|Year : 2009 | Volume
| Issue : 3 | Page : 135-138
Natural prevalence of antibody titres to GTF of S. mutans in saliva in high and low caries active children
BC Kirtaniya1, HS Chawla2, A Tiwari3, NK Ganguly4, V Sachdev1
1 Department of Pedodontics, Himachal Dental College, Sunder Nagar, H.P, India
2 Oral Health Science Centre, PGIMER, Chandigarh, India
3 Oral Health Science Centre, Dean, PGIMER, Chandigarh, India
4 Former Director General ICMR (New Delhi), India
|Date of Web Publication||15-Oct-2009|
B C Kirtaniya
Himachal Dental College Sundernagar
| Abstract|| |
The present study was conducted to find out the role of natural immunity against dental caries. Whole stimulated saliva of various caries active children was collected. Antigen glucosyltransferase (GTF) was prepared from Streptococcus mutans serotype c and the antibody titre was estimated using ELISA. Salivary IgG, s-IgA and total immunoglobulins (IgG + s-IgA+ IgM) concentration were assayed. The result showed an increased level of salivary IgG concentration with the increased number of dental caries, which was not statistically significant. But there were significant decrease of s-IgA titre as well as total immunoglobulin concentration in saliva with the increased number of dental caries. This study showed that because of lack of local immunity the children are more prone to dental caries.
Keywords: Antigen, glucosyltransferase, immunoglobulins, polysaccharides, saliva, S. mutans
|How to cite this article:|
Kirtaniya B C, Chawla H S, Tiwari A, Ganguly N K, Sachdev V. Natural prevalence of antibody titres to GTF of S. mutans in saliva in high and low caries active children. J Indian Soc Pedod Prev Dent 2009;27:135-8
|How to cite this URL:|
Kirtaniya B C, Chawla H S, Tiwari A, Ganguly N K, Sachdev V. Natural prevalence of antibody titres to GTF of S. mutans in saliva in high and low caries active children. J Indian Soc Pedod Prev Dent [serial online] 2009 [cited 2013 May 18];27:135-8. Available from: http://www.jisppd.com/text.asp?2009/27/3/135/57092
| Introduction|| |
It is well documented that mutans streptococci are primarily responsible for the production of dental caries in human. These organisms produce extracellular polysaccharides from sucrose with the help of glucosyltransferase (GTF), an enzyme present inside the cell, cell bound and extracellularly. The production of water-insoluble polysaccharides called mutans with a 1:3 linkage is the important determinant for virulence of cariogenicity of Streptococcus mutans because it helps in the adhesion and colonization of microorganisms to the tooth surface and creates a diffusion barrier for acids to leak away from the vicinity of the tooth surface. Therefore, GTF is regarded as a key enzyme in the production of dental caries; if this enzyme activity is inhibited or destroyed, there should be reduction of dental caries. The most advantage of GTF is its unique presence in all types of S. mutans and it does not produce cross-reactive antibody as do whole cell of S. mutans. , Glucosyltransferase is equal in antigenicity to protein antigen I/II.  It is more potent antigen than LTA , glycosidic hydrolase, LDH and FTF . With these facts as a background along with the clinical observations that some children with almost parallel local factors and diet habits are more prone to caries than others lead the present investigation to asses the prevalence of naturally existing antibodies to GTF of S. mutans in saliva.
| Materials and Methods|| |
Forty six children in the age group of 6-14 years were selected with caries experience ranging from 0 to 15 DMFT/deft. They were divided into four groups according to the severity of dental caries as No Dental Caries (NDC) consisting of 11 children, Low Dental Caries (LDC) with DMFT/deft 1-2 consisting of 10 children, Moderate Dental Caries (MDC) with DMFT/deft of 3-4 consisting of 10 children and High Dental Caries (HDC) with DMFT/deft of 5-15 consisting of 15 children. Care was taken to select healthy, non-tonsillectomized children with no history of allergic reaction or hypogammaglobulinemia or infection of any kind for at least six months [Table 1].
From the above table it is evident that filling component is missing showing active and open carious lesions in the LDC, MDC and HDC groups.
