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

Induction of myocarditis lesions in Lewis rats by formalin-killed cells of group A Streptococcus

The feasibility of inducing rheumatic myocarditis lesions in Lewis rats by immunization with formalin-killed group A Streptococcus was evaluated. The rats were divided into three groups. Group A was immunized by injecting formalin-killed group A Streptococcus suspended in complete Freund's adjuvant (CFA) into the hind-foot pads and repeat immunization was given 1 week later by subcutaneous injection into the belly. The rats were then sacrificed 3 weeks after the initial immunization. In group B, the rats received the same initial immunization as group A, but the repeat immunization was carried out at 1, 2 and 3 weeks after the initial immunization and the rats were sacrificed 6 weeks after the initial immunization. Group C was a control group with the rats injected with saline/CFA and sacrificed on the same schedule as group A. Heart pathology sections showed that myocarditis lesions, focal inflammatory cell infiltration in interstitial near small vessels and valvulitis were induced in Lewis rats following immunization with formalin-killed group A Streptococcus.

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.

The scientific and public-health imperative for a vaccine against dental caries

Dental caries is caused by one of the most ubiquitous bacterial infections of humans. In many countries such as Brazil and China, this disease is reaching epidemic proportions, and it is clear that a more effective public-health measure to combat dental caries is needed, because disadvantaged children are the most severely affected. One of the main groups of oral microorganisms, the mutans streptococci, has been associated with the aetiology of dental caries, and preclinical studies of immunological interventions have shown the feasibility of interfering with this disease. Moreover, clinical trials have indicated that a mucosal immune response to a crucial antigen(s) of mutans streptococci can influence the pathogenesis of dental caries. Evidence that this antigen(s) is appropriate for use in a vaccine against dental caries, as well as evidence for an appropriate target population of individuals and a logical time of administration, has now emerged.

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.

Immunization against dental caries

Dental caries is one of the most common infectious diseases. Of the oral bacteria, mutans streptococci, such as Streptococcus mutans and S. sobrinus, are considered to be causative agents of dental caries in humans. There have been numerous studies of the immunology of mutans streptococci. To control dental caries, dental caries vaccines have been produced using various cell-surface antigens of these organisms. Progress in recombinant DNA technology and peptide synthesis has been applied to the development of recombinant and synthetic peptide vaccines to control dental caries. Significant protective effects against dental caries have been shown in experimental animals, such as mice, rats and monkeys, which have been subcutaneously, orally, or intranasally immunized with these antigens. Only a few studies, however, have examined the efficacy of dental caries vaccines in humans. Recently, local passive immunization using murine monoclonal antibodies, transgenic plant antibodies, egg-yolk antibodies, and bovine milk antibodies to antigens of mutans streptococci have been used to control the colonization of the organisms and the induction of dental caries in human. Such immunization procedures may be a safer approach for controlling human dental caries than active immunization.

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.

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.