Alveolar bone loss in rats after immunization with Actinomyces viscosus

Abstract

We investigated a possible cause-and-effect relationship between sensitization against Actinomyces viscosus Nyl and destructive periodontal disease in RIC-Sprague-Dawley rats. Germfree rats (66) were either immunized with A. viscosus Nyl (day 20) or orally infected with A. viscosus Nyl (days 38 and 39) or both. We measured alveolar bone loss in maxillary and mandibular molars, in vitro Tlymphocyte responsiveness, and serum antibody titers. In immunized and monoassociated rats bone loss in both jaws progressed rapidly between days 37 and 72, whereas the rate of further resorption decreased until day 100. In monoassociated rats, development of bone loss was much slower, and the maxiimum resorption measured was, at best, half of the bone loss compared with the former group. However, no amplification of bone loss by immunization was observed in a second experiment using 63 conventional rats kept in relative gnotobiosis. Antibody titers to A. viscosus Nyl in gnotobiotic monoassociated rats were higher in immunized animals, whereas no difference was found in the respective groups of the relative gnotobiotic experiment. The fact that immunization more than doubled alveolar bone loss in gnotobiotic monoassociated rats confirms the allergic nature of the disease. The lack of such an effect under conventional conditions points to suppressor mechanisms whose decrease might convert stable periodontal lesions into progressive ones.

Periodontal bone level and gingival proteinase activity in gnotobiotic rats immunized with Bacteroides gingivalis

“…The positive effect of immunization is in agreement with previous investigations reporting reduced periodontal bone loss in germ-free rats immunized against Streptococcus mutans (9), Aetinoinyces naeshtndii (9), and Eikenella corrodens (2) prior to tnonoinfection with the homologous organism. Other investigators have found increased bone loss in similar studies after immunization against Actinomyees viscosus (5,19,20) and Aetinobaeillus actinomycetemeomitans (51). This discrepancy may be explained by differences in imtnunization route and cotnposition of antigen preparation.…”

Immune responses and vaccination against periodontal infections

“…Such animal models might be useful for the test of principle in evoking immune responses, and for safety studies (i.e. Burckhardt et al 1981, Kesavalu et al 1992, Genco et al 1999, Mori et al 2000, O'Brien‐Simpson et al 2000).…”

The protective nature of host responses in periodontal diseases

“…Therefore, we suggested that it is necessary to enhance the protective aspects of the immune response and minimize the detrimental aspects to modify the disease. The ability of immune responses induced by active immunization with Actinomyces viscosus to interfere with periodontal bone loss has also been examined in gnotobiotic rats (11). Significant antibody titers were shown in the serum of immunized rats, and alveolar bone loss was greatest in the immunized and infected animals compared with rats that were only infected with the microorganism.…”

“…€? gingivulis in- T cell clones increased antibody Protection Burckhardt et al (11) Immunized l? gingivalis Protection Behling et al (5) Immunized (17) immunized mice with heatkilled l?…”