Characterization of Fim A in Porphyromonas gingivalis genotype IV.

It has been reported that a large majority of periodontitis patients carry organisms with either type II or IV- fim A, while type I is the most prevalent fim A genotype among Porphyromonas gingivalis-positive healthy adults. Here we report characterization of recombinant fimbrial protein (r Fim A) produced in Escherichia coli from genotype IV- fim A. In SDS- PAGE and immunoblot analysis after partial dissociation, type IV-r Fim A showed a ladder-like pattern representing oligomeric/polymeric forms of native fimbrial structure. Unlike anti-type I-native fimbriae which can only recognize conformational epitopes of the respective proteins, both anti-type IV-native fimbriae and anti-type IV-r Fim A antibodies recognized conformational as well as linear epitopes in type IV-fimbriae. These results suggest that the type IV-r Fim A proteins retain the native fimbrial antigenicity and the antigenicity of type IV-fimbriae is different from that of type I-fimbriae. [ABSTRACT FROM AUTHOR]