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Biomedical subjects

S J Challacombe

Publications and source records attributed to S J Challacombe.

At least 145 records · Page 8Linked to original sources
PubMed1977

A sequential bacteriological and serological investigation of Rhesus monkeys immunised against dental caries with Streptococcus mutans.

In a serial investigation of the effects of immunisation with S. mutans in rhesus monkeys maintained on a "human" type of cariogenic diet, the numbers of S. mutans in cervical plaque, crevicular-fluid washings, fissures of teeth, and in saliva were lower in immunised animals than in sham-immunised controls. Immunisation also caused a delay in initial colonisation and a slowing of the rate of colonisation with S. mutans. These bacteriological changes were associated with a reduction in the smooth-surface-caries score. No relationship was found between the presence of S. sanguis and caries, but there was an inverse relationship between the proportions of S. mutans and S. sanguis isolated. Increased titres of complement-fixing, haemagglutinating and precipitating antibodies to S. mutans were found in the sera of immunised but not of control monkeys. A significant increase in salivary haemagglutinating antibodies was not detected. The results suggest that immunisation with S. mutans causes an increase in serum antibodies and a reduction in the number of S. mutans in the oral flora, and that these are associated with a reduction in dental caries.

Animals↗
PubMed1976

Serum and salivary antibodies to cariogenic bacteria in man.

Antibodies in serum and parotid saliva against cell wall preparations from four serotypes of S mutans were examined in 110 subjects aged 18 to 25 years. In subjects with no detectable carious lesions, significant negative correlations were found between the DMF index and serum IgG and IgM antibodies, especially in S mutans of serotype c, whereas positive correlations were found between the DMF index and salivary IgA antibodies. In subjects with active caries, positive correlations were found between serum IgG antibodies and S mutans (serotypes c and a) and the DMF index. Sequential antibody analysis during a period of up to 32 months showed that development of carious lesions was associated with a rise in serum antibody titer to S mutans, but no change was detectable in salivary antibodies. Treatment of caries led to a decrease in serum IgG and IgM antibodies to S mutans cell wall, but in parotid saliva an increase in antibody titer to a culture extract of S mutans was found. The results support the concept of dental caries as an infective disease and suggest that serum antibodies may contribute to caries immunity in man.

Adolescent↗
PubMed1976

Immunologic basis for vaccination against dental caries in rhesus monkeys.

The effects of immunization with Streptococcus mutans on the development of caries and the immune responses were investigated in 37 young rhesus monkeys (Macaca mulatta) during a period of up to 33 months. The monkeys were supplied a human type of carbohydrate-rich diet that contained about 15% sucrose. The monkeys were separated into seven groups, and the effects of two whole cell vaccines and an extracellular culture extract of S mutans in Freund's incomplete adjuvant were compared with a vaccine of a noncariogenic Streptococcus CHT, the adjuvant alone, and a sham immunized group. Sequential analysis of complement fixing, hemagglutinating and precipitating antibodies to the cell wall, and extracellular culture extract have shown that a significant reduction in smooth surface and fissure caries resulted from immunization with the S mutans vaccines, if antibodies reached an optimum level before caries development started. Protection was not elicited by the culture extract of S mutans or the noncariogenic Streptococcus CHT vaccines. A recently developed bacteriological sampling technique of crevicular fluid, plaque, and saliva showed that caries reduction in immunized animals was associated with a significantly decreased percentage of S mutans in crevicular fluid. Immunochemical studies showed IgG and IgM classes of antibodies in serum and secretory IgA antibodies in saliva, but it appears that reduction in caries was best associated with serum IgG antibodies to the culture extract of S mutans. The humoral and cellular mechanisms involved in the immunologic control of caries are discussed in terms of a central afferent mechanism required for antigen processing and cellular proliferation, and two peripheral effector mechanisms that function in the crevicular and salivary domains.

Animals↗
PubMed1976

Serum glucosyltransferase-inhibiting antibodies and dental caries in rhesus monkeys immunized against Streptococcus mutans.

Serum antibodies to glucosyltransferase (GTF) of Streptococcus mutans serotype c were assayed sequentially by means of an enzyme inhibition radio-assay in twenty-six Rhesus monkeys immunized with S. mutans. Pre-immune and control sera had a GTP-enhancing effect which was shown also by albumin and non-immune immunoglobulin fractions. GTF-inhibitory activity was found in IgG fractions from some immune sera and could be absorbed by S. mutans cells possessing cell-bound GTF. Inhibitory antibodies to GTF developed in the sera of four monkeys immunized with hydroxylapatite extract of culture supernatant (HACS), and in four out of fifteen monkeys immunized with S. mutans cells, but in none of the seven sham-immunized control animals. The monkeys immunized with HACS showed no reduction in caries. A correlation has been demonstrated between protection against caries and the early development of serum IgG antibodies to antigens present in HACS but there was no consistent association between protection against caries and GTF-inhibitory antibodies. The results also suggest the possibility that other antibodies, possibly present in the IgM or IgA fractions and having an enhancing effect on GTF, may increase the incidence of caries.

Animals↗
PubMed1975

Immunoconglutinins and C3 in human saliva.

High titres of immunoconglutinin activity (antibody to bound complement components) have been found in the parotid, sublingual and submandibular saliva of most healthy subjects. The immunoconglutinin (IK) titre in mixed saliva was substantially lower than in the other samples of saliva. C3 was detectable in only three of 164 samples of parotid, submandibular and sublingual saliva but was present in forty-seven of 117 mixed saliva samples. It is suggested that crevicular fluid is the major source of C3 in mixed saliva. A negative correlation was found in mixed saliva between the C3 concentration and the IK titre, and this suggested that C3 was the inhibitor of IK in mixed saliva. Binding of C3 to IK has been demonstrated in mixed saliva by using highly purified salivary IK and C3. Purified C3, C3i, C3c and C3d inhibited the activity of purified IK. It is suggested that salivary IK represents the secretion of a B-lymphocyte population which has evaded the mechanism responsible for inducing B-cell tolerance to autologous serum proteins. The reason for its persistence in the salivary glands, however, is not known at present.

Adolescent↗