Tonsillar application of killed Streptococcus mutans induces specific antibodies in rabbit saliva and blood plasma without inducing a cross-reacting antibody to human cardiac muscle

Immune response in humans to a nasal boost with Streptococcus mutans antigens

We previously reported that a Streptococcus mutans enriched-glucosytransferase (E-GTF) preparation induces an immune response following intranasal, but not tonsillar, immunization of humans. In this study, we determined whether intranasal immunization of these subjects 2 years later resulted in augmented immune responses compared to those seen in control subjects. Subjects previously immunized via the intranasal (IN, n = 7) or tonsillar (IT, n = 7) route and control (n = 12) subjects were immunized via the intranasal route with E-GTF. Nasal wash, saliva, and serum were collected before immunization and then weekly for 3 months after immunization. Significant (P < 0.05) mucosal and serum immunoglobulin A (IgA) anti-E-GTF responses were observed in all three groups. Nasal and serum IgA anti-E-GTF responses were significantly higher (P < 0.05) in the IN group. The salivary responses in the three groups were, in general, similar. These results indicate that intranasal immunization primes the immune system for a localized secondary response to S. mutans antigens.

Induction of salivary antibodies to inhibitCandida albicansadherence to human epithelial cells by tonsillar immunization in rabbits

To examine the possibility of a vaccine for Candida albicans infection in the oral cavity, we induced salivary antibodies by immunization of killed-C. albicans ATCC 18804 on the palatine tonsils of rabbits. The enzyme-linked immunosorbent assay reaction of salivary antibodies was high against C. albicans serotype A. The saliva antibodies greatly inhibited C. albicans adherence to cloned epithelial cells from human gingiva. Tonsillar immunizations of C. albicans ATCC 18804 induce salivary antibodies that prevent C. albicans adherence to epithelial cells, and thus should prove useful in the prevention of oral candidiasis caused by C. albicans serotype A.

Evaluation of interleukin 1 as a mucosal adjuvant in immunization with Streptococcus sobrinus cells by tonsillar application in rabbits

To evaluate interleukin 1 (IL-1) as a mucosal adjuvant in the induction of salivary antibodies to Streptococcus sobrinus, S. sobrinus together with IL-1 was applied through the palatine tonsils of rabbits. IL-1 caused approximately 50 and 100% increases in the antibodies reacting against S. sobrinus fragments in the saliva and blood plasma, respectively, compared to the antibodies in those same fluids after tonsillar applications of S. sobrinus alone. In the case of the addition of IL-1, the antibodies reacting to the protein antigens of S. sobrinus increased in each fluid, without affecting the antibodies reacting to saccharide antigens. Delayed-type hypersensitivity to S. sobrinus, characterized by ear swelling and by an increase in IFN-gamma mRNA in RT-PCR analysis, was found to be induced only in rabbits immunized with IL-1. S. sobrinus protein antigens caused ear swelling as intense as that caused by S. sobrinus fragments. Thus, IL-1 induced an antibody response and cell-mediated immunity mainly reacting to protein antigens of S. sobrinus.

Humans immunized with Streptococcus mutans antigens by mucosal routes

Strategies aimed at the prevention of Streptococcus mutans infection and dental caries include mucosal immunization, which results in salivary anti-S. mutans responses. The purpose of this study was to evaluate the effectiveness of nasal vs. tonsillar immunization with S. mutans antigens in inducing salivary immune responses. Twenty-one adult subjects were immunized twice, within a seven-day interval, with a glucosyltransferase-enriched preparation (E-GTF) administered by nasal or tonsillar topical spray. Parotid saliva, nasal wash, and serum were collected prior to and at one- to two-week intervals for 3 months following immunization and were assayed by ELISA for anti-E-GTF activity. Results were analyzed by means of the mixed-models procedure with p < 0.05 level of significance. Significantly higher anti-E-GTF responses were detected in saliva and nasal wash samples from the group immunized by the nasal compared with the tonsillar route, indicating that nasal immunization was more effective in inducing mucosal responses in adults.

The effect of monoclonal antibody and route of immunization on the humoral immune response againstPorphyromonas gingivalis

Immunomodulation mediated by exogenous antibodies has been proposed as a vaccine strategy to improve immune protection against pathogenic microorganisms and suggested to contribute to protection following passive immunization. To test whether a monoclonal antibody directed against an adhesion epitope of the periodontal pathogen Porphyromonas gingivalis could influence the humoral immune response following mucosal immunization, BALB/c mice were immunized orally or intranasally with P. gingivalis alone or P. gingivalis coated with monoclonal antibody 61BG1.3. Differences in antigenic specificity of anti- P. gingivalis serum immunoglobulin G (IgG) were demonstrated between groups of mice that received monoclonal antibody-coated P. gingivalis versus those that received P. gingivalis alone by either route of immunization. Binding of monoclonal antibody 61BG1.3 to P. gingivalis prior to immunization did not influence the serum IgG subclass distribution. However, minor differences in subclass distribution were observed between the various routes of mucosal immunization. These results support the hypothesis that specific monoclonal antibody bound to a bacterial vaccine can alter the quality of the humoral immune response to that organism.

