This document discusses the development of a vaccine against dental caries. It notes that dental caries remains a prevalent disease despite preventive efforts. A caries vaccine targeting the bacteria Streptococcus mutans could help protect vulnerable groups from experiencing caries. Potential vaccine components discussed include adhesins, glucosyltransferases, and glucan binding proteins from S. mutans. Different types of vaccines that could be developed include subunit vaccines using protein epitopes, recombinant vaccines using DNA technology, and conjugate vaccines fusing bacterial components to carriers. Human trials have shown promise for both active immunization and passive immunization approaches. However, challenges remain in developing a vaccine that provides sufficient long-term protection against the multifactorial disease of

1. CARIES VACCINE
Dr. J. Nesa Aurlene
III year MDS
Department of Public Health Dentistry
SRM Dental College, Ramapuram

2. CONTENTS
 Introduction
 Immunity
 Types of Immunity
 Streptococcus mutans
 Ontogeny of immune response
 Molecular pathogenesis of dental
caries
 Bacterial components for vaccines
 Adhesin I/II
 Glucosyl transferases (GTF)
 Glucan Binding Proteins (GBP)
 Subunit vaccines
 Recombinant vaccines
 Conjugate vaccines
 Routes of administration
 Adjuvants/ Delivery systems
 Human trials
 Conclusion

3. Introduction
■ “Dental caries is an irreversible microbial disease of the calcified tissues of the
teeth, characterized by demineralization of the inorganic portion and destruction
of the organic substance of the tooth, which often leads to cavitation.”
■ Despite numerous preventive strategies dental caries is still a prevalent
disease in both developed and developing countries.
■ A vaccine against dental caries would be a marked public health measure that
would protect vulnerable people from experiencing caries and reduce billions of
costs that are expended on restorative treatment.

4. CARIESVACCINE
■ CariesVaccination is a programmed and planned approach to immunize and protect
caries prone people mainly children by using proteins present on oral flora bacterial
surfaces mainly Streptococcus mutans
■ In late 1969, the modern era of vaccination began with intravenous immunization
experiments conducted byWilliam Bowen on animals like irus monkeys

5. IMMUNITY

6. Types of Immunity

7. Streptococcus mutans
Streptococcus mutans is a facultatively anaerobic, gram-positive coccus commonly found in the
human oral cavity and is a significant contributor to tooth decay.
The microbe was first described by J Kilian Clarke in 1924.
Children become permanently colonized with mutans streptococci between the middle of the
second year and the end of the third year of life, during a so-called “window of infectivity”
The primary source of infection is maternal

8. • Vaccine – A vaccine is a biological preparation that improves immunity to a
particular disease
• Antigen - an antigen is a molecule capable of inducing an immune response
in the host organism.
• Antibody - a protective protein produced by the immune system in
response to the presence of an antigen
• Epitope – Antigenic determinant, the part of an antigen that is recognized
by the immune system
• Recombinant vaccine – vaccines produced using recombinant DNA
technology
• Conjugate vaccine - A conjugate vaccine is a substance that is composed of
a polysaccharide antigen fused (conjugated) to a carrier molecule.

9. Ontogeny of Immune Response
Secretory IgA – Principal immune component and effector of adaptive
immunity in the oral cavity
Secreted by major and minor salivary glands
S IgA is absent at birth but mature form occurs in saliva at one month of
age.
Two sub-classes Ig A1 and Ig A2
Ig A1 – predominantly present in serum
Ig A2 – predominantly present in secretions
Salivary antibody to oral commensal microbiota can be detected in both
subclasses at six to nine months of age.
Mucosal immune system is relatively well-developed by the period
during which children typically become infected with S. mutans

10. Molecular Pathogenesis of Dental Caries
INITIAL ATTACHMENT - interaction of bacterial proteins with binding proteins
(lectins) in the dental pellicle covering the tooth surface
Streptococcal adhesins - Antigen I/II or PAc
At least 2 binding regions of antigen I/II may be involved in salivary-component-
mediated adhesive activities
The pathogenicity of mutans streptococci occurs through erosion of the
hydroxyapatite-like mineral in dental enamel by lactic acid.
Significantly destructive concentrations of lactic acid require the substantial
accumulation of these acidogenic streptococci in dental plaque.

