Leukocidal activity of staphylococci isolated from human periodontal lesions

Staphylococci isolated from subgingival samples of patients with advanced periodontitis were tested for leukocidal activity. Intact organisms, bacterial sonicates or bacterial culture supernatants were incubated with human neutrophils that had been prelabeled with 51chromium. The majority of Staphylococcus aureus periodontal isolates provoked dose-dependent extracellular release of the radiolabel. By contrast, other strains of staphylococci had marginal or no demonstrable leukocidal activity. Leukocidal activity was heat-sensitive and was neutralized by horse anti-leukocidin antibodies. The results indicate that S. aureus colonizing human periodontal lesions elaborate a leukocidin that may conceivably destroy neutrophils that emigrate into the gingival region. This could adversely affect the overall status of this antimicrobial defense system in the gingival area and contribute to the pathogenicity of S. aureus as well as other potential periodontopathic organisms.