Differential virulence and innate immune interactions of type I and II fimbrial genotypes of Porphyromonas gingivalis

Abstract

Introduction The fimA-encoded fimbriae of the periodontal pathogen Porphyromonas gingivalis display genetic diversity. Type I fimbriated P. gingivalis (Pg-I) has been most widely studied at the molecular level, whereas Pg-II is the most frequent isolate from severe periodontitis. Methods To investigate virulence differences between Types I and II fimbriae, we examined strains 33277 (Pg-I) and OMZ314 (Pg-II), reciprocal swap mutants (i.e., expressing the heterologous fimbrial type), and their respective FimA-deficient derivatives. These organisms were tested in a mouse periodontitis model and in interactions with mouse macrophages, a cell type that plays important roles in chronic infections. Results Strain 33277 induced significantly more periodontal bone loss than OMZ314, and substitution of Type II fimbriae with Type I in OMZ314 resulted in a more virulent strain than the parent organism. However, the presence of Type II fimbriae was associated with increased proinflammatory and invasive activities in macrophages. Conclusion The inverse relationship between proinflammatory potential and ability to cause experimental periodontitis may suggest that an aggressive phenotype could provoke a host response that would compromise the persistence of the pathogen.

Genetic Diversity in the Oral Pathogen Porphyromonas Gingivalis : Molecular Mechanisms and Biological Consequences

“…This ability to permanently colonize distinct niches implies that these bacteria have sophisticated mechanisms to adapt to the local environment. In vitro and animal model studies confirm the clinical observations: comparison of distinct P. gingivalis strains demonstrates extensive differences in behavior and pathogenic potential [28,30,31,39–52]. …”

Differential expression and adherence of Porphyromonas gingivalis FimA genotypes

“…Differential host innate immune responses were also observed when mice were infected with either P. gingivalis 33277 (FimA I) or OMZ314 (FimA II; Kato et al. , 2007; Wang et al. , 2009).…”

Frecuencia de los genotipos de FimA de Porphyromonas gingivalis y Tanerella forsythia, Treponema denticola y Aggregatibacter actinomycetemcomitans en pacientes diabéticos con enfermedad periodontal / Frequency of FimA Genotypes of P. gingivalis...

“…Es un patógeno cuyo principal factor de virulencia son las fimbrias, de las cuales existen 6 genotipos con base en la secuencia de nucleótidos (FimA I-V y IB). Los genotipos FimA II y FimA IV se han asociado a cepas más virulentas en previos estudios; mientras que los genotipos FimA I y FimA III se asocian a cepas poco virulentas y se aíslan en mayor frecuencia de pacientes sanos (15)(16)(17)(18)(19). Sin embargo, Dávila-Pérez y colaboradores (20) reportaron una mayor frecuencia del genotipo FimA I (cepas poco virulentas) en pacientes diabéticos en México.…”