Due to considerably high degree of sequence homology between bacterial and human heat shock proteins (hsp), it has been widely thought that this protein might be involved in autoimmune disease mechanisms in humans.To elucidate how stress proteins contribute in the immunopathogenesis of periodontitis, the present study was performed to evaluate the T cell immune responses specific to Porphyromonas gingivalis ( P. gingivalis ) heat shock protein (hsp)60 and T-cell epitope specificities for P. gingivalis hsp60 in periodontitis. Anti- P. gingivalis IgG antibody titers were elevated in all patients. We could establish P. gingivalis hsp-specific T cell lines from the peripheral blood of periodontitis, a mixture of CD4⁺ and CD8⁺ cells. Of 108 overlapping synthetic peptides spanning whole P. gingivalis hsp60 molecule, ten peptides with epitopes specifities for T-cell were showed. Interestingly, ten epitopes were also identified as T-cell epitopes in the present study as well as B-cell epitopes in periodontitis. Therefore, all the ten representative epitopes were designated as common T-and Bcell epitopes for periodontitis. It is critical in developing a peptide vaccine strategy for potential prevention of periodontitis. It was concluded that P. gingivalis hsp60 might be involved in the immunoregulatory process of periodontitis with heat shock protein specificities.