Detection and rapid increase of salivary antibodies to Staphylococcus lentus, an indigenous bacterium in rabbit saliva, through a single tonsillar application of bacterial cells

In rabbits, Staphylococcus lentus is one of the major bacteria in saliva and a minor bacteria in jejunum fluids and nasal wash. The presence and induction of naturally occurring antibodies reacting to rabbit indigenous bacteria were studied. In non-immune rabbits, the proportion of anti-S. lentus IgA antibodies to total IgA in the saliva was several times higher than that in the intestinal fluids and the nasal wash. The salivary antibodies were found to have increased 1 week after a single tonsillar application of isolated S. lentus cells but not after a single nasal application or a single intragastric instillation. In addition, the anti-S. lentus antibodies in the saliva highly increased with weekly tonsillar applications of isolated S. lentus but increased only one-fifth with weekly nasal applications of the same cells. These results strongly suggest that the palatine tonsils, which we believe had already been sensitized by S. lentus in the physiological condition, induced naturally occurring antibodies in rabbit saliva.

Monoclonal antibody-mediated modulation of the humoral immune response against mucosally applied Streptococcus mutans

Systemic immunization with antigen coupled to monoclonal antibody (MAb) has been used by several investigators to increase the number of MAb-producing hybridomas against an antigen and to elicit antibodies specific for poorly immunogenic epitopes. This strategy has implications for vaccine design in that protective immunity is not necessarily directed at immunodominant epitopes of pathogens and may be improved by deliberately shifting the immune response toward subdominant epitopes. To our knowledge, no studies to date have addressed the potential for immunomodulatory activity mediated by MAbs bound to mucosally applied antigen. To test whether administration of an exogenous MAb directed against a streptococcal surface protein could influence the humoral immune response, BALB/c mice were immunized orally by gastric intubation or intranasally with Streptococcus mutans alone or S. mutans complexed with a MAb directed against the major surface protein P1. Significant changes in the subclass distribution, as well as the specificity, of anti-P1 serum immunoglobulin G antibodies were demonstrated in groups of mice which received S. mutans coated with the anti-P1 MAb versus those which received S. mutans alone. Alterations in the humoral immune response were dependent on the amount of anti-P1 MAb used to coat the bacteria. In addition, differences in the anti-P1 immune responses were observed between groups of mice immunized via oral versus intranasal routes. In summary, an exogenous MAb complexed with a streptococcal antigen prior to mucosal immunization can influence the immunoglobulin isotype and specificity of the host humoral immune response against the antigen.

Streptococcus sobrinus antigens that react to salivary antibodies induced by tonsillar application of formalin-killed S. sobrinus in rabbits

We previously found that tonsillar application of antigen induces a strong antibody response to Streptococcus sobrinus in saliva and blood plasma. Rabbits immunized against S. sobrinus by tonsillar application were highly resistant to experimental dental caries triggered by oral inoculation of living S. sobrinus organisms with sucrose. In the present study, we examined the reaction of S. sobrinus antigens to the antibodies induced by the tonsillar application of S. sobrinus AHT-k in rabbits and compared them to those antibodies induced by intramuscular injection. In an enzyme-linked immunosorbent assay using ultrasonic fragments from mutans group streptococci, the saliva and blood plasma selectively reacted to S. sobrinus AHT-k (serotype g) and serologically related streptococci (serotypes a, d, and h) in the sixth week after tonsillar application, whereas the blood plasma in the sixth week after intramuscular injection reacted to the unrelated streptococci (serotypes b, c, e, and f) in addition to the aforementioned streptococci. The antibody reactivity induced after tonsillar application was not lost after treatment of the antigen with heat or proteinase digestion, whereas these treatments resulted in a 70% decrease of the antibody reactivity induced by intramuscular injection. The inhibition by haptenic sugars and the decrease in immunoreactivity by heat treatment and proteinase digestion suggested that 80% of the antibodies induced by tonsillar application reacted to saccharides. These saccharide antigens appeared to be involved in a specific reaction with S. sobrinus-specific streptococci and a selective reaction with serologically related streptococci. These antigens are probably involved in anticaries reactions in experimental dental caries.

A controlled clinical study of the effect of nasal immunization with a Streptococcus mutans antigen alone or incorporated into liposomes on induction of immune responses

Recent attention to mucosal immunization strategies has been focused on the nasal route for vaccine delivery. This study was designed to determine the effectiveness of a liposome-protein vaccine compared to that of a protein-only vaccine in inducing immune responses in humans. Healthy subjects were randomly assigned to two groups and immunized intranasally with a crude antigen preparation rich in glucosyltransferase (C-GTF) from Streptococcus mutans, alone or in liposomes. Parotid saliva, nasal wash, and serum were collected prior to and at weekly intervals following immunization and were analyzed for anti-C-GTF activity by enzyme-linked immunosorbent assay. The levels of immunoglobulin A (IgA) anti-C-GTF activity in the nasal wash from both groups after immunization increased to a mean peak of fivefold over the baseline level on day 28. Salivary IgA anti-C-GTF responses were induced to a lesser extent. IgG and IgA anti-C-GTF responses in serum were detected on day 14. The IgA responses were predominantly of the IgA1 subclass. These results show that C-GTF vaccines were more effective in inducing a local secretory IgA antibody response than a salivary or serum response when they were given intranasally. The IgA1 anti-C-GTF response in nasal wash samples for liposomal antigen versus antigen only was the only response which was significantly different (P < 0.04). This suggests that the form of the antigen affects the magnitude of the local mucosal response but not that of a disseminated response. These results provide evidence for the effective use of a nasal protein vaccine in humans for the induction of mucosal and systemic responses.

Tonsillar application of formalin-killed cells of Streptococcus sobrinus reduces experimental dental caries in rabbits

Living Streptococcus sobrinus cells were orally inoculated into nonimmune rabbits and rabbits immunized with formalin-killed cells of S. sobrinus through tonsillar application to examine the anticaries potential of this method of immunization. The living S. sobrinus cell numbers and the caries areas in the rabbits immunized by tonsillar application decreased to a level one-fifth of that in nonimmune rabbits.