|Caries Vaccine – An Alternative Or Necessity?
Jain Pankaj, Jain Isha
Like all the developing countries, dental caries remains a major public health problem for the people of India. Since ages, it has been managed with the surgical intervention but our aim is to intercept the occurrence of this disease. Mutans streptococci is one of the main causative organism of this disease. More recently, dental caries vaccine has been the primary area of research and concern for various scientific communities across the globe in order to prevent and control this disease more effectively.
Keywords: Dental Caries vaccine, S IgA, Mutans streptococci
Dental caries, as we all know, is a multifactorial irreversible disease of microbial origin. A wide variety of microorganisms have been found responsible in the progression of Dental caries and S. Mutans is the commonest of them. This is amongst the most ignorant diseases in the world, reaching to the epidemic levels. This disease can be possibly prevented by interfering with the transmission, colonization and acid production of the micro-organisms. This can be best done with the help of the vaccines.
Vaccine is an immune-biological substance stimulating the production of protective antibody and other immune mechanism; and is prepared from live modified organism, killed or inactivated organisms, extracted cellular fractions, toxoids or a combination1. Vaccines are well suited for the public health application especially in the environments that do not lend themselves to regular healthcare.
History of Caries Vaccine
In 1930s, various caries immunization experiments were done, with lacto bacillus being major part of all as an antigen. This immunization against lactobacillus tasted little success and was unable to provide much protection again the caries. It was later found out, that it’s probably due to the reason that lactobacillus is more of a consequence rather cause of caries2 and has a low affinity to the tooth structure3. Mutans streptococci was first described by J Killian Clarke4 in 1924, but only after its redetection in 1960 it was recognized as the major pathogen due to its initial colonizing property in early dental plaque.
Mechanism of Caries Vaccine
The first step in the initiation of dental caries is the colonization of S. mutans, so a caries vaccine must target the virulence factors of S. mutans with its ability to form biofilm and adhesion5. Salivary IgA act with the bacterial surface receptors inhibiting colonization and subsequent caries formation. The gut-associated lymphoid tissue and peyer’s patch are a rich source of precursers IgA B cells that can populate distant lymphoid tissue and salivary glands which can in turn inhibit the activity of Glucosyltransferase. On subcutaneous immunization with S. mutans, it is phagocytosed and undergoes antigenic processing by macrophages. Hence it can be said that several stages in the molecular pathogenesis of dental caries are susceptible to immune intervention.
These can be of various types like the caries vaccine based on active immunization which stimulates the secretory IgA production. The secretory IgA prevents adhesion of micro-organism to the tooth surface, thus inhibiting the initiation of bacterial colonization6,7. Another type of caries vaccine is the one based on passive immunization which acts by introduction of specific antibodies to S.mutans in the oral cavity. In this type, pre-formed antibodies are taken from immunized bovine milk, eggs, cultured monoclonal antibodies, or by transgenic bacteria and are introduced orally; thus avoiding any risk that might arise by active immunization8,9.
Nucleic acid based vaccines (DNA) induce the immune reponse by activating the antigen presenting cells (APC’s)10. These APC’s can capture antigens expressed by transfected cells, process them and submit them via MHC as peptides to T lymphocytes in regional lymphoid organs, where antigen specific T cells are activated11,12,13.
It is universally accepted that S. mutans and Streptococcus sobrinus are closely related with the initiation of dental caries and use of Fluorides has a marked potential to limit caries progression. Still it is found to be incompetent, even when used in consolidation with oral prophylaxis and dietary counseling in populations highly exposed to the cariogenic microbiota, in order to control its virulence.
Active and passive immunization strategies, which aims at the causative elements in the pathogenesis of mutans Streptococci, hold promising repercussions. Integration of these approaches into public health programs may yet preclude dental caries in many populations, out of which the high risk might be benefitted most lucratively.
Despite the reassuring fall in the prevalence of this disease observed in recent years, millions of children remain at risk of experiencing extensive tooth decay which is distressing as some of them may be amongst the least likely to obtain satisfactory treatment.
In addition to a large array of established methods of caries prevention, it cannot be overlooked that caries vaccines have an immense role in curbing the disease and has proved to be an attractive option.
Henceforth, many experimental studies are still being conducted in search of an effective vaccine against caries, with promising advances that may allow development of this immunogen in the future.
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