Identification of T-cell epitopes of Porphyromonas gingivalis heat-shock-protein 60 in periodontitis.

The heat shock proteins (hsp) of bacterial species are considered to be involved in regulating the autoimmune mechanism in human diseases due to the considerable homology of their sequences with human hsp. To elucidate how stress proteins contribute to the immunopathogenesis of periodontitis, mononuclear cells from gingival connective tissue of 10 periodontitis patients were simulated with Porphyromonas gingivalis hsp60. T-cell lines reactive to P. gingivalis hsp60 were established from each patient to define T-cell epitope specificities. Anti-P. gingivalis IgG antibody titres were elevated in all patients. We could establish P. gingivalis hsp-reactive T-cell lines from gingival mononuclear cells that were mixtures of CD4+ and CD8+ cells. Of 108 overlapping synthetic peptides spanning the whole P. gingivalis hsp60 molecule, 10 peptides with epitope specificities for T-cells were identified, and were identical to those reported be B-cell epitopes in periodontitis.