Cell-mediated immune responses in oral disease: A review

Crohn's disease: clinical manifestations of orthodontic interest

Crohn's disease is a chronic inflammation of the small intestine; it can involve other organs, such as the skin, eyes, lungs, and joints. Oral manifestations are common, especially ulcers and stomatitis, which macroscopically and histologically resemble those found in the gastrointestinal tract. However, orthodontic alterations are not yet known. This article reviews aspects related to the diagnosis of Crohn's disease and clinical considerations for an orthodontic patient.

Immunoregulatory aspects of periodontal disease

This manuscript reviews our studies of the composition and functional capabilities of gingival tissue lymphocytes from patients with periodontal disease. The emphasis has been on phenotyping the local lymphoid infiltration in gingival and periodontal disease. The preparation and phenotypic analyses of cells recovered from diseased and healthy human periodontal tissues indicated that T-cell subset ratios from diseased tissue were significantly decreased compared with peripheral blood or normal tissue ratios. These reductions were verified in a second study we performed using two-color immunofluorescence analyzed by flow cytofluorometry. Local variations in the CD4 + cell population were also found in diseased tissue cells when these were compared with normal tissue cells. The relative percentage of CD4+ cells labeled with anti-helper inducer (4B4) or anti-suppressor inducer (2H4) monoclonal antibodies was increased above that of normal tissue cells. Functional studies of immunoglobulin production by gingival cells from adult periodontitis tissues showed two discrete patterns of synthesis and also suppression of immunoglobulin synthesis after addition of mitogen to the cultures. Removal of macrophages also drastically reduced immunoglobulin synthesis by gingival cells. These results indicate that there is an abundance of suppressor T-cells in diseased tissue and that functional suppression is demonstrated by lymphocytes from periodontal disease tissue. The findings of these investigations have suggested potentially important roles for immune regulation in periodontal disease.

Effects of a Fusobacterium nucleatum extract on immunoregulation in mice

The purpose of this study was to examine the effect of an extract of Fusobacterium nucleatum on humoral and cell-mediated immunity and phagocyte functions in mice. The extract was obtained from the heat-inactivated supernatant of sonicated F. nucleatum. Mouse splenocytes were cultured with sheep red blood cells (SRBC), and antibody formation was assayed by counting the plaque-forming cells (PFC). After C3H mouse skin was grafted onto the BALB/c mouse, cytotoxicity of BALB/c mouse splenocytes to L-cells was enumerated, T- and B-cell blastogenesis was determined by the uptake of 3H-thymidine. In vivo phagocyte functions were measured using carbon clearance test, bactericidal, and acid phosphatase activity assays. The number of SRBC-specific and non-specific PFC in splenocytes stimulated with the extract increased 2.5-8.7-fold over that of unstimulated splenocytes. Cytotoxicity of splenocytes from the extract-injected mice decreased in a dose-dependent fashion at 12 days after grafting. T-cell mitogenicity of the extract was observed. The carbon clearance rate was reduced, and bactericidal and acid phosphatase activities were elevated by the extract injection of the mice. In conclusion, F. nucleatum extract has an adjuvant effect on humoral immunity, and a suppressive effect on cell-mediated immunity and activated phagocyte functions.

In vitro sorption of albumin, immunoglobulin G, and lysozyme to enamel and cementum from human teeth

Sorption of three 125I-labeled human proteins (albumin, immunoglobulin G, and lysozyme) to enamel and cementum was investigated. All three proteins sorped most when suspended in 0.0005 M solution of phosphate or calcium chloride where the least competition between solute ions and label occurred. The addition of human serum to labeled proteins caused a decrease in their sorption which could be partially reversed by increasing the concentration of label. Kinetic experiments demonstrated that sorption was dependent on protein concentration and incubation time and that most of the sorption occurred within the first minute of the reaction. In conclusion, the binding of the three labeled proteins was affected by the charge of the solute ions and was dependent on ion concentration and reaction time. Sorption correlated for the most part with the pK values of the proteins and thus lysozyme, the most basic protein, sorped more than immunoglobulin G, which sorped more than albumin. In all cases, cementum bound more basic protein than did enamel. Increased levels of albumin sorption to enamel occurred when the protein was suspended in the CaCl2 solution rather than in phosphate. In addition, based on Scatchard analysis, approximately twice as many potential protein binding sites were found for cementum versus enamel.

