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Intra-oral colonization of macaque monkeys by Actinobacillus actinomycetemcomitans
Abstract:
Actinobacillus actinomycetemcomitans was acquired by captive Macaca fascicularis 3 to 6 months after birth, and all monkeys aged over 6 months harbored detectable levels. This microorganism was most frequently isolated from the gingival plaque of the incisor (and other) teeth compared with other oral sites. Strains were leukotoxic by bioassay and Western blot analysis. Antibodies in macaque serum contained neutralized the leukotoxin of a human A. actinomycetemcomitans strain. High titres of maternal neutralizing anti-leukotoxin antibodies were detected in neonates; the titre then fell rapidly so that by 6 months the antibody titer was zero. Antileukotoxin antibody production was detected after 6 months of age, rapidly reaching a high level within 2 years after birth. The presence of leukotoxic strains of A. actinomycetemcomitans in the gingival region did not appear to be correlated with an increase in susceptibility to periodontal disease.
Insights
Actinobacillus actinomycetemcomitans colonizes macaques early in life, with leukotoxic strains present in the mouth. Macaques develop antibodies to neutralize the toxin, but this doesn't prevent colonization or disease.
Area of Science:
- Microbiology
- Immunology
- Primate Research
Background:
- Actinobacillus actinomycetemcomitans is a bacterium associated with periodontal disease.
- Understanding its acquisition and host response in animal models is crucial.
Purpose of the Study:
- To investigate the acquisition and immune response to Actinobacillus actinomycetemcomitans in captive Macaca fascicularis.
- To determine the prevalence and characteristics of leukotoxic strains in macaques.
- To assess the correlation between leukotoxic strains and periodontal disease susceptibility.
Main Methods:
- Bacterial isolation and identification from oral sites of macaques.
- Leukotoxicity assays (bioassay and Western blot).
- Antibody detection and neutralization assays in macaque serum.
Main Results:
- Actinobacillus actinomycetemcomitans was acquired by macaques 3-6 months after birth, with detectable levels in all monkeys over 6 months old.
- Leukotoxic strains were frequently isolated from gingival plaque.
- Maternal antibodies neutralized the leukotoxin, but neonatal titers waned by 6 months.
- Macaques developed their own anti-leukotoxin antibodies after 6 months.
- No correlation was found between leukotoxic strains and increased periodontal disease susceptibility.
Conclusions:
- Captive macaques acquire Actinobacillus actinomycetemcomitans early, developing an immune response to its leukotoxin.
- Despite colonization and leukotoxin production, macaques did not show increased susceptibility to periodontal disease in this study.
- This model provides insights into host-pathogen dynamics and immune responses relevant to Actinobacillus actinomycetemcomitans infections.