SECRETION OF PORPHYROMONAS-GINGIVALIS FIMBRILLIN POLYPEPTIDES BY RECOMBINANT STREPTOCOCCUS-GORDONII

The fimbriae of Porphyromonas gingivalis plays an important role in th e pathogenesis of periodontal disease. A structural subunit of the P. gingivalis fimbriae, fimbrillin, has been shown to promote adherence o f the bacteria to host surfaces and also induce an immune response. Bi ologically active domains of fimbrillin responsible for adherence or e liciting immune responses have been determined. In a previous study, w e engineered the human oral commensal organism Streptococcus gordonii to express such biologically active domains on the surface of the bact eria as a vaccine delivery system. In this study we report an alternat ive approach of secreting fimbrillin polypeptide domains into the medi um by modification of the surface-expression system described earlier. Such recombinant S. gordonii, in addition to being a source for antig en presentation to trigger a protective immune response, may have the added advantage of directly blocking the fimbriae-mediated adherence o f P. gingivalis to the oral cavity following implantation. This approa ch can also be utilized for secreting other biologically important the rapeutic molecules on mucosal surfaces for modulating local microenvir onments. (C) 1997 Academic Press.