicated that the polysaccharide was composed of galactose and glucose in a 2:1 ratio. The antigen contained two serologically active sites: one site specific for group d and a second site common to both group d and group a strains. Agar diffusion and immunoelectrophoresis indicated that the two sites existed on a single molecule. The immunological specificity of the group d polysaccharide site depended on a terminal d-galactose. The purified B13 antigen did not react with antisera specific for the glycerol teichoic acid from streptococci. Anti-d serum rapidly agglutinated whole cells, indicating that the antibody receptor sites of the polysaccharide antigen were at the surface of the streptococcal cell.

Mechanism of adherence of Streptococcus mutans to smooth surfaces. II. Nature of the binding site and the adsorption of dextran-levan synthetase enzymes on the cell-wall surface of the streptococcus

The mechanism of adsorption of the Streptococcus mutans enzymes responsible for the synthesis of insoluble dextran-levan to the S. mutans cell-wall binding sites has been studied. Certain characteristics of these binding sites are presented. The adsorption of these enzymes to the cell surface occurred rapidly without the addition of a source of energy and over a pH range of 3 to 11. The adsorption was inhibited by soluble dextran, probably due to the strong affinity of the polymer to the enzyme. All other polymers and sugars studied showed little or no inhibition. The adsorption was also inhibited by antibody globulin to the a-d immunologically specific group antigen surface polysaccharide of S. mutans and by anti-dextran globulin. The inhibition by anti-a-d globulin is considered to be due to a restriction of access of enzyme to the binding site of the enzyme which may be located in close proximity to the group antigen. On the other hand, anti-dextran globulin appeared to directly inhibit the adsorption by covering the binding site. Dextranase destroyed the binding site and released glucose from the S. mutans cells. These data indicate that S. mutans grown in media containing glucose possesses a small amount of dextran on the cell surface, and that this dextran is, or is a part of, the binding site for enzymes which synthesize the insoluble dextran-levan polymer. Trypsin inhibited the synthesis of insoluble polysaccharide and the adherence of cells. It is not clear in this case that destruction of the binding sites occurred. These data present a partial explanation of the processes which may be concerned in the formation of dental plaque on the smooth surfaces of teeth.

Antigens of Streptococcus mutans. II. Characterization of an antigen resembling a glycerol teichoic acid in walls of strain BHT

Cold 10% trichloroacetic acid was used to extract antigens from purified cell walls of Streptococcus mutans BHT. Column chromatography on Biogel P-100 resolved two serologically reactive fractions (B and C). These fractions were ascertained to be relatively pure by recycling on Biogel P-100, Ouchterlony double-diffusion analysis, and immunoelectrophoresis. Fractions B and C demonstrated bands of absolute homology by double-diffusion but different mobilities by immunoelectrophoresis. Chemical analysis indicated that fraction B is a polysaccharide composed principally of rhamnose and galactose, with smaller amounts of glucose and glucosamine. Small quantities of glycerol and phosphorus also were found. Fraction C was composed mainly of galactose, glycerol, and phosphorus. Alkaline hydrolysis of this fraction yielded products typically released by the degradation of a glycerol teichoic acid, such as glycerol monophosphate, glycerol diphosphate, inorganic phosphorus, and several glycosyl glycerol phosphates. Diglycerol triphosphate was not detected. Side-group analysis revealed that glycerol was substituted by mono- and trigalactosyl moieties. Fraction C was deduced to contain 25 glycerol phosphate units per polymer length. Hapten inhibition studies revealed a beta-galactoside as the probable hapten on this antigen. The BHT teichoic acid reacted strongly with FA-1 antiserum. It showed bands of homology with both BHT and FA-1 crude acid extracts upon double-diffusion, using antisera to either strain. The BHT teichoic acid also displayed immunoelectrophoretic behavior identical to one of the mobile FA-1 cell wall antigens, again using either serum to develop precipitin bands. It is concluded this antigen may possess a serotype-specific determinant for S. mutans serotype b.

Mechanism of adherence of Streptococcus mutans to smooth surfaces. I. Roles of insoluble dextran-levan synthetase enzymes and cell wall polysaccharide antigen in plaque formation

The mechanism of adherence of Streptococcus mutans to smooth glass surfaces has been studied. The results with both viable and heat-killed cells showed that the process required (i) the synthesis of a water-insoluble dextran-levan polymer by cell-bound enzymes and (ii) the participation of a binding site on the surface of the S. mutans cell. Synthesis of the polymer from sucrose in the presence of the cells was required for adherence, and indicates that an "active" form of the polymer was required. Polymer synthesized by cell-free S. mutans enzymes when added to S. mutans cells did not produce adherence. Purified antibody globulin, specific for the a-d site in the polysaccharide S. mutans group a antigen, completely inhibited adherence. Antibody to the second antigen present in the polysaccharide molecule, the a antigen, did not inhibit adherence. The evidence indicates that adherence did not require an antigenic binding site which might be common to all S. mutans strains. The orientation of the synthetase enzyme(s), antigenic binding site, and dextran-levan polymer on the cell surface is under study.

Extraction, purification, and chemical and immunological properties of the Streptococcus mutans group "a" polysaccharide cell wall antigen

An antigen of Streptococcus mutans has been extracted from HS6 (group "a") whole cells and repeatedly fractionated by Sephadex chromatography. The antigen is shown to be a polysaccharide and contains the S. mutans group "a" antigenic site and also a second antigenic site which is common to "a" strains and 2 of 3 group "d" strains. Immunological electrophoretic and chromatographic data indicate that the two sites exist in a single molecule. The polysaccharide has a molecular weight of 107,000 and is composed of glucose, galactose, glucosamine, and galactosamine. No significant quantities of lipid, phosphorus, glycerol, or ribitol are present. Immunological specificity of the group "a" polysaccharide site depends primarily on a d-glucose . d-glucose sequence, the "a-d" site on a terminal d-galactose. Water at 100 C and pepsin (pH 2.5) at room temperature are very effective in extracting the polysaccharide from lyophilized S. mutans cells. Trypsin and lysozyme are less effective. The antigen-antibody combining site appears to be located at the cell wall surface. A small quantity of enzyme-resistant protein (5%) is firmly linked to the antigen and is considered to be a remnant of a protein to which the polysaccharide is attached in the cell wall. The composition of the protein does not identify it as a part of the peptidoglycan. No reaction to the purified polysaccharide is obtained with antisera specific for teichoic acid glycerophosphate polymers from streptococci, staphylococci, or lactobacilli.