Caries vaccine ppt

Information about Caries vaccine ppt

Published on July 29, 2014

Author: venkitr2006



DENTAL CARIES VACCINE: DENTAL CARIES VACCINE Dr. R. Venkitachalam , PG I year, Department of Public Health Dentistry, Amrita School of Dentistry Learning objectives: Learning objectives How immune system works The need for caries vaccine in public health point of view Methods of caries vaccine administration CONTENTS: CONTENTS Introduction Immunity Need for caries vaccine Microbiology of dental caries Routes of administration Advantages Disadvantages Passive immunization Public Health perspective Summary References INTRODUCTION: INTRODUCTION Definition: Dental caries is an infectious microbiological disease of the teeth that results in localized dissolution and destruction of the calcified tissue. It is one of the most common diseases in humans . Dental caries is a major public health problem. Vaccine : An immunobiological substance designed to produce a specific protection against a given disease . IMMUNITY: IMMUNITY It is defined as resistance exhibited by the host against any foreign antigen including microorganisms. Classification - ?? Classification of immunity: Classification of immunity Classification of immunity: Classification of immunity Antibodies (Immunoglobulin): Antibodies (Immunoglobulin) Definition: An immunoglobulin, a specialized immune  protein, produced because of the introduction of an antigen into the body, and which possesses the remarkable ability to combine with the very antigen that triggered its production. Types of Immunoglobulins : IgG - protects the body fluids IgA - protects the body surfaces IgM - protects the blood stream IgD - serves as recognition receptors for antigens IgE - mediates allergic response or hypersensitivity Need for vaccination: Need for vaccination Dental caries is a major public health problem. Has an impact on Oral health related quality of life loss of man hours Keyes triad : Keyes triad Newbrun tetrad: Newbrun tetrad Fejerskov and Manji concept (1990): Fejerskov and Manji concept (1990) MICROBIOLOGY: MICROBIOLOGY A wide group of microorganisms are identified from carious lesions which include: Mutans group of streptococci S. mutans , S. sobrinus , S. crecitus , S. rattus , S. ferus , S. macacae , S. downei Streptococcus mutans (initiation) Lactobacillus (progression) Actinomyces species (root surface) Streptococcus mutans: Streptococcus mutans PROFILE : Gram positive and facultative anaerobe colonize the host only after the first teeth erupt, and their preferential colonization site is the teeth they are highly localized on the surfaces of the teeth and their abundance in the plaque is highest over initial lesions their level of colonization within the plaque is increased by sucrose consumption they synthesize certain macro-molecules from sucrose that foster their attachment to the teeth they are rapid producers of acid from simple carbohydrates ( acidogenic ), including sucrose, and are tolerant to low pH ( aciduric ). they are essentially always recovered on cultivation of initial and established carious lesion sites Antigenic determinants of S. mutans: Antigenic determinants of S. mutans ADHESINS (WALL ASSOCIATED PROTEINS) Form the 2 principal human pathogens of S.mutans (Ag I/II, Pac, or P1) and of S.sobrinus (Spa-A or Pag ) and have been purified. Ag I/II: Associated with binding or attachment of S. mutans with tooth surface GLUCOSYLTRANSFERASE S.mutans has 3 forms of GTF’s: - Water insoluble glucan sythesizing enzyme: GTF-I - Water insoluble & water-soluble glucan synthesizing enzymes: GTF-S-I. - Water-soluble glucan synthesizing enzymes: GTF-S . Genes encoding the 3 forms are: - GTF-I: GTF-B - GTF-SI: GTF-C - GTF-S: GTF-D Antigenic determinants: Antigenic determinants GLUCAN BINDING PROTEIN (GBP): - S.mutans secretes at least 3 distinct proteins with glucan binding activity: GBP-A, GBP-B and GBP-C. - It helps in binding of glucan to S. mutans DEXTRANASES: - Dextran is an important constituent of early dental plaque. - Dextranase is an enzyme produced by mutans streptococus . They destroy dextran and thus the bacteria can invade dextran-rich early plaque. Dextran, when used as an antigen, can prevent the colonization of the organism in early dental plaque. ROUTES OF ADMINISTRATION: ROUTES OF ADMINISTRATION Common Mucosal Immune Pathway Systemic Route Active Gingivo -salivary Route Routes of administration: Routes of administration COMMON MUCOSAL IMMUNE SYSTEM: Mucosal applications of dental caries vaccines are generally preferred for the induction of Secretory-IgA antibodies. Several routes which have been used for induction are as follows. PowerPoint Presentation: ORAL ROUTE: Relied on oral induction of immunity in the GALT. Antigen was applied by oral feeding, gastric intubation, or in vaccine containing capsules or liposomes. Routes of administration PowerPoint Presentation: INTRANASAL ROUTE: Intranasal instillation of antigen, the NALT, has been used to induce immunity to bacterial antigens including those associated with mutans Streptococcus colonization and accumulation. Routes of administration PowerPoint Presentation: TONSILLAR ROUTE: The tonsillar tissues contain the required elements of immune induction of S-IgA and IgG . Palatine tonsils, especially the nasopharyngeal tonsils have been suggested to contribute precursor cells to mucosal effector sites, such as salivary glands.   