Related Experiment Videos
Leukotoxicity of an extract from Actinobacillus actinomycetemcomitans for human gingival polymorphonuclear leukocytes
Abstract:
A soluble extract from Actinobacillus actinomycetemcomitans (designated strain Y4) caused dose-dependent cytotoxic changes in PMN isolated from the gingival crevices (C-PMN) of normal adults. When the toxin was preincubated with sera from patients with juvenile periodontitis, there was a significant inhibition of toxic activity. In contrast a variety of other sera from normal subjects with healthy gingiva, and from patients with chronic gingivitis, chronic periodontitis, recurrent herpes labialis, rheumatoid arthritis, or ulcerative colitis enhanced the leukotoxic activity. The neutralization of toxin by serum from patients with juvenile periodontitis was probably due to specific antibodies. Since Actinobacillus actinomycetemcomitans organisms can be frequently identified in subgingival plaque from patients with juvenile periodontitis, the capacity of Y4 toxin to kill C-PMN may contribute to the pathogenesis of this disease.
Insights
A toxin from Actinobacillus actinomycetemcomitans killed gingival neutrophils (C-PMN). Juvenile periodontitis patient serum neutralized this toxin, suggesting a role in disease pathogenesis.
Area of Science:
- Microbiology
- Immunology
- Periodontology
Background:
- Actinobacillus actinomycetemcomitans is associated with juvenile periodontitis.
- Neutrophils (PMN) are key immune cells in the gingival crevice.
- The cytotoxic effects of A. actinomycetemcomitans extracts on PMN are not fully understood.
Purpose of the Study:
- To investigate the cytotoxic effects of an Actinobacillus actinomycetemcomitans (strain Y4) soluble extract on crevicular PMN.
- To determine the effect of sera from various patient groups on the toxin's activity.
Main Methods:
- Preparation of a soluble extract from Actinobacillus actinomycetemcomitans (strain Y4).
- Isolation of polymorphonuclear leukocytes (PMN) from gingival crevices (C-PMN) of normal adults.
- Incubation of the toxin with sera from patients with juvenile periodontitis and other conditions, followed by assessment of cytotoxic activity on C-PMN.
Main Results:
- The A. actinomycetemcomitans Y4 extract exhibited dose-dependent cytotoxicity against C-PMN.
- Sera from patients with juvenile periodontitis significantly inhibited the toxin's cytotoxic activity.
- Sera from healthy individuals and patients with other inflammatory conditions enhanced the leukotoxic activity.
Conclusions:
- Specific antibodies in juvenile periodontitis patient sera likely neutralize the A. actinomycetemcomitans Y4 toxin.
- The leukotoxic capacity of this A. actinomycetemcomitans toxin may contribute to the pathogenesis of juvenile periodontitis.