Radioimmunoassay of class-specific antibodies to Streptococcus mutans in monkey serum and saliva.

A radioimmunoassay (RIA) has been developed to measure class-specific antibodies to Steptococcus mutans in the serum and saliva of monkeys (Macaca fascicularis). Anti-human immunoglobulin antibodies purified by affinity chromatography on immobilised monkey immunoglobulins and labelled with 125I were employed. Formolised cells of S. mutans and an extract of culture supernatant adsorbed to polystyrene wells were used as solid-phase antigens. The coefficients of variation for IgG, IgA and IgM assays were less than or equal to 10% for both antigen systems. Two monkeys were immunised with formolised cells of S. mutans by subcutaneous injection and subsequent instillation of bacterial cells into their right parotid ducts. IgG, IgA and IgM antibody responses to S. mutans in samples of serum and saliva were quantitated by RIA. Immobilisation of purified components of S. mutans on polystyrene wells enabled the measurement of antibody response to a number of antigens to be made. The RIA is a sensitive, reproducible and quantitative method of measuring serum and salivary antibody responses in monkeys.

Biotyping, serotyping and phage typing of Streptococcus faecalis isolated from dental plaque in the human mouth.

Thirty Streptococcus faecalis isolates from mixed dental plaque samples were classified into four groups on the basis of biotype, tetracycline susceptibility, phage type and serotype combinations. The organisms were from patients on haemodialysis, from staff of the dialysis unit, and from controls. Three biotypes were distinguished by seven biochemical tests: production of acid from inositol, sucrose and xylose; rapid or delayed production of acid from sorbitol; gelatin liquefaction; and production of alkaline phosphatase and beta-galactosidase. With a set of eight typing antisera for S. faecalis, 15 strains were non-typable, 12 were serotype 1 and three were serotype 19. With a set of 17 bacteriophages specific for S. faecalis, all of the oral isolates were typable; 40% were lysotype I1 and the remainder lysotype V6b. On the basis of biotype-serotype-phage-type combinations, indications of possible spread of strains between haemodialysis patients and dialysis unit staff were obtained. Biotyping and serotyping of 13 German isolates of S. faecalis of phage type I1 from four clinical sources and tripartite typing of three control strains provided additional evidence for the potential of biotyping in distinguishing between strains of identical serotype and phage type. One oral isolate of S. faecium was of phage type XX. None of the oral isolates of S. faecalis, of which 14 exhibited delayed sorbitol fermentation, reacted with group-G streptococcal grouping reagents or antiserum. Slow sorbitol fermentation does not appear to be a definitive phenotypic marker for S. faecalis strains possessing antigens that react with both group-D and group-G grouping reagents.

A medium for the isolation and enumeration of oral actinomycetaceae from dental plaque.

A supplemented, infusion-based medium that supports the growth of most oral Actinomycetaceae is described. The inclusion of Naf and colistin sulfate enabled actinomyces to be isolated from dental plaque in the presence of few other oral microorganisms.

Cigarette smoking and the microbial flora of the mouth.

A range of selective media was used to culture the microbial flora of the dental plaque, tongue and palate, The subjects were five young men who smoked more than twenty cigarettes a day and four who did not smoke. Neisseriae were less numerous on the mucosal surfaces of the smokers.

Antibody responses to antigens of Streptococcus mutans in monkeys (Macaca fascicularis) immunized against dental caries.

Immunization of rabbits or monkeys with walls prepared from Streptococcus mutans by a procedure including extraction with SDS at room-temperature induced antibodies to three antigens (A, B and C) detectable by crossed immunoelectrophoresis. Antigens A and B have previously been characterized as proteins of molecular weight 29 000 and 190 000, respectively. Antigen C was characterized as having a molecular weight of 70 000 and was purified by immunosorbent affinity chromatography and hydrophobic interaction chromatography. Another wall protein, antigen D, of molecular weight 13 000, was extracted from walls with Triton X-100. Immunization of monkeys with walls prepared from cultures of S. mutans grown at a high (D = 0.5 h-1) or low (D = 0.05 h-1) dilution rate in a chemostat showed that only the latter induced protection against dental caries. There was a positive correlation between levels of antibody to antigens A and C and induction of protection and a negative correlation between protection and the level of antibody to antigen B. No antibody to antigen D was detected in protected monkeys and an experiment in which monkeys were immunized with pure antigen D confirmed that it does not induce protection.