11. Molecular Pathogenesis of Dental Caries
ACCUMULATION
Accumulation process is initiated by the activity of extracellular glucosyltransferases secreted by S.
mutans
In the presence of sucrose, GTFs synthesize several forms of high-molecular-weight branched
extracellular glucans.
GTFs that synthesize insoluble forms of glucan (S. mutans GTF-B and GTF-C) have been most closely
associated with pathogenicity.
These glucose polymers provide scaffolding for the aggregation of mutans and other oral
streptococci through interaction with bacterial cell-associated glucan-binding proteins.
GBP’s bind to glucans, GTF’s also have glucan binding domains which allows them to bind to glucans.
The interactions of glucans with cell-associated glucan-binding domains of GTFs and GBPs combine
to cause extensive accumulation of mutans streptococci in the dental biofilm.

13. BACTERIAL
COMPONENTS
FORVACCINES -
ADHESINS
 S. mutans – Ag I/II or PAc or P1
 S. sobrinus – PAg or SpaA
 Ag I/II - 185-kDa protein composed of a single
polypeptide chain of approximately 1600 residues
 S. mutans Ag I/II contains an alanine-rich region in the N-
terminal third and a proline-rich repeat region in the
center of the molecule.
 These regions have been associated with the adhesin
activity of Ag I/II.
 Immunization approaches have shown that active
immunization with intact antigen I/II or passive
immunization with antibody to salivary-binding domain
epitopes can protect rodents, primates, or humans from
dental caries caused by S. mutans.
(Lehner et al 1981, Ma et al 1990)

14. BACTERIAL
COMPONENTS
FORVACCINES –
GTF’s
 Enzyme synthesized by both S. mutans and S. sobrinus
 Sequence varies between 1400 to 1600 amino acid
residues
 Genes responsible for synthesis of enzyme are gtfB and
gtfC in S. mutans and gtfI and gtfS in S. sobrinus
 Activity is mediated through catalytic and glucan
binding functions.

15. Glucosyltransfera
ses  N- terminal residues – catalytic activity and homology to alpha
amylases
 C- terminal – Glucan binding function
 Induction of SIgA antibody in humans by oral or topical GTF
administration is accompanied by interference with accumulation
of indigenous mutans streptococci after dental prophylaxis.
(Smith 187, Taubman 1990)

16. BACTERIAL
COMPONENTS
FORVACCINES –
GBP’s
 Binding of S.mutans to glucans is mediated by cell wall
associated Glucan binding proteins.
 Each glucan-binding protein has the ability to bind a α
1-6 glucan
 Gbp A – 563 amino acids residues, C- terminal
expresses homology to glucan binding domains of GTF
 Gbp B – 431 amino acid residues, N- terminal
immunodominant regions
 Gbp C – 583 amino acid residues, dextran dependent
aggregation
 Of the three S. mutans glucan-binding proteins, only
GbpB has been shown to induce a protective immune
response to experimental dental caries

17. SUB-UNIT VACCINES
• Contain structural elements of Ag I/II, GTF or GBP’s
• Copies of functional epitopes associated with salivary binding, catalytic processes or glucan
binding are used to optimize immune response.
• Multivalent subunit vaccines contain multiple epitopes which target different functions
• Designing vaccines in this way also permits one to eliminate regions which may induce
unwanted antibody specificities.
• The Ag I/II family of proteins shares extensive sequence homology with surface proteins of non-
cariogenic S. gordonii, S. intermedius, and S. oralis
• These homologous sequences may induce cross-reactive responses that could influence
colonization, attachment, or accumulation of commensal microbiota.

18. Recombinant Vaccines
• Uses recombinant DNA technology for production of vaccine

19. RECOMBINANT VACCINES
• Gene fusions of a functionally relevant sequence linked to a mucosal adjuvant
sequence can result in chimeric proteins inherently able to enhance immune
responses to the functional epitopes.
• Oral immunization with recombinant Salmonella typhimurium, expressing surface
protein antigen A of Streptococcus sobrinus, was able to induce persistent
mucosal immune responses which could confer protection after challenge of
Fischer rats with cariogenic S. sobrinus.
(Redman 1994)

20. CONJUGATE VACCINES
• Chemical conjugation of functionally associated protein/peptide components
with bacterial polysaccharides.
• Adhesin-associated 14mer synthetic peptide coupled to the serogroup f
polysaccharide of S. mutans induced IgM and IgG antibody responses to peptide
and polysaccharide components.
• Conjugation of either tetanus toxoid or S. sobrinus GTF to the water-soluble
glucan enhances serum IgG and salivary IgA antibody levels

21. ROUTES OF ADMINISTRATION
• Oral Route –
• Involves oral induction of immunity in the gut-associated lymphoid tissues (GALT)
to elicit protective salivary IgA antibody responses
• Oral feeding
• Gastric intubation
• Vaccine-containing capsules or liposomes.
• The disadvantage is that antigen is susceptible to acidity of stomach contents

22. • INTRA-NASAL ROUTE
• Intra-nasal administration of antigen which targets the Nasal Associated Lymphoid
tissue
• TONSILLAR
• Palatine tonsils and nasopharyngeal tonsils
• Tonsillar application of particulate antigen can induce the appearance of IgA
antibody-producing cells in both the major and minor salivary glands animals
(Inoue 1999)

23. • MINOR SALIVARY GLANDS
• The minor salivary glands populate the lips, cheeks, and soft palate.
• These glands have been suggested as potential routes for mucosal induction of
salivary immune responses
• Short, broad secretory ducts facilitate retrograde access of bacteria and their
products
• Lymphatic tissue aggregates that are often found associated with these ducts.
• Labial application of GTF in adults has lowered the mutans streptococci in whole
saliva after six weeks of follow up.

24. • The colo-rectal region as an inductive location for mucosal immune responses in
humans is suggested from the fact that this site has the highest concentration of
lymphoid follicles in the lower intestinal tract.
• This route could also be used to induce salivary IgA responses to mutans
streptococcal antigens such as GTF
(Lam 2001)

25. AdjuvantsCholera
toxin/Heatlabile
enterotoxin
 Cholera toxin (CT) is a powerful mucosal
immunoadjuvant used to enhance mucosal
immune response
 CT toxin has A and B sub-units, B is non-toxic
and A is toxic.
 Peptide antigen alone does not produce sustained
IgA responses whereas combining with CT or
heat labile enterotoxin greatly enhances immune
responses.

26. DeliverySystems–
Microparticles/
Microcapsules
 Combinations of antigen in or on various types of
particles
 Microspheres and microcapsules made of
poly(lactide-co-glycolide) (PLGA) have been used
as local delivery systems.
 PLGA can control the rate of release, evade pre-
existent antibody clearance mechanisms, and
degrade slowly without eliciting an inflammatory
response to the polymer

27. DeliverySystems
-Liposomes
 Phospholipid membrane vesicles manufactured
to contain and deliver drugs and antigens
 Facilitates M cell uptake and delivery of antigen
to lymphoid elements of inductive tissue

28. HUMAN TRIALS
■ ACTIVE IMMUNISATION
■ Smith andTaubman 1990 – GTF from S. sobrinus topically applied to lower lip of young adults.
On days 13, 20, 34 and 40 following immunisation the indigenous S.mutans was lower in
immunised group compared to placebo.
■ Childer’s 1994 – Oral immunisation using dehydrated liposomes containing S. mutans GTF
induced IgA response of primarily Ig A2 subclass.
■ Childer’s 1997 – Nasal immunisation using dehydrated liposome containing S. mutans GTF
induced IgA response of Ig A1 subclass when nasal wash was examined at the end of 6 weeks.

29. HUMANTRIALS
■ PASSIVE IMMUNISATION
■ Filler SJ 1991 – Mouthrinse of bovine milk containing antibodies to S. mutans led to
decrease in S. mutans in a group of nine individuals
■ Hatta 1997 – Passive immunisation using mouthrinse containing egg yolk antibodies to S.
mutans (IgY) showed a reduction in S. mutans count after seven days.
■ Ma 1990, 1998 - Longer-term effects on indigenous flora were observed after topical
application of mouse monoclonal IgG or transgenic plant secretory SIgA/G antibody, each
with specificity for Ag I/II. In these experiments, teeth were first treated for nine days with
chorohexidine. Following anti-bacterial treatment, antibody was topically applied for three
weeks. Recolonization with mutans streptococci did not occur for at least two years after
treatment of subjects with mouse monoclonal antibody or at least 4 months after
treatment with the transgenic antibody to the Ag I/II epitope.

30. LIMITATIONSOF CARIESVACCINE
■ The goals for vaccination against most other, mainly acute, infectious diseases are
usually to provide near-complete protection of the individual against infection, and to
achieve a sufficient prevalence of immunity in a population that the chain of
transmission is broken and the pathogen cannot sustain itself in the community.
■ However, the biology of caries is different from that of acute infections, and as with
other modalities of intervention it is conceivable that immunization will not attain
complete effectiveness.
■ Dental caries is a multifactorial disease and therefore a caries vaccine against S.
mutans alone may be insufficient to protect against the occurrence of caries.
■ Also, the safety of the vaccine has not been established in sufficient clinical trials to
recommend its usage in children below 2 years of age.

31. CONCLUSION
■ Several challenges face the development of an effective dental caries vaccine.
■ However, the oral health impact on children of the twenty-first century would be
enormous, especially for those whose economic or cultural position puts them at
increased caries risk.
■ The expected reduction in disease would save tens of billions of dollars annually in
expenditures for dental treatment.
■ Hence, caries vaccine is an intervention that merits continued research and
development.

32. References
1. Smith DJ. Dental caries vaccines: prospects and concerns. Critical Reviews in Oral
Biology & Medicine. 2002 Jul;13(4):335-49.
2. Smith DJ. Caries vaccines for the twenty-first century. Journal of Dental Education.
2003 Oct 1;67(10):1130-9.
3. Filler SJ, Gregory RL, Michalek SM, Katz J, McGhee JR. Effect of immune bovine milk
on Streptococcus mutans in human dental plaque.Archives of oral biology. 1991 Jan
1;36(1):41-7.
4. Childers NK, Zhang SS, Michalek SM. Oral immunization of humans with dehydrated
liposomes containing Streptococcus mutans glucosyltransferase induces salivary
immunoglobulinA2 antibody responses. Molecular Oral Microbiology. 1994 Jun
1;9(3):146-53.

33. References
5. Childers NK, Long G, Michalek SM. Nasal immunization of humans with dehydrated
liposomes containing Streptococcus mutans antigen. Molecular Oral Microbiology. 1997
Dec 1;12(6):329-35.
6. FukuizumiT, Inoue H,TsujisawaT, Uchiyama C.TonsillarApplication of Formalin-Killed
Cells ofStreptococcus sobrinus Reduces Experimental Dental Caries in Rabbits. Infection
and immunity. 1999 Jan 1;67(1):426-8.
7. Hatta H,Tsuda K, Ozeki M, Kim M,YamamotoT, Otake S, Hirasawa M, Katz J, Childers NK,
Michalek SM. Passive immunization against dental plaque formation in humans: effect of
a mouth rinse containing egg yolk antibodies (IgY) specific to Streptococcus mutans.
Caries research. 1997;31(4):268-74.
8. LehnerT, Haron J, Bergmeier LA, Mehlert A, Beard R, Dodd M, Mielnik B, Moore S. Local
oral immunization with synthetic peptides induces a dual mucosal IgG and salivary IgA
antibody response and prevents colonization of Streptococcus mutans. Immunology. 1989
Jul;67(3):419.

34. THANK YOU!!