Routes of administration PowerPoint Presentation: MINOR SALIVARY GLAND They populate the lips, cheeks and soft palate. They have been suggested as potential routes for mucosal induction, given their short, broad secretory ducts that facilitate retrograde access of bacteria & their products & give the lymphatic tissue aggregates. Routes of administration PowerPoint Presentation: RECTAL This region as an inductive location for immune responses in humans is suggested as this site has the highest concentration of lymphoid follicles in the lower intestinal tract. Hence the use of vaccine suppositories as an alternative in children in whom respiratory ailments preclude intranasal route may be considered.     Routes of administration PowerPoint Presentation: SYSTEMIC ROUTE This route was used successfully and elicited predominantly IgG , IgM and IgA antibodies. The antibodies find their way into the oral cavity via GCF and are protective against dental caries. The development of serum IgG antibodies takes place within months of immunization. Protection against caries was associated predominantly with increased serum IgG antibodies. Routes of administration PowerPoint Presentation: ACTIVE GINGIVO-SALIVARY ROUTE In order to limit the potential side effects and to localize the immune response, gingival crevicular fluid has been used as the route of administration. It induces both IgA and IgG antibodies .   Routes of administration PASSIVE IMMUNIZATION : PASSIVE IMMUNIZATION It involves passive or external supplementation of the antibodies. Several approaches tried were : 1. Monoclonal antibodies: - Monoclonal antibodies to S.mutans cell surface Ag I/II have been investigated. - Topical application in humans brought a marked reduction in the implanted S.mutans . 2. Bovine milk: - Systemic immunization of cows with a vaccine using whole S.mutans led to the products containing polyclonal IgG Abs. - This milk was then added to the diet of a rat model which reduced caries - This whey was also used in mouth rinse which resulted in lower percentage of S.mutans in plaque. PowerPoint Presentation: 3. Egg-yolk antibodies: - Vaccines used were formalin killed whole cells & cell associated GTFs. - Caries reduction has been found with both these treatments. 4. Transgenic plants: - Researches have developed a caries vaccine from a genetically modified (GM) tobacco plant. - Vaccine is colorless, tasteless and can be painted onto the teeth. - It is the first plant derived vaccine from GM plants.   Passive immunization Adjuvants and delivery systems of caries vaccine: Adjuvants and delivery systems of caries vaccine Synthetic Peptides Coupling With Cholera Toxin Subunits Fusing With Salmonella Microcapsules And Macroparticles Liposomes ADVANTAGES: ADVANTAGES Prevents the disease in children Can be incorporated to universal immunization programme Cost effective in the long run Provides life long immunity DISADVANTAGES/PITFALLS: DISADVANTAGES/PITFALLS Clinical trials are few and concentrated only on S. mutans . As caries is multifactorial, it’s effectiveness is questionable Risk of hypersensitivity Cross reactivity of certain antigenic components of S. mutans with heart tissue (structurally similar to myosin) Microbial resistance PUBLIC HEALTH PERSPECTIVE: PUBLIC HEALTH PERSPECTIVE Caries – declining trend due to various preventive measures But are they effective enough ??  An effective, safe, and readily deliverable vaccine may not only help against pain and health issues associated with caries but also save the billions of dollars that are currently spent for restorative treatment.   PowerPoint Presentation: Considerable caries reduction could be attained if colonization of  S. mutans  could be prevented or reduced at the time of eruption of both deciduous and permanent teeth. Thus, a successful vaccination directed against  S. mutans  could be a valuable adjunct to other caries-preventive measures. Public Health Perspective SUMMARY: SUMMARY S.mutans is closely associated with dental caries. Active and passive immunization strategies, which target key elements in the molecular pathogenesis of mutans streptococci could be more helpful. Integrating these approaches into broad-based public health programs may be of great value.  A nalysis of the need, cost benefits, and risk-benefits of a vaccine against dental caries to be performed For further reading refer . . : For further reading refer . . Hiremath S. S. Textbook of Preventive and Community Dentistry. (2 nd edition). New Delhi : Elsevier; 2011 Shivakumar KM, Vidya SK, Chandu GN. Dental caries vaccine. Indian J Dent Res 2009;20:99-106 . Jason M. Tanzer et al. The Microbiology of Primary Dental Caries. J Dent Educ. 2001 Oct;65(10):1028-37 THANK YOU: THANK YOU

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