Stimulated whole saliva was collected in a wide mouth test tube in the morning hours between 9 AM and 12 noon. The samples were heated in a water bath at 56C for 30 min to inactivate enzymes and microorganisms. It was then centrifuged at 1000 rpm for 15 min to remove any particulates and the supernatant was stored in sterile disposable plastic vials at -20C till ELISA was done. The GTF was prepared and purified according to Chludzinnski, Germaine and Schachtele, 1976 from S. mutans serotype c. The estimation of antibody was done using ELISA of Engvall and Permann, 1972.
| Results|| |
The salivary immunoglobulin concentrations measured by ELISA have been expressed in Optical Density (OD) and are shown in [Table 2],[Table 3],[Table 4].
s-IgA: The mean salivary s-IgA concentration to GTF in saliva in the NDC group was 0.490± 0.142, in LDC group it was 0.428± 0.134, in the MDC group it was 0.391± 0.055 and in the HDC group it was 0.345± 0.141. The mean s-IgA concentration in saliva was found to be decreased with the increased number of carious lesions, showing an inverse correlation of s-IgA with the increased number of dental caries. The mean s-IgA in NDC group when compared with HDC group was found to be statistically significant at 5% level (p < 0.05). Also a marked difference in mean levels of salivary immunoglobulin-A between NDC with LDC and NDC with MDC was noticed, which were not statistically significant.
IgG: The mean IgG concentration of saliva in NDC group was 0.207± 0.101; in LDC group it was 0.204± 0.044; in MDC group it was 0.210± 0.043 and in the HDC group it was 0.229± 0.055. The mean IgG concentration of saliva was found to be increased with the increased number of carious lesions, depicting a direct correlation of salivary IgG with the increased number of dental caries. However, this raised antibody titre was not statistically significant.
Total Immunoglobulins: The mean total immunoglobulin concentration (IgG + IgA + IgM) in saliva in NDC group was 0.555± 0.146, in LDC group it was 0.364± 0.146; in the MDC group it was 0.398± 0.223 and in the HDC group it was 0.310± 0.152. The mean total immunoglobulin concentration was found to be decreased with the increased number of carious lesions reflecting an inverse correlation of total immunoglobulin concentration with dental caries. The mean total immunoglobulin concentration when compared with NDC versus LDC and NDC versus MDC were statistically significant at one percent level (p < 0.01). The mean total immunoglobulin concentration of NDC group when compared with HDC group was highly significant at 0.1% (p < 0.001).
The mean s-IgA, IgG and total immunoglobulin concentration in saliva are shown in the Graphs 1-[Additional file 1], Graph 2- [Additional file 2], Graph 3- [Additional file 3].
| Discussion|| |
The s-IgA antibody is the predominant immunoglobulin in our body secretions including saliva, tear, bronchial secretions, prostate secretions, breast milk etc. It is the main antibody, which protects humans from local infection. The s-IgA is the major antibody in the saliva. On the other hand, IgG antibody contributes about 80% in serum, which protects us from all types of systemic infections. But this is not the major antibody in saliva. It is usually raised in secondary response to the infection. The IgM antibody is about 6% in serum, which is raised in primary response to the infection.
Salivary IgA to GTF was estimated in all the four groups (i.e. NDC, LDC, MDC and HDC) and was found to be decreased with increased number of carious lesions. When NDC was compared with LDC and MDC groups, this decrease of antibody titre was not statistically significant. These findings were in agreement with Everhart, et al,  Bowen, et al,  Lehner, et al.  But when anti-GTF antibody of NDC group was compared with HDC group, the decrease of antibody titer was statistically significant at 5% level (p < 0.05). It seemed that the NDC group where there was no caries were being protected by the higher s-IgA level in saliva as compared to HDC group with 5-15 DMFT/deft with low antibody titre. This result was in agreement with Lehner, et al,  Zengo, et al, 1970 , Everhart, et al,  Challacomb, et al,  Bolton, et al and Bhatia, et al. 
The possible reason for decrease of s-IgA in saliva in high risk caries active group may be due to the fact that the children were having higher number of S. mutans count in saliva from the early childhood (six months of age), which they swallowed repeatedly when their immune system or lymphoid system were developing or not yet matured. Therefore it is the s-IgA for which there was marked reduction of total antibody titres and not IgG + IgM. Therefore, with the continuous exposure of higher number of S. mutans, from early infancy the gut associated lymphoid tissues became tolerant to produce immune response to GTF but the other lymphoid systems were active, hence there was no complete cessation of antibody production. The above reason may explain why Cole, et al and Gahnberg and Bo Krasse  could not find any significant increase of salivary IgA titre in human after oral immunization with S. mutans.
Salivary IgG concentration was found to increase with the increase number of carious lesions. But the results were not statistically significant. These results were in agreement with Everheart, et al,  who suggested that IgG in saliva might not be the antibody protecting against dental caries. The possible reason for the inadequacy of salivary IgG to contribute towards caries resistance could be that it was not protected by secretory component as s-IgA. Therefore, it was sensitive and may be destroyed by proteolytic enzymes of saliva. The raised IgG level in saliva might be the result of gingival stimulation through crevicular fluid when there was plaque accumulation around gingiva.
