Adhesion of Porphyromonas gingivalis serotypes to pocket epithelium

Background: Porphyromonas gingivalis, a key pathogen in periodontitis, is able to adhere to and invade the pocket epithelium. Different capsular antigens of P gingivalis have been identified (K-serotyping). These P gingivalis capsular types show differences in adhesion capacity to human cell lines or to cells cultured on a feeder layer or stromal equivalent. Methods: The adhesion capacity of different P gingivalis serotypes (6 capsular types and non-encapsulated strains) was compared on in vitro cultured epithelial monolayers from periodontal pockets of patients with periodontitis. The degree of adherence of P gingivalis was evaluated by both culture and fluorescence microscopy. Results: Non-encapsulated strains adhered significantly more than their capsulated variants. Capsule type 4 (K-4) adhered slightly better than the remaining K-types. Conclusion: This study indicates that the presence and type of capsule have a significant influence on the initial adhesion of P gingivalis to human periodontal pocket epithelial cells.