In control subjects no significant expression of IFN-γ or interleukin 4 was induced. These results suggest that periodontitis patients have human hsp60-reactive T cells with a type 1 cytokine profile in their peripheral blood T-cell pools.Heat shock protein 60 (HSP60) is homologous to HSP65 (a major antigenic mycobacterial protein) and E. coli GroEL. HSP60, also referred to as chaperonin-60, P1 and mitonin, has been classified as a member of a family of proteins termed chaperonins which act to recognize and stabilize polypeptide intermediates during folding, assembly and disassembly. HSP60 is an abundant protein which is constitutively expressed and is induced by environmental stress. HSP60 exists as a large oligomer composed of 14 ~60 kDa subunits arranged as two stacked rings.