The total salivary immunoglobulin concentration showed a marked decrease with the increase number of DMFT/deft. The mean total immunoglobulin titre against GTF in saliva of NDC group was found to be significantly higher than LDC and MDC groups at 1% level (p < 0.01). The difference of total immunoglobulin concentration in saliva of NDC versus HDC was highly significant at 0.1% level (p < 0.001). From the above findings it was evident that the total immunoglobulin concentration in saliva was very much decreased in high risk caries active children. The decrease of total immunoglobulin concentration in saliva was due to decrease of s-IgA, which was the predominant antibody in saliva. Apparently, it seemed that the decrease of total immunoglobulin titre in saliva might be due to the decrease of IgM also. Since the IgM is basically a serum antibody having no secretary component and which contributes about 6% of total antibody titre in serum, it cannot be the causative antibody. Moreover, the IgM antibody is raised in primary response of the infection and not in the secondary response hence, it cannot contribute towards the decrease of total antibody titre.
| Conclusion|| |
In this present study our samples were having open carious lesions for a long period of time, which would theoretically give rise to an increase in IgG and s-IgA concentrations in saliva. The IgG concentration was in increasing order with an increased number of caries, where as s-IgA concentration was in decreased order. It seemed that in the high risk children there was a lack of local protective mechanism for which there was exaggeration of colonization of S. mutans on tooth surface thereby increasing susceptibility to dental caries. Hence, it is the secretory IgA antibody in saliva that provides protection against dental caries in children.
| Acknowledgments|| |
Dr. Anshul Sachdeva, P. G. student, 2nd Year, for his help to type this article and corresponding to the Journal office repeatedly.
| References|| |
|1.||Rijn VD, Bleiweis AS, Zabriskie JB. Antigens in S. mutans cross-reactive with human heart muscle. J Dent Res 1976;55 Spec No:c59-84. |
|2.||Ferretti JJ, Shea C, Humphrey MW: Cross-reactivity of S. mutans antigens and human heart tissue. Infect Immun 1980;30:69-73. |
|3.||Challacombe SJ. Serumand salivary antibodies to streptococcus mutans in relation to the development and treatment of human dental caries. Arch Oral Biol 1980;25:495-502. [PUBMED] |
|4.||Everheart DL, Grigsby WR, Carter WH Jr. Evaluation of dental caries experience and salivary immunoglobulins in whole saliva. J Dent Res 1972;51:1487-92. |
|5.||Bowen WH, Cohen B, Cole MF, Colman G. Immunisation against dental caries. Br Dent J 1975;39:45-58. |
|6.||Russell MW, Challacombe SJ, Lehner T. Serum glucosyltranferase inhibiting antibodies and dental caries in rhesus monkeys immunized against S. mutans. Immunology 1976;30:619-27. |
|7.||Bolton RW, Hlava GL. Evaluation of salivary IgA antibody to cariogenic microorganisms in children correlation with dental caries activity. J Dent Res 1982;61:1225-8. [PUBMED] [FULLTEXT] |
|8.||Bhatia S, Chawla HS, Tewari A, Ganguli NK. Status of serum and salivary antibodies specific to LTA derived from S. mutans in relation to dental caries activity. M.D.S. Thesis in Pedodontics and Preventive dentistry, Punjab University; 1986. |
|9.||Cole MF, Emilson CG, Hsu SD, Li SH, Bowen WH. Effect of oral immunization of humans with streptococcus mutans on induction of salivary and serum antibodies and inhibition of experimental infection. Infect Immun 1984;46:703-9. [PUBMED] [FULLTEXT] |
|10.||Krasse GL. Salivary immunoglobulin A antibodies and recovery from challenge of S. mutans after oral administration of S. mutans vaccine in humans. Infect Immun 1980;39:514-9. |
[Table 1], [Table 2], [Table 3], [Table 4]
|This article has been cited by|
||Salivary IgA in minor-gland saliva of children, adolescents, and young adults : Salivary IgA in minor gland saliva
| ||Mikael Sonesson, Kristina Hamberg, Marie-Louise Lundin Wallengren, Lars Matsson, Dan Ericson |
| ||European Journal Of Oral Sciences. 2011; 119(1): 15 |
||Immunological and Microbiologic Changes during Caries Development in Young Children
| ||T.M. Parisotto, W.F. King, C. Duque, R.O. Mattos-Graner, C. Steiner-Oliveira, M. Nobre-dos-Santos, D.J. Smith |
| ||Caries Research. 2011; 45(4): 377 |