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Novel polysaccharide capsular serotypes in Porphyromonas gingivalis
M L Laine1, B J Appelmelk, A J van Winkelhoff
1Department of Oral Microbiology, Academic Centre for Dentistry Amsterdam, The Netherlands.
Journal of Periodontal Research
|May 1, 1996
Summary
Three new capsular serotypes of Porphyromonas gingivalis, designated K4, K5, and K6, were identified in periodontitis patients. These novel polysaccharide antigens are distinct from previously identified K1-K3 serotypes.
Area of Science:
- Microbiology
- Immunology
- Periodontology
Background:
- Virulent Porphyromonas gingivalis strains possess novel serotypes based on polysaccharide antigens, designated K1, K2, and K3.
- These antigens are likely capsular structures contributing to virulence.
Purpose of the Study:
- To identify and characterize novel capsular serotypes of Porphyromonas gingivalis.
- To determine if these novel serotypes are associated with periodontitis.
Main Methods:
- Isolation and characterization of P. gingivalis strains from periodontitis patients.
- Wet India ink preparations to visualize encapsulation.
- Detection and analysis of thermostable antigens in autoclaved cell supernatants.
- Serological cross-reactivity testing using antisera against known and novel P. gingivalis serotypes.
Main Results:
- Three novel capsular serotypes (K4, K5, K6) were identified in P. gingivalis strains ATCC 49417, HG 1690, and HG 1691.
- The novel antigens are negatively charged, periodate-sensitive, and proteinase K-resistant extracellular polysaccharides.
- Limited cross-reactivity was observed between K2 antiserum and K5/K6 antigens, which was eliminated after absorption.
Conclusions:
- The identified antigens represent novel capsular polysaccharides of P. gingivalis.
- These novel serotypes (K4, K5, K6) are distinct from previously described K1-K3 serotypes.
- The findings contribute to a more comprehensive understanding of P. gingivalis heterogeneity and its role in periodontitis.