Human immune responses to oral microorganisms. II. Serum antibody responses to antigens from Actinobacillus actinomycetemcomitans and the correlation with localized juvenile periodontitis

Human serum antibody responses to antigens from a suspected oral pathogen, Actinobacillus actinomycetemcomitans (Aa), were studied. IgG and IgM isotype antibodies to four antigen preparations, sonicate antigen (SA), leukotoxin (LT), group carbohydrate (LG), and lipopolysaccharide (LPS), were determined using an ELISA. An ELISA inhibition technique was developed to show that human serum antibodies reacting with the LT, LG, or LPS materials were binding to different antigenic moieties in each preparation. Cross-sectional studies of serum IgG antibodies showed that patients with localized juvenile periodontitis (LJP) had a greater frequency of occurrence and a higher level of antibodies to the SA (82%), LT (70%), and LG (62%) antigens compared to all other diseased (11-46%) or normal (4-13%) groups. Serum IgM antibodies to LPS were increased in LJP, generalized juvenile periodontitis, and adult periodontitis patients compared to all other groups. Therefore, while both IgG and IgM antibodies were found against various Aa antigens, the detection of IgG antibodies was most clearly associated with the specific disease classification of LJP. Blocking studies suggested that the human serum responses were specific for the Aa antigens and that the LT, LG, and LPS comprise major antigenic determinants on the organisms to which human serum antibody reacts.

Two-hour bacterial colonization of dental luting cements in vivo

Test specimens of zinc phosphate, polycarboxylate, zinc oxide-EBA, silico-phosphate and resin cements were carried in the mouth for 2 hours. The bacteria adhering to the cement specimens were quantified after culture on selective and non-selective, solid media. Significantly fewer bacteria could be recovered from the EBA cement than from the other cement types. All cement specimens, as well as samples from tooth surfaces, showed selective enrichment of Actinomyces viscosus compared with the proportion of this organism in saliva. The silicophosphate and particularly the polycarboxylate cement were poor substrates for the adhesion of Streptococcus mutans. Scanning electron micrographs revealed heavy accumulations of coccoid and filamentous organisms on zinc phosphate cement surfaces. Fewer bacteria, mainly cocci, were seen on the polycarboxylate and silico-phosphate cements, whereas the micrographs of the EBA and resin cement surfaces were difficult to interpret.

Stereology of inflammatory connective tissue infiltrates in oral mucosa

In the present summary, different approaches to analyse inflammatory connective tissue infiltrates are reviewed. The most appropriate model for this purpose was found to be the stereological analysis at the electron microscopic level. This method furnishes data comparable with results obtained by other quantifying methods, such as biochemical analysis. The presently used methodology for the analysis of diseased portions of oral mucous membranes, as well as selected results thereof are described. The usefulness and reliability of the method are discussed and future developments are suggested.

Determination of the specificity of plasma cells for bacterial antigens in situ

We developed a method for determining the specificity of plasma cells for bacterial antigens in situ. The method consists of applying rhodamine-labeled whole bacteria to frozen sections of tissue in which inflammation had been induced by injection of the same bacterial strain. After appropriate washings, the tissue sections were briefly treated with a fluorescein-labeled antiserum to endogenous immunoglobulins to detect plasma cells. Plasma cells which could recognize bacterial somatic antigens appeared as clumps of orange-fluorescing bacteria overlying a green-fluorescing cell. The fidelity of the procedure was determined by performing several competition experiments, which showed that pretreatment of the inflamed tissue sections with homologous unlabeled bacteria (i.e., the same bacteria used to induce the tissue inflammation) decreased binding of the labeled bacteria to a significant extent. Pretreatment of the inflamed tissue sections with heterologous unlabeled bacteria, however, did not significantly decrease binding of the labeled bacterium. Additionally, binding of rhodamine-labeled heterologous bacteria to the tissue sections was insignificant. In further experiments, we demonstrated that there was no natural affinity between the bacterial strains employed and lymphocytes taken from the strain of rabbit used and that pretreatment of the sections with anti-immunoglobulin abrogated the binding of the bacteria to which the animal had been specifically sensitized.

Immunology in dentistry

Implications of immunology in dental treatment are explained through discussion of the basic scientific principles of allergy, autoimmunity, immunization, immune dysfunction, tumor immunology, immunosuppression, and transplantation immunobiology.

Plasma cells and immunoglobulin-synthesis in oral precancer and cancer. Correlation with dysplasia, cancer differentiation, radio- and chemotherapy

The subepithelial and peritumoral inflammatory infiltrates of 202 oral premalignant and malignant lesions -- 108 leukoplakias and 94 squamous cell carcinomata with different grades of dysplasia were examined using an immunoenzymatic method. In addition, the influence of radiation and bleomycin-therapy on the stromal reaction of 24 carcinomata was studied. The incidence of immunoglobulin labelled plasma cells (IgA and IgG) was twice as high in those cases of leukoplakia where dysplasia was present. The number of plasma cells, especially IgA- and IgG-containing plasma cells, decreased significantly with progressive tumor dedifferentiation. The plasma cell response differed before and after radiation with a decrease in IgA- and IgG-containing plasma cells after therapy. In contrast, bleomycin-therapy did not produce distinct changes in the humoral and cellular stromal reaction. In the epithelium, IgA and IgG were localized throughout all epithelial layers in leukoplakias with dysplasia. This finding indicates a leakage of locally synthesized immunoglobulins through an altered oral mucosa. This investigation reveals alterations in the local immune homoeostasis of the oral mucosa in premalignant and malignant lesions which varies with the grade of dysplasia, tumor differentiation and therapy.

A clinical study of gingival inflammation in renal transplant recipients taking immunosuppressive drugs

The relationship between the gingival inflammation and plaque scores of patients who had received kidney transplants and were taking immunosuppressive drugs to combat rejection pheomena was compared with data from a control group. Equivalent plaque scores were associated with less gingival inflammation in the patients taking the immunosuppressive drugs. While there was no signficant difference between the plaque scores of the two groups the control group displayed signficantly more gingival inflammation. The implications of these results with respect to possible etiological mechanisms operating in periodontal disease are discussed.

Alveolar bone loss in thymectomized golden hamsters

Fifty-six neonatally thymectomized and 41 neonatally sham-operated female golden hamsters (Mesocricetus auratus) were divided into 2 groups, one inoculated with Actinomyces (N16) and the other not inoculated. All animals were raised and maintained on a high sucrose, soft diet (Diet 2000) and water, ad libitum. White blood cell counts, differentials and total lymphocyte counts were determined at 4 to 5 weeks of age. The rejection of albino hamster skin grafts and the hemagglutination response to sheep red blood cells (SRBC) were used to determine inhibition of T lymphocyte function. Evaluation of alveolar bone loss at the end of 160 days indicated that the thymectomized animals with a significant depression of the hemagglutination response to SRBC and a lack of skin graft rejections had a significantly higher bone loss than sham-operated animals. This suggests that the cellular immune response plays a role in the periodontal syndrome in hamsters. Further investigation is necessary to establish how significant this role is in relationship to the numerous other factors that are present. These data suggest that the role of the cellular immune response in the hamster periodontium may be protective rather than destructive. The role of Actinomyces (N16) in the development of bone loss was not significant.

Nutritional deficiency in oral candidosis

A retrospective study of 108 patients was carried out to investigate the possible relationship between infection of the mouth with Candida albicans and blood levels of iron, folic acid and vitamin B12. The patients were separated into two groups--those with hyperplastic and those with atrophic candidal lesions--and compared with separate control groups. Twenty-one patients had chronic hyperplastic candidosis and seven were iron deficient. Comparison with an age- and sex-matched control group showed the differences to be significant only at the p less than 0.1 level. Seven of the patients with hyperplastic lesions had folic acid deficiency and the difference between patients and controls was statistically significant (less than 0.05). However, no significant differences in iron or folic acid deficiency were noted between 87 patients with atrophic candidosis and 65 conttrols, and vitamin B12 deficiency was not statistically significant for either the hyperplastic or the atrophic group. It is concluded that deficiency of iron, folic acid or vitamin B12 alone does not promote growth of Candida albicans on the oral mucous membrane but that in some susceptible individuals, iron or folic deficiency may facilitate epithelial invasion by hyphae of Candida albicans.

The predominant cultivable microflora of advanced periodontitis

A study on the predominant cultivable microorganisms harbored in the base of deep periodontal pockets of eight patients aged 34-48 years was carried out using the roll tube culture technique. From a total of 475 isolates, 425 (89.5%) were obligate anaerobes, 356(74.9%) were Gram-negative, and 441(92.8%) were categorized as rods. Bacteroides melaninogenicus and Fusobacterium nucleatum constituted the majority of the isolates in seven samples, but their mutual proportions differed considerably between the samples. One sample was dominated by Actinomyces species. Some periodontopathic potentials of the predominating Gram-negative rods are summarized.

Oral manifestations of Crohn's disease

In a systematic study of 100 patients with Crohn's disease, 100 with ulcerative colitis, and of 100 normal subjects matched for age, sex, and denture status, nine patients with Crohn's disease, two with ulcerative colitis, and one normal control were found to have oral lesions. In Crohn's disease, the macroscopic and histological appearances resembled those encountered elsewhere in the gastrointestinal tract and their incidence was related to the activity of the disorder. The lesions in the other two groups were different macroscopically and histologically. Production of salivary IgA was found to be reduced in Crohn's patients with active bowel disease. It is suggested that the occurrence of oral lesions in patients with Crohn's disease might represent a local immunological reaction to oral antigens.

Reactions in the periodontium to continuous antigenic stimulation in sensitized gnotobiotic rats

The purpose of our experiment was to evaluate the destructive potential of a strain of Actinomyces viscosus on the periodontium of sensitized rodents, describing the induced lesions on the basis of quantitative cytology. The experimental design comprised in principle the following procedures. Young germfree rats were immunized either by intravenous or intradermal injections with heat-killed cells of A. viscosus Ny 1 or sham immunized intradermally with physiological saline. After a period suitable for activation of the humoral and cell-mediated immune systems, Ny 1 was monoassociated in all animals by oral implantation. During the ensuing 42 days the animals were allowed to react against the continuous peripheral oral antigen challenge. Since A. viscosus is known as a heavy dental plaque-forming organism, the animals could be expected to develop local immunopathological lesions in the periodontal tissues. These lesions were then studied by quantitative cytology after sampling procedures allowing optimal tissue preservation. The degree of bone loss observed in all treatments was unrelated to the destructive capacity of the infiltrates, suggesting the presence of distinct mechanisms responsible for the activation of osteoclasts and factors interfering with fibroblast activity. Although the cellular composition of the infiltrated tissues was analyzed at the end of the experiment only, distinct stages of the lesions in the different treatments allowed reconstruction of the sequence of events. After an acute inflammatory phase, a classic delayed hypersensitivity reaction developed which was transformed after some time by a large superimposed plasma cell accumulation. The particular but undefined immune status was the significant factor determining the final type of peripheral infiltrative reaction.

Oral infections with Candida albicans

The majority of oral infections with Candida albicans have a local cause. However some Candida infections, such as chronic muco-cutaneous candidosis, which may be widespread over skin and mucous membranes are associated with systemic disorders. Indeed, antibiotic or corticosteroid therapy and severe debilitating disease are proven causes of Candida infection while the association of various endocrinopathies with candidosis has now become well established. More recently, other systemic factors such as impaired cellular immunity and nutritional deficiency have been recognised as influencing Candida infections, and this knowledge is now being successfully applied to the treatment of the disease.