Cariologia y s.Mutans

Immunology 1980 40 97

Specificity of antibodies induced by Streptococcus mutans during immunization against dental caries

M. W. RUSSELL, S. J. CHALLACOMBE & T. LEHNER Department of Oral Immunology and Microbiology, Guy's Hospital Medical and Dental Schools, London

Acceptedfor publication 27 October 1977*

Summary. Protection against smooth surface dental caries was investigated infifteen young rhesus monkeys which were immunized subcutaneously with Streptococcus mutans serotype c in Freund's incomplete adjuvant. Monkeys immunized with killed whole organisms developed significantly less caries than control animals. Monkeys immunized with pronasetreated cell walls developed significantly more caries than control animals while monkeys immunized with untreated cell walls showed nosuch enhancement of caries. Haemagglutinating and complement-fixing antibodies to cell walls and culture supernatant antigens (SN Ag) of S. mutans developed in the sera of all immunized animals to a similar degree. Antibodies to lipoteichoic acid and to an insoluble dextran preparation were found in all immunized animals and showed no relationship to the prevalence of caries. Antibodies to theserotype c polysaccharide were also found in animals immunized with whole cells and pronase-treated cell walls. However, precipitating antibody levels to partially purified antigens I/II and II, derived from SN Ag, but present also in cells, were related to the development of caries. Animals immunized with whole cells and with untreated cell walls
Correspondence: Dr T. Lehner, Department of OralImmunology and Microbiology, Guy's Hospital Medical and Dental Schools, London SEI 9RT. * Publication delayed because Patent Applicaton was pending. 0019-2805/80/0500-0097S02.00 (0 1980 Blackwell Scientific Publications

developed a brisk antibody response to antigen I/II, while those immunized with pronase-treated cell walls responded more slowly. The results suggest that immunization may induceboth caries reduction and enhancement, depending on the antibody response which is developed.
INTRODUCTION The induction of immunity to dental caries has been studied in rhesus monkeys vaccinated with cells and extracellular products of Streptococcus mutans serotype c (Lehner, Challacombe & Caldwell, 1975b; Russell, Challacombe & Lehner, 1976). It appears that subcutaneous immunization withkilled organisms in Freund's incomplete adjuvant (FIA) induces both systemic antibody and cellular responses (Lehner, Challacombe, Wilton & Caldwell, 1976b) and reduces the development of dental caries. It has been postulated that serum antibodies could reach the site of carious attack by passage through the gingival crevice (Lehner, Challacombe & Caldwell, 1976a; Challacombe, Russell & Hawkes, 1978).Serum antibody levels have been assayed by means of passive haemagglutination and complement fixation tests, using trypsin- or pronase-treated cell walls and an extracellular antigen preparation obtained from culture supernatants (supernatant antigen; SNAg), which has glucosyltransferase (GTF) activity. The results indicate that protection is associated with the early development ofcomplement-fixing anti-

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bodies, possibly of the IgG class, directed against antigens to be found in both cell walls and culture supernatants (Lehner et al., 1976a). Tests for the presence of antibodies capable of inhibiting GTF activity, suggest that such antibodies are not responsible for the observed protection (Russell et al., 1976). There havebeen no investigations into the specificity of the antibody response to different antigenic components of S. mutans. Several different antigens of S. mutans serotype c have recently been described, and some have been purified and characterized. They include the serotype c polysaccharide (c PS) (Wetherell & Bleiweis, 1975; Linzer, Gill & Slade, 1976), lipoteichoic acid (LTA) (Markham